Evaluation of Root Canal System in Mandibular Third Molars

Objective: To investigate the morphology of root canal system in mandibular third molars. Methods: A total of 147 mandibulars were treated by using clearing technique, and then the root canal systems of all the teeth were investigated under stereomicroscope. Results: Of the 147 mandibular third molars, 66 had a fused root and 81 had separated roots. Of the 66 mandibular third molars with fused root, 41.0% showed type Ⅴ configuration, which was the main root canal type of mandibular third molars with fused root. In the 81 mandibular third molars with separated roots, the main root canal type was type Ⅳ totally in 41.3%. Of the 147 mandibular third molars, lateral canal, ramification and communication between canals and apical delta were all found. The prevalence of inter-canal communication in the mandibular third molars with fused root was 51.5%. Conclusion: The morphology of root canal system in mandibular third molar is very complicated, which may increase the difficulty of root canal therapy, so the dentists should pay attention to examinations before clinical treatment.