Root and canal symmetry in the mandibular anterior teeth of patients attending a dental clinic: CBCT study

The aims of this study were to evaluate the number of roots/root canals in the mandibular anterior teeth of a Turkish population, to assess the relationship between gender or age and the frequency of two canals in a single root, and to determine the symmetry in root/root canal numbers between contralateral sides among patients. Cone-beam computed tomography images (n = 1128; 6253 teeth) taken at the Department of Dentomaxillofacial Radiology of the Faculty of Dentistry of Gazi University were examined by three observers and a supervisor, all of whom were blinded to patient gender and age. Axial, sagittal, and cross-sectional slices with a thickness of 1 mm were used. Numbers of roots and canals for each type of tooth were recorded. Most teeth had a single root and single root canal. Roots with two canals were more frequent in the incisors (14.9%, 17.2%, and 6.1% of the central incisors, lateral incisors, and canines, respectively). Teeth with two roots were more frequent in the canines (3.1%vs. 0% or 0.1%). Females more often had canines with double root canals (p < 0.001). When at least one tooth had two root canals, bilateral symmetry between contralateral teeth was found in 45.0%, 29.0%, and 28.0% of cases for central incisors, lateral incisors, and canines, respectively. Patients older than 56 years had fewer teeth with double root canals (p ≤ 0.001). A small proportion of the mandibular anterior teeth had two roots or root canals. Double root canals were mostly unilateral. Age and gender were associated with the number of root canals.

本研究旨在评估土耳其人群下颌前牙（mandibular anterior teeth）的牙根/根管数量，分析性别或年龄与单牙根双根管发生率的相关性，并探究患者双侧同名牙之间牙根/根管数量的对称性。本研究纳入加济大学牙科学院口腔颌面放射科拍摄的锥形束计算机断层扫描（cone-beam computed tomography，CBCT）图像共1128份，涵盖6253颗牙齿，由3名观察员及1名质控监督员进行阅片，所有阅片者均对患者的性别及年龄采取盲法处理。本次分析采用层厚为1mm的轴位、矢状位及横断面切片，记录每类牙齿的牙根及根管数量。绝大多数牙齿为单牙根单根管结构。双根管牙根在切牙中更为常见，其中中切牙、侧切牙及尖牙的双根管牙根占比分别为14.9%、17.2%及6.1%。相较于其余两类牙的0%或0.1%，尖牙的双牙根占比达3.1%。女性双根管尖牙的发生率显著更高（p < 0.001）。当至少存在1颗双根管牙齿时，中切牙、侧切牙及尖牙的双侧同名牙对称性发生率分别为45.0%、29.0%及28.0%。年龄超过56岁的患者，其双根管牙齿的数量显著更少（p ≤ 0.001）。下颌前牙中存在双牙根或双根管的比例较低，双根管多为单侧分布。性别与年龄均与根管数量存在显著相关性。