Root and canal morphology of permanent mandibular incisors in a Kenyan population

Abstract

Background: Knowledge of root and canal anatomy is essential in designing and preparing access cavities that give straight line access to the main root canals. Thorough knowledge and understanding of dental anatomy and variations in root and canal morphology of mandibular incisors which include length, shape, position and number is important for favorable root canal treatment. Objective: To determine the root and canal morphology of permanent mandibular incisors in a Kenyan population. Study duration: The study was conducted for a period of three years, from 2011 to 2014. Study Design: This was a descriptive cross sectional study. Study area: The study was conducted in selected public dental institutions within Nairobi and its environs namely Kenyatta National Hospital - Dental clinic, University of Nairobi - Dental Hospital, Mbagathi District Hospital, Kiambu District Hospital, Thika Level Five Hospital, Social League Dispensary, Gatundu District Hospital, Kajiado District Hospital, Machakos Level Five Hospital, Ngong District Hospital and Mathari District Hospital. Materials and methods: A total of 208 permanent mandibular incisors (124 lateral and 84 central) that conformed to the inclusion criteria were collected from the selected centres. The teeth were washed in 3.85% m/v sodium hypochlorite (Reckitt Benckiser E.A Nairobi, Kenya) to remove adherent tissue and then stored in labeled containers containing 10% formalin (ART- M3 Bonart, Taiwan). First, data was collected on root morphology by direct observation. Root length was measured using a calibrated electronic vernier caliper. A standard clearing technique was applied to determine the number of canals and canal configurations according to Vertucci’s classification. A data collection form was used to record the findings for each tooth examined. Data analysis and presentation: The data was stored, coded and analyzed using Statistical Package for Social Sciences (SPSS Version 16, Illinois-Chicago). Obtained data was used to calculate frequencies, means, chi-square and t-statistics of various variables and inferences were drawn from the values obtained. The values obtained from inferential statistics were used to compare results with those obtained in studies done in other populations. A value of P < 0.5 was considered statistically significant. Results were presented in form of frequency tables and pie charts. Results: A total of 208 mandibular incisors (124 lateral and 84 central) were analyzed. All the incisors had one root. Of the central incisors, 56 (66.67%) had curved roots while 86 (69.35%) of lateral incisors had curved roots. Distal curvatures were the most prevalent. The mean root lengths were 12.38 ± 0.244mm and 13.55 ± 0.4mm in central and lateral incisors respectively.. Majority of central, 68 (80.5%) and lateral, 102 (82.26%) incisors had one canal at the floor of the pulp chamber. Type I canal configuration was the most frequent in both central (71.43%) and lateral (67.74%) incisors. Single apical foramina were the commonest in both central (88.1%) and lateral (90.32%) incisors. Conclusions: All central and lateral incisors had one root. Roots were mostly centrally located and distally curved. Majority of teeth had a single canal at the pulpal floor and anatomical apex and type one canal configuration was the most prevalent. Lateral canals, apical deltas and intercanal anastomosis were uncommon in central and lateral incisors. Recommendations: There is need for investigation of a second canal and unusual canal morphology in permanent mandibular central and lateral incisors during routine endodontic treatment.