[Preliminary study on root canal morphology of maxillary second molars].

Purpose: To investigate the root canal morphology and anatomy of maxillary second molars using transparent tooth technique and cone-beam computed tomography (CBCT), and explore the consistency of 2 methods in identifying root canal configurations and morphology.

Methods: Fifty extracted maxillary second molars were scanned by CBCT and analyzed using assistant software. Root canal configurations of each root were identified based on Vertucci's classification and recorded. All transparent teeth samples were made with modified root canal staining technique, and the root canal configurations of each root were classified based on Vertucci's classification. The results were analyzed statistically with SPSS17.0 software package.

Results: According to transparent tooth technique, type I was the most common configuration in distobuccal root and palatal root. An additional configuration type 3-2-2 was found in the present study, which was not included in Vertucci's classification. The wide variety of canal systems was seen in the mesiobuccal root. Type I configuration was most prevalent(54.4%), followed by Type II, IV,V,VI. The prevalence of second canal in mesiobuccal root (MB2) was 41.3%. The results of canal morphology and configuration were consistent between transparent tooth technique and CBCT.

Conclusions: Maxillary second molars have the most complex root and canal morphology, especially for the mesiobuccal root. For identifying root canal and root anatomy, CBCT can be used as an alternative to transparent tooth technique in clinical practice. The application of 3D reconstruction based on CBCT helps us to visualize the root canal anatomy.