The Value Of Diagnose Mandibular Incisor Root Canal Morphology Using Cone Beam Computed Tomography:a Three-Dimensional Imaging Technology

Complex root canal system makes root canal treatment more difficult,therefore,the understanding of the anatomy of the root canal system and its variation rule is a prerequisite for successful root canal treatment on clinical,preoperative evaluation of root canal morphology is important to root canal treatment.The aim of this experiment is to:(1)to Compare the root canal morphology of mandibular incisors by using Cone beam CT and canal staining and clearing technique;(2)to investigate the relation between labial-lingual and mesial-distal dimensions and root canal morphology in mandibular incisors by using CBCT.Experiment one:sixty-one extracted mandibular incisors with complete dental root and apex which received no endodontic treatment and no post crown restoration were selected. Each tooth was radiographed with cone beam CT,and the root canal system was stained by canal staining and clearing technique.The classifications of the root canal types according to Vertucci’s type with the two methods were compared.The results showed that:the accuracy of root canal morphology observed by CBCT was 93.44%.The Kappa value between cone beam CT and canal staining and clearing technique was 0.861(P<0.001) which suggested that the two kinds of method had a almost perfect consistency. Their’s detection rate of lateral accessory canal were 8.19% and 21.31% respectively.,have a significant statistically difference(P=0.041).The canal staining and clearing technique is significantly higher than the CBCT in detection rate of lateral accessory canal.Experiment Two:Analyzed the root canal morphology from CBCT images of 282 mandibular incisors from 75 patients.The labial-lingual and mesial-distal dimensions of each tooth were measured at the level of cemento-enamel junction.The results showed that: Statistical analysis showed that the mean labial-lingual of single canal and double canals were 5.62mm and 6.35mm respectively which had a significant difference (p<0.001),the optimal cut-off point was 6.05mm,the mean mesial-distal of single canal and double canals were 4.00mm and 4.04mm respectively which had not a significant difference(p=0.423). The mean ratio of labial-lingual and mesial-distal dimension in single canal and double canals were 1.41 and 1.58 respectively which had a significant difference(p<0.001),the optimal cut-off point was 1.53.Consequently,CBCT can reflect the root canal types almost perfectly,but inferior to the canal staining and clearing technique in lateral accessory canal,CBCT is a comparatively accurate clinical diagnosis method of root canal morphology. In the population,during the clinical practice,the labial-lingual dimension of the tooth crown and the ratio of labial-lingual and mesial-distal dimension should be considered as a preoperative predictor related to the canal morphology before root canal treatment. By CBCT—a three-dimensional image technology,we could indirectly study the teeth and root canal anatomical features,which can provide references for clinical treatment.