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Study analyses MB2 root canal prevalence among world population

The differences in MB2 root canal prevalence may be associated with specificities within each region, as well as patient demographics. (Photograph: Sergii Kuchugurnyi/Shutterstock)
Dental Tribune International

Dental Tribune International

Tue. 16. October 2018


LISBON, Portugal: Previous research has shown that endodontic treatment failure in maxillary molars can result from missed second mesiobuccal (MB2) canals. However, an MB2 canal is present in as many as 95 per cent of maxillary molars. In a recent study, a group of researchers from the University of Lisbon’s dental school analysed the worldwide prevalence of the MB2 root canal to understand its possible relation to sex, age, side and root configuration.

In an interview with Dental Tribune International, lead author Dr Jorge Martins explained how he and his team went about the study. Over the course of ten months, 21 observers from 21 countries and five continents were involved. They were calibrated to achieve a similar CBCT assessment methodology and instructed to collect data from 250 maxillary first molars from previous examinations. Intra- and inter-rater reliability tests were performed. The sample included 5,250 molars and was defined by way of a preliminary trial. Data collected included MB2 presence, sex, age, side, number of roots per tooth, and mesiobuccal root configuration.

“The calibration of the observers was done through sharing very strict written criteria, images and a tutorial video with the step-by-step assessment methodology that each one had to perform,” Martins said. “Our main goal was to make sure everyone was assessing the morphology the same way. In the end, we shared ten CBCT scans of 20 maxillary first molars among everyone and everyone performed their analysis so that we could perform some reliability tests of the group involved before going to the field. All this sounds easy, but it took a few hundred emails between the research team and observer team to achieve the calibration.”

In the end, the difficult work paid off as the researchers made interesting findings: the worldwide CBCT-assessed MB2 prevalence was 73.8 per cent, ranging from 48.0 per cent in Venezuela to 97.6 per cent in Belgium. The prevalence in males and females was 76.3 per cent and 71.8 per cent, respectively. Significantly higher MB2 proportions were found in younger patients and three-rooted molar configurations. Overall, the MB2 prevalence in the analysed regions varied widely. The differences may be associated with specificities within each region, but also patient demographics, according to the researchers. Males, younger patients and three-rooted configurations were associated with higher MB2 proportions.

Axial slices of maxillary first molars presenting MB2 root canals. Obtained from Venezuela, China and Portugal. (Image: University of Lisbon)

As to what these findings mean for endodontic dentists and patients, Martins said: “It has been proven previously that the maxillary molar MB2 root canal is the one that more commonly is forgotten or not identified in endodontic treatment. These results show some influence of demographic factors in this anatomy prevalence, and that may be used as preoperative information that may anticipate more complex maxillary molar morphologies.”

The study, titled “Worldwide analyses of maxillary first molar second mesiobuccal prevalence: A multicenter cone-beam computed tomographic study”, was published online in the Journal of Endodontics on 19 September 2018 ahead of inclusion in an issue.


One thought on “Study analyses MB2 root canal prevalence among world population

  1. Dr Munir Oladele Azeez says:

    Great job by the team. Personally had not seen MB2 in my practice experience. However have seen several first mandibular molars with three, (2 mesial), and some with four canals. Has any studies been done on this. I practise in Port Harcourt Nigeria.

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