Incidence of the middle mesial canals in mandibular permanent molars in a Romanian population by cone-beam computed tomography.

INTRODUCTION: Untreated middle mesial canals (MMCs) of mandibular permanent molars can result in endodontic treatment failure. AIM: The aim of this retrospective study was to investigate the incidence of MMC of mandibular molars in a Romanian population. PATIENTS, MATERIALS AND METHODS: In total, there were evaluated 144 mandibular first permanent molars and 140 mandibular second permanent molars by using cone-beam computed tomography (CBCT) scans. RESULTS: The MMC was identified in 5.67% of mandibular first permanent molars, respectively in 4.28% of mandibular second permanent molars. The male∕female ratio of MMC presence was 1:3 of mandibular first molars and inverted for mandibular second molars (5:1). The presence of MMC in mandibular first molars was associated in all cases of our study with a second distal canal, unlike the mandibular second molars where no second distal canal was associated with a MMC. CONCLUSIONS: In Romanian population, the MMC of mandibular first molars, when present, is commonly associated with a second distal canal, unlike the mandibular second molars where the occurrence of a MMC was associated with only one distal canal. When performing the preoperative evaluation, it has also to be considered the patient gender, since the male∕female ratio of MMC was 1:3 in mandibular first molars and 5:1 in mandibular second molars.