Root thickness evaluation of mandibular incisors

Aims: Mandibular incisors are the smallest teeth in the mouth. They have thin roots with concavities and are very important for aesthetic and also for speaking. Due to their narrow internal anatomy, preparing the root canal and post space might be very difficult and endangers them for root wall perforation or fracture. The aim of this study was to measure the root thickness of mandibular incisors. Methods: Root wall thicknesses of eighty mandibular incisors were measured in four sections including the CEJ, 3 mm apical to the CEJ, 4 mm and one mm coronal to the apex and in buccal, lingual and proximal surfaces of concavity areas, using a stereomicroscope. Data were statistically analyzed by repeated measured ANOVA and paired t-test. Results: Buccal surface of the buccal canals and lingual surface of the lingual canals in double-canalled incisors had the greatest root thicknesses compare to the proximal surfaces. Root thickness of single-canalled root was more than of double-canalled ones. Proximal walls had the least root thicknesses in all the sections especially in section 4, at 1 mm from the apex, which was less than 1 mm. Conclusion: In order to avoid technical mishaps during root canal procedures, attention must be paid to the thin concavity proximal walls using anticurvature flaring and also in selection of proper size of master apical file.