Radiographic and microscopic comparison of additional canal incidence in Iranian lower premolars (In Vitro)

Dentist’s incomplete awareness about root canal shape and anatomy produces serious problems in diagnosis and treatment plan which is one of the main causes of root canal therapy failures. There are many different reports about root canal numbers and variations of lower premolars. Method & Materials: In this study, 156 Iranian extracted lower premolars with mature apex and recognible crown were selected. Each tooth was radiographed from two different directions. To diagnose the additional canals, all of the radiographs were separately evaluated by three endodontists and were noted on data forms. Then the teeth were sectioned at least in three levels and an endodontist evaluated them by a streomicroscope. The data was analyzed by Mc – Nemar test.

Results showed that the additional canal incidence in first lower premolars was 14.1% by radiographic method and was 21.8% by microscopic method. On the base of our samples, Mc-Nemar test showed that this difference wasn’t significant (P<0.01). In second lower premolars it was 7.7% by radiographic method and 26.9% by microscopic method and the difference was statistically significant (P<0.01).

Upon these results, it seems that radiography can help us in recognizing first lower premolars additional canals with high confidence but it not in second lower premolars.