Arshad Hasan¹                                                 BDS, FCPS

Muhammad Ali²                                             BDS, MCPS Resident

INTRODUCTION

he restoration of endodontically treated tooth with a post retained crown is a time tested treatment modality with a fair amount of clinical success^[1]-3. A post and core restoration with adequate ferrule can salvage teeth that might otherwise be replaced by other more expensive and invasive treatment options, e.g. an endosseous implant^4-6. Literature is however, replete with comparisons of longevity of both single endodontically treated tooth and single implant restorations^7-11. It is important that each case be diagnosed and planned individually without been overly influenced by the implant survival studies¹. However, with improved outcomes of peri-implant soft tissues and immediate implant provisionalizations on implants placed in fresh extraction sockets, there might be a tendency to favor extraction and subsequent implant placement in borderline cases^13-15. Such borderline cases must be assessed individually and treatment must be instituted in the best interest of patient. The present case report is about such a borderline case where we provided the patient with a post and core retained crown to rehabilitate a badly damaged maxillary canine.

CASE REPORT

A 63 year old healthy male presented in the dental office with a dislodged crown of left maxillary canine (FDI no 23).(fig 1, 2 & 3) The crown was placed about a year ago. Patient also reported that this was the second

dislodgement of the crown. The first time this crown was dislodged, the tooth received a tooth colored post. Patient reported no other associated symptom. Clinically, the patient had a completely restored dentition. In the left upper quadrant, there was a crown on central incisor, an implant retained restoration replacing the lateral incisor, canine had a dislodged crown and a fixed prosthesis from first premolar to first molar. Right upper quadrant was similarly restored with fixed prosthesis. The opposing arch was restored with a cast partial denture retained via precision attachments on a fixed partial denture from canine to canine. Soft tissues appeared healthy.

On a close intra-oral radiographic inspection, it was found that the tooth was previously restored with a custom metallic post and core retained crown.(fig 2) The

Fig. No. 2

post had fractured leading to the subsequent dislodgement of crown and core in one piece. The fractured part of the post was retained inside the root canal space. The tooth was otherwise asymptomatic and responded negatively

to palpation and percussion. The remaining tooth structure of the tooth was less than 1 mm.(fig 1) There was adequate keratinized gingiva around the tooth with absence of inflammation and the biotype was thick. Periodontal probing depths around the tooth were within normal limits. Since there was an implant in adjacent tooth (No. 22) and a fixed partial denture (from 24 to 26) the treatment options were limited. Following options were presented to the patient.

1. Extraction of the tooth followed by an implant supported restoration
2. Restoring the tooth with a new cast post and core retained crown, provided the broken fragment of post is removed.

The patient opted to retain his tooth and it to be restored. The patient was presented following treatment plan.

1. Removal of broken fragment of post with ultrasonic vibration.
2. Surgical crown lengthening of the tooth to improve the ferrule
3. Impression of the canal space for a new custom cast post and core
4. Final impression of the tooth once the gingival architecture has healed and matured after the surgery 5. Delivery of the final crown.

A consent was obtained from the patient for the treatment plan and to obtain necessary clinical photographs. In order to remove the retained post, an ultrasonic tip (start x #3 Dentsply Maillefer, Ballaigues, Switzerland) in an ultrasonic (U/S) hand piece (Maco, China) was used at medium power. In order to enhance vision, a 4x dental loupe (TAO’s Jiangsu, China (Mainland)) and a light source (TAO’s Jiangsu, China

(Mainland)) was used.(fig 4) The U/S tip was used intermittently with and without water to prevent the buildup of excessive heat. The tip was used in circular motion and was never kept at one spot for longer than a few seconds. The tip helped in breaking the cement seal and the post fragment was removed. Since the tooth was asymptomatic and the quality of endodontic treatment was satisfactory, it was not re-treated. The access cavity was sealed with a temporary restorative material (Cavit, 3M, Germany)

Surgical crown lengthening was the next step. The probing depth measured was 3mm (mesio-buccal), 3mm (mid-buccal and mid-palatal) and 3 mm (disto-buccal).

Since there was an adequate band of thick keratinized attached gingiva devoid of inflammation and adequate sulcus depth, a gingivoplasty was performed with a 15 no BP blade. It helped to gain an additional ferrule of 1.5mm. After a healing period of 2 weeks, a ferrule of 2mm was achieved.

On a subsequent visit, the temporary restorative material was removed with a U/S tip (Dmetec Co. Ltd., Korea). The canal space was enlarged with gates glidden drills (Dentsply Maillefer, Ballaigues, Switzerland) in a slow speed hand piece (NSK, Nakanishi, Japan). A short tapered diamond bur (Crosstech, Thailand) in a highspeed handpiece (Alegra, W&H, Austria) to refine the preparation and place an anti-rotation groove.(fig 5) An

addition silicon polyvinyl siloxane impression material consisting of a light body and a putty in a single step was used to make an impression of the canal space. (fig 6) The impression was send to lab for fabrication of

a cast metal post. The post was received from the lab after a week.(fig 7 & 8) Fit of the post inside the canal space was checked with a radiograph.(fig 9) After radiographic confirmation, new post was luted with a

self-adhesive resin luting cement (relyx u200, 3M, Germany). Patient’s old crown was internally relieved and relined with a Bis-Acryl temporary crown and bridge material (Tempron, GC Japan) luted with a eugenol free temporary luting cement (Freegenol, GC, Japan)and patient was dismissed to allow complete healing of gingiva.(fig 10).

Four weeks after gingivoplasty, patient returned for final impression. The gingival architecture appeared healed and healthy. The temporary crown was removed and tooth structure was cleaned and dried. A braided metal reinforced retraction cord (No. 2 Roeko Stayput, Coltène/Whaledent AG Switzerland) was packed into the gingival sulcus with a cord packing instrument (Roeko retraction cord packers, , Coltène/Whaledent AG Switzerland) in order to push gingiva apically to allow impression of root surface beyond tooth preparation. (fig 11) The preparation margin was further refined with a round ended tapered diamond bur (GC4L, Crosstech, Thailand). Final impression of the preparation was taken with an addition silicon polyvinyl siloxane consisting of a light body and putty in a single step. The light body was expressed onto tooth surface and gentle stream of air was blown. Another increment of light body was expressed onto the preparation and putty was simultaneously loaded into a stock impression tray and inserted over the preparation. After setting of impression material it was removed from mouth, disinfected and sent to the laboratory for final crown fabrication.(fig 12).

Porcelain fused to metal crown was received from the laboratory after 10 days. Its marginal fit, proximal and occlusal contacts and overall aesthetics were assessed and adjusted accordingly. The resultant occlusion on the left side was group function. The crown was subsequently luted permanently with a self-adhesive resin luting cement (relyx u200, 3M, Germany).(fig 13) Patient returned for

a regular followup after 2 years and the crown was assessed to be functioning adequately.

DISCUSSION

Present report highlights the use of a multi-disciplinary approach to treat a badly broken tooth. Patient was explained about all the possible treatment options and their consequences before formulating a treatment plan. The options were limited due to implant supported restoration and a fixed partial denture in adjacent teeth. Connecting a natural tooth to an implant has been proposed in literature^16-18. However, this option is associated with intrusion of natural tooth. Use of a metal coping is advocated to counteract the negative effects of intrusion^19,20. We decided not to connect the existing fixed partial denture to the implant since the resultant span would have increased the flexion in the restoration and chances of fracture of veneering porcelain would have increased²¹.

Extraction of canine and its subsequent replacement with an implant supported restoration was not approved by the patient. Research has shown a favorable outcome of immediate implant provisionalization of implants placed in fresh extraction sockets^13-15. This option also has the benefit of restoring the esthetics in a single visit. More importantly, it allows the maintenance of soft tissue levels especially the interdental papilla¹⁴.

Most crucial factor deciding the fate of the tooth was removal of the broken fragment of the post. The post was removed with an U/S tip. Ultrasonics have been used widely in clinical dentistry for a variety of indications and have a proven safety record. Other techniques to remove posts include trephine burs, Roto-pro bur and various extractors²². U/S tips were used due to intraradicular location of the fragment. The use of ultrasonics for removal of post may result in dentine crack formation and buildup of excessive heat with subsequent damage to the periodontal ligament^23-25.  In order to prevent these mishaps, the U/S tip was moved constantly in a circumferential manner. This helped to loosen the luting cement and facilitated a safe removal^26,27. Vision was enhanced with the use of a loupe and an external light source. Enhanced vision has been reported to improve the changes of successful post removal²⁸. Although an operating microscope would have been an ideal tool in this scenario, it was not available to the authors.

We used a custom cast post for this case. This decision was based on the fact that tooth had received a fiber post in past which failed. The currently failed post was also a cast post but its dimensions were inadequate, which might have resulted in the ‘favorable’ fracture pattern of the post. Cast posts have been reported to result in root fractures while the fiber posts fail more favorably owing to similarity in modulus of elasticity with dentin²⁹. The addition of atleast 2mm of ferrule may result in improved survival of teeth restored with cast posts.^5,6,30. Therefore, we performed a crown

lengthening of the residual root to improve its outcome. Also, to prevent future failures a group function occlusal scheme was used. A group function occlusion allows to share the occlusal load with adjacent teeth as the mandible goes into a lateral excursion³¹. A canine guided occlusion may worsen the outcome in our case due to presence of a post and a history of failure³².

CONCLUSION

Restoration of an endodontically treated maxillary canine with a custom cast post, an adequate ferrule and a favorable occlusion pattern resulted in a successful outcome of our case at 2 year followup.

REFERENCES

1. Schwartz RS, Robbins JW. Post placement and restoration of endodontically treated teeth: a literature review. J Endod. 2004;30:289-301.
2. Torbjörner A, Karlsson S, Ödman PA. Survival rate and failure characteristics for two post designs. J Prosthet Dent. 1995;73:439-444.
3. Dammaschke T, Steven D, Kaup M, Ott KHR. Longterm Survival of Root-canal-treated Teeth: A Retrospective Study Over 10 Years. J Endod. 2003;29:638-643.
4. Ferrari M, Cagidiaco M, Grandini S, De Sanctis M, Goracci C. Post placement affects survival of endodontically treated premolars. J dent res. 2007;86:729734
5. Tan PL, Aquilino SA, Gratton DG, Stanford CM, Tan SC, Johnson WT, et al. In vitro fracture resistance of endodontically treated central incisors with varying ferrule heights and configurations. J Prosthet Dent. 2005;93:331-336
6. Pereira JR, De Ornelas F, Conti PCR, Do Valle AL. Effect of a crown ferrule on the fracture resistance of endodontically treated teeth restored with prefabricated posts. J Prosthet Dent. 2006;95:50-54.
7. Doyle SL, Hodges JS, Pesun IJ, Law AS, Bowles WR. Retrospective cross sectional comparison of initial nonsurgical endodontic treatment and single-tooth implants. J endod. 2006;32:822-827.
8. Salehrabi R, Rotstein I. Endodontic treatment outcomes in a large patient population in the USA: an epidemiological study. J endod. 2004;30:846-850.
9. Farzaneh M, Abitbol S, Lawrence HP, Friedman S. Treatment outcome in endodontics-the Toronto Study. Phase II: initial treatment. J endod. 2004;30:302-309.
10. Simonis P, Dufour T, Tenenbaum H. Long-term implant survival and success: a 10-16-year follow-up of non-submerged dental implants. Clin Oral Implants Res. 2010;21:772-777.
11. Busenlechner D, Fürhauser R, Haas R, Watzek G, Mailath G, Pommer B. Long-term implant success at the Academy for Oral Implantology: 8-year follow-up and risk factor analysis. J periodontal implant sci. 2014;44:102-108.
12. Iqbal MK, Kim S. For teeth requiring endodontic treatment, what are the differences in outcomes of restored endodontically treated teeth compared to implantsupported restorations? The Int j oral maxillofacial implants. 2006;22:96-116.
13. Kan JK, Rungcharassaeng K. Immediate Implant Placement and Provisionalization of Maxillary Anterior Single Implants. Principles and Practice of Single Implant and Restoration. 2013:119.
14. Hartlev J, Kohberg P, Ahlmann S, Andersen NT,Schou S, Isidor F. Patient satisfaction and esthetic outcome after immediate placement and provisionalization of single?tooth implants involving a definitive individual abutment. Clin Oral Implants Res. 2014;25:1245-1250.
15. Maló P, Araújo Nobre M, Lopes A, Ferro A, Gravito I. Single-Tooth Rehabilitations Supported by Dental Implants Used in an Immediate-Provisionalization Protocol: Report on Long-Term Outcome with Retrospective Follow-Up. Clinical Implant Dentistry and Related Research. 2015.
16. Olsson M, Gunne J, Ästrand P, Borg K. Bridges supported by free?standing implants versus bridges supported by tooth and implant. A five-year prospective study. Clin Oral Implants Res. 1995;6:114-121.
17. Gross M, LAUFER BZ. Splinting osseointegrated implants and natural teeth in rehabilitation of partially edentulous patients. Part I: laboratory and clinical studies. J oral rehab. 1997;24:863-870.
18. Sheets CG, Earthman JC. Natural tooth intrusion and reversal in implant-assisted prosthesis: evidence of and a hypothesis for the occurrence. J Prosthet Dent. 1993;70:513-520.
19. Schlumberger TL, Bowley JF, Maze GI. Intrusion phenomenon in combination tooth-implant restorations: a review of the literature. J Prosth Dent. 1998;80:199203.
20. Pesun IJ. Intrusion Of Teeth In The Combination Implant-to-Natural-Tooth Fixed Partial Denture: A Review of the Theories. J Prosthodont. 1997;6:268-277.
21. De Backer H, Van Maele G, De Moor N, Van den Berghe L. Long-term results of short-span versus longspan fixed dental prostheses: an up to 20-year retrospective study. Int j prosthodont. 2007;21:75-85.
22. Hargreaves KM. Cohen’s pathways of the pulp expert consult: Mosby; 2010.
23. Huttula AS, Tordik PA, Imamura G, Eichmiller FC, McClanahan SB. The effect of ultrasonic post instrumentation on root surface temperature. J endodon. 2006;32:1085-1087.
24. Budd J, Gekelman D, White J. Temperature rise of the post and on the root surface during ultrasonic post removal. Int endodon j. 2005;38:705-711.
25. Çapar ?D, Uysal B, Ok E, Arslan H. Effect of the Size of the Apical Enlargement with Rotary Instruments, Single-cone Filling, Post Space Preparation with Drills, Fiber Post Removal, and Root Canal Filling Removal on Apical Crack Initiation and Propagation. J endodon. 2014.
26. Buoncristiani J, Seto BG, Caputo AA. Evaluation of ultrasonic and sonic instruments for intraradicular post removal. J endodon. 1994;20:486-489.
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28. Abbott P. Incidence of root fractures and methods used for post removal. Int endodon j. 2002;35:63-67.
29. Pontius O, Hutter JW. Survival rate and fracture strength of incisors restored with different post and core systems and endodontically treated incisors without coronoradicular reinforcement. J endodon. 2002;28:710715.
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32. Fragou T, Tortopidis D, Kontonasaki E, Evangelinaki E, Ioannidis K, Petridis H, et al. The effect of ferrule on the fracture mode of endodontically treated canines restored with fibre posts and metal-ceramic or all-ceramic crowns. J dent. 2012;40:276-285.

1. Associate professor Department of Operaitve Dentistry Dow Dental College, DUHS.
2. Department of operative dentistry. Fatima Jinnah Dental College Hospital Karachi.

Corresponding author: “Dr Arshad Hasan ”  < arshad.hasan@duhs.edu.pk  >

Shanila Faisal¹

Nosheen Zehra²

Mujtaba Hussain³

Huzaifa Ali Jaliawala ⁴

Asima Faisal ⁵

INTRODUCTION

Anxiety can be defined as a condition of unidentified concern, discomfort about something with a vague outcome1. Dental anxiety is one of the utmost commonest anxieties among several other types of anxieties that have been widely studied worldwide2,3. According to a one study, 73% to 79% of patients were undergoing through some kind of dental anxiety before going for dental procedure3, which was resulted into unsuccessful treatment, and so dissatisfied patient that further might prevent future visits to a dentist3. The recent advancement in the quality of oral health care has resulted in better and satisfied patient care4. Previous researches on dental anxiety in developed countries have shown that people usually avoid dental treatment because of dental fear results in poor oral health5,6.
It has been observed that large proportion number of patient visit their dentist only when they have any emergency7 or alternate treatment become less or ineffective for their particular problem, which may further worsen their oral health8. Literature was unable to divulge the exact cause of dental anxiety; however possible factors of dental anxiety were mentioned in some studies as gender, age, objects and situations3. It has also been observed in previous studies that dental instruments could be one of the reasons for dental anxiety, as when it is placed in a mouth results in gag reflex and confrontation in breath9 thus patient who are sensitive to these things may face greater probability of having dental anxiety. Kirova et al. found that 25-26- year-old age group tends to experience higher dental anxiety than other people9.
The seriousness of problem can be understood by its worldwide ranking. Dental anxiety is ranked 4th among the common fears and 9th among intense fears1.
Understanding the frequency and seriousness of a problem many treatment modalities for dental anxiety has been suggested by various researches10. In most of the developing countries the access to dental treatment is limited due to treatment cost ignorance about importance of oral hygiene11. When compared this to developed countries thus chances of dental anxiety is more due to less exposure and little awareness. Dealing with a patient suffering from dental anxiety is usually found to be a difficult task for the dentists to diagnose and manage12-15. In country like United States of America, 10-19% of population faces dental anxiety16-17. However, data on this topic is scarce in Pakistan.
The aim of this study therefore was to compare the presence of dental anxiety among the patients attending Public and Private dental hospital of Karachi, and to also compare the presence of dental anxiety among different demographics of patients visiting dental hospitals of Karachi, Pakistan.

METHODOLOGY

This study was a cross sectional study and it was conducted at one Public and one Private Dental hospitals of Karachi. It was conducted in year 2014 and completed over a period of four months. The target population was included of patients from age 18-70 years of both genders. Sample size was calculated by WHO sample size estimation calculator. For sample size calculation anticipated population proportion of anxiety was taken as 50%, at 95% confidence level and keeping 0.05 margin of error. The minimum number of participants required for inclusion in the sample was calculated as 385 but to avoid data wastage 400 participants were included in the study. Patients who visited dental OPD (outpatient department) for routine check-up, scaling, extraction, filling and root canal were consented to participate in the study. Patients with impactions, extensive periodontal treatment and edentulous ridges were excluded, furthermore those who were undergoing psychiatric therapy or were suffering from generalized anxiety disorders were also excluded from the study after taking detailed history from patients. Non probability purposive sampling technique was used to induct patients in the study.
The data collection questionnaire was comprising of four parts, the first part contains information about the study and a request for a consent for participation, the second part includes demographic details which proceed with the third part where questions regarding previous dental experience, reason for last dental visit and the facility where dental procedure took place (Public, Private hospital or by unskilled person) were asked, fourth part contain Modified Dental Anxiety Scale (MDAS) Proforma which has an online open access which is used for measuring patient anxiety level.
The MDAS consist of five items which have been coded from 1 to 5 (not anxious to extremely anxious respectively). The items that were included in MDAS are;

• If you went to your dentist for treatment tomorrow, how would you feel?
• If you were sitting in the waiting room (waiting for treatment), how would you feel?
• If you were about to have a tooth drilled, how would you feel?
• If you were about to have your teeth scaled and polished, how would you feel?
• If you were about to have a local anesthetic injection in your gum, above an upper back tooth, how would you feel?

Maximum and minimum scores that can be obtained are 25 and 5, moreover it also has cut-off value 19. Therefore those who score at or above this score would be considered as ‘very dentally anxious’. The study participate were approached in the OPD waiting area of public and private hospitals and face to face interview was conducted. The study was reviewed and approved by Research Ethical Committee of Institute of Business
Management (IOBM) Karachi, Pakistan. Standard procedure of informed consents was applied and confidentiality of patients was well maintained and
data collected was only used for this study. The questionnaire was completed on the spot by the researcher. Data was analyzed by using SPSS version
20 software. All qualitative variables were presented as percentages and frequencies and all quantitative variables were presented as mean and standard deviation.
Independent t- test and ANOVA was used for quantitative variables with two and more than two categories of independent variables respectively. While Chi square was used for qualitative data while p value less than 0.05 was considered significant.

RESULTS

In this study total 400 patients participated with 200 each from public and private dental hospitals. Of them 184 (46%) were males and 216 (54%) were females. Age of the study participants was distributed as 183 (45.8%), 98 (24.5%), 76 (19%) and 43 (10.8%) in age groups of 18-30, 31-45, 46-60 and more than 60. In our study population 100 (25%) patients were illiterate while 136 (34%) had primary and high school education, 127 (31.8%) had graduation and 37 (9.3%) ha post graduation. Patients were inquired about the reason for their visit at dental OPD and their previous dental visit

experience, the details are provided in table 1. Dental anxiety score was calculated from Modified Dental Anxiety Scale (MDAS) that comprised of 5 items. Mean score obtained by study participants was 10.24 ± 4.7 with 0 and 25 as minimum and maximum score. MDAS score for various demographic factors is presented in table 2, where mean MDAS score was different between type of hospital, past dental visit experience and reasons for dental visit with statistically significant p- value. MDAS scores further transformed according to the suggested cut off value of 19 into two groups as No Dental Anxiety (score <19) and Dental Anxiety (score > 19). Among 400 study sample dental anxiety was found in 12 (3%) patients. Association of Dental

 Anxiety with demographic factors was also analyzed and illustrated in table 3.

DISCUSSION

Oral health is not only essential in term of appearance and oral wellbeing but it has connection with your whole body. If not properly taken care off might result in serious conditions like cavities and gum diseases which may contribute to diabetes and respiratory diseases18.
Research showed that one of the common reasons for impediment in health care utilization was dental fear which usually let people delay their dental visit or even cancellation of appointments16,19,20. From the results of this study we analyzed the frequency of dental anxiety among the patients visiting public and private dental hospital of Karachi and dental anxiety was found more among the patient visiting private hospital.
The literature shows that women have a lower level of pain threshold which results in higher number of dental anxiety21-22. However in this study, no significant association was found between dental fear and gender, which has also been supported by some previous studies23. Similarly, regarding dental anxiety and age relation, it has been observed from the previous studies that dental anxiety found less in older patient then young.
This might be because of increase in pain threshold of adult as time passes19,24. Alike our study where dental anxiety is found most among the patient age grouped 18-30, one study also found that 20-30-year-olds that tend to experience higher dental anxiety than other people3.
The attitude of dentist has a great role in developing dental anxiety, if the dentist is caring and spends appropriate time in informing and relaxing the patients about the dental procedures, the people do not develop dental fear even if they experience painful procedures23,25.
Usually it has been observed and also literature supports that previous positive dental experience reduces future dental anxiety26 but in this study patient with previous positive experience faced more dental anxiety. Further incidence of dental anxiety can be prevented with pain control and considering patient as whole and behavior management27 and creating awareness of dental procedures among common people.
Literature shows that patient with higher level of education has awareness about oral health28 and visit dentists on regular basis thus exhibit low dental anxiety but in our study two extreme group patient with no education and patient with higher education exhibit lesser dental anxiety when compare to middle level education. In one more study conducted in Lahore, Pakistan found that educated group of and people in jobs were more dental phobic (55%) which followed by students(21%)22. In this study high socioeconomic group faces more dental anxiety then low socioeconomic group
alike few of the studies in relationship29,30. However, other studies do not found such relationship31,32.
Our study also exhibited that postponement of dental visit was significantly associated with anxiety level, similar results were found in the study conducted in India Chenai28.
This study was conducted in Karachi, Pakistan which is one of the developing countries where majority of population belong to low and middle socioeconomic status and most of them are catered by public health facilities. A study conducted in Australia stated that people from lower socio-economic backgrounds has reduced access to resources29 and have less options available for dental treatment thus showed less dental anxiety. Similar finding was found in our study that shows no dental anxiety among patient visited public hospital. However, one study also states that no matter
how much experienced dentist is, patients fear of experiencing pain during dental visit exist in patient mind31-3 which can make pain as one of the cause for dental fear among patients.
The MDAs score of this study shows that patients visited for dental filling exhibit most dental fear followed by patients came for extraction. These result correspond to the literature which states that procedures dealing with drill and needle injections are the most provoking stimuli for dental anxiety34-6.
At the cut off value of > 19 for MDAS score, 3% of the patients had extremely high level of dental anxiety; this was similar to the findings of Acharya et al. (2.2%) among Indian population33. The percentage of people with dental anxiety was less when compared with Western countries like UK (11%)34, Northern Ireland (19.5%)35, Turkey (23.5%)36 and Finland (3%)34.

CONCLUSION

It was concluded from the results of this study that Mean MDAS Score was high among patients attending private dental hospitals.

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30. Moura-Leite FR, Ramos-Jorge ML, Bonanato K, Paiva SM, Vale MP, Pordeus IA. Prevalence, intensity and impact of dental pain in 5-year-old preschool children. Oral Health Prev Dent 2008; 6: 295-301
31. Craddock HL, Carry JA, Kelly S. Integrated teaching of basic and clinical sciences in anxiety and pain management. Eur J Dent Educ 2009; 13: 142-146.
32. Negra JS, Paiva SM, Saul M, Oliveira M, Ferreira E, Maia FF, Pordeus I. Self-Reported Dental Fear among Dental Students and Their Patients. Int J Environ Res Public Health 2012; 9: 44-54
33. Acharya S. Factors affecting dental anxiety and beliefs in an Indian population. J Oral Rehab 2008; 35: 259-267
34. Humphris GM, Dyer TA, Robinson PG. The modified dental anxiety scale: UK general public population norms in 2008 with further psychometrics and effects of age. BMC Oral Health 2009; 9:20.
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Tunc EP, Firat D, Onur OD, Sar V. Reliability and validity of the Modified Dental Anxiety Scale (MDAS) in a Turkish population. Comm Dent Oral Epidemiol 2005; 33: 357-362.

1. Department of Health and Hospital Management, Institute of Business Management, Karachi.
2. Department of Community Health Sciences, Ziauddin University, Karachi.
3. Department of Community Health Sciences, Ziauddin University, Karachi.
4. Department of Community Health Sciences, Ziauddin University, Karachi.
5. Department of Health and Hospital Management, Institute of Business Management, Karachi.
Corresponding author: “Dr Nosheen Zehra ” < Nosheen_zehra130@hotmail.com >

Sidra Mohiuddin¹                                       BDS, MDS

^{Nighat Nisar2                                                        MBBS, MPH, MCPS, FCPS}

^{Narendar Dawani3}                                BDS, MDS

INTRODUCTION

Oral health is considered as a primary part of general health of an individual. Therefore, oral health as a vital aspect of general health can be defined as “a standard of health for oral and related tissues that facilitates an individual to eat, speak, and communicate without any discomfort or embarrassment and contribute in general well-being”¹.

Globally, oral health problems among the population with in numerous countries still persist, despite of immense improvements in it¹. These problems have been found among underprivileged group in both industrialized and non industrialized countries. Oral diseases like dental decay, periodontal conditions, tooth loss, oral cavity lesions and carcinomas, immunodeficiency related oral disorders as well as oro-dental traumatic injuries are reported universally to be a chief public health problems². Oral health is not only limited to healthy teeth, but also healthy gums, oral soft and hard tissues are also equally considerable². At the same time, missing or decayed teeth have great impact on people’s routine lives as they experience pain, distress and having difficulties with eating, swallowing as well as in socializing. Additionally these oral diseases also restrict the activities of students in school, at work as well as at home by affecting millions of school and work hours to be wasted yearly worldwide^2,4.

As far as dental caries is concerned, it is found to be the disease of an economically developed country with its less severity among developing countries, affecting 60 to 90% of school aged children and huge quantity of elders too³. Initially, higher level of dental caries were found among several American and European countries with the total DMFT score 3.00 and 2.6 respectively among 12 years old school-children, whereas it appeared to be less common among African regions reported to be an overall DMFT score of 1.7^2,3. According to World Health Organization, dental caries is ranked as third most prevalent yet non transmittable oral disease that affect person irrespective of their demography⁵. Until recent years in most of the developing countries the levels of dental decay were found to be lower, but currently the trend has been changed due to increase consumption of sugars and inadequate exposure to fluoride supplements⁶. On other hand, a number of western developed countries had shown remarkable decline among prevalence and severity of dental decay and continually growing of caries free individuals over past two decades, because of various public health campaigns that includes awareness related to effectiveness of fluoride coupled with primordial mode of prevention and enhanced self care practices as well as organized and efficient school based preventive programs².

For dental caries an universal goal has been set by WHO for developing countries which they wanted to achieve by year 2020, stated that about 50% of 6 year old school-children should be free of decayed teeth and on average not more than 3 DMFT score should be observed in children at the age of 12 years⁷.

In Pakistan, oral health trends have shown miserable results; dental caries are found to be most prevalent childhood disease which is 5 times more common than asthma and 7 times more common than hay fever⁸. According to last situation analysis reported in 2004, stated that, in rural areas the total DMFT scores among permanent dentition of 12 year old was found to be 1.59, rising to 2.26 in 15 years old children, 8.73 in 35-44 year old adults and 18.9 in individuals age 65 years and above⁹. Thus increasing trend of dental caries among the growing individuals had indicated towards need of oral health and preventive knowledge as well as unavailability of restorative services. However, in this study all the children who were below 12 years of age, having primary or mixed dentitions were not participated neither this age group has received due value⁹. Although, the mean DMFT score of 12 years old children was found to be significantly low but its alarming that more than 97% untreated dental caries were still there. Currently, some local studies have been conducted in Pakistan about prevalence of dental caries with in various cities and had found higher levels of DMFT scores that are from 2.08 till 6.33 among primary school-children, whereas lower DMFT scores were reported among secondary school-children ranging from 0.8 till 1.14^8,10-13.

It has been seen that previous researchers focused presence of dental caries among school-children from various cities of Pakistan, but with the limitation of small sample size as well as selection of sample either from one town, from private or public school. However, this current study has overcame this limitation by selecting a large sample (n=1600) from nine different towns of Karachi city covering private and public schools from each town, in order to induce primordial and primary mode of prevention among these school-children along with school based oral health education and promotion program.

OBJECTIVES

To determine the occurrence of dental caries among school-children assess of 6-years  and 12-years  in both public and private schools of Karachi city.

METHODOLOGY

It was an analytical cross sectional study that was performed in Karachi city. Ethical approval for the study was taken from Institutional Review Board of Dow University of Health Sciences. Sample selection was based on inclusion criteria that were, school-children aged 6-years and 12-years attending the school on the day of examination, children with deciduous and mixed dentitions, both male and female school-children as well as children whose parents gave consent for their child’s dental examination whereas exclusion criteria were, school-children whose parents returned the consent form stating that they do not want their child to be the part of dental examination, partially erupted teeth, retained roots and teeth with peri-apical lesions, children undergoing orthodontic treatment or malaligned teeth, children with medical or physical disabilities.

The duration of the study was six months , a computer software open epi was used to calculate sample size by taking the reference values of dental caries prevalence to be 57.1% and 49.25% for class 1 and class 6 schoolchildren, respectively⁶.This sample size was calculated with 95% Confidence Interval, 80% Power of test and 5% margin of error. Hence the total of 1328 sample size (n) attained. Adding to it a 20% non-response rate a total sample of 1593⁶. was achieved. Therefore, the sample size of 1593⁶. was rounded to 1600 and equivalent quantity of school-children was examined in this study. The total number of private schools in Karachi city is 2560 and public sector includes about 3948 school. It has been observed that after the registration of a private school, these schools open five to six campuses at different locations in the city. On the other hand, public schools are situated in one building divided into primary, secondary and high school and are being run in two shifts in the same school premises for morning and afternoon shifts. This shows limited numbers of public schools and increased number of private schools because of many mushroom campuses. Because of this reason, the division of this study sample is based on 3:1 ratio that is, taking 1200 school-children from private schools and 400 from public schools. We have selected nine towns out of 18 towns randomly through cluster sampling. In the next stage, from each selected town we identified one private and one public school randomly. The selected towns were Sadder, Jamshed, Gulshan Iqbal, Liaquatabad, North Nazimabad, Kaemari, Malir and Shah Faisal.

After selecting the schools, permission to conduct the study was taken from school’s Principal, and then consent forms were distributed among class teachers, so that they would forward it to the parents of schoolchildren to obtain their acquiescence about their child’s participation as the part of dental examination.

Parents of all selected subjects were not informed before clinical examination in order to minimize the potential bias (e.g. by extra tooth brushing). The children were examined by a single dentist with over three  years of clinical experience,  with in class room, with the child seated on an ordinary chair, in which dental caries status was assess by following the World Health Organization (WHO) criteria for diagnosis of dental caries⁴. An autoclavable mouth mirror in the natural light and explorer were used for examination of dental caries. On every child disposable mask and gloves were used as well as gauze to dry the tooth before examination. A dark spot or staining (non-cavitated) along with feeling of softness or a catch on probing the tooth surface as well as a cavity or softening of the tooth surface was considered as an indicator for presence of dental caries.

Sufficient sets of sterilized examination instruments were arranged for each day before use in oral cavity to minimize and avoid cross infection. The rule implemented for scoring of missing teeth component of dmft index was that a tooth was marked as missing if (a) no successor tooth was visible in the position of missing tooth, (b) tooth is badly broken down by caries.

The data were entered and managed by using Statistical Package for Social Sciences (SPSS) Version 17. Descriptive analysis of the data including frequencies, percentages and means of school-children’s decayed, missing and filled components. Then comparisons among  dental caries status of private and public school-children were performed by using independent sample t test. Level of significance set at p=0.05.

RESULTS

A total of 1600 school-children belonging to 6-years and 12-years of age were examined for prevalence of dental caries, with the mean age of 6.0 and 12.0 years respectively. Age and gender distribution is presented in table no 1. The caries prevalence (n=1600) of study

population was 69.6% (n=1114) with an overall mean DMFT score of 2.98(3.47). Age wise prevalence of caries among study sample (n=1600) was reported as; among 6 years old dmft score was 59.6% (n=664) with mean 2.01 (3.30). Whereas, among 12 year old  DMFT score was found to be 40.39%(n=450) with mean of 0.97(1.72).

Gender wise prevalence of caries among boys (n= 721) were reported as; at 6 years caries prevalence among boys were found to be 51.6% (n=439) with mean dmft scores of 2.07(3.10) where as in girls (n=623) it were reported as 46.4% (n=348) with mean dmft scores of 1.95 (3.50). At 12 years of age prevalence of dental caries among boys(n=721) were 33.2%(n=282) with mean DMFT score of 0.90 (±1.68) while among girls (n=623) reported as 36.6%(n=275) with mean DMFT score of 1.04 (±1.75).(Table I&II)

Among private school-children (n=1200),mean DMFT was found to be 2.27(3.49) whereas public school children it was found to be 5.13(2.31) Similarly, mean of permanent and deciduous dentition among public school-children were 2.87(2.20) and 2.26(2.64) as compare to their private school counterparts (0.33(0.84) and (1.93(3.49), respectively.(Table II)

On comparing, age wise difference among 6 years and 12 years old school-children by using independent sample t test,  mean DMFT index(mean difference=1.44, 95% of CI= 1.11- 1.78) was statistically significant (p<0.001). On comparing, gender wise difference among boys and girls, the mean difference of permanent dentition (DMFT index) (mean difference= -0.13, 95% of

CI= -0.30- 0.03) was statistically insignificant (p>0.109) whereas for deciduous dentition (dmft index) (mean difference= 0.121, 95% of CI= -0.20 – 0.44) was statistically insignificant (p>0.461).(Table III).

On comparing, dental caries status of private vs public school-children by independent sample t test, the mean difference score of permanent teeth of public school-children were found to be more than private school-children with (mean difference= -0.115, 95% of CI -0.19 – -0.03) and  was statistically significant (p<0.001). However, among deciduous teeth, the mean difference of public school children (mean

difference = -0.684, 95% of CI -0.95 – -0.41) and was statistically insignificant (p=0.050).(Table IV).

DISCUSSION

The overall prevalence of dental caries among study population of selected school- children, was found to be more than half with mean DMFT score of 2.98(3.47).These findings were in accordance with studies conducted in India among school-children of same age group, findings of the dental decay among these schoolchildren were also around three forth and more than half respectively^14,15. The reasons of such similar findings may be due to the fact that dental caries has been a major public health problem among different populations affecting school-children, youngsters and adults. Moreover, another reason may be similar sociodemographics and oral hygiene patterns behaviors among both regions’ defined age group. On other hand, a study¹⁶ conducted among Ethiopian school-children of same age group, was in disagreement with current study. The reasons may be due to low socio economic status and lack of proper oral hygiene followed by poor oral health education and promotion strategies, were the main factors for caries prevalence.

In current study it was observed that, as age advances, prevalence of dental caries among school-children decreases. These findings were in agreement with the studies reported^17-19. The increase susceptibility of dental caries among 5 years age group, is because of the fact that deciduous teeth has less enamel thickness due to decrease in calcium content along with altered tooth morphology when compared to permanent teeth as well as increased consumption of sugar enriched diet followed by irregular and unsupervised tooth brushing^17,18,20,21. Another reason that reduces caries prevalence amongst children at 12 years could be that the index recommended by WHO does not record dental caries at incipient stage thus only measuring the carious lesion when it involves the dentinal tissues²².Rodrigues et al²³ and Kulkami et al²⁴ reported increased in caries incidence with advancing age. However, Retnakumari and colleagues²⁵ did not find any increase in prevalence of dental caries with the increase in the age.

The statistics related to deciduous dentition in present study have revealed that near to three forth of six years old school-children were having caries. These findings were in agreement with some   local studies^26-33. It is alarming that primary school-children are found to be at utmost need of dental services and dental health education. The reasons may be due to the lack of oral health care access among school-children, modification of life styles followed by increase accessibility to sugar enrich diet and frequent intake of fizzy drinks with an increase unmet treatment needs, in addition to poor oral hygiene practices and lack of appropriate dental health knowledge and supervision among those school-children.

Caries prevalence among permanent dentition was found to be more than half with an overall decreased in mean DMFT score of 0.97(1.72) hence, we can state that we have achieved WHO goals for year 2020 in which it was stated that children at age of 12 years should having DMFT score 3⁷. Similarly findings of studies^34-36 were in accordance with current study; the reason of lower caries prevalence among permanent dentition may be due to the fact that these teeth have less vulnerability for dental decay as well as children at 12 year of age had just acquired the complete permanent dentition. In addition factors including low sugar availability, disparity in socioeconomic status and dietary habits of study sample were also important to consider. On the other hand, studies^37-39 were not in accordance with the findings of this study. The reason of increase caries prevalence is due to increase consumption of sugar in sweet form, chocolates, inadequate oral hygiene procedures and irregular dental visits, lack of oral health knowledge and poor attitudes towards availing oral health care services. Gender wise statistically in significant findings among deciduous and permanent dentition was reported. Studies^34,39,40 were in agreement with current findings. The reason may be due to similar cultural and dietary habits among school-children.

In current study statistically significant difference has been revealed  among prevalence of dental caries in public and private school children, as public schoolchildren were suffering from dental caries more as compare to their private school counterparts, it was in accordance with the study¹⁴. The reason may be because school children belonging to public schools are coming from low socio economic areas as well as they have lack of oral health awareness followed by proper oral hygiene practices.

CONCLUSION

This study suggests that considerable proportion of children (both among younger and older age categories) had dental caries.  Children of public private schools experienced more dental decay.

RECOMMENDATIONS

It has been recommended  that raise awareness along with organized community oriented regular dental examination surveys; in order to evaluate and assess the school-children’s oral health status as well as promotion of primordial and primary mode of prevention that should be disseminated  equally among private and public schoolchildren.

ACKNOWLEDGEMENT

I am thankful to Dow University of Health Sciences, Karachi  for financial assistance of this study.

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1. Community Dentistry Ziauddin College of Dentistry Ziauddin University.
2. Supervisor & Professor Community Medicine Department, DIMC, DUHS.
3. Community Dentistry Co-Supervisor DIKIOHS, DUHS.

Corresponding author: “Dr Sidra Mohiuddin ” < sidramohiuddin83@gmail.com >

Shujah Adil Khan¹                             BDS, MDS

Haroon Rashid^{2                                            BDS, MDSc}

Adnan Sukkurwalla^{3                       BDS, MMedSci}

Asma Naz⁴                                                          BDS, FCPS (Prosthodontics)

INTRODUCTION

oss of a teeth leads to impairment of oral function, esthetics and phonetics, making prosthodontic involvement necessary¹. Since there has been an increase in the life expectancy of elderly individuals, an increase in the demand of prosthetic restorations has also been noted.  Edentulism in Pakistan occupies an estimated

4.1% of the total population aged 65 years and above, with a projected increase to 9.3% by 2030¹. Due to an increase in the life expectancy of elderly individuals, prosthetic treatment for edentulous patients shall never lose importance².

Removable partial and complete dentures are two commonest treatment modalities that are simple and cost effective. However faults in prosthesis may arise due to improper denture designing by the clinician and lack of technical skills. One of the most common reasons for denture failure in Pakistan is the allocation of vital clinical denture work to the dental technician by the dentist³. Prosthodontic technicians have an important role in successful complete denture therapy however; denture faults and subsequent failures may occur due to lack of technical skills of a laboratory technician. Thus, it is highly recommended that a trial denture is always examined by the clinician in a meticulous manner⁴.

Due to ridge resorption with time, retention and stability of a denture is compromised leading to compromised patient’s function (mastication). Pain and inability to communicate properly due to reasons outlined above, may give rise to psychosocial problems5. The aim of the current study was to evaluate satisfaction among complete denture wearers while understanding specific complaints regarding denture usage.

METHODOLOGY

In this cross sectional analytical study, data from 65 edentulous patients who were wearing complete dentures was collected. The patients were wearing dentures for a period of 1 year and were recalled between March 2014 to May 2014 at the department of Prosthodontics, Dr. Ishrat ul Ebad Khan Institute of Oral Health Sciences. Inclusion criteria only involved patients who had worn complete dentures fabricated by post graduate residents and undergraduate students of DIKIOHS. The dentures were examined and patients were interviewed. Every patient’s age, gender, and variables for satisfaction were recorded on a Visual Analog Scale (VAS)⁶. The VAS scale was used to record the satisfaction of the patients regarding the chewing ability, aesthetics of the denture and the phonetics.

Each denture was examined for its vertical dimension and graded as low, normal or high, whereas the centric relationship was recorded as either correct or incorrect. Phonetic method as proposed by Silverman was used to establish the vertical dimension⁷ and three-finger chinpoint guidance method was used to assess the centric relation⁸. Following complications associated with complete denture wearers were observed and recorded:

• Development of ulcers
• Teeth lost due to fracture of the denture teeth
• Fractures of the Denture base
• Denture related stomatitis
• Loss of denture retention

Various parameters that have potential effects on patient satisfaction and denture complication were assessed using SPSS version 18. Descriptive statistics like percentage, mean and median were used. Quantitative data were tested with student t-test to find the relation between different variables.

RESULTS

A total of Sixty-five patients with a mean average age of 63.48 ± 8.42 years were included in this study. Amongst all, 31 were females (47.6%) while the remaining 34 were males (52.3%). The complications observed in the patients with regards to their frequency were:

• 84.6% – Loss of denture retention
• 44.6% – Developing of ulcers
• 30.7% – Loss of denture teeth due to fracture
• 27.6% – Fractures of the denture base
• 7.6% – Denture  stomatitis

Age and gender distribution has been enumerated in Table 1 and Table 2 shows VAS scores of patient’s denture aesthetics, the phonetics and their chewing ability.

Denture’s condition, vertical dimension and the centric relation are the parameters that are enumerated in Table 3 while incidence of complications are shown in Table 4. There is no significant relation between the patient’s

satisfaction and complications in the procedures (P > 0.05); also the VAS scores or incidence of complications. It was also found that centric relation or vertical dimensionhad no significance between them (P > 0.05).

DISCUSSION

The majority of the edentulous patients were more than 65 years old and were using dentures for more than 10 years. That had resulted in mucosal changes which was noticed in about 44-63% of cases. A clinical analysis has recommended that 40% of the dentures after a period of 5 years and 80% of dentures after a 10 year period must be replaced9. Elderly individuals are more likely to have difficulty in accepting a new denture specially if they face difficulty in chewing, or have noticed a significant change in their facial appearance^10,11. The mandibular dentures are more likely to show instability and lack of retention due to presence of limited surface area. These problems become even more significant in cases where there is severe residual ridge resorption in mandible.  Major problem reported by such patients is unbearable pain during chewing possibly due to denture trauma^12,13,14.

The present study drives our attention to the most commonly encountered problem i.e. loss of retention (84.6%) closely followed by mucosal irritation (44.6%). Ongoing bone atrophy may have attributed to the above mentioned problems as it leads to a decrease in the alveolar crestal height^14,15. According to the current study, 27.6% patients have had fractures in their dentures, which may have been due to careless handling of the denture during maintenance and accidental droppings. Accidental damage or heavy occlusal forcees are found to be the main reasons behind the midline fracture of an acrylic denture10,16.

Rest vertical dimension (RVD) and occlusal vertical dimension (OVD) become compromised when bone

resorption occurs^15,17. Generally, a relatively low OVD is preferred by the clinicians as it causes less discomfort. The results of the present study are consistent with these findings (69.2%). An increase in the OVD results in denture clicking sounds during speech or may cause unclear phonetics specially if the patient consciously tries to stop the clicking sound¹⁴.  Centric relation has shown to effect denture’s comfort^12,19 however; no such findings were recorded in the present study.

Current study only focused on data collected from the department of prosthodontics DIKIOHS and was limited. Studies have indicated that the results are different if the data is collected  from a larger general population of complete denture wearers rather than a single teaching hospital^{1-3,5,12,13,14}. A cross-sectional study involving larger number of patients from different clinical centers is required to reach a more reliable conclusion in future.

CONCLUSION

Within the limitations of the current study, complete denture wearers in a teaching hospital commonly encountered the problem of retention loss. Other problems included development of ulcers, loss of denture teeth and fractures of the denture base.

REFERENCES

1. Bilhan H, Erdogan O, Ergin S, Celik M, Ates G, Geckili O. Complication rates and patient satisfaction  with removable  J  Adv Prosthodont 2012 ; 4:109115.
2. Butt AM, Ahmed B, Parveen N, Yazdanie N (2009) Oral health related quality of Life in complete dentures.
   Pak Oral & Dent J 30:397-402
3. Beck CB, Bates JF, Basker RM, Gutteridge DL, Harrison A (1993) A survey of the dissatisfied denture patient. Eur J Prosthodont Restor Dent 2, 73-78.
4. Brunello DL, Mandikos MN (1998) Construction faults, age, gender, and relative medical health: factors associated with complaints in complete denture patients. J Prosthet Dent 79, 545-554.
5. Dorner S, Zeman F, Koller M, Lang R, Handel G, Behr M (2010) Clinical performance of complete dentures: a retrospective study. Int J Prosthodont 23, 410-417.
6. Smith M. Measurement of personality traits and their relation to patient satisfaction with complete dentures. J Prosthet Dent 1976; 35:492-503.
7. Silverman MM (2001). The speaking method in measuring vertical dimension. J Prosthet Dent 85, 427- 431.
8. Celenza FV (1984) The theory and clinical management of centric positions: II. Centric relation and centric relation occlusion. Int J Perio Rest Dent 4, 62-66.
9. de Grandmont P, Feine JS, Tache?R, Boudrias P, Donohue WB, Tanguay R, Lund JP. Within-subject comparisons of implant- supported mandibular prostheses: Psychometric evaluation. J Dent Res 1994; 73:1096-104.
10. Grant AA, Heath JR, McCord JF (1994) Complete prosthodontics: problems, diagnosis and management, C.V. Mosby, St Louis, 44-45.
11. Zarb GA, Bolender CL, Eckert S, Jacob R, Fenton A, Mericske-Stern R (2004) Prosthodontic treatment for edentulous patients: complete dentures and implantsupported prostheses. 12th ed. C.V. Mosby, St Louis, 298.
12. Bergman B, Carlsson GE (1972) Review of 54 complete denture wearers. Patient’s opinions 1 year after treatment. Acta Odontol Scand 30, 399-414.
13. Heyink JW, Heezen JH, Schaub RMH (1986) Dentist and patient appraisal of complete dentures in a Dutch elderly population. Community Dent Oral Epidemiol 14, 323-326.
14. Van Waas MA (1990). The influence of clinical variables on patients’ satisfaction with complete dentures. J Prosthet Dent 63, 307-310.
15. Basker RM, Davenport JC (2002) Prosthetic treatment of the edentulous patient 4th ed, Blackwell, Oxford, 1-21
16. Van Waas MA (1990) Determinants of dissatisfaction with dentures: a multiple regression analysis. J Prosthet
    Dent 64, 569-572
17. Atwood DA (1971) Reduction of residual ridges: a major oral disease entity. J Prosthet Dent 26, 266-279
18. Basker RM, Davenport JC (2002). The prosthetic treatment of the edentulous patient. 4th ed, Blackwell, Oxford, 269-311.
19. Basker RM, Davenport JC (2002. The prosthetic treatment of the edentulous patient. 4th ed, Blackwell, Oxford, 260-269.

1. Department of Prosthodontics Dr Ishrat ul Ebad Khan Institute of Oral Health Sciences Dow University of Health Sciences, Karachi, Pakistan.

2. Assistant Professor. Department of Prosthodontics, Ziauddin College of Dentistry, Karachi, Pakistan.

3. Senior Registrar, Department of Community Dentistry,Fatima Jinnah Dental College, Karachi, Pakistan.

4. Assistant Professor and Head, Department of Prosthodontics, Dr. Ishrat ul Ebad Khan Institute of Oral Health Sciences – Dow University of Health Sciences, Karachi, Pakistan.

Corresponding author: “Dr Sujhah Adil Khan ” < shujah.adil@gmail.com >

Madiha Pirvani¹                             BDS, MSc

Shoaib Khan^{2                                             BDS, MSc}

Sofia Malik^{3                                     BDS, MSc}

INTRODUCTION

ndodontically treated (ET) teeth are known to have a higher fracture rate than vital teeth. This happens because the tooth structure is lost as a result of caries and then access preparation for root canal treatment (RCT)^1,[1]. To improve the prognosis of ET teeth, they should be restored to enhance their structural integrity^[2].  In this regard post plays an important role in providing retention to a core which supports the coronal restoration. The decision to place post  depends on the amount of  remaining natural tooth substance after the removal of caries and endodontic treatment in order to provide adequate retention to the core buildup and to support the restoration⁴.

There are different types of posts available according to their mode of retention including active and passive posts which can be further subdivided⁵. Various materials have been used to fabricate posts such as metals, ceramics or fiber-reinforced composites. Metallic posts exhibit good physical properties but due to their disadvantages like high incidence of root fracture due to wedging effect, corrosion and nickel sensitivity, metal-free post and core system such as ceramic and fiber reinforced posts has been introduced^4,6.

A number of fiber posts have been introduced during the past decade which are pre fabricated and can be cemented to the root canals. They have similar elastic modulus as that of dentine decreasing the incidence of root fracture, aesthetic acceptable, easy to remove in case of retreatment, do not corrode and are able to be cemented with a luting agent to avoid friction between the post and the root dentine walls^7-10.

Glass fiber posts were introduced in 1992 to overcome the aesthetically unpleasant appearance of carbon fiber posts¹. They can be made of either Electrical glass (E-Glass), Silica Glass (S-Glass) or Quartz fibers¹¹.They are white or translucent and are ideal for situations of higher cosmetic demand. Some major advantages associated with glass fibers include distribution of stress over a broad surface area¹², increased light transmission within the root and overlying gingiva¹³, value of elastic modulus less than carbon fiber posts¹¹,  thus transmitting a very small fraction of forces to the root dentine walls¹⁴.

Composite resin luting cement is the most suitable adhesive to be used with fiber-reinforced posts¹⁵. Fiberreinforced composites (FRCs) have shown improved mechanical properties than the conventional composite resin material¹⁶. It consists of difunctional monomer bisGMA, diluents and quartz or silica fillers. The surfaces of the fillers are treated with a coupling agent to improve their bonding to the matrix thus exhibit better mechanical properties¹⁷. The resin cement bonds to the glass fiber posts either by interdiffusion of the resin monomer into the polymer structure of the posts or by free radical polymerization^18,19. In enamel micromechanical retention is achieved by etching the enamel surface with acid²⁰. Whereas in dentine the retention is achieved by the flow of resin in the dentinal tubules that have been exposed during the procedures of cutting and smear layer removal, resulting in the formation of resin tags²¹. The application of adhesives is a multi-step procedure which is time consuming, complex and technique sensitive²². Therefore, self-etching adhesives have been introduced in which the polymerizable acidic monomers etch and prime the enamel and dentine thus eliminating the need for pretreatment of the teeth²³.

Although resin cements are predominantly used with fiber posts, Glass ionomer cement (GIC) may offer several advantages over resin cements for luting fiber posts. GIC is inherently adhesive to tooth without the need of pre-conditioning²⁴. GIC has enjoyed a fair amount of success as a luting cement and is widely used for a variety of indications²⁵.

Literature is replete with studies on different types of resin cements and their interaction with fiber posts in extracted teeth. Few studies as available to date that compare the bonding efficacy of resin cement and GIC with fiber posts. Therefore; the aim of the study was to compare the bond strengths of two luting cements with two types of fiber posts system and with dentine using a push-out test setup.

METHODOLOGY

Specimen Preparation

Forty intact, extracted, non-carious human single rooted teeth were selected. The teeth were cleaned and stored in alcohol. Then the crowns of all the teeth were cut approximately at the level of cemento-enamel junction (CEJ) with a water- cooled diamond blade on a precision slicing machine (Microslice 2, Malvern Instruments, Malvern, England). Post spaces were made in each root with the help of drills supplied by 3M, UK. These drills were color coded according to their sizes (yellow drill: 1.3mm; red drill: 1.6mm & blue drill: 1.9mm). The drills were fixed in a bench drill machine and a straight post space was made in each root with continuous supply of water acting as a coolant. The root canal in each tooth was rinsed with distilled water and dried gently. Total 40 roots were prepared and were assigned to four equal groups (A1, A2, B1 & B2) according to the luting cement and fiber posts used to fill the post space as shown in table 1.

Two luting agents were used, glass ionomer luting cement (AquaCem®, Dentsply, DeTrey, Germany) and a dual-curing self-adhesive universal resin cement (RelyX™ Unicem, 3M ESPE, USA). Two types of glass fiber posts were used, one with resin impregnated nonpolymerized E-glass fibers (Everstick® POST, Stick Tech, Turku, Finland) and the other containing pretensioned glass fibers embedded in a resin matrix (RelyX™ Fiber Post, 3M ESPE, St Paul, USA).The composition of all the materials used in the study is given in Table 2.

The Everstick® POST were first cut according to the length of the root canal, then coated with a thin layer of a light cured adhesive (3M ESPE Adper™ Scotchbond™, Multipurpose Adhesive, USA), placed in the post space and then light cured for 5 seconds. The posts were then taken out of the post space. The other fiber posts; the RelyX™ Fiber Post did not need any kind of pretreatment with the adhesive.

3M ESPE RelyX™ Unicem was manually mixed according to the manufacturer’s instructions and then both type of fiber posts in groups A2 and B2 were coated with the cement. The cement coated posts were inserted directly into the post space with the application of a slight pressure. Then for the cement to set, it was light cured for 20 seconds. AquaCem® Dentsply, was also manually mixed according to the manufacturer’s instructions and then coated onto the fiber posts of groups A1 and B1, the posts were inserted into the post space with slight pressure and left so that the cement can set by self-curing. Each post cemented root was sectioned horizontally into three slices of 2mm thickness with the help of water cooled diamond blade on a precision slicing machine (Microslice 2, Malvern Instruments, Malvern, England).

Bond Strength Assessment

To assess the bond strength between the luting cement and the fiber posts, push-out test was selected. Each section was placed on a horizontal stainless steel platform with a central circular perforation. The plunger tip is a metal rod 1mm thick and is used to apply a vertical static load to only the post without stressing the surrounding root canal walls. To avoid any limitation to the  post movement during load application due to root canal taper the load was applied in an apical aspect of the root slice in an apical-coronal direction so that the post could be pushed towards the larger part of the root slice. Force was applied by a testing machine (J J Instruments T30K, tensile testing machine from Lloyd Instruments, UK) at a crosshead speed of 1mm.min-1 till the post was extruded out of the root section manifesting bond failure. The bond strength (MPa) was calculated by dividing the load at failure (Newton) with bonding surface area (mm²).

MPa =    N/2 X prh

Where p = 3.14, r is the radius of the post segment (mm), and h is the thickness of the post segment (mm). A digital caliper was used to measure the thickness of each section and the range was in between 1.9- 2.2 mm.

SEM Analysis

Two cross sections of root from each sample were taken for SEM analysis. Each cross section was cut in the middle with water- cooled diamond blade on a precision slicing machine (Microslice 2, Malvern Instruments, Malvern, England). These halves and the post extruded from them after the push-out test were mounted with carbon cement on the stainless steel platforms. After drying the samples were then sputtercoated with gold. They were kept covered until they were analyzed by using a field emission scanning electron microscope JSM- 6300F (JEOL, Tokyo, Japan).

Statistical Analysis

The differences between the bond strengths of the two luting cements used with two types of fiber posts were assessed using a statistical software package (SPSS® version 22 for Windows). A non-parametric test, kruskul wallis was used for comparing the medians of the four study groups. Tukey’s post hoc analysis was used to determine the group with statistically significant values. Level of significance was kept at 0.05. A p value < 0.05 was considered as significant.

RESULTS

The mean push-out bond strength and standard deviation (SD) achieved after the extrusion of both types of posts from the root segments in each group are listed

in Table 3.  Multiple comparisons with kruskul wallis test and tukey’s post hoc analysis demonstrated that the bond strength was significantly influenced by the interaction between the type of luting cement and fiber post used (Table no 4). The mean bond strengths of RelyX™ Fiber Posts cemented with AquaCem® and RelyX™ Unicem were not statistically significant (p=0.696). Whereas the mean bond strength of Everstick glass fiber posts cemented with AquaCem or RelyX™

Unicem was lower than RelyX™ Fiber Posts cemented

with either cement. This difference was statistically significant. (p<0.05) (Table 4).

Regarding SEM analysis, there was significant difference in the interaction between the luting cement and dentine after the push-out test. Etched dentine and pieces of the AquaCem®  attached to the tooth structure were clearly visible whereas very little amount of AquaCem® could be detected attached to RelyX™ Fiber posts. The interactions of RelyX™ Unicem with the dentine also illustrated formation of resin tags but penetration of the IPN polymer structure of Evertsick® POST by RelyX™ Unicem was also evident as a considerable amount of cement could be seen with the RelyX™ Fiber Post after the push out test.

DISCUSSION

In this study bonding strength of two types of luting cements (AquaCem® and RelyX™ Unicem) with the two types of fiber posts (Everstick® POST and RelyX™ Fiber Posts) and dentine was evaluated. The factors affecting the bond strength are degree of micromechanical interlocking as well as chemical adhesion between the root canal dentine, the luting agent and the posts. The two basic modes of adhesion of the resin materials are  resin monomer diffusion into the polymer phase of the substrate and free radical polymerization of the bonding resin²⁶. It was also concluded by a study conducted by Sperling et al 1994 and Mannocci et al 2005, that there are two requirements for the resin based materials to undergo interdiffusion i.e. availability of a polymer substrate that is not cross linked and has partially or totally linear polymer structure such as the IPN polymer structure and a close match between the solubility parameters of the solvent so the linear or IPN polymer structure can be dissolved by monomers of the resin^18,19.

The push-out test results for model A1 and A2 showed a significant difference between the bond strengths of the two luting cements used with Everstick® POST (p<0.005). The RelyX™ Unicem cement exhibited much higher bond strength with the Everstick® POST (1.621 MPa; SD±0.686) than the AquaCem (0.613 MPa; SD±1.496). This could be due to the fact that the monomers of RelyX™ Unicem cement penetrated into the linear phase of the IPN polymer structure of everstick posts which is polymethylmethacrylate (PMMA), whereas there process of interdiffusion  is not possible in AquaCem  and its setting reaction is primarily an acid base reaction which allows it to bond  to the tooth substance chemically. This occurs by the  chelation of the carboxyl groups in the acid  present in AquaCem with the calcium and phosphate ions present in the apatite of enamel and dentine and thus had no effect on the polymer structure of the posts^27,28.

The results showed that there was no significant difference between the bonding strengths of both the luting cements when used with RelyX™ Fiber Posts (Model B1 and B2).The results obtained were quiet expected as there is a basic structural difference between the two fiber posts. The Everstick® POST contain a semi-IPN polymer structure while the RelyX™ Fiber Posts have an already cured and cross-linked epoxy resin matrix leaving  little if any reactivity required  for free radical polymerization bonding  therefore there was no actual chemical bonding  between the resin cement and the posts²⁹. This structural difference results in different modes of adhesion of the luting cement to the posts. The semi-IPN makes interdiffusion mechanism possible in Everstick® POST. But, in the RelyX™ Fiber Posts neither interdiffusion nor free radical polymerization was possible. So in that case where resin based cements could not penetrate into the posts polymer structure their bond strength was almost same as that of AquaCem®. These results can be further supported by comparing them with the results obtained from a study carried out by Mannocci et al (2005) in which the penetration of two different bonding resins applied on glass reinforced composite root canal posts was compared, one containing an interpenetrating polymer network (IPN) and the other containing a cross-linked polymer matrix. The posts with IPN were EverStick® POST and the ones with cross linked polymer matrix were C Post Millennium. These posts were immersed in bonding resins (Scotchbond Multi Purpose Plus, 3 M, St Paul, MN, USA and Stick Resin, Stick Tech Ltd). The confocal microscopic results showed that the degree of penetration of resin into the EverStick® POST was remarkably higher than in the C Post Millenium¹⁸.

The similar bond strengths of the luting cements in models B1 and B2, could also be due to the fact that the RelyX™ Fiber Posts are tapered in shape i.e. they are cylindrical coronally and conical apically. This configuration resembles the anatomical structure of the root. Additionally, the post holes were made by the drills which were provided by the manufacturer according to the size and shape of the RelyX™ Fiber Posts so these posts fit in the post spaces quite well. On the contrary, the Everstick® POST are not tapered and sometimes two or three posts were used to pack the post space. Therefore, it can be hypothesized that RelyX™ Fiber Posts were fixed quiet tightly and gained much of the retention by their shape in the canals and hence both the cements showed higher bond strength with these posts as compared to Everstick® POST.

In the present study there was no pretreatment done on the root canal dentine before the application of both the cements. The pretreatment such as acid etching could have generated different results because acid etching removes the smear layer from the root canal dentine and smear plugs are formed by the resin cement resulting in more efficient micromechanical retention³⁰.

SEM Analysis

The SEM results revealed the interaction of the two luting cements with the dentine after the push-out test. The AquaCem® showed bonding to dentine by chelation and little if any cement was observed to be attached with the Everstick® POST after the test concluding that the bond failure occurred between the post and the cement.

This result confirms that the lower bond strength values obtained from the combination of AquaCem® and Everstick® POST was because of the fact that the cement made a chemical bond with dentine and did not show any affinity towards the posts’ polymer structure. The same mode of adhesion occurred in both the cases i.e. AquaCem® with Everstick® POST and AquaCem® with RelyX™ Fiber Post. But the latter provided higher bond strength values because the RelyX™ Fiber Posts were tapered in shape and fitted quiet well into the prepared post spaces as these post spaces were made with the drills which were supplied by the manufacturer according to the size of the posts.

The RelyX™ Unicem SEM images show etching of the dentine and hence resin tags formation, but it is also clear from the images that this resin cement penetrated into the IPN polymer structure of Everstick® POST and made a bond with them. In the case of RelyX™ Fiber Posts the cement could have reacted with the polymer network to make a bond with these posts too. Therefore a considerable amount of cement was seen attached to the Everstick® POST and RelyX™ Fiber Posts after the push-out test. This indicates that adhesive failure of the cement occurred in these cases and the bond strength values obtained were therefore higher.

CONCLUSIONS

Within the limitations of the study it can be concluded the type of luting cements and posts significantly affected the bond strength. RelyX™ Unicem was more effective and demonstrated the highest bond strength values with both type of fiber post systems used in the study compared to AquaCem®. AquaCem® presented similar bond strength values as the RelyX™ Unicem with RelyX™ Fiber Post (p =0.696). The study also highlighted that bonding mechanism to root canal dentine was dependant on the type of luting cement rather than the glass fiber posts used in the study. With AquaCem®, the mode of failure as observed by SEM, was predominantly at the interface of glass fiber post and root canal dentine, whereas the mode of failure associated with RelyX™ Unicem was predominantly adhesive in nature.

ACKNOWLEDGEMENTS

“Based on a dissertation submitted to School of Engineering and Materials, Queen Mary University of London, London, United Kingdom, in partial fulfillment of Master of Science (MSc) in Dental Materials degree.”

REFERENCES

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7. Newman MP, Yaman P, Dennison J, Rafter M, Billy E. Fracture resistance of endodontically treated teeth restored with composite posts. J Prosthet Dent. 2003; 89:360-367.
8. Pontius O, Hutter JW. Survival Rate and Fracture Strength of Incisors Restored with Different Post and Core Systems and Endodontically Treated Incisors without Coronoradicular Reinforcement. Journal of Endodontics. 2002 10//;28:710-715.
9. Qualtrough AJ, Chandler NP, Purton DG. A comparison of the retention of tooth-colored posts. Quintessence international (Berlin, Germany : 1985). 2003; 34:199-201.
10. Sirimai S, Riis DN, Morgano SM. An in vitro study of the fracture resistance and the incidence ofvertical root fracture of pulpless teeth restored with six postand-coresystems. J Prosthet Dent. 1999 ;81:262-269.
11. Lassila LVJ, Tanner J, Le Bell A-M, Narva K, Vallittu PK. Flexural properties of fiber reinforced root canal posts. Dental Materials. 2004 1//;20:29-36.
12. Boschian Pest L, Cavalli G, Bertani P, Gagliani M. Adhesive post-endodontic restorations with fiber posts: push-out tests and SEM observations. Dent Mater. 2002; 18:596-602.
13. Balbosh A, Kern M. Effect of surface treatment on retention of glass-fiber endodontic posts. J Prosthet Dent. 2006; 95:218-223.
14. Artopoulou, II, O’Keefe KL, Powers JM. Effect of core diameter and surface treatment on the retention of resin composite cores to prefabricated endodontic posts. Journal of prosthodontics : official journal of the American College of Prosthodontists. 2006; 15:172- 179.
15. Anusavice KJ. Phillips Science of Dental Materials. 11th Edition ed. St. Louis: Elsevier; 2003.
16. Aquilino SA, Diaz-Arnold AM, Piotrowski TJ. Tensile fatigue limits of prosthodontic adhesives. J Dent Res. 1991;70:208-210.
17. Jacobsen PH, Rees JS. Luting agents for ceramic and polymeric inlays and onlays. Int Dent J. 1992; 42:145-149.
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1. Assistant Professor, Department of Science of Dental Materials, Dr. Ishrat-ul- Ebad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, Pakistan.
2. Assistant Professor, Head of the Department, Department of Science of Dental Materials, Ziauddin College of Dentistry, Ziauddin University, Karachi, Pakistan.
3. Assistant Professor, Department of Science of Dental Materials, Dow International Dental College, Dow University of Health Sciences, Karachi, Pakistan.

Corresponding author: “Dr Madiha Pirvani ”  < madihapirvani@hotmail.com  >

Muhammad Amin¹                             BDS, FCPS

Farah Naz^{2                                                          BDS, FCPS}

Abubaker Sheikh^{3                             BDS, FCPS}

Adeel Ahmed^{4                                                BDS, MFDS RCS (Ed), FCPS}

INTRODUCTION

The demand for more esthetic posterior dental restorations has dramatically increased the use of directly placed composite restorations¹.

One of the most frustrating situations in the dental office is to craft an aesthetic restoration and have the patient call the office the following day, to complain that the tooth is sensitive. To the patient, it does not matter how beautiful the restoration looks if he or she experiences sensitivity or discomfort².

Postoperative sensitivity (POS) in posterior teeth restored with resin composite has been a problem experienced by clinicians for almost twenty years³. The occurrence of postoperative sensitivity is varies from clinician to clinician and factors other than operator’s experience and technique may be responsible⁴.

Introduction of new adhesive systems have reduced the number of steps in application of composite restoration. Self-etch adhesives, appeared to be advantageous to clinicians with lesser steps (no etch and rinse), less potential of over-drying, low technique sensitivity and so less reported post- operative sensitivity^5,6. Sale of self-etch adhesive has also grown considerably in past 10-12 years due to the view of clinicians that self-etch causes less post-operative sensitivity than total etch adhesive⁷.

When  total-etch dentine adhesive was used in a study while restoring posterior teeth with a resin composite, up to 56 % of the restorations resulted in sensitivity⁸. Few studies have also found total etch restorations to show lesser post-operative sensitivity⁹. A meta-analysis of clinical trials done on TE and SE comparisons showed that there is no significant difference in post-operative sensitivity¹⁰.

There are many studies on these two adhesives but there is still no confirmation regarding the assured lesser post-operative sensitivity in any one material.  We therefore planned this study with a directional hypothesis that total etch adhesive has more postoperative sensitivity as compared to self-etch adhesive.

To test this hypothesis, the objective of this study was therefore, to compare the level of post-operative sensitivity (POS) in teeth restored with posterior dental composite restorations using self-etch (SE) and total-etch (TE) adhesive systems.

METHODOLOGY

Eighty patients visiting the out-patient department of Altamash Dental Hospital were included. Patients with premolars (maxillary or mandibular) presenting with simple class I cavities with vital pulp, radiographic evidence of caries in outer to middle third of dentin and sound occlusal and proximal contacts were included in the study. Patients with any of the following complaint were excluded: teeth with preoperative sensitivity, generalized sensitivity, non-vitality, abnormal occlusion or history of para-functional habits, recent history of desensitizing treatment or any periodontal disease were excluded. Objectives and protocols of the study were explained to the subjects and consent was taken. Patients were then divided into two groups. Non probability purposive sampling was done for group allocation of patients. All patients with odd OPD numbers were placed in group I which was of self-etching bonding system; while all patients with even OPD numbers were placed in group II which was of total-etch bonding system. Local anesthesia was administered. Teeth were isolated by using rubber dam. All cavity preparations were of conventional design. In Group I, the self-etching adhesive (L-POPs 3M, ESPE) was applied for twenty seconds. The tooth surface was then light cured for 10 seconds. In Group II, phosphoric acid-etchant (37%) (Scotchbond 3M, ESPE) was applied for thirty seconds which was then washed with water and dried with air from triple syringe. In the end, bonding agent (Prime and Bond NT, Dentsply) was applied and light cured for ten seconds. In both groups, after application of respective adhesive, composite resin (Filtek Supreme, 3M) restorations were placed in increments by using layering technique to minimize polymerization shrinkage. The composite was cured for 20 second using Quartz tungsten curing light (HILUX 200, Turkey).Finishing of the restorations was carried out using flame shaped diamond burs and then polished with rubber cups by using composite polishing paste (Prisma gloss composite polishing paste, Dentsply).

Post-Operative Sesitivity:

The presence of post-operative sensitivity was noted by placing an ice stick upon the junction of restoration and natural tooth structure on the occlusal surface for five seconds. The degree of severity in sensitivity was marked by using Visual Analogue Scale (VAS), with readings from 0-10. Zero denoting absence of sensitivity, 1-3 was taken as Mild, 4-7 was taken as moderate and 8-10 was taken as severe sensitivity. The readings were marked on 1st, 4th and 7th post- operative day. All the readings were recorded in a self-structured proforma. All the procedures and evaluations were performed by one operator (principal investigator) according to manufacturer’s instructions to minimize the technical / procedural variations. The data was analyzed in SPSS version 12.0. Frequency and percentage were computed for categorical variables like gender and depth, while mean and standard deviation were computed for quantitative variables like age and VAS score. Mann-Whitney test was applied to compare the difference in sensitivity between both groups. Wilcoxon sign rank test was also applied to compare VAS with respect to time for both groups. P < 0.05 was considered as the level of significance.

RESULTS

In a total of 80 patients, the average age of the patients was 26.59 ± 13.55 years. Age range was 13-40yrs.

Histogram of age distribution is presented in Figure I. There were 29 males (36%) and 51 females (64%). The sensitivity in terms of VAS scores at the time of each follow-up visits are displayed in table I. In both groups, sensitivity was found at Day 1, these scores reduced till day 7 in both groups.

Mann-Whitney test was used to compare the sensitivity

Mean ± SD = 26.59 ± 13.55 Years
Age range (13-40 years)

(VAS scores) in the two treatment groups at postoperative day-1 (p=0.027) and day-4 (p=0.006).  Postoperatively, at day-7, sensitivity (VAS score) between groups were not statistically significant (p=0.67). (Table I) Generally, in all follow-up visits, mean values of VAS were higher in treatment group I (Self etch group) as evident in Table I.

There was statistically significant difference in the sensitivity level within each group when the values were compared with each postoperative visits (Day1, Day 4, Day 7) in both groups. A progressive improvement was observed in sensitivity within a week in both groups. (Table II)

DISCUSSION

Our study results showed statistically significant difference in VAS scores within each group with respect to post-operative days. There was more initial sensitivity in self etch group but later on, no significant difference in sensitivity was found among both groups by the end of one week. Thus the hypotheses that total etch adhesive has more postoperative sensitivity as compared to selfetch adhesive was rejected till day 4, as by the end of the week there was no statistically significant difference among both groups. (Table I)

Post-operative sensitivity after application of a posterior dental composite resin restoration is reported as a common problem by dentists. It is generally found that postoperative sensitivity decreases during the first few weeks after restoration placement, but it sometimes persists for a longer period. POS can be caused by several factors, including etching, bacterial penetration of pulp, occlusion discrepancies, technique of restoration placement, depth of cavity, over drying of dentin, deformation of the cusps by shrinkage stress during polymerization of the posterior resin restorations, deformation of the cusps by the shrinkage stress and deformation of composite by occlusal forces¹¹. Literature reveals that in newer adhesive agents, postoperative sensitivity is still found in 30 % of the studied population ^9,12-16.

Our study was an experimental one which involved eighty patients in an academic environment to solve the problem of post-operative sensitivity with posterior dental composites. In comparison to our study Herrero¹ evaluated postoperative sensitivity in 104 class I composite resin restorations, placed with a self-etching and total-etch adhesive system using a visual analogue scale. Most of the studies have used the Visual Analog Scale measure the sensitivity score from 0 to 10 which is in accordance with our study.

In our study we used an ice stick to assess postoperative sensitivity after the placement of posterior dental composites, clinically. Many other studies have used an ice stick but few have also used other methods as compressed air, cool water from a disposable syringe and ethyl chloride spray^3,17.

In our study there was significant difference in the sensitivity level (VAS Score) during a week. This was later reduced to zero by end of the week. Yousaf A conducted a similar study and concluded that SE adhesive may be helpful in reducing post-operative sensitivity during first 24 hours after placing the restorative material as compared to TE adhesives¹⁸. These results were different from our study where SE group showed more sensitivity initially as compared to TE group in first 4 days. The reason for this could be because of use of a different brand of test material or bonding failure since SE adhesives have weak etchant and thus weaker bond strengths⁷. Some clinicians have suggested the use of SE in cavities with more dentin (deeper cavities) and TE in cavities with more enamel (shallow cavities)¹⁹. The cavities included in our study were all shallow extending not more than upper third of dentin. Other possibility could be due to some unintentional breach in application protocol which is less likely. Difference in brands is also important because there could be difference in bonding ability as well as concentration of etchant in various products. A study by Perdigao et al¹² evaluated the clinical performance of three different self-etch adhesives. The clinical efficacy of these self-etch adhesives was compared to the total etchadhesives as control. This study showed that significant post-operative sensitivity was present with one of the selfetch adhesive as compared to the control group. In another study by Baratieri et al ²⁰ , clinical performance of the self-etching adhesive system and the total-etch adhesive system in classes I and II for a period of 4 years was compared, this study showed that post-operative sensitivity was found with self-etchant adhesive. The same study also showed that the incidence of post-operative sensitivity reduced with the passage of time for the self-etch adhesive system.

The sensitivity in both groups in our study also reduced completely in one weeks time, the reason for this could be the accumulation of precipitated protein in the dentinal tubules in few days after application of adhesive, limiting the fluid flow and reducing or eliminating the sensitivity.

Some of the studies regarding the issue of postoperative sensitivity with posterior dental composite showed no statistically significant difference either by using self-etching adhesives or by total-etch adhesives²¹. A meta-analysis was conducted by Krithikadatta on comparison of different clinical outcome of composite restoration placed with SE and TE found that there was no significant difference in post-operative sensitivity¹⁰. VV Gordon²²,  evaluated the post-operative sensitivity of posterior restorations restored with a resin-based restorative material and a self-etching primer showed that no statistically significant difference was found on either short term nor long term. Herrero et al¹ showed that there was no statistically significant difference either by using both self-etching or total-etch adhesives. Jorge Perdigao et al¹² also showed that no statistically significant differences in post-operative sensitivity was found between the self-etch and total etch adhesives at any recall time. This variation in results of all these studies leads us to understand that the clinical technique and operator factors of applying the composite restoration may be more important than the choice of adhesive system⁷. The results of many clinical trials do not support the anecdotal evidence of self-etch being better in terms of sensitivity; they found it similar in both the adhesive groups^7,23. Generally, mild self-etch systems are expected to have little or no , and total etch  systems are found to have more frequent and intense post-operative sensitivity⁷. This was not the case in our study, maybe because all the restorations were placed under meticulous isolation with rubber dam and were performed by single operator.

CONCLUSION

TE adhesives significantly showed less POS compared to SE group during the first four days of restoration placement after which the difference between the groups faded. The study results showed that post-operative sensitivity was found with both total-etch adhesive and self-etch adhesive till one week post-operatively. A reduction in sensitivity was found in both groups from day one to day seven.

LIMITATION / WEAKNESS OF THE STUDY

One group of the permanent teeth from patient’s mouth, a pre-molar was selected, which did not   represent the entire dentition. POS was measured in response to cold stimulus only. Stimuli like hot, biting forces, and air could have been used to simulate the natural oral environment more closely. Class I cavity design was selected which has a maximum ‘C’ factor (configuration factor) . This can inflate the VAS score.

CLINICAL SIGNIFICANCE/ STRENGTH OF THE STUDY

The problem discussed in this study is of vital importance in clinical practice of Operative dentistry. Post-Operative sensitivity is a very commonly associated with composite restorations. There are many subjective beliefs among clinicians that this sensitivity is reduced when self-etch adhesives are used with composites than total etch adhesives. Clinical trials however tend not to support this evidence. This study will also help the clinicians in a better understanding of the fact that technique of placement of restoration is more important than the choice of adhesive system used.

RECOMMENDATIONS

It is recommended that studies should be conducted while involving different groups of   patient’s dentitions like molar, canines and incisors to have a generalized assessment of post-operative sensitivity. Studies should be conducted to measure post-operative sensitivity in response to other stimuli like hot, biting forces and air to have more accurate assessment of post-operative sensitivity. Studies should be conducted to involve various cavity designs or classifications like class II, class V to establish more accurate evidence about post-operative sensitivity.

ACKNOWLEDGEMENT

We would like to acknowledge the continuous guidance and support of Dr. Ismail Sheikh, Dr. Mumtaz Khan and Dr. Azmat Mumtaz, Consultants of Operative Dentistry, during this research work.

REFERENCES

1. Herrero AA, Yaman P, Dennison JB.Polymerization shrinkage and depth of cure of packable composites. Quintessence Int. 2005;36:25-31.
2. Ward DH.Treating patients with CARE (comfortable aesthetic restorations): reducing postoperative sensitivity
   in direct posterior composite restorations. Dent Today. 2004;23:60, 62, 64-65.
3. Perdigão J, Anauate-Netto C, Carmo AR, Hodges JS, Cordeiro HJ, Lewgoy HR, Dutra-Corrêa M, Castilhos N, Amore R. The effect of adhesive and flowable composite on postoperative sensitivity: 2-week results. Quintessence Int. 2004;35:777-84.
4. Burke F.J. What’s New in Dentine Bonding? SelfEtch Adhesives. Dent Update. 2004;31:580-2, 584-586, 588-589.
5. Casselli D.S. Martins L.R. Postoperative sensitivity in Class I Composite Resin Restorations In Vivo. J Adhes Dent. 2006;8:53-58.
6. Cardoso MV, de Almeida Neves A, Mine A, Coutinho E, Van Landuyt K, De Munck J, Van Meerbeek B. Current aspects on bonding effectiveness and stability in adhesive dentistry. Aust Dent J. 2011;56 :31-44.
7. Perdigão J, Swift EJ Jr. Critical appraisal: post-op sensitivity with direct composite restorations.J Esthet Restor Dent. 2013;25:284-288.
8. Manchorova NA, Vladimirov SB, Donencheva ZK, Drashkovich IS, Kozhuharov PZh, Manolov SK, Todorov RG.A study of post-operative sensitivity in class I and class II restorations with self-etching adhesive and nanofilled composite. Folia Med (Plovdiv). 2006;48:63- 69.
9. Opdam NJ, Feilzer AJ, Roeters JJ, Smale I. Class I occlusal composite resin restorations: in vivo post-operative sensitivity, wall adaptation, and microleakage. Am J Dent. 1998;11:229-234.
10. Krithikadatta J. Clinical effectiveness of contemporary dentin bonding agents. J conserve Dent 2010; 13:173-83)
11. Auschill TM, Koch CA, Wolkewitz M, Hellwig E, Arweiler NB. Occurance causing stimuli of post operative sensitivity in composite restorations. Oper Dent 2009; 34: 3-10.
12. Perdigão J. New developments in dental adhesion. Dent Clin North Am. 2007;5:333-357, viii
13. Eick JD, Welch FH. Polymerization shrinkage of posterior composite resins and its possible influence on postoperative sensitivity. Quintessence Int. 1986 ;17:103-111.
14. Opdam NJ, Roeters FJ, Feilzer AJ, Verdonschot EH. Marginal integrity and postoperative sensitivity in Class 2 resin composite restorations in vivo. J Dent. 1998;26:555- 562.
15. Berkowitz GS, Horowitz AJ, Curro FA, Craig RG, Ship JA, Vena D, Thompson VP. Postoperative hypersensitivity in class I resin-based composite restorations in general practice: interim results. Compend Contin Educ Dent. 2009 ;30:356-363.
16. Blanchard P, Wong Y, Matthews AG, Vena D, Craig RG, Curro FA, Thompson VP. Restoration variables and postoperative hypersensitivity in Class I restorations: PEARL Network findings. Part 2. Compend Contin Educ Dent. 2013; 34(4):e62-68.
17. Browning WD, Blalock JS, Callan RS, Brackett WW, Schull GF, Davenport MB, Brackett MG. Postoperative
    sensitivity: a comparison of two bonding agents. Oper Dent. 2007;32:112-117.
18. Yousaf A, Aman N, Manzoor MA, Shah JA, Dilrasheed. Postoperative sensitivity of self etch versus total etch adhesive. J Coll Physicians Surg Pak. 2014;24:383-386.
19. Blanchard P, Wong Y, Matthews AG, Vena D, Craig RG, Curro FA, Thompson VP. Restoration variables and postoperative hypersensitivity in Class I restorations: PEARL Network findings. Part 2. Compend Contin Educ Dent. 2013; 34(4):e62-68.
20. Baratieri LN, Ritter AV. Four-year clinical evaluation of posterior resin-based composite restorations placed using the total-etch technique. J Esthet Restor Dent. 2001; 13:50-57
21. Burrow MF, Banomyong D, Harnirattisai C, Messer HH. Effect of glass-ionomer cement lining on postoperative sensitivity in occlusal cavities restored with resin composite–a randomized clinical trial. Oper Dent. 2009 ;34:648-655.
22. Gordan VV, Mjör IA. Short- and long-term clinical evaluation of post-operative sensitivity of a new resinbased restorative material and self-etching primer. Oper Dent. 2002;27:543-548.
23. Ermis RB , Kam O, Temel UB. Clinical evaluation of a two step Etch and rinse and a two step self etch adhesive system in class II restorations: two year results. Oper Dent. 2009;39:656-663.

1. Assistant Professor & Consultant, Department of Operative Dentistry, Dental section, Dow International Medical College; DUHS, Karachi.
2. Associate Professor & Consultant, Department of Operative Dentistry, Dental section, Dow International Medical College; DUHS, Karachi. Clinical Faculty member (Part time), Department of Surgery, Section of Dentistry, The Aga Khan University and Hospital, Karachi.
3. Assistant Professor & Consultant, Department of Operative Dentistry, Fatima Jinnah Dental College, Karachi.
4. Assistant Professor & Consultant, Department of Operative Dentistry, Dental Section, Dow International Medical College; DUHS, Karachi. Corresponding author: “Dr Muhammad Amin ” < dr_mohdamin@yahoo.com >

Anam Fayyaz1                                                                   BDS, FCPS Resident

Mohammad Amber Fareed2                               BDS, MSc, PhD

Saroosh Ehsan3                                                               BDS, FCPS

Qaiser Ali Baig4                                                               BDS, MSc

INTRODUCTION

The recent advances in bonded restorative materials has persuaded minimally invasive treatment strategies for tooth preservation, reinforcement of the remaining tooth structure, better marginal seal and eventual increased life span of restorations1. In recent years, the extensive usage of resin-based composite restorative materials (RBCs) in clinical dentistry is attributed to its excellent aesthetics. The advent of RBCs with better mechanical properties and less shrinkage has led to their use in posterior teeth compared to amalgam2. Composite restorations have a number of advantages for example: conservation of remaining tooth, adhesion to tooth structure, strengthening of restored tooth unit, satisfactory aesthetics and ease of repair1. Directly bonded restorations commonly undergo marginal deterioration and are generally more susceptible to secondary caries. Consequently, a localized defect in a composite restoration is a common situation for dentists to decide between repair and replacement.Restoration repair is the partial replacement of a

defective restoration showing no clinical or radiographic signs of failure whereas restoration replacement is the complete removal of previous restoration followed by placing a new restoration¹. Conventionally, a defective composite restoration was replaced but recently, repair is a conservative treatment option that has been advocated^3,4. Complete replacement of a composite restoration may be considered unduly interventional in conditions where the restorations (>80%) may be found to be healthy clinically and radiographically^5,6. The invariable outcome of restoration replacement and the unwarranted removal of sound tooth structure from sites that are unaffected by any localized defect result in the weakening of the remaining tooth structure. This along with the added possibility of pulpal insult results in acceleration of the “restoration death spiral”⁷. Moreover, patient factors also play an important role in the progression of defective restorations over an extended period of time⁸. This provides the clinician a chance to deal with the cause of the defect and to repair the restoration with minimal intervention thereby prolonging the lifespan of the restoration⁹.

There is substantial evidence validating the significance of procedures to repair defective restorations¹⁰. Since the last decade, an increase in placement of composite restoration in general dental practice resulted in increased evidence that repair rather than replacement is considered as a treatment option for defective composite restorations¹¹. Therefore, aim of this study was to examine the extent of contemporary knowledge and practices about the indications of composite restoration repair among dentists working in various teaching dental hospitals in Lahore, Pakistan.

METHODOLOGY

A survey questionnaire (consisting 16 questions) was designed and distributed to 200 dental graduates in 4 teaching dental hospitals in Lahore Pakistan. Participants were informed that their demographics will be kept confidential. All designed questions seeking the information about composite repair were close ended. The survey items were pre-tested for ambiguity, content validity, reliability and clarity by the authors in their institute. The survey inquired about the knowledge, attitude and practices of treating a defective composite restoration. The survey also inquired for information about the most common indications of repair of a defective composite restoration. The returned questionnaires were coded and data wad entered and analyzed using Statistical Package for the Social Sciences (SPSS) Version 20.0. Descriptive and analytical statistics were used to analyze each variable and associations were tested for statistical significance using Chi-square tests at 95% significance level.

RESULTS

Completed questionnaire responses were received from four dental schools giving a response rate of 100% (200 participants). No incomplete responses were received. Eighty nine percent of the participants had less than 4 years of clinical experience [1-2 years = 107 (53.5%), 2-4 years = 70 (35%), 4-6 years = 20 (10%) and 6-8 years =3 (1.5%)]. Majority of dentists (64.5%) reported that they consider patients preferences for repair or replacement of the defective composite restoration. The most common indication for repair was secondary caries (37%) (p=0.010), followed by partial loss of composite

(29.5%), fracture of composite (21%) and 12.5% of the respondents selected composite discoloration as an indication for repair (Table 2). Sixty five percent chose

repair to treat a small defect in composite restoration. When enquired if repair was a less invasive treatment option as compared to replacing a composite restoration, 68% of the respondents agreed. Results of our study revealed that 49.5% of the participants thought repair was less time consuming than replacement of the whole composite filling. Table 3 shows that 73% responder

thought that repair increased longevity of a previously done defective composite restoration. The large number of participants considered repaired restorations as permanent fillings (65%) whereas 30% considered repair as an intermediate filling and 5% considered it as a temporary filling. More than half of respondents 121 (60.5%) reported that they were not taught about composite repair during BDS training. However, 162 (82%) respondents have replaced a defective composite restoration and 121 (60.5%) have performed composite repair in their clinical practice as a treatment option (Table 4). The results

showed that as experience of the dentist increased (3-8 years) the awareness of repair as a treatment option also increased (p=0.003) as well as repair being performed as a treatment (p=0.028).

DISCUSSION

As with all questionnaire-based surveys, risks exist in relation to the reliability of responses and the potential of non-response bias. Our study had a 100% response rate but the limitation of this study was the group (n=200) of dentists based in one city were questioned. Irrespective of this weakness the results are consistent with the findings of previously published studies^4,6,12. Additionally, there is a strong agreement amongst academicians in conservative dentistry around the world that there are merits in repairing rather than replacing defective direct resin composite restorations7,8,12,13.

Hickel and Manhart argued that clinician factors, material properties and patient factors are responsible for repair or replacement of defective restoration¹⁴. The refurbishment is a minimal intervention approach to treat the defects which are superficial while localized defects which are accessible can be treated by repairing^2,9. The benefit of this minimal interventional approach to treatment of defective restorations is a restored tooth with minimal removal of healthy tooth tissue which is stronger and better able to withstand functional loads resulting in better long term prognosis. A restoration that is replaced tends to be larger than the one it is replacing therefore, extensive restorations have shorter longevity than smaller restorations in clinical service¹⁰. Gordan et al. reviewed the data published regarding the repair of composite restorations and concluded that repaired restorations had higher survival rate; improved sealing of crevice or ditch with superior longevity when compared to restorations which remained untreated. These restorations showed marginal wear after 7 years¹¹.

All restorative materials fail under masticatory loads of oral cavity and the annual failure rate of RBCs have been reported in lower range (2.2%)^12-14. Therefore, Mjor reported that nearly half of the dental restorations were done to replace existing defective restorations¹⁵. The results of the present study suggest that the replacement of faulty restorations is regarded as a preferred alternative (82%). However, the longevity of a restoration is invariably affected by the choice of repair versus replacement of a defective composite filling^16,17. Replacement of a previous large composite restoration is time consuming which may cause pulpal damage due to needless tooth structure destruction and also increases chances of tooth crown fracture^12,18. Hence, some flawed composite restorations may be salvaged to increase longevity by repairing the composite restoration¹³. Performing restoration repair, if appropriate, may conserve tooth structure and is less time consuming due to better patient experience and in some cases needs no local anesthesia¹³. Defects in composite restorations which are sound both clinically and radiographically, are the most suitable candidates for performing repair; for example defects at the cavo-surface margin, secondary caries, partial loss and discolouration^2,13. Kallio reported that repairing of old restorations leads to tooth tissue preservation and is more cost-effective than the removal and insertion of a new restoration¹⁹. This is in accordance with our finding in which 68% of the

respondents agreed that repair was less invasive than replacement. It is critical to select a minimally invasive treatment option for restorations that have already been done to increase the longevity of the tooth. The main reason for repair was found to be secondary caries (43%) by Gordon et al⁸ whereas the results of present study indicated that secondary caries (37%) was also the most common repair indication selected by the participants. Most universities in Europe (88%), USA (88%) and Scandinavia (92%) reported that they have included teaching of composite repair techniques in dental

curriculum^13,12,20. Almost all universities regard repair as a minimally invasive treatment option resulting in delaying the degradation or failure of restorations²².

Tyas reported that repair was not the usual standard of care and considered it as “patchwork dentistry”²³. Nonetheless, repair was considered a treatment of choice depending upon each case therefore, 50-71% dentists choose replacement rather than repair of the restorations. This is contradictory to our study in which 82% dentists performed replacement of composite restorations. However the findings of our study revealed that majority of dentists have not received didactic instructions about various factors during their undergraduate dental training to consider composite repair as a viable treatment option for defective restorations. Only 39% of dentists claimed that they were taught/trained the subject of composite repair during BDS and only 60% of participants recognized repair as a treatment option if required. When we inquired the dentists whether they have knowledge about composite repair, 61% replied positively as they have performed repair (60.5%) in their general dental practice.

CONCLUSIONS

There are many factors which may influence the choice to repair rather replace a defective composite restoration. Our study highlighted that the preferred choice as indication for composite repair was secondary caries and partial loss of composite restoration. More than two third of respondents agreed that repair increased longevity of a defective composite restoration. Based on the results of this survey, it is evident that most of the participants were not taught about the indications and techniques for repair of composite restorations as compared to other countries in the world. The results of this study also indicated teaching tooth restorative techniques influenced the practicing habits of dentists when considering treatment options of defective composite restoration.

RECOMMENDATIONS

It is suggested that teaching of composite repair should be vigorously implicated in teaching institutions of Pakistan as it is in the best interest of the patient. Dental students should be provided didactic and clinical training on this topic. Future research can be carried out for refining the guidelines and technique utilized for composite repair.

REFERENCES

1. Blum IR, Jagger DC, Wilson NH. Defective dental restorations: to repair or not to repair? Part 1: direct composite restorations. Dent Update. 2011;38:78-84.
2. Lynch CD, Wilson NH. Managing the phase-down of amalgam: part I. Br Dent J. 2013;215:109-113.
3. Sharif MO, Catleugh M, Merry A, Tickle M, Dunne SM, Brunton P et al. Replacement versus repair of defective restorations in adults: resin composite. Cochrane Database Syst Rev. 2006;CD005970.
4. Opdam NJM, Bronkhorst EM, Loomans BA, Huysmans MC.Longevity of repaired restorations: a practice based study.J Dent.2012;40:829-835.
5. Gordan VV, Mjör IA, Blum IR, Wilson NHF. Teaching students the repair of resin based composite restorations: a survey of North American dental schools. J Am Dent Assoc. 2003;134:317-323.
6. Gordan VV, Riley JL, Worley DC, Gilbert GH, The DPBRN Collaborative Group. Restorative material and other tooth-specific variables associated with the decision to repair or replace defective restorations: findings from the Dental PBRN. J Dent 2012;40:397-405.
7. Blum IR, Lynch CD, Wilson NHF. Factors influencing repair of dental restorations with resin composite. CliniCosmInvesti Dent. 2014;6:81-87.
8. Gordan VV, Riley JL, Geraldeli S, Rindal DB, Ovist V, Fellows JL. Repair or replacement of defective restorations by dentists in The Dental Practice-Based Research Network. JAm Dent Assoc. 2012:143:593-601.
9. Gordan VV. Clinical evaluation of replacement of Class V resin based composite restorations. J Dent. 2001;29:485-488.
10. Da Rosa Rodolpho PA, Cenci MS, Donassollo TA, Logue´rcio AD, Demarco FF. A clinical evaluation of posterior composite restorations: 17-year findings. Journal of Dentistry 2006;34:427-435. Fayyaz A / Fareed MA / Ehsan S / Repair or Replacement of Defective Direct Composite Baig QA / Noor NA JPDA Vol. 24 No. 01 Jan-Mar 2015 21
11. Gordan VV, Garvan CW, Blaser PK, Mondragon E, Mjoer IA. A long-term evaluation of alternative treatments to replacement of resin-based composite restorations: results of a seven-year study. J Am Dent Assoc. 2009;140:1476-1484.
12. Lynch CD, Frazier KB, McConnell RJ, Blum IR, Wilson NHF. Minimally invasive management of dental caries: contemporary teaching of posterior resin – based composite placement in U.S. and Canadian dental schools. J Am Dent Assoc. 2011;142:612-620.
13. Blum IR, Lynch CD, Wilson NHF. Minimally invasive management of defective composite restorations: Contemporary teaching of composite restoration repair in Scandinavian dental schools. J Oral Rehab. 2012;39:210-216.
14. Manhart J, Chen H, Hamm G, Hickel R. Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition. Oper Dent 2004;29:481-508.
15. Mjor IA, Moorhead JE, Dahl JE. Reasons for replacement of restorations in permanent teeth in general dental practice. Int Dent J. 2000;50:360-366.
16. Goldstein GR. The longevity of direct and indirect posterior restorations is uncertain and may be affected
    by a number of dentist-, patient-, and material-related factors. J Evid Based Dent Prac. 2010;10:30-31.
17. Hickel R, Manhart J. Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent.
    2001;3:45-64.
18. Yousef MK, Khoja NH. Repair and replacement perception of dental restorations. Med Sci J. 2009; 16:75-85.
19. Kallio TT, Tezvergil-MutluayA, Lassila LVJ, Vallittu PK. The effect of surface roughness on repair bond strength of light-curing composite resin to polymer composite substrate. Open Dent J. 2013;7:126- 131.
20. Blum IR, Lynch CD, Wilson NH. Teaching of direct composite restoration repair in undergraduate dental schools in the United Kingdom and Ireland. Eur J Dent Educ. 2012;16:53-58.
21. Lynch CD, Blum IR, Frazier KB, Haisch LD, Wilson NH. Repair or replacement of defective direct resin-based composite restorations: contemporary teaching in U.S. and Canadian dental schools. J Am Dent Assoc. 2012;143:157-163.
22. Hickel R,Brüshaver K, Ilie N. Repair of Restorations-Criteria for Decision Making and Clinical Recommendations. Dent Mater. 2013;29:28-50.
23. Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention dentistry – a review, FDI Commission Project 1-97. Inter Dent J. 2000;50:1-12.

1. FCPS Resident, Department of Operative Dentistry, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan.
2. Associate Professor, Department of Dental Materials Science, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan.
3. Assistant Professor, Department of Operative Dentistry, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan.
4. Assistant Professor, Department of Community Dentistry, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan.
5. Assistant Professor, Department of Dental Materials Science, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan. Corresponding author: “Dr Muhammad Amber Fareed ”< docamberfareed@hotmail.com  >

Farhan Raza Khan1                            BDS, MSc, MCPS, FCPS

Sadia Mahmud2                                   MSc, MS, PhD

Munawar Rahman3                            BDS, MCPS, DDS

INTRODUCTION

Endodontics is a branch of dentistry that is concerned with the diagnosis and treatment of dental pulp and associated periapical diseases^[1]. It is considered as one of the most skill intensive discipline of dentistry. In other words, the psychomotor skill of the clinician has the most bearing on the success and failure of an endodontic case^[2]. Globally, a wide majority of the root canal treatment are still undertaken by general dental practitioners. Although, studies have compared endodontists or endodontic residents with general practitioners for their decision making and quality of root canals but we have appraised this quality of endodontic care with a different approach. Whitworth et al. ^[3] showed that there was a significant difference in the endodontic practice and among dental graduates of 70’s compared to a younger group (graduates of 90’s) from British dental colleges (n=643 participants). This kind of compassion is not applicable in our scenario because there were only a few dental institutions in Pakistan before 1990 and the dental community in Pakistan is mainly a young cohort (median age 35 years). However, we speculated that there would be significant difference between dentists belonging to academic institution (irrespective of their specialty training) compared to general practitioners. This has stemmed from the observation that a considerable proportion of dentists do not adhere to the stated guidelines on the quality of root canal treatment⁴.

The professional education, advanced training and practice environment appear to be major determinants of clinical decision making in dentistry. Other important factors are individual preferences, availability of resources and clinical workload. There are two major avenues that provide dental care to the public; private dental clinics and the dental institutions. Cost effectiveness and time restraints are the two important factors that dictate the decision making in private practice. Therefore, we hypothesized that the endodontic services vary with the type of the clinical setup. Thus, it’s imperative to map the endodontic practice.

OBJECTIVE

The objective of the study was to compare the knowledge regarding endodontic materials and techniques selection among dentists employed at dental institutions and private practices in Karachi.

METHODOLOGY

Across sectional study was done at twelve dental colleges and their affiliated teaching hospitals in Karachi and selected private dental practices located in Karachi. We included PMDC registered dentists and excluded ones whose information was incomplete or deemed retired or deceased.

Pakistan Dental Association Karachi office provided the list that served as sampling frame. The data was last updated in 2007. A stratified random sampling approach was used to select the study participants in teaching and non-teaching groups. WHO sample size software was used and a sample size of 75 teaching dentists and 220 non-teaching dentists was calculated. Aga Khan University Hospital ethical review committee approved the protocol (573-Sur/ ERC-06). The informed consent of the participants was taken. A structured, selfadministered questionnaire (written in English) regarding preferences, selection of materials and techniques was used. The questionnaire had two parts:

• First part dealt with demographics (independent variables)
• Second part had 11 questions on endodontics practice (response variables).

Data Collection: Questionnaires were circulated to the study subjects by hand. A telephonic reminder was made at an interval of 2 weeks for non-responders. A second reminder was made at an interval of four weeks then collection of questionnaire was done. Two questions were repeated at the end to establish the information reliability.

Data Analysis: SPSS 19.0 was used for the data analysis. Means and standard deviations of the quantitative variables and proportions for the categorical variables were determined. The response variables in the study were about the preferences in material and clinical technique selection. These responses are measured on nominal or ordinal scale.

Independent sample t-test was applied to compare numerical variables (age and experience of the participants). Chi Square test (or Fisher’s exact test) was applied to determine if endodontic knowledge and material selection are different for the two groups. For the ordinal data, Mann-Whitney U test was used. A p-value less than 0.01 was taken as statistically significant. Kappa statistic was used to determine percent agreement between the first and second response on the two repeated questions.

RESULTS

In the teaching groups, 71 out of 75 (94.6%) responded while in the practitioners group, only 97 out 220 (44.1%) returned the forms. Both groups showed comparable result for age (p-value 0.1) and years of experience (p-value 0.07) as exhibited in table 1.

Table 2 displays that out of 168 participants; there were 71 (42.3%) teaching and 97 (57.7%) non-teaching dentists. There were more males in either group.

The decision making in routine Endodontics (table 3) was significantly different for the two groups. This included use of engine driven endodontic equipment, Gates-Glidden burs, irrigants selection, use of intra canal medicaments, use of endodontic sealer and preferred obturation technique (p-value < 0.001). More teachers

used engine driven endodontic equipment and GatesGlidden burs than private practitioners. A larger proportion of private practitioners used peroxide irrigant, puperyle and eugenol based intra canal medicaments and ZOE based endodontic sealer than the teaching dentists (p-value < 0.001). In addition to cold lateral compaction technique for obturation, more teachers utilized utilize warm vertical, warm lateral or thermoplasticized gutta percha than the practitioners (p-value < 0.001).

With regards to the decision making in surgical endodontics and restoration of root  treated teeth (table 4), the two groups had differences between them regarding core build up material selection (p-value < 0.001), decisions about failed root canals (p-value < 0.001) and method of gaining retention on root treated teeth (p-value < 0.001). However, the two groups were similar in their preference for core build up technique selection (p-value 0.04) and flap design selection for periapical surgery (p-value 0.89). The reliability of our study data was excellent, Kappa value 0.81 to 0.88 (table 5).

DISCUSSION

Whitworth et al.³ did a survey amongst two groups of dentists, an older group (graduates of 70’s) and a younger group (graduates of 90’s) from British dental colleges (643 participants). Questions were asked on use of rubber dam, selection of irrigant and factors influencing endodontics practice. The response rate was 85%. Investigators observed that the local anesthetic was the most commonly used endodontic irrigant. Irrigant selection was strongly associated to the use of rubber dam and to the graduation cohort. About 75% of rubber dam users irrigated with sodium hypochlorite, compared with only 38% of nonusers. This pattern was reversed for local anesthetic irrigation i.e. younger graduates more likely to irrigate with local anesthetic than their older counterparts. Our study results are somewhat different than Whitworth’s survey as 70-73% respondents reported hypochlorite as preferred irrigant and we did not find any association between age of the participant and irrigant selection. The probable explanation of this finding is that in our sample constituted of mainly young subjects in both the study arms (mean age of nearly 33 years in each group). With the relative absence of older age dentists in the study, any association of irrigant use with dentist age is meaningless.

Wilson & Christensen⁵ investigated on endodontics practice in England and Scotland. They sent questionnaire to 1,000 randomly selected dentists and obtained 70% response rate. The most commonly used obturation technique was the cold lateral condensation (75%). Our results are in accordance with Wilson & Christenson as 75-95% of our respondents reported cold lateral compaction as their preferred obturation technique.

In our study, calcium hydroxide and pulperyle was the predominant intra-canal medicament. About 75-80% of our respondents favored calcium hydroxide based sealer along with obturation whereas only 8-23% selected ZnO based sealers. Jenkins & Hayes⁶ who collected information from the dental graduates of Cardiff, UK with a study response rate of 41.5% reported that antiseptic solution was the most preferred interappointment medicament in UK. Two-thirds of practitioners in UK used a zinc oxide based material as their root canal sealer. Thus, dentists in Pakistan have significantly different preferences than dentists in UK regarding root canal sealers.

Slaus & Bottenberg⁷ studied routine endodontics performed by 4,500 Flemish dentists (Belgian belonging to dutch background) and obtained 25% response rate. The most preferred root canal irrigant was sodium hypochlorite. AH26- resin based sealer was the most prevalent and nearly 80% dentists reported that they performed re-treatments. Our sample is different from Flemish dentists as only 1-5% of Pakistani dentists use resin based sealer and only 27-34% reported carrying out endodontic re-treatment themselves.

Hommez & Braem⁸ and Hommez & De Moor⁹ obtained information on root canal treatment in Belgium: A questionnaire was distributed to 312 dentists in Flemish Universities. Data on various issues relating to endodontics was gathered. The response rate was 99%. The results of this study indicate that the theoretical knowledge of dentists is good. They reported that approximately one-third of the dentists did not use any intra-canal medicament. Cold lateral condensation of gutta-percha was the widespread obturation method employed by the respondents (65.8%). Resin-based

sealers were prevalent (88.6%). The findings of Hommez & colleagues 8-9 on root canal obturation technique and endodontic referrals are somewhat very close to our Pakistani data except that resin based sealer are not favored here.

Ahmed & colleagues¹⁰ evaluated the endodontic practice in Sudan. Fifty-two dentists responded to questionnaire. Nearly 80% respondents selected hydrogen peroxide as the irrigant of choice and around 75% dentists used formocresol as an inter-appointment medicament. Almost all dentists used hand instruments to prepare root canals.  Cold lateral condensation was the most favored obturation technique (75%). It’s evident that Pakistani dental practitioners exhibited significantly different choices in endodontic practice than Sudani dentists. About 43-60% of our dentists routinely use Engine driven rotary endodontic instruments and the numbers are continuously rising.

Our study showed that the two study groups exhibited entirely different choices in Surgical Endodontics and restoration of endodontically treated teeth, core build up material, decisions about failed root canals and method of gaining retention on root treated teeth (p-value < 0.001). However, they were similar in flap designing for surgical endodontics.

Our study results can be compared to a number of studies^4-10 on this subject but it would be irrelevant to compare our local data to developed countries where the prevalence of dental diseases and hence demand of dental services may be different. Availability of material resources can be factor for inappropriate decision making in some clinical scenarios in our study. However, our study has the advantage that it has included both the conventional and surgical aspects of endodontics. It’s a high time for dentists to engage themselves in a life long continuing education to predictably carry out goodquality dentistry.

STRENGTHS & LIMITATIONS

The response rate from the non-teaching group (44.1%) appears low but upon exploring into the reasons behind this feeble response rate, it’s revealed that the busy clinical practitioners are not interested in filling out questionnaires & proformas during work hours. On similar studies, Jenkins⁶ in UK had a response rate of 41.5% and Slaus⁷ had a response rate of 25% in Belgium. This proposes that it’s not uncommon for practicing dentists to give low response rate on such questionnaires^11-12 in this context; our response rate of 44.1% does not appear that weak. Since, the detailed demographic information of non-responding subjects was not available, so we could not explore any further in this direction. This non-response has the potential to give rise to biased results.

In comparison to the practitioners, the teaching group showed a better compliance in responding to the questions. Probably they were more conversant to research activities and hence unruffled in participation. Our study included dentists from all dental colleges except one because that particular dental institution refused the permission for distribution of questionnaire.

CONCLUSIONS

. The two groups of dentist showed similarities in selection of irrigants as they both preferred sodium hypochlorite for irrigation. The obturation technique for both groups was cold lateral compaction. Flap design selection for periapical surgery was also common for the two groups. Similarly, amalgam remained the material of choice for core build up in both the groups. . However, there were significant differences in the following parameters: Teaching group favoured calcium hydroxide based endodontic sealer while practitioners favoured ZnO based sealer. The decision making about failed root canals and method of gaining retention on root treated teeth were different as teaching dentists favoured more crown lengthening and attempted periapical surgery more frequently than the non-teaching dentists.

RECOMMENDATIONS

Re-validating the dental practice license after accumulating required numbers of continuing professional development hours should be made a mandatory requirement for practicing dentistry.

REFERENCES

1. Torabinejad M, Walton RE. Endodontics: Principles and Practice 4th ed. Mosby Elsevier, St Louis, MO, 2011.
2. Mounce R. The biologic objectives of root canal therapy: meeting the standard. Compend Contin Educ Dent. 2004; 25: 578-581.
3. Whitworth JM, Seccombe GV, Shoker K, Steele JG. Use of rubber dam and irrigant selection in UK general dental practice. Int Endod J. 2000; 33: 435-441.
4. Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod
   2004; 30: 559-597.
5. Wilson NH, Christensen GJ, Cheung SW, Burke FJ, Brunton PA. Contemporary dental practice in the UK: aspects of direct restorations, endodontics and bleaching. Br Dent J. 2004; 197:753-756.
6. Jenkins SM, Hayes SJ, Dummer PM. A study of endodontic treatment carried out in dental practice within the UK. Int Endod J 2001; 34: 16-22.
7. Slaus G, Bottenberg P. A survey of endodontic practice amongst Flemish dentists. Int Endod J. 2002; 35: 759-
   767.
8. Hommez GM, Braem M, De Moor RJ. Root canal treatment performed by Flemish dentists. Part 1. Cleaning and shaping. Int Endod. 2003; 36:166-173.
9. Hommez GM, De Moor RJ, Braem M. Endodontic treatment performed by Flemish dentists. Part 2. Canal filling and decision making for referrals and treatment of apical periodontitis. Int Endod J. 2003; 36: 344-351.
10. Ahmed MF, Elseed AI, Ibrahim YE. Root canal treatment in general practice in Sudan. Int Endod J. 2000;
    33: 316-319.
11. Khan FR, Mahmud S, Rahman M. Pediatric dentistry training for dentists in Pakistan. J Pak Dent Assoc 2013;
    22: 03-08.
12. Khan FR, Mahmud S, Rahman M. Is there a difference in Operative Dentistry Care offered by teaching versus non-teaching dentists? J Pak Dent Assoc 2014; 23:30-35.

1. Assistant Professor, Operative Dentistry Dental Clinics, JBHS Building Aga Khan University & Hospital Stadium Road, 74800, Karachi.
2. Associate Professor, Department of Community Health Sciences Aga Khan University, Karachi.
3. Senior Lecturer, Operative Dentistry Dental Section, Aga Khan University, Karachi.
Corresponding author: “Dr Farhan Raza Khan ” < farhan.raza@aku.edu  >

Shahbaz Khan1                                        BDS, MPhil (Scholar)

Muhammad Amber Fareed2              BDS, MSc, PhD

Muhammad Kaleem3                            BDS, MSc, PhD

Shahab Ud Din3                                       BDS, MSc, PhD

Kefi Iqbal4                                                 BDS, MSc, PhD

INTRODUCTION

The use of a material for restoration of endodontic and its associated periodontal defects require excellent integrity and compatibility with the surrounding biological environment¹. In addition to excellent sealing ability and marginal adaptation², an ideal endodontic material is required to generate a conductive healing environment for pulpal  tissues¹. The introduction of Mineral Trioxide Aggregate (MTA) led to considerable interests in its wide spread endodontic applications because of superior physical and biological properties over other materials. MTA is reported as material of choice for various clinical applications such as, pulp capping³, pulpotomy⁴, apexification⁵, repair of perforations⁶ and root end filling⁷ due to its favorable properties like excellent biocompatibility⁸, sealing ability⁹, marginal adaption¹⁰, minimal solubility¹¹, and ability to regenerate dentin¹² and cementum⁶.

An updated review of current knowledge regarding compositional analysis, material characteristics, setting behavior, mechanism of action and physical properties of MTA was provided in part-1 of the review. Whereas, aims of the part-2 updated review are to emphasize biological properties of MTA, its clinical applications and to provide a comprehensive comparison of MTA  with other alternative materials. Therefore, a systematic research of previously published work in PubMed/MEDLINE (National Library of Medicine, Bethesda, MD), Scopus and Google Scholar databases were conducted from 1995 to November 2014 using different combinations of the following key words: “mineral trioxide aggregate”, “biological properties”, “clinical applications” and “calcium silicate cements”. The literature was screened by authors for relevancy and key findings of the current concepts of MTA are reported here.

2. Biological properties

2.1 Biocompatibility

Endodontic materials are often placed in direct contact with periodontal tissues therefore they are required to be biocompatible¹³. MTA is a non-mutagenic¹⁴ and nonneurotoxic material¹⁵ which does not exert adverse effects on microcirculation¹⁶ therefore, it is considered as the least cytotoxic dental materia^8,17-20. Torabinejad et al., showed that MTA either freshly mixed or set, is less cytotoxic then Super EBA (alumina-fortified cement) and IRM (reinforced zinc oxide-eugenol cement)⁸. Moreover, cytotoxicity and cellular attachment of cell cultures have reported better results for MTA compared to Ketac Silver¹⁷, glass ionomers²¹, gutta percha²², Diaket²¹, Dycal²³ and calcium hydroxide²⁴ and have comparable degree of cytotoxicity as that of chemically inert titanium alloy¹⁸. MTA have good interaction with mineral tissue forming cells and released collagen²⁵. According to Koh et al., MTA acts as a biologically active substrate for bone forming cells and up regulates interleukin production²⁶ and shows minimal or no inflammatory response when placed in contact with soft tissues²⁷. Moreover, intraosseous implantation studies also revealed mild reaction to MTA with only minor inflammation^22,28.

2.2 Mineralization

MTA induced mineralization of dentine and cementum^12,29-31 and the induction of mineral tissue formation by MTA is attributed to its excellent sealing ability, biocompatibility, alkalinity and other material characteristics^2,10,32. According to Holland et al., calcium released from MTA reacts with carbon dioxide present in pulp tissue to form calcite crystals followed by observation of fibronectin rich extracellular network around the crystals to initiate mineral tissue formation³³.

The ability of MTA to induce mineral tissue formation is considered similar to calcium hydroxide³⁴ however, in the case of MTA hard tissue bridge formation is more fast, thick and with uniform structural integrity in comparison to calcium hydroxide^35,36. Ford et al., compared calcium hydroxide and MTA for direct pulp capping and reported that all teeth capped with MTA were free from inflammation and at five months showed formation of calcified bridges, whereas, calcium hydroxide treated teeth showed inflammation and significantly less calcification³⁷.

2.3 Bioactivity of HA surface layer

The precipitation of HA on MTA surface is of great significance since HA is a biocompatible, bioactive, osteoconductive and osteogenic material^38,39. It should be emphasized that cellular adhesion and spreading is dependent on specific interactions between integrins and extracellular matrix⁴⁰. These interactions control intracellular signals and significantly influence a number of cellular functions such as, proliferation, differentiation and apoptosis^41,42. HA have strong adsorptive affinity for proteins and its bioactive nature may be explained by its ability of binding to serum proteins and growth factors which promotes adhesion and proliferation of mineral tissue forming cells^43,44.

2.4 Antibacterial and antifungal properties

The antibacterial effects of MTA can be attributed to its high pH² and its ability to prevent bacterial ingress into root canals by virtue of its excellent marginal adaptation and sealing ability⁴⁵. However, its direct antibacterial effect is limited and dependant on powder/water ratio used for mixing². Torabinejad et al., investigated antibacterial effect of MTA, amalgam, zinc oxide eugenol and super EBA on nine facultative and seven anaerobic bacteria and

showed that MTA have antibacterial effect on some of facultative bacteria, but no effect on anaerobes. Whereas, zinc oxide eugenol and super EBA showed some antibacterial effect on both types of bacteria⁴⁶. Whereas, Estrela et al. reported superior antibacterial activity for calcium hydroxide paste compared to MTA against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, Bacillus subtilis and Candida albican⁴⁷.

3.Clinical applications and performance of MTA

MTA is a material of choice for a number of endodontic applications such as pulp capping³, pulpotomy⁴, perforation repair⁶, apexification⁵ and root end filling⁷. This section will discuss the following clinical application bellow.

3.1 Pulp capping

Aeinehchi et al. compared MTA and calcium hydroxide as pulp capping agents after mechanical pulp exposure and reported the formation of dentinal bridge and mild chronic inflammation at 2 months after capping with MTA. While teeth capped with calcium hydroxide showed irregular and thin dentinal bridge formation with associated pulpal inflammation, hyperemia and necrosis after 3 months³⁵. Nair et al., compared the histological outcomes of MTA and calcium hydroxide after capping intact third molars and showed that most MTA specimens were free from inflammation after 7 days, whereas at 1 month majority of specimens showed the presence of hard tissue formation which advanced and thicken with time. In contrast, specimens treated with calcium hydroxide showed inconsistent hard tissue formation³. Tuna and Olmez investigated the performance of calcium hydroxide and MTA in capped primary molar teeth and reported clinical as well as radiographic success for both materials after 24 months⁴⁸. Moreover, successful treatment of either mechanically or cariously exposed pulps of permanent teeth by MTA is also reported^49,50. Bogen et al., reported clinical and radiographic success rate of 97.96% in permanent teeth capped with GMTA or WMTA after carious exposure⁵¹.

3.2 Pulpotomy

MTA is advocated as a suitable material for pulpotomy and an alternative to calcium hydroxide⁵². Holan et al., reported 14% higher success rate for GMTA compared to Formocresol as pulpotomy material in primary molars⁵³. Chako and Kurikose investigated outcomes of MTA and calcium hydroxide as pulpotomy materials in premolars and reported relatively less inflammation and better dentinal bridge formation in specimens treated with MTA³⁰. Similarly, histological study of cariously exposed pulps showed complete bridge formation at 2 months after treatment with MTA⁵⁴.

3.3 Root end filling

MTA is considered as the most biocompatible material for root end filling⁵⁵. Favieri et al. reported successful treatment of a maxillary lateral incisor having perforationof buccal cortical bone with MTA as a root end filling in combination with lyophilized bone and calcium sulphate for osteoinductivity and osteoconductivity⁵⁶. A prospective case series study on 276 teeth with root end fillings of WMTA reported clinical and radiographic (88.8%) success after 4-72 months⁵⁷. A clinical trial that compared WMTA root end filling with orthograde guttapercha showed significantly better healing in teeth with WMTA root end filling⁵⁸.

3.4 Apexification

Calcium hydroxide is considered as the material of choice for apexification and its use has been advocated for many years⁵⁹. However, calcium hydroxide apexification procedures require multiple visits and are also susceptible to root fractures^59,60. Several studies have reported successful effects of MTA for the treatment of teeth with necrotic pulps and open apexes^61-63. Pradhan et al., assessed the outcomes of calcium hydroxide and GMTA for forming apical barrier and reported that calcium hydroxide required significantly longer time to induce hard tissue barrier compared to GMTA⁶². Similarly, evaluation of WMTA and calcium hydroxide for the  treatment of immature roots showed no failure for WMTA treated teeth, whereas clinical and radiographic signs of failure were shown by 13.33% calcium hydroxide treated teeth⁶³. Holden et al., studied the outcomes of WMTA or GMTA for inducing apical barrier in cases with necrotic pulps and open apexes for a period of 12-43 months and reported 85% success rates⁶⁴.

3.5 Repair of root perforation and resorption

The use of MTA is also promoted for root perforations repair and has demonstrated successful outcomes^65,66. Main et al., reported no clinical and radiographic pathological changes in teeth with various types of perforations treated with MTA after 12-45 months⁶. Likewise, 90% teeth healed after treatment of perforations in furcation or cervical third of root with MTA⁶⁶. Additionally, a number of studies reported successful treatment of external as well as internal resorption with MTA67-69.

4. Other available materials

Although MTA embraces ideal characteristics of an endodontic filling material but its usage in dentistry remained limited due to certain potential drawbacks such as difficult handling characteristics, extended setting time, discoloration and higher cost². Due to the shortcomings of MTA, a need for modifications in its properties was felt and led to extensible research to develop improved versions of MTA. The white variant of MTA is considered as first modified version of MTA, which was introduced by the manufacturers of original gray formulation⁷⁰. WMTA was introduced to overcome the potential discoloration associated with the use of GMTA^2,70. The basic difference between the two variants of MTA was exclusion of iron from WMTA’s composition^71-73. Over the years a number of modified or alternate materials with similar composition to MTA have been introduced. Some of these alternate materials includes: gray MTA Angelus (AGMTA) and white MTA Angelus (AWMTA) (Angelus Solucoes Odontologicas, Londrina, PR, Brazil)⁷⁴ MTA Bio (Angelus Solucoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont, Saint-Maur-Fosses Codex, France)⁷⁵, DiaRoot Bioaggregate (Innovative bioCeramix, Vancouver, BC, Canada)⁷⁶ and MTA Plus (Avalon Biomed Inc., Bradenton, FL, USA)⁷⁷.

4.1 MTA-Angelus

According to manufacturer, MTA-Angelus contains calcium silicates (PC) and bismuth oxide⁷⁴. Compositional comparison of MTA-Angelus and PC have shown similar constituents and both materials contained an aluminate phase⁷⁸ and no detectable amount of sulphate^78,79. The absence of calcium sulphate and presence of aluminate phase in MTA-Angelus was aimed at reducing setting duration⁷⁸ to 10-15 minutes⁸⁰ which was significantly less than reported setting duration of MTA⁸¹. Although similar loading of bismuth oxide in MTA-Angelus and MTA has been reported⁷⁹ however, Song et al., have shown less amount of bismuth in MTA-Angelus compared to MTA⁸². The release of heavy metals (arsenic) for both MTA-Angelus and MTA was similar and at values that do not harm human tissues⁸³. Clinical studies have shown successful results for MTA-Angelus in the treatment of internal resorption⁸⁴ and root perforations⁸⁵.

4.2 MTA Bio

MTA Bio is a white variant of calcium silicate material which is similar in composition to ‘white MTA Angelus’ instead and introduced by the same manufacturer⁸⁶ which claims its synthesis in a specially controlled laboratory environment to ensure it free from undesirable contaminants, especially arsenic⁸⁷ MTA Bio has identica indications as for MTA and stimulate biomineralization⁸⁶ and have low cytotoxicity⁸⁸

4.3 Biodentine

Biodentine like MTA, is based mainly on tricalcium silicate⁸⁹ however, in contrast to MTA it contains zirconium as a radiopacifying agent and does not contain tricalcium aluminate⁷⁸. The compositional analysis of Biodentine shows 15% loading of calcium carbonate which acts as nucleation site and improves the microstructure as well as setting characteristics of Biodentine^90,91. The liquid of Biodentine consists of calcium chloride and a water reducing hydro-soluble  polymer (polycarboxylate)⁷⁸ for ease of handling and faster setting reaction. However, the surfactant effect of hydrosoluble polymer is responsible for unfavorable washout characteristics of Biodentine⁹². Moreover, addition of zirconium instead of bismuth oxide resulted in low radio-density of Biodentine compared to other calcium silicate endodontic materials⁹³. Studies have advocated use of Biodentine for pulp capping⁹⁴, pulpotomy⁹⁵ and retrograde filling⁹⁶.

4.4 Bioaggregate

Bioaggregate is also a tricalcium silicate based reparative material with same indications as MTA⁹⁷. Resembling Biodentine, Bioaggregate also lacks the tricalcium aluminate phase which is verified by XRD analysis of powder as well as set form of the material^70,78,97. Moreover, unlike MTA, Bioaggregate diffraction patterns showed strong peaks of tantalum oxide added by the manufacturer for radiopacity^70,97. The MSDS indicates addition of calcium monophosphate (HA) and amorphous silicon oxide in Bioaggregate⁷⁶ which reduced the content of calcium hydroxide in the set structure of the material^70,93. The sealing ability of Bioaggregate is comparable to MTA⁹⁸ and is also shown to favor cell attachment and osteocalcin expression⁹⁹. Chung et al., showed that Bioaggregate was nontoxic to human pulp and periodontal ligament cells and its biocompatibility was comparable to MTA¹⁰⁰.

4.5 MTA Plus

MTA Plus was recently introduced and there are few studies regarding its material characteristics and properties. MTA plus is almost similar in composition to MTA and MTA-Angelus, but its particle size is finer in comparison to MTA and X-ray diffraction showed  similar mineral phases⁷⁰. Evaluation of specific surface area of MTA and MTA Plus indicated that MTA Plus have surface area (approximately 1.5 times that of MTA), which was attributed to its finer particle size⁹⁰.

5. Conclusions

This review systematically summarized the contemporary knowledge regarding biocompatibility, bioactivity and clinical applications of MTA. Cell culture studies indicated both gray and white variants of MTA are non-toxic, non-mutagenic, relatively inert and superior in maintaining cell viability. The precipitated HA surface layer on MTA provides an active substrate for adhesion and proliferation of mineral tissue forming cells. The ability of MTA to induce mineralization of dentin and cementum is relatively superior to calcium hydroxide and promotes comparatively homogenous and thicker dentinal bridges. Clinical studies documented best results for MTA and by the virtue of its excellent biocompatibility, sealing ability, marginal adaptation, and antibacterial effects indicated it to be the material of choice for pulp capping, pulpotomy, apexification, repair of root perforation and resorption and root end filling. The modified or alternate products for endodontic applications inspired from MTA can be employed in clinical practice if they overcome potential weaknesses of the predecessor and have generally superior properties. Indeed the aforementioned variants of MTA material were successfully modified from the original MTA however; considerable evaluation in laboratory and in clinical trials is required to improve clinical practices.

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1. Phil Student, Department of Dental Materials, Army Medical College, National University of Sciences and Technology, Islamabad, Pakistan. Department of Operative Dentistry, Bolan Medical College, University of Balochistan, Quetta, Pakistan.
2. Associate Professor, Department of Dental Materials Science, FMH College of Medicine and Dentistry, University of Health Sciences, Lahore, Pakistan.
3. Assistant Professor, Department of Dental Materials, Army Medical College, National University of Sciences and Technology, Islamabad, Pakistan.
4. Professor, Department of Dental Materials Science, Baqai Dental College, Baqai Medical University, Karachi, Pakistan.

Corresponding author: “Dr Muhammad Amber Fareed ”<docamberfareed@hotmail.com >

‘Cheating is a choice, not a mistake’- Anonymous

lagiarism in its most simple form means to copy paste someone else’s work and represent it as your own. Plagiarism is not only morally and ethically incorrect but it’s a theft a crime. . The holy prophet (PBUH) abhorred theft crimes and prescribed harsh punishments for it. It is surprising to note that that in our Muslim dominated country, the instances of this form of misconduct among scientific community is on the rise. It is therefore, the duty of our editorial board to educate our readers about this crime.
A recent survey by Turnitin, the market leader for detecting plagiarism, has outlined various types of plagiarism1

• Let’s visit each type with a hope that our readers will develop a better understanding of the topic.

1. CLONE: It happens when a published paper is copy pasted with-out changing a word. Exceptions to this type of plagiarism are instances where the authors have mistakenly uploaded their work on HEC or any other repository while checking it for plagiarism. If such a paper is checked second time, a 100% similarity will be displayed. It is important for new users of turnitin to be aware of this issue and always uncheck this option while performing plagiarism check. Also make sure not to give your manuscript to anyone for plagiarism checking who might do the same mistake. In past turnitin used to entertain retractions of such erroneous repository submission, not anymore. Only solution now is to rewrite. In our experience this is one of the biggest problems faced by authors who submit thesis based manuscripts.

2. CTRL-C: It is another common mal-practice where the author simply changes a few values in results or a few words here and there from a single source. We have rejected one paper where entire article was plagiarized
from a single source and only the values in results were changed.
3. FIND-REPLACE: This is very similar to the above mentioned one. Only difference is that in this type, words or even entire phrases are changed but the essential content of the source is retained.
4. REMIX: As the name suggests, content is copied from various sources and is re-phrased and fit together.
5. RECYCLE: This is an example of self-plagiarism where one uses his own previous work without proper citations and presents it as something new.
6. HYBRID: It is similar to remix; only difference is that the citations are removed to make it look original.
7. MASHUP: Similar to remix and hybrid.
8. 404 ERROR: This type includes misquotations. This is also a very common mal-practice. In this type the author fabricates the results of published data and cites it usually in the discussion part to justify his results.
9. AGGREGATOR: This happens when the copy pasted and re phrased manuscript contains proper citations. Entire work is plagiarized, just like in CTRL-C
10. RE-TWEET: Similar to Aggregator. The readers are encouraged to visit the turnitin website to get a better idea of each type of plagiaism. The editorial team of Journal of Pakistan Dental Association hopes that this editorial will help improve their understanding of the subject and that they will exercise maximum caution.
Plagiarism and academic misconduct was also a hot topic at a recently concluded conference in Iran on publication ethics2

• This conference was a joint venture with Committee on Publication Ethics (COPE), UK. The readers are encouraged to visit the website of Pakistan Journal of Medical Sciences and read the full report of the conference.

Dr Arshad Hasan
Associate Editor

REFERENCES
1 http://go.turnitin.com/paper/plagiarism-spectrum
2 Jawaid SA. Second International Conference on Publication Ethics organized by Shiraz University of Medical Sciences (Shiraz Iran December 4-5, 2014). Pak J Med Sci 2015;31(2):251-262.