News

Fizza Abidi                                               BDS

Mervyn Hossein                                     FDSRCS(Ed), FDSRCS, FFDRCSI

Saima Akram                                          BSc, BDS, MDS

Angabeen Anjum                                   BDS

INTRODUCTION

The integrity of the human genome is maintained by DNA damage response pathways which includes DNA repairing, chromatin remodelling, cell cycle checkpoint regulation and apoptosis.1-3 There are different types of DNA damage repair pathways which include Nucleotide excision repair (NER) pathway, Base excision
repair pathway(BER), Mismatch excision repair(MER) pathway and Double strand breakage repair (DSB) pathway
and if these pathways are not regulated properly then leads to the process of tumourigenesis.4 The DNA repair mechanism failure and the risk factor for the familial genetic cancer had been established earlier, from last 20 years studies had reported the possible association of genetic polymorphism and cancer formation.5 An electronic article search was done by using keywords Nibrin, NBS1, DNA Damage Response Pathway (DDR) and P95on Google Scholar, PubMed. Different types of research articles including original, review, clinical observation, case reports, longitudinal studies and randomized con trolled trials were selected. The aim of the review is to point out the impact of double-strand breakage and the role of Nibrin in development of cancers.
The double-strand breakages are pathological insults for all microorganisms because they can cause the gain or loss
of the essential genetic information, leading to the genetic transformation which provokes the process of tumourigenesis. DNA replication stress are the main causative factor for endogenous double strand breakage. The double strand breakage are responsible for the destruction of the genetic information by lethal metabolites includes UV radiation, products of cellular metabolism, harmful chemicals and toxins. Scientist has been working for the last 40 years to discover the specific critical role of DSB to understand the phenomenon.5-7 There are 800 DNA damages occurring per hour, estimated upto 19,200 DNA damages occurring daily.8,9
In humans, The DNA damage may increase the process oftumour formation if they remain unchecked. There are
different pathways to conserve the integrity of the human genome by controlling the DNA damage repair and controlling the program cell death.4,10
The Double strand breakage of DNA consists of 2 important pathways: Non-homologous end joining (NHEJ) and the Homologous repair pathway, In non homologous pathway DNA breaks down occurs and the broken DNA
strand is covered by specific enzymes .The Non-homologous repair are independent on homologous template, the double strand breakage are detected by sensor proteins, that causes activation of proximal kinases such as ATM and MRN complex ., However, Nibrin plays an pivotal role by controlling the enzymatic activity of these proteins ( MRE
11and Rad 50) by identifying the damage sites in DoubleStranded Breakages within 5 minutes that is called as Nibrin relocalization, Nibrin is phosphorylated by ATM in response to DNA damage that is called as Nibrin phosphorylation, this process of phosphorylation plays an important role in cell cycle S phase checkpoint activation.11-13
Homologous repair are error-free whereas they require homologous template such as sister chromatid. The DNA
end-resection enzymes which includes MRE11-RAD50- NBS1(MRN complex), the CtIP, Exonuclease 1 plays an important role in the formation of single stranded DNA, Whereas RAD 18 involves in the process of translation of
DNA synthesis. The non-homologous end-joining contains the group of DNA dependent protein kinases (kuo, ligases, nuclease, and polymerase) which are responsible for converting the non-ligating proteins to ligating protein in the presence of factors for protein alignment which act as a caretaker for genomic stability and chromosomal aberrations in the immune system. Thus, DNA ligases IV are the characteristic hallmark of the NHEJ pathways.Deficiency of DNA ligase IV will increase the immunodeficiency and radiosensitivity in the phenotypes and are known as NIJMEGEN BREAKAGE SYNDROME in which there is a defective formation of a protein called Nibrin.14-16
The nibrin protein interacts with functional proteins like ataxia-telangiectasia associated protein(ATR), histones
modifying enzymes such as RNF20 and chromatin remodelling granules (nucleolin). These useful interactions
perform a major role in DSB pathways and a pivotal role in cell cycle regulation.9
Nibrin/p95/ NBS1 is a protein formed by a defective gene NBS gene and it is an important member of the DNA
double-strand break (DSB) repair complex (hMre11 complex) located on human chromosome 8q21 and act as a cell cycle s phase checkpoint.8
The MRN complex a trimeric combination ofMre11, Rad 50, & NBs1. This Nibrin containing protein complex plays a crucial role in regulating numerous phases of doublestrand breakage and repair pathways.17,18 A 754 amino acid containing protein Nibrin, consists of three districts: the N-end containing forkhead-associated domain and two breast cancer-associated domains ( BRCA and carboxy-terminal BRCT), a Central region containing Ataxia telangiectasia mutated kinase (ATM Kinase) and C-terminal for the binding site of MRN complex (MRE 11 and ATM binding Domain). Recent investigations showed that greater than 600 polymorphism variants of Nibrin gene had been reported.17,19
Researchers have reported that more than 10 mutations of Nibrin had been observed earlier and are more frequent in Polish and Czech populations. However, the most frequent mutation of Nibrin is 5 base pair deletion (657del5) in the NBS1 gene which is accountable for a reduction of protein size, i.e. truncation of the Nibrin protein (p95) into two uneven reduced protein fragments which include p26 and p70. (NIBRIN).11,20,21 Nibrin acts as a guardian maintaining genomic stability because it is a presenter of chromosomal dysfunction. Any mutation in the MRN complex due to SNPS or reduction in full length nibrin protein formation stimulates the process of double-strand breakage by increasing the mis-localizationof Mre11 and Rad 50 in the cytoplasm of the cells. All these cyclic events cause a deficiency of protein kinases, which stimulates the formation of Nijmegen breakage syndrome.12,22
The Nijmegen syndrome is an autosomal recessive disorder specified by a mutation in the N BN gene, loss of
chromosomal stability, increased insensitivity to ionization radiation, immunodeficiency, mental retardation and ovarian insufficiency. The major life-threatening complication of Nijmegen syndrome is lymphoma in childhood.23-25

ACTIVATION OF NIBRIN

Nibrin is activated by proto-oncogenes such as C-MYC. The function of C-MYC includes diverse cellular functions
such as cell formation and maintains the integrity of cellular metabolism. Deregulated overexpression of c-myc occurs in a broad range of human cancers and is often associated with aggressive, poorly differentiated phenotypes.
Overexpression of oncoprotein C-MYC is associated with cancer formation in humans, which further stimulates the
overexpression of Nibrin which causes downstream Activation of Phosphatidylinositol (PI) 3-kinase/Akt pathway, this pathway regulates the cellular proliferation, cellular growth and cellular survival. , Phosphatidylinositol (PI) 3-kinase causes down-regulation of tyrosine kinase growth receptors. and activation of phosphorylation of Akt (protein kinase BPKB) controls the cell proliferation and survival proteins e.g. glycogen synthase kinase-3 , GSK3,BAD and cell growth proteins.Thus PI3-kinase/Akt pathway regulates processes which are associated with tumourigenesis , any mutation or

Table: Role of nibrin in different cancers

alteration in expression will results in tumour proliferation in human being.26-28

DISCUSSION

Nibrin plays a pivotal role in neuronal development in the brain; a mutation in the nibrin gene causes neurodevelopmental defects by increasing the apoptosis results in hampered brain growth.The DNA damage response causes microcephaly and brain tumours, thus playing a major role in embryonic development. 2 9Heterozygous mutation(c.698_701delAACA Nibrin variant) in the nibrin gene can initiate the process of breast cancer formation.30
However different populations have different genetic variants of nibrin but in Turkish population NBN gene 924 T>C, responsible for exacerbating breast cancer in young females Whereas NBN gene 8360 G>C variant and NBN gene 30537 G>C variant are less significant.11 Whereas the increase in expression of nibrin was associated with the poor patient survival rate in a recurrent ovarian cancer trial. Moreover,nibrin act as an independent predictive marker in ovarian cancer patients in different treatment modalities (comparison of Doxorubicin therapy with Trabectin plus therapy) out of 13 DNA damaging proteins the Nibrin expression were significantly raised in Trabectin plus therapy and it was associated with poorer clinical prognosis.31 Heterozygous mutation (657del5 NBS1 allele )in the quality of nibrin gene forms will lead to increase in the mutant form of nibrin protein (NBS1) and has been recognized in both sporadic and familial instances of prostate cancers.32,33 The most prevalent variant of NBN Gene mutation is c.657del5 in hereditary prostate cancers. The risk of prostate cancer development is 4.3 times higher in patients with a known familial cancer history as compared to non-cancer patients in which chances of occurrence of prostate cancer is 2.5%. (34)Researchers had reported that Nibrin ( NBN P6S )plays an important role in lymph node metastasis in gastric carcinoma by increasing the process of lymphangiogenesis intramucosal gastric tumours.35 The mutation of nibrin protein can give rise to fertility defects in human males and premature ovarian failure in humans females.36 but in the mouse, it destroys seminiferous tubules by increasing the process of apoptosis and causes sperm count reduction.Whereas in the female mouse it is responsible for the failure of oocyte
maturation stage in meiosis, oocytes were degenerated and were arrested in diplotene stage of meiosis. 3 7 Squamous cell carcinoma is the most commonly recognised neoplasm of the aerodigestive tract.38 Whereas,
nibrin plays a significant role in DNA repair. However,CMYC(Proto-oncogenes) causes the activation of mutant nibrin formation by increasing the process of tumorigenesis (phosphatidylinositol3-kinase (PI3 K)/Akt pathway.27,28,39,40 Thus in Esophageal Squamous Cell Carcinoma nibrin plays an independent marker for survival and is inversely correlated with the nodal status, in which increased in expression of nibrin is correlated with initial tumour stages and better survival of patients.39
In OSCC and in Non Head and Neck Squamous Cell Carcinoma, overexpression of nibrin acts as an independent
marker of prognosis in advanced cancers.41 In OSCC nibrin overexpression was observed in poorly differentiated oral squamous cell tumour tissue overexpression of Nibrin in early stages of oral cancer had been associated with the
disease recurrence and aggressiveness of cancer therefore it could be used as a prognostic marker for the early-stage
diagnosis of OSCC.8 Nibrin mutation was shown to increase laryngeal cancer formation and secondary tumour formation in lung cancer patients along with head and neck cancer patients in Czech population whereas it does not play a role in the pathogenesis of non-Hodgkin lymphoma.42,43 In medulloblastoma long term hypoxia causes decrease in the level of Nibrin and other members of MRE complex which results in chemotherapy and X-rays resistance.44

CONCLUSION

The clinical findings presented in this review show that increased DNA damage and deficiencies in enzyme systems to repair it, are the key factors implicated in the pathogenesis of cancer formation. Among the various cancers studied in this review, we observed various patterns over and underexpression of Nibrin. This clearly indicates that the expression of Nibrin is important in cancer progression and recurrence. , Nibrin is the first DNA repair gene whose overexpression is capable of transforming and promotes the process of tumorigenesis by the activation of the process of tumourigenesis( phosphoinositol 3 kinase /akt of PI3-) in human cancers Thus we conclude that the role of nibrin still requires a detailed and thorough investigations.8,45

CONFLICT OF INTEREST

None declared

REFERENCES

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26. Chen Y-C, Chiang H-Y, Yang M-H, Chen P-M, Chang S-Y, Teng S-C, et al. Activation of phosphoinositide 3-kinase by the NBS1 DNA repair protein through a novel activation motif. J Molecular Medi. 2008;86:401-12. https://doi.org/10.1007/s00109-008-0302-x
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1. Lecturer/Mphil trainee, Department of Pathology, Ziauddin College of Dentistry.
2. Principal, Ziauddin College of Dentistry.
3. HoD, Associate Professor, Department of Oral Pathology, Ziauddin College of Dentistry.
4. Mphil trainee, Department of Oral Pathology, Ziauddin College of Dentistry. Lecturer Sir Syed Medical College for Girls.
   Corresponding author: “Dr. Fizza Abidi” < dentistrulz12@gmail.com >

Beenish Fatima Alam¹                                                       BDS, Msc, MFDS RCSED

Sidra Mohiuddin2                                                               BDS, MDS

Salim Hosein3                                                                      MD

Mervyn Hosein4                                                                  FDS RCS, FDS RCSE, FFD RCSI

INTRODUCTION

Trauma to the maxillofacial region can cause injuries affecting the craniofacial skin, bones and neurovascular-sensory organs. These occur as consequences of falls, interpersonal violence, accidents or other associated etiological factors.1 The mandible is most commonly affected because of its prominent position on the face.2 Studies have concluded that within the mandible, 36% of fractures involve the condyle and 21% affect the mandibular body. The angle is involved in 20% of cases while parasymphyseal fractures account for 14% and the symphysis, coronoid, ramus and alveolar areas all account for up to 3% each. Within the maxillary bone, Le Fort II fractures were the commonest followed by Le Fort I and Le Fort III.3

The factors associated with maxillofacial traumatic injuries vary considerably from one geographical region to the other. Statistics from developed countries show that physical assault is the most common cause of trauma whereas among developing countries road traffic accidents (RTA) are the leading factor.4,5,6 The WHO has documented that nearly one-third of traumatic injuries reported in developing countries are due to road traffic accidents (RTA) which significantly contribute towards increased mortality rates.7,8 The purpose of the current study was to assess the association of age, gender, and mechanism of injuries in patients presenting at tertiary care facilities of Karachi, Pakistan. Locally reported data have shown that males are more prone to facial injuries during their 2nd and 3rd decades of life with the most common etiologic factor being road traffic accidents (RTA).6,9 Moreover, studies conducted in past focused more upon the relation between different etiological factors and gender; therefore the association between facial injuries with gender, age and mode of injury needs to be addressed. Hence the objective of the current study is to assess the association of age and gender with mode of injury, as well as to analyze the site of injury with respect to age.

METHODOLOGY

This analytical cross sectional study was carried out in tertiary trauma care centers, based on primary data collected by a single examiner over a period of five years. A total of (n=1038) cases were recorded; data collection was based on detailed history, thorough clinical examination as well as radiographic evaluation. Radiographs commonly used were: Orthopantomogram (OPG), Postero-anterior (PA) view of face, lateral view and lateral oblique view for mandibular injuries, with Occipito- Mental (OM /PNS) view used for mid face injuries. Computed Tomography (CT scans) tended to be used for complex and pan facial fractures usually associated with head injuries.

For evaluating dento-alveolar injuries intra oral radiographs were additionally used including periapical and occlusal views, as necessary.

Data was collated regarding age, gender, mode of injury, anatomical location of fracture in mandibular and maxillary bones based on R. Dingman and P. Natvig’s classification10 as well as side of face affected: right, left or bilateral involvement.

Data analysis was performed using SPSS version 21 (Statistical Package of Social Sciences). Qualitative variables were calculated as frequencies and percentage whereas means and standard deviation of quantitative variables were analyzed. Association among dependent and independent variables were assessed by chi square test. Level of significance was kept p<0.05.

RESULTS

A total of n=1038 patients were reported, out of which 85.5% (n=887) were males and 14.5% (n=151) were females. Ages ranged from 02 years to 80 years, with the mean age of 24.65 ±13.76 years. In eighteen percent (n=189) of cases, the ages ranged from of 0-10 years; the peak incidence was in patients with age range of 11 to 30 years that accounted for fifty seven percent (n=593) of cases. However, twenty one percent (n=216) of cases were from age range of 31-50 years, three percent (n=33) from 51 to 70 years and less than one percent (n=07) were of 71 and above.

presented with sports related injuries and three percent (n=34) had industrial traumatic injuries while four percent (n=38) of cases presented with other mode of injury.

Regarding the location of fracture in mandible; the mandibular body was most frequently involved at 32% (n=327) followed by condylar process of mandible at 29% (n=299). The chin region and angle of the mandible were reported to be 18.4% (n=191) and 17% (n=178) respectively while the least involved parts were alveolus 2.6% (n=27) and Pterygoid body 0.1% (01). The left side of the mandible was found to be most frequently involved at thirty eight percent (n=395) while thirty six percent (n=368) and twenty three percent (n=239) of the cases reported with right side and bilateral involvement, respectively.

Only seventeen percent (n=174) maxillary fractures were reported, among which the most common site was the Zygomatic/orbit region 5.8% (n=60) followed by the maxilla body at five percent (n=52). In maxillary fractures 9.5% (n=99) patients were reported with bilateral involvement, 5.6% (n=58) and 5.1% (n=53) with right and left side, respectively. (Table 1) Statistically significant difference was found between gender and cause of injury (p<0.003), with males injured more through road traffic accidents (n=513) f o l l o w e d b y accidental  falls (n=174). Whereas, females  also encountered RTA more frequently.

Table 1: Descriptive analysis of the demographic variables, etiology and location of Mandibular & Maxillary fractures along their sites

(Table 2) Statistically From the reported etiology of injury fifty six percent (n=582) were road traffic accidents, twenty two percent (n=224) claimed to have accidental falls, twelve percent (n=122) were victims of assault, four percent of cases (n=38) significant difference was found among gender and location of the fracture in

Table 2: Association of gender and mode of injury

Table 3: Association of gender and mandibular fractures

Table 4: Association of age and mode of injury

mandibular bone (p<0.000), among males, mandibular body (n=280) followed by condylar process (n=255) were the most frequent reported sites. (Table 3)

Statistically significant difference was noted among the age ranges of the study subjects and the cause of the injury (p<0.000). In the age range of 11 to 30 years road traffic accidents (n=365) were more frequently reported. However, histories of accidental fall (n=107) were more common in the age range of ten years and below. (Table 4)

DISCUSSION

The majority of the samples in the current study were adult males, in the second and third decade of life and this was statistically significant. Road traffic accidents are a major cause of injury followed by accidental falls. The latter mode of injury was found to be more common amongst children in the first decade of life. Being most prone to injury the body of mandible was the most commonly affected site, followed by the condyle itself. Zygomatic region was noted to be more likely to be injured followed by trauma to maxillary bone among fractures associated with the mid face.

In the current study, the majority of injuries involved the males; these findings concur with previous studies.11,12,13

The overall male to female ratio was 4:1 which was similar to the findings of other studies.14,15 Furthermore, males in the second and third decades of life were most commonly involved; these findings also were similar to other regionally reported local studies.16,17,18 This may be because men are more freely mobile and involved in outdoor activities as compared to women, particularly in our socio-economic setting, often relying on unsafe modes of transport such as motorcycles, hanging on to buses or jaywalking. Furthermore, in the current study, young children in the one to ten years age group were more prone to injuries caused by accidental falls, and these findings are consistent with other studies.19,20,21 Children of that reported age group are growing up fast and are more liable to injuries while playing; occasionally they fall from beds or slip from parents hands due to inadequate safety measures and carelessness.

In the current study road traffic accidents were found to be a major cause of injury, approximately half of the sample however differs from other studies.22,23 Moreover, statistics from western world have demonstrated physical assault as an important cause of maxillofacial injury.24 RTA’s are more common due to failure to follow safety measures while driving; such as the use of seat belts or wearing of helmets and weaving through traffic by bikers, and also due to poor maintenance of roads. In industrialized countries these basic rules of the road are strictly applied and followed. Injuries due to accidental falls were the next most common cause of injury; this is consistent with the study conducted in India and with previously reported studies.25,26 While child abuse must always be considered in cases of trauma especially those that do not fit described histories and patterns, or when issues of possible negligence of parents and caretakers is involved, the active nature of growing children does tend to make them more accident prone.27

The most common mandibular site of fracture observed in the current study was of the body of mandible followed by the condylar part. Similar finding were reported by previously conducted studies.28,29 Apart from road traffic accidents being more common in our part of the world, high mobility and relative lack of surrounding bony support of the mandibular bone as compared to other facial bones is a contributing factor. However these finding were divergent from the statistics reported from developed countries.30,31,32 In the west, assault was a major risk factor which has been attributed to stressful everyday routines and interpersonal differences along with higher usage of drugs and alcohol in those societies. Strict laws regarding drinking and driving and casual alcohol breath testing by police make RTA’s on this account relatively less common. In the current study, statistically significant association

has been found between gender and mode of injury. Males predominate, due to their aggressive nature as well as more involvement in outdoor activities and freedom of movement, as compared to females in our eastern society. Current study demonstrated RTA as major cause of trauma among males, which can be attributed to improper implementation of traffic rules and regulations, among other reasons. Females reportedly suffered more from falls, some of which could be due to domestic violence which is reportedly more common yet unrecognized within developing countries.33 Location of fracture within the mandible also demonstrates considerable relation with gender. It is seen that body of mandible is the most commonly involved site followed by condyle, due to road traffic accidents and falls, commonly affecting males belonging to second and third decades of life.

Among the maxillary fractures noted in the current study, zygomatic region was the commonest site to be involved and affected by trauma; similar findings were stated by previous studies.34 The subsequent frequently affected sites were the maxillary bone region which coincides with study conducted by previous researchers.35,36,37 Zygomatic bone is a prominent bone of the face and during interpersonal assault is frequently subjected to trauma. The basic protective tendency in the midface area is to turn the face downwards and to the side in order to protect the thinner central naso-orbital structures.38

CONCLUSION

RTA’s are the most common cause of injuries in males and females between the second to third decade with the body of mandible being most frequently involved followed by the condyle. Falls among young children was the primary cause of injury followed by RTA.

RECOMMENDATIONS

It is strongly recommended that road infrastructure needs urgent maintenance to reduce the tendency of sudden braking and evasive driving. Equally, the driving rules and regulations, especially those related to the age of drivers, speed control and the wearing of seat belts and helmets needs to be strongly followed and strict actions needs to be taken against violators. Thirdly, public awareness programs regarding safely measures and precautions needed while driving; and relating to issues of child safety and negligence/ abuse precautions must be widely publicized via the media.

CONFLICT OF INTEREST

None declared

REFERENCES

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   29. Oji Jaw fractures in Enugu, Nigeria, 1985-95. Brit J Oral Maxillofac Surg. 1999; 37:106-9. https://doi.org/10.1054/bjom.1997.0083
   30. Schön R, Roveda SI, Carter Mandibular fractures in Townsville, Australia: incidence, aetiology and treatment using the 2.0 AO/ASIF miniplate system. Brit J Oral Maxillofac Surg. 2001; 39:145-48. https://doi.org/10.1054/bjom.2000.0607
   31. Adhikari RB, Karmacharya A, Malla Pattern of mandibular fractures in western region of Nepal. Nepal J Med Sci. 2012;1:45-8. https://doi.org/10.3126/njms.v1i1.5798
   32. Chrcanovic BR, Abreu MH, Freire-Maia B, Souza 1,454 mandibular fractures: a 3-year study in a hospital in Belo Horizonte, Brazil. J Cranio-Maxillofac Surg. 2012;40:116-23. https://doi.org/10.1016/j.jcms.2011.03.012
   33. Le BT, Dierks EJ, Ueeck BA, Homer LD, Potter Maxillofacial injuries associated with domestic violence. J Oral Maxillofac Surg. 2001;59:1277-83. https://doi.org/10.1053/joms.2001.27490
   34. Klenk G, Etiology and Patterns of Facial Fractures in the United Arab Emirates. J Craniofac Surg. 2003;14: 78-84. https://doi.org/10.1097/00001665-200301000-00014
   35. Manodh P, Shankar DP, Pradeep D, Santhosh R, Murugan Incidence and patterns of maxillofacial trauma-a retrospective analysis of 3611 patients-an update. Oral Maxillofac Surg. 2016;20:377-83. https://doi.org/10.1007/s10006-016-0576-z
   36. Eggensperger N, Smolka K, Scheidegger B, Zimmermann H, IIZuka A 3-year survey of assault-related maxillofacial fractures in central Switzerland. J Cranio-Maxillofac Surg. 2007;35:161-67. https://doi.org/10.1016/j.jcms.2007.01.002
   37. Krishnan UC, Byanyima RK, Faith A, Kamulegeya Maxillofacial injuries among trauma patients undergoing head computerized tomography; A Ugandan experience. International journal of critical illness and injury science. 2017;7:236-40 https://doi.org/10.4103/2229-5151.219950
   38. Tripathi GM, Sharma D, Gaharwar AP, Gupta R, Shukla D, Shukla Analysis of Prevalence and Pattern of Zygomatic Complex Fractures in North-Eastern Part of Madhya Pradesh, India. Int J Contemp Med Res 2016;3:1878-81.

1. Assistant Professor & HoD, Department of Oral Biology, Bahria Universtiy Medical and Dental College.
2. Assistant Professor & HoD, Department of Community & Preventive Dentistry, Ziauddin College of Dentistry,
3. General Surgeon, Department of M.I.S, General Surgery, University of Nebraska Medical Center,
4. Dean, Ziauddin College of Dentistry, Ziauddin University
5. Corresponding author: “Dr. Mervyn Hosein” < mmh5617@gmail.com >

Azam Muhammad Aliuddin                                                              BDS

Jabeen Zafar Ali                                                                                     BDS

Abubakar Sheikh                                                                                   BDS, FCPS

Saqib Rashid                                                                                            BDS, MSc, FCPS

Muhammad Ali                                                                                       BDS, MCPS

Faryal Abdullah                                                                                      BDS, DCPS

Azam Muhammad Aliuddin                                                              BDS

Jabeen Zafar Ali                                                                                     BDS

Abubakar Sheikh                                                                                   BDS, FCPS

Saqib Rashid                                                                                            BDS, MSc, FCPS

Muhammad Ali                                                                                       BDS, MCPS

Faryal Abdullah                                                                                      BDS, DCPS

OBJECTIVE: The outcome of endodontic treatment is dependent on many factors, but the success of endodontic treatment depends primarily on the quality of the obturation. The objective of this research was to analyze the standard of obturation and to recognize the iatrogenic errors on periapical radiographs and also to equate between the caliber of endodontic treatment and procedural errors executed by male and female house officers.

METHODOLOGY: This was a cross sectional study in which data of 350 treated root canal fillings radiographs along with their proforma showing demographic variables with the name of house officers who treated the patients were assessed. All 350 periapical radiographs were taken from a single institute Fatima Jinnah Dental College Karachi Pakistan from the year 2014- 2016. All endodontic treatments were performed by house officers using crown down technique by hand instrumentationand for each tooth, three periapical radiographic images were assessed. Two calibrated investigators assessed the radiographs for quality and procedural errors. The sample size was calculated using the WHO Calculator and the results were evaluated using chi-square test. SPSS version 21 was used to analyze the results.

RESULT: Overall 122(35%) of radiographs were up to the acceptable quality as per quality parameters. Gouging and apical perforations were the most common procedural errors found on periapical radiographs. Overall male house officers have performed an acceptable degree of obturation. Chi-square analysis was used  to assess the results. CONCLUSION: Gouging and apical perforations were the most common procedural errors found on periapical radiographs. Overall male house officers have performed better quality of root canal filling in anterior, premolar and molar tooth and overall 122(35%) of radiographs were up to the acceptable quality as per quality parameters.

KEY WORDS: Procedural errors, radiographic quality, house officers, teaching institute

HOW TO CITE: Aliuddin AM, Ali JZ, Sheikh A, Rashid S, Ali M, Abdullah F. Radiographic quality of root canal filling performed by house officers at a teaching institute in karachi, pakistan. J Pak Dent Assoc 2019;28(2):55-62.

DOI: https://doi.org/10.25301/JPDA.282.55

Received: 06 November 2018, Accepted: 26 January 2019

INTRODUCTION

The result of endodontic treatment is based on many factors, but the technical quality of root canal filling is one of the main factors in the success of root canal

treatment.1 Root canal treatment is one of the primary forms of therapy provided as part of oral health care.2 Many studies have revealed a low percentage of technically sufficient root fillings, 45% was recorded by Ahmed et al.3

Different techniques used to control the end result of root canal treatment are mostly established on radiographic assessment.4 The outcome of root canal treatment is affected by the extent of root canal filling compared to the radiographic apex.5 Less dense and non-homogenous root canal fillings adversely affect the result of root canal treatment.6 Procedural faults affect the root canal cleaning and shaping procedure causing deficient root canal filling, which compromises the effectiveness of the treatment.

Several studies have been performed previously to determine the quality of root canal treatment such as Dadresanfar and co-authors determined that the technical quality of root canal treatment performed by undergraduate dental students using step-back preparation and cold lateral condensation was adequate in 32.5% of the cases.8 H. Balto and co-author demonstrated that the technical quality of root fillings performed by undergraduate dental students were classified as acceptable in 23% of cases.9 Saeed Muradi and a co-author reported radiographic quality of root canal treatment performed by 6th year undergraduate students were classified as acceptable in 38% of cases in Mashhad, Iran.

A review of the treatment quality and frequency of various procedural errors can guide us to formulate better educational programs and clinical teaching methods which will lead to an improvement of the quality of root canal treatment. Literature shows that few local studies have been conducted in our population, the most recent ones being by Fayyaz et al and Ahmed et al.11,3 This gives us a strong rationale to conduct this study. The purpose of this study was to evaluate the quality of root canal filling and to identify the iatrogenic errors on periapical radiographssuch as ledge formation, furcation perforation, fractured instrument, strip perforation, apical transportation, apical perforation, gouging, missed canal and zipping in cases treated by house officers at Fatima Jinnah Dental College Karachi, Pakistan. Furthermore, a comparison between the quality of the root canal treatment and procedural errors performed by male and female house officers was also made.

METHODOLOGY

 In this cross sectional study, we investigated radiographic records of 350 obturations done by house officers at Fatima Jinnah Dental College, Karachi, Pakistan between the years of 2014-2016. An approval from the institutional ethical review committee was taken (BEH NO. OCT-2016-OPR01). Inclusion criteria were patients of either sex between the ages of 18 and 65 years. Three periapical radiographs were done during the whole treatment. These included the preoperative, working length and postoperative radiographs. Exclusion criteria were the cases with missing radiographs or radiographs that did not allow proper evaluation due to poor imaging or processing technique and superimposition of anatomical structures, retreated cases and those where endodontic treatment was not completed. Sample calculation was done using WHO Calculator.

All RCTs were carried out by house officers with crown down technique using hand instrumentation and irrigation with 2.5% sodium hypochlorite solution. An aseptic technique with rubber dam isolation was used in all cases.

Working length was established by using digital radiographs (DIGORA), followed by cleaning and shaping. Root fillings were performed with the lateral compaction technique using gutta purcha and calcium hydroxide based sealer (SEALAPEX). For each tooth, the three periapical radiographs were assessed: preoperative, working length confirmation, and postoperative.

Two investigators assessed the immediate post-operative radiographs separately and evaluated whether the radiographic quality of root filling was adequate or inadequate. The standard of root filling length was evaluated radiographically in relation to the radiographic apex, and density was evaluated based on the presence of voids. Any observed under extension and over extension of obturation, presence of voids and insufficient taper was termed inadequate. Acceptable quality was described as appropriate length, adequate density and taper with the exclusion of iatrogenic errors as categorized by Khabbaz et al12 as shown in Table 1. Previous studies by Balto et al9 and Vukadinov et al2 have also used a similar criteria for judging adequacy of the root filling material and procedural errors. Any procedural faults evaluated on the radiographs were counted as unacceptable root canal fillings and assessment of radiographs were done according to the criteria used by Khabbaz et al12 as shown in Table 2. In cases of disagreement amongst the investigators, a third experienced investigator was requested to evaluate the radiograph and a consensus was reached. In cases where multi-rooted teeth were under evaluation, the overall quality was termed inadequate if one single canal had unacceptable root filling or any procedural error was noted in a single canal.

The results were analyzed by using SPSS version 21.0 for windows. Chi-square test was used to statistically analyze variations between the technical standard and also iatrogenic

The criteria to judge quality of endodontic treatment were as follows:

Table 1: Criteria to judge root canal filing

The criteria to assess procedural errors were as follows:

Table 2: Criteria to judge procedural errors

mishaps to the tooth type. The significance level was set at P<0.05.

RESULT

Descriptive statistics were enumerated by using SPSS version 21. Stratification was done and post stratification Chi-square test was employed to notice the effect of modifiers on the result. A p value <0.05 was taken as significant. The outcome showed that there were 109 male patients and 241 female patients treated by 100 male and 250 female

house officers. We found 190 (54%) adequate results among male and female patients of root canal filling length 68 teeth out of this were treated by male house officers (36%) and 122 teeth were by female house officers (64%). The second criteria of root canal filling density was found to be adequate in 194 (55.4%) among male and female patients, out of which 63 teeth were treated by male house officers (32%) and 131 teeth were treated by female house officers (68%).The third criteria of acceptable root canal filling was root canal filling taper which was adequate in 221 (63%) of total results. Out of this 70 teeth were treated by male house officers (32%) whereas 151 teeth were treated by female house officers (68%). The comparison of root canal filling done

Table 4: Comparison of radiographic quality of root canal filing in various teeth (Anterior teeth VS Posterior Teeth

by male and female house officers is shown in Table 3. Acceptable root canal filling quality as assessed by three parameters discussed earlier along with absence of procedural errors was found to be 34.9% out of which 40% teeth were treated by male house officers and 60% by female house

officers as shown in Table 3.

Adequate root canal filling lengthwas seen in 47(83.9%) anterior teeth, 73(61.9%) pre molar teeth and 70(39.8%) molar teeth. Adequate root canal density was found in 28(50%) anterior teeth, 75(63.6%) in pre molar teeth and 91(51.7%) in molar teeth. Adequate root canal taper was found 40(71.4%) in anterior teeth, 87(73.7%) in pre molar teeth and 94(53.4%) in molar teeth. Therefore overall acceptable root canal filling quality was found in 25(44.6%) of anterior teeth, 54(45.8%) of premolar teeth and in 43(24.4%) of molar teeth as  shown in Table 4.

The different procedural errors identified in the root canal filling were as follows:

Ledge formation: As a quality assessor it was found 14% in 350 cases. Out of these 51 cases 9 teeth were treated by male house officers and 42 teeth by female house officers. Furcation perforation:The procedural error of furcation perforation was found to be 4.6% out of which 3 cases were treated by male house officers and 13 by female house officers.

Fractured instrument: This error was found in5.7% (20) out of which 5 teeth were treated by male house officers and 15 teeth by female house officers.

Apical perforation:This error was found in 33 %( 116) out of which 22 teeth were treated by male house officer whereas 94 teethby female house officers.

Apical transportation: This error was found to be 14% (49), out of which 7 cases were done by male house officer whereas 42 casesby female house officer.

Gouging:This was found in 43% (151) of total cases out of which 42 teeth were done by male house officer and 109 teeth by female house officers.

Zipping:It was found as a procedural error in 13.4 % (47) cases out of which 8 teeth were treated by male house officers whereas 39 teeth were done by female house officers. No results for strip perforations and missed canals were recorded during our study since no such data for these particular procedural errors could be collected. These results have been shown in Table 3.

DISCUSSION

Our study demonstrates the radiographic evidence of the nature of root canal fillings and iatrogenic errors executed by male and female house officers at Fatima Jinnah Dental

Table 5: Comparison of radiographic quality of root canal filing in various teeth performed by male house and female house offeicers

College, Karachi, Pakistan. In most studies, the acceptable root canal filling is considered to be within 2mm of the radiographic apex,13,14,15 which was noted in our study as acceptable root canal filling with an overall percentage of 34.9%. Various studies have shown differing percentages regarding acceptable root canal fillings such as 76% reported by Al-Yahya16 39% by Dugas N et al17 55% by Eleftheriadis G et al18 and 13% by Hayes S et al19 however since all these studies have had a different rating criteria, it is hard to establish a true comparison.

In the current study the percentage of acceptable obturations are similar in the anterior and premolar teeth when compared to the study by Boucher Y et al, where the percentage of acceptable root canal fillings is greater in molars unlike our study.1 This is primarily attributed to the differing anatomy of the teeth along with lack of experience of the operators. According to our study, the percentage of root canal fillings reaching adequate length is 54.3%, this is lower when compared to Er et al20 and higher when compared to the study reported by Lupi-Pegurier21 which have reported 70% and 39% respectively. One of the primary reasons for this conflict is that house officers perform

periapical radiographs with a non-parallel technique and sometimes are unable to judge the length on radiographs.22 Secondly, since the periapical radiographs are two dimensional, assessing adequate lengths is problematic. Study by Gordon et al has stated that regular use of an apex locator followed by a confirmatory radiograph using a K-file to determine the working length is a good technique for establishing length of root canals.23

The density of adequate root canal filling in our study was reported to be 54.3%, which is comparatively lower than other studies such as Yoldas etal and Sagsen etal which demonstrated 64% and 92.6% respectively.24,25 No significant association between the tooth type and density of the root filling was established in our study. Kirkevang et al demonstrated that failure of root canal treatment occurs due to poor density of root canal filling.26 A 5 year follow up study by Burke et al also concluded that the success rate of an endodontically treated tooth depends on the length and quality of the root canal filling.27

The incidence of teeth having adequate taper of the root canal filling was recorded in our study as 63.1% which when compared to  other studies is  relatively lower.14,24,25 A significant relation between tooth type and adequate taper of obturation was noted in the present study. A study conducted by Ranya FElemam et al, has reported the increased percentage of taper of root filling in anteriors (87.5%) and premolars (81%) whereas lower percentage in molars (54.5%) owing to the increased incidence of curved roots and narrow canals.28 Our study shows similar findings with taper being greater in the anterior (71.4%) and premolar (73.7%) region and being less in molars (53.4%). This can be attributed to the fact that less skilled operators find it difficult to achieve good taper in molar teeth due to anatomical variations and the fact that reaching adequate working length in curved roots is a difficulty faced by many house officers. Procedural errors are one of the major determinants for long term success of the endodontically treated tooth. In the present study ledge formation during root canal treatment was lower in anterior teeth (3.6%) and premolar teeth (16.1%) as compared to molars (17%) because molars have a high prevalence of complex root canal anatomy such as narrow and curved canals. The percentage of ledge formation in molars was lower as compared to other studies which reported a higher percentage of ledge formation like those reported by Kapalas (52%)29 and Eleftheriadis(39%).18 One of the primary reasonsfor the low percentage of ledges in the present study was the use of gates Glidden to straighten the coronal part of the canal, the use of EDTA in curved canals and pre curving of the stainless steel file before cleaning and shaping of curved canals. Apical perforation (33.1%), apical transportation (14%) and zipping (13.4%) were found to be

as high as compared to other studies15 and there was also significant association with tooth type. These errors more commonly occurred in molars because of complex root canal anatomy and the use of stainless steel files. Several authors have reported that nickel titanium files cause less transportation than stainless steel.30,31

In our study, 4.6% furcation perforation occurred in molars and there was a high percentage of instrument separation/ fracture noted in molars because preparation of curved canals in molars was challenging and was performed by less experienced operators. In the present study gouging occurred in 43.1% and it was unrelated to the tooth type, but this variable is measured only on radiographs therefore it is not very subjective. However, the results are higher when compared to a study conducted by Hendi SS et al which showed only 3.2% of cases with gouging.32 The results of a study conducted by Mukhaimer RH on undergraduate students were in agreement with the present study with a 4.6% observed cases of perforation.33

The outcome of this study was affected by gender which is different from other studies.34,9 Out of 350 house officers, the ratio of male to female house officers was 2:5. There was a significant difference in acceptable quality of root canal filling among both genders. Male house officers performed root canal treatment with better quality (49%) as compared to female house officers which was found to be 29.2% and similar differences were noted in procedural errors such as in apical perforation, apical transportation and zipping. The study also showed gender wise difference in the quality of root canal among various teeth as indicated in Table 4 and Table 5 which was found to be 64.7% in premolar teeth done by male house officers and 38.1% done by female house officers. The difference in quality was found to be 36.5% done by male house officers and 19.4% by female house officers performed in molars. This study also revealed that more root canals were overfilled by female house officers (53.2%) as compared to male house officers (28.8%). This study also highlighted that female house officers performed more apical perforations (55.6% vs. 28.8%) and apical transportations (26.6% vs.13.5%) in molar teeth as compared to male house officers (Table 3). This may be due to the fact that working hours of male house officers were more and in our set up males attend more educational courses. Male house officers do more attachments therefore exhibit better skill due to more practice. Disparity in results can also be explained by the difference in the number of male and female house officers being assessed.

One of the limitations of the present study wasthat roots of all teeth were scored individually and the tooth was taken as a unit. Errorin one root canal filling in a multi-rooted tooth was considered as failure of whole tooth. Any such

faults in single rooted teeth will also be considered inadequate and result in failure of the endodontic treatment. Certain errors were not evaluated in this study such as strip perforation and missed canals etc. because periapical radiograph is two dimensional and cannot study different angulations. Acceptable obturations were found to be lower in our study which was consistent with previous studies. This could be because of the technique utilized while performing the root canal treatment. Another reason could be the variability among supervisor to house officer ratio which is usually less in our setup.These results could be re-verified by expanding the study population to other institutes.

Since the prognosis of root canal treatment is a multifactorial phenomenon, judging only the technical quality of obturations, as shown on radiographs, should not be used as the sole determinant of the quality of treatment in general. While such epidemiological studies are critical for research, many key elements of root canal treatment are left unresolved. Efforts to achieve adequate cross infection control, isolation, chemicomechanical debridement and canal preparation along with use of appropriate materials and techniques are all significant components which affect the prognosis of the treatment

CONCLUSION

According to our study, procedural errors were more common in posterior teeth when compared to anterior teeth due to anatomical variations. Male house officers tend to have better radiographic obturation quality during endodontic procedures than female house officers.

FINANCIAL SUPPORT AND SPONSORSHIP

Nil.

CONFLICTS OF INTEREST

• Khabbaz MG, Protogerou E, Douka Radiographic quality of root fillings performed by undergraduate students. Int Endod J. 2010;43:499-08. https://doi.org/10.1111/j.1365-2591.2010.01706.x

There are no conflicts of Interest.

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