Root canal morphology of the mesiobuccal root of maxillary first molars: a micro-computed tomographic analysis

To investigate ex vivo, the root canal morphology of the MB root of maxillary first molar teeth by means of micro-computed tomography. Thirty extracted intact human maxillary first molar teeth were selected for micro-tomographic analysis (SkyScan 1072, Aartselaar, Belgium) with a slice thickness of 38.0 mu m. The following data regarding the MB root were analysed and recorded: number and type of root canals, prevalence of isthmuses, prevalence of intercanal connections, presence of accessory canals, presence of loops and number of apical foramina. The MB2 canal was present in 80% of specimens and was independent in 42% of these cases. When present, the MB2 canal merged with the MB1 canal in 58% of cases. Communications between the two canals were found in all specimens, with isthmuses in 71% of the cases. These communications and isthmuses were respectively in 42% and 54% of the cases in the coronal third, in 59% and 79% of the cases in the middle third and in 24% and 50% of the cases in the apical third. A single apical foramen was found in 37% of specimens, two apical foramina were present in 23% of the cases, with three or more separate apical foramina occurring in 40% of the specimens. The MB root canal anatomy was complex: a high incidence of MB2 root canals, isthmuses, accessory canals, apical delta and loops was found.