preparation curved molar root canals assessed by Computed Tomography

Objective:The differences in using 3 kinds of root canal preparation instruments assessed by CT and three-dimensional reconstruction technology. Methods: 15 frash maxilla molars of adults,45 root canals in all (MBII do not count in ).divided into 3 groups at random.Be scaned in 0.625mm level and prepared by hand-use K-file,mobile Protaper,mobile Hero642.Then scaned the teeth in the same conditions and established the three-dimensional model to prepare the different preparation effects in using different root canal instruments. Result: 1. Compared with original root canal,after preparation,changes of K-file,mobile Protaper,mobile Hero642 was most signicant in group Protaper,lest in group hand-use K-file.Intergroup differences were analized statistically by LSD method.significant difference was found between group Protaper and proup K-file,no difference between group K-file,no difference between group K-file and group Hero642. 2. Root canal transportation after Preparation:most significant in group hand-used K-file .less in group Hero642. Intergroup differences were analized statistically by LSD method.significant difference was found between group Hero642 and proup K-file,no difference between group K-file,no difference between group Protaper and group Hero642. Conclusion: 1. The mobile nickel titanic root canal instruments has the good cutting ability,mobile Protaper is better than mobile Hero642. 2. The mobile nickel titanic root canal instruments is better than hand-use K-file on the keeping the root canal shapes. Key words Curved root canal preparation Computed tomography Three-dimensional recontruction