Retrospective analysis of root-canal variations and root fusion of maxillary molars with cbct

Aim: The aim of this in vivo cone beam computed tomography (CBCT) study was to evaluate the number of roots, the prevalence of root fusion, merged canals and C-shaped canals, anatomical features of root fusion, correlation between molars and differences between sexes of maxillary first and second molars in the Turkish, Tokat subpopulation. Materials and Methods: In this study, CBCT images of 756 maxillary first (378) and second (378) molars from 189 patients were examined; root numbers and root fusion were evaluated. Teeth with root fusion were classified and merged canals and C-shaped canal configurations were evaluated. Partial or total connections between root canals were evaluated as merged canals. C-shaped canals were investigated and the identified variations were classified. The correlation between first and second molars, bilateral symmetry of root fusion and differences according to gender were evaluated on the obtained results. Z test was used for differences in independent proportions, chi-square test for differences between genders and Cohen kappa test for bilateral symmetry. Results: In maxillary molars, 81% had 3 separated roots, 18.7% had root fusion, and 0.3% had 4 roots. 2 second molars with 4 roots were detected; one of the accessory roots was observed on the palatal and the other on the mesial side. The prevalence of root fusion in maxillary first and second molars was found to be 6.1% and 31.2%, respectively. Type III fusion was observed most in maxillary first molars, and type II fusion was observed in second molars. 73.8% of root fusion occurred as a result of fusion of two roots, and 26.2% as a result of fusion of three roots. It was determined that the canals of teeth with root fusion merged in 30.4% of first molars and 35.6% of second molars. While none were identified in first molars, C-shaped canal configuration was identified in 6 (1.6%) teeth in second molars. In 11.3% of 71 cases with root fusion in maxillary molars, root fusion was observed in all first and second molars. When bilateral symmetry was evaluated according to the root fusion type of maxillary molars with Cohen Kappa test, it was found that there was a almost perfect agreement with a value of 0.862 for first molars and 0.683 for second molars. The prevalence of root fusion in maxillary molars was 23.6% in female patients and 11.9% in male patients. Conclusion: Maxillary second molars have more complex root canal anatomy than maxillary first molars. Within the limitations of this study, 18.7% root fusion, 6.5% merged canals and 0.8% C-shaped canal configuration were observed for all maxillary molars. Bilateral symmetry of root fusion, merged canals and C-shaped canals showed almost perfect agreement. Root fusion and merged canals were observed statistically significantly more in female patients.