Waqas Yousuf1 BDS
Moiz Khan2 BDS
Abubakar Sheikh3 BDS, FCPS
INTRODUCTION: The purpose of this cross sectional study was to determine the prevalence of three rooted permanent first mandibular molar in a sample of southern Pakistani population.
METHODOLOGY: A total of 405 participants were included in this study, out of which 234 were females and 171 were males. A total of 810 peri-apical radiographs were taken with 30 degree mesial angulation and were evaluated using Digora® Optime software. Prevalence, gender of the participant and symmetry of the mandibular first permanent molars were assessed.
RESULTS: Our findings showed an overall 3.2% prevalence of three rooted mandibular first permanent molar in a sample of Southern Pakistani population. In males, it was 3.5% and in females 3.0%. Overall bilateral prevalence was 1.0%. In males, it was 1.2% and in females 0.9%. Overall prevalence of 2.7% on the right and 1.5% on the left side was found. Chi square test showed P value >0.05 indicating no significant relationship of three roots with gender (male versus female) or sides (right versus left).
CONCLUSION: Although there is a low prevalence of three rooted mandibular first permanent molar in Southern Pakistani population, but it is significant enough to warrant caution when performing endodonticprocedures on these teeth to achieve consistent and desirable results.
KEY WORDS: Three roots, mandibular molar, first permanent molar.
HOW TO CITE: Yousuf W, Khan M, Sheikh A. Prevalence of three rooted permanent mandibular first molar in southern Pakistani population. J Pak Dent Assoc 2015; 24(3):136-139.
Received: August 31 2015, Accepted: October 26, 2015
Mandibular first molars are one of the most commonly treated teeth in dentistry.
Anatomical knowledge regarding this tooth is essential to produce a desirable and consistent treatment outcome. Themost common configuration of permanent mandibular first molars is having two roots1 (mesial and distal) and three canals (mesiobuccal, mesiolingual and distal). However, many variations have been documented in different populations. One such significant variation is the presence of three rooted permanent mandibular first molar.
This variationappears to be significant in particular populations with as high as 33.33% in Taiwanese2population,14.5 % in Chinese3 population, 16% in Malay4 population,12.5% in Eskimo5 population,19.2% in Thai6 population,22.7% in Japanese7 population and 16% in American and Canadian Indian8 populations and relatively of low significance in other populations such as German9 with prevalence of 1.35%, 2.5% in southeastern Brazilian10 and 3.12% in Senegalese11 populations.
These anatomical variations when not taken into consideration can lead to treatment failures.12 Thus, knowledge of this prevalence in any particular region is of great value to local practitioners. Surprisingly, little work has been done on this topic onthe Pakistani population.
The aim of our study was to determine the prevalence of three rooted permanent mandibular first molars in southern Pakistani population. This will give us better understanding of anatomical variation of their root structure in order to achieve more predictableand successful endodontic outcomes.
Study design: Cross Sectional
Setting: Removed by editor
Sample size: 405
All patients coming to the dental OPD for routine dental checkup.
- Both male and female patients
- Age between 12 to 75 years
- Patients with both permanent mandibular firstmolars erupted.
- Teeth with external root resorption.
- Grossly carious teeth where root anatomy may notbe appreciable.
- Radiograph of poor quality.
After being sanctioned by theInstitutional Ethical Review Committee all patients visiting the Dental Hospital OPD who fulfill the inclusion criteria (after taking informed consent)were included in this study.Two periapical radiographs were taken of bothlower mandibular first permanent molars with a paralleling technique at 30° mesial angulation13 and the numbers of roots were assessed using Digora® Optime software for prevalence and symmetry. Peri-apical radiographs were assessed independently by two assistant professors in the department of Endodontics. In case of difference of opinion, the radiograph was shown to the professor in the department and his decision was taken as final.
SPSS version 21 was used for data analysis. Descriptive statistics were computed.
Our findings showed an overall 3.2% prevalence of three rooted mandibular permanent first molar in a sample of Southern Pakistani population. In males, it was 3.5% and in females 3.0%. Overall bilateral prevalence was 1.0%. In males, it was 1.2% and in females 0.9%. Overall prevalence of 2.7% on the right and 1.5% on the left side was found. See: tables 1- 2.
Table 1: Overall and bilateral prevalence of three rooted permanent mandibular first molar n=405.
This cross sectional study demonstrated a significant prevalence of three rooted mandibular permanent first molars in a southern Pakistani population. The overall prevalence was 3.2%. Bilateral prevalence was 1.0%. Male to female distribution was fairly even. Males showed a prevalence of 3.5% and female showed a prevalence of 3.0%. See tables 1.
In order to determine this anatomical variation various screening methods can be used such as peri-apical radiographs13, cone beam computerized tomography (CB-CT)14, human extracted teeth15 and OPG. Although the most reliable method is CB-CT but it is not practical in most of the developing countries
because it is costrestrictive and is not widely available. Bilateral incidence is difficult to determine using extracted teeth since cases of bilateral extraction are very rare. OPG is one of the most widely used screening methods, however it gives a flattened image which contains superimposition and therefore is not conducive in determining the exact root morphology. Peri-apical series of radiograph is the most commonly
used and economical method of screening in the developing countries with minimal radiation exposure and limited training requirements. Peri-apical radiographs have an advantage over other radiographic methods (such as OPG) as it easy to perform tube shift technique and give a better idea of three dimensional root anatomy. According to American Dental Association (ADA)revised 2012 guidelines16, individualized radiographic exam consisting of selected peri-apical view can be taken of a new patient being evaluated for oral disease. A full mouth intraoral radiographic exam is preferred when the patient has clinical evidence of generalized oral disease or a history of extensive dental treatment.
Similarly, this racial variation even exists amongst different regions within south Asia. In a study by Garg et al.13 prevalence of 5.97% was found in an Indian population. Al-Nazhan et al17 found a similar prevalence in a Saudi Arabian population. In a Sri Lankan18 population 3% of the people had a three rooted mandibular first permanent molar and a prevalence of 10% was found in a Burmese19 population.
Table 3: Prevalence of three rooted permanent mandibular first molar worldwide
The high incidence of three rooted mandibular permanent first molar in different regions of the worldindicates that dental treatment can result in failure if this anatomical variation is overlooked.
These findings are significant from an endodontic perspective. Although the prevalence is infrequent, one should always be aware of the possibility of the third root to preclude the possibility of treatment failure and to provide the best quality of treatment.
Similarly, from a surgical standpoint, the extraction of three rooted mandibular permanent first molar can be challenging and may require modification of technique if such an anatomical variation is not taken into consideration.
Orthodontically, three rooted mandibular first permanent molar can be utilized as an advantage in providing increased anchorage due to increased surface area of an additional root. Conversely, this can also prove to be a disadvantage in achieving the desired movement of such teeth.
Although there is a low prevalence of three rooted mandibular first permanent molar in southern Pakistani population, but it is significant enough to warrant caution when performing endodontic procedures on these teeth.
Author Contribution: WY contributed to the design, conception, data collection, and write up and gave the final approval. MK contributed to the design, conception, and data collection, write up and gave the final approval. AS contributed to the design, conception and gave the final approval. Disclosure: None disclosed
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1. House officer at Fatima Jinnah Dental Hospital
2. Demonstrator, Department of Oral Pathology and Oral Surgery, Fatima Jinnah Dental Hospital
3. Assistant Professor, Department of endodontics, Fatima Jinnah Dental Hospital
Corresponding author: “Dr Waqas Yousuf ” < firstname.lastname@example.org >