Introduction: This study evaluated the presence of midmesial canals (MMCs) in a random sample of mandibular molars and the relationship of the intracanal distance between mesiobuccal and mesiolingual canal orifices. Methods: fifty extracted mandibular molars were divided into sample of 5 teeth, mounted in modeling wax before cone beam computed tomographic imaging. The teeth and the CBCT images were interpreted for the presence of MMCs and the mesial intracanal distance. CBCT softwere measured the distance between the buccal of the MB canal to the lingual of the ML canal at the pulpal floor to determine the average length between the canals. Results: 8 distinct MMCs were seen on CBCT images (incidence of 16%). 20 had ambiguous broad isthmus between the MB and ML canal orifices. MMCs were present at the furcation level but merged with the MB and ML canal toward the apex in 6 of 8 teeth with distinct MMCs (87.5%). The mean distance between the MB and ML canals in teeth with MMCs was 3.4mm, and the mean distance was 3.6 mm for teeth without MMCs. The results of the independent sample t test showed no statistically significant difference in the mesial intracanal distance in teeth with and without MMCs (p>0.05). Conclusions: The incidence of MMCs in mandibular molars appears consistent with the literature. However, there does not appear to be a statically significant difference in the mesial intracanal distance in teeth with and without MMCs. Visualization of MMCs on CBCTs may be subjective. There does not appear to be a co-relation between the presence of MMCs and an increased or decreased mesial intracanal distance.
Key words: Cone- beam computed tomography; mandibular molars; midmesial canal