Elsevier

Journal of Endodontics

Volume 44, Issue 11, November 2018, Pages 1641-1649.e1
Journal of Endodontics

Clinical Research
Worldwide Analyses of Maxillary First Molar Second Mesiobuccal Prevalence: A Multicenter Cone-beam Computed Tomographic Study

https://doi.org/10.1016/j.joen.2018.07.027Get rights and content

Abstract

Introduction

Maxillary first molar second mesiobuccal (MB2) root canal prevalence may change among different populations. The aim of this study was to analyze the worldwide prevalence of the MB2 root canal and understand its possible relation with sex, age, side, and root configuration using in vivo cone-beam computed tomographic (CBCT) assessment.

Methods

Observers from 21 regions were calibrated to achieve a similar CBCT assessment methodology and instructed to collect data from 250 maxillary first molars in previously existing examinations. Intra- and interrater reliability tests were performed. The sample size included 5250 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 z test for proportions in independent groups was used to analyze the differences among subgroups. P < .05 was considered significant.

Results

The worldwide CBCT-assessed MB2 prevalence was 73.8%, ranging from 48.0% in Venezuela to 97.6% in Belgium. The prevalence in males and females was 76.3% and 71.8%, respectively (P < .05). Significantly higher MB2 proportions were found in younger patients and 3-rooted molar configurations. The group intraclass correlation coefficient and the percentage of agreement for the MB2 presence were 0.95 and 0.91, respectively. The intrarater Cohen kappa value was above 0.61 for all observers.

Conclusions

MB2 prevalence in the analyzed regions varied widely. The differences may be associated with specificities within each region but also patient demographics. Males, younger patients, and 3-rooted configurations were associated with higher MB2 proportions.

Section snippets

Material and Methods

Twenty-one observers (20 endodontists and 1 dentist with a master's degree in radiology) from 21 different regions evaluated MB2 root canal prevalence in maxillary first molars using preexisting CBCT examinations from private clinics. The principal researcher (J.M.) provided all observers with identical information, including written guidelines, CBCT images with several mesiobuccal root configurations, bibliographic references, deadlines, and a tutorial video giving step-by-step instructions on

Results

The geographic location and the CBCT characteristics of each region are shown in Table 1. The group intraclass correlation coefficient and the percentage of agreement for the primary outcome were 0.95 and 0.91, respectively. A global view of the deidentified intrarater reliability test results are detailed in Supplemental Table S1 (available online at www.jendodon.com).

A total of 5250 maxillary first molars from 3935 patients (1723 males and 2212 females) were included in the study. The average

Discussion

Extensive research has been performed over the years on the maxillary first molar MB2 root canal 4, 5, 6, 14, 15. The methodologies used vary from in vivo techniques such as clinical findings (2), radiographic examinations (16), and CBCT interpretations (17) to ex vivo methodologies such as clearing (18) or micro–computed tomographic imaging 19, 20. These methodologies appear to be valid to study the mesiobuccal root anatomy; however, the research methods used depend on the information to be

Conclusions

Patient demographics may play an important role in the maxillary first molar MB2 canal prevalence. Males and younger patients presented with higher MB2 proportions when compared with females and older patients. Differences in these sample characteristics make it difficult to compare the results among regions. Three-rooted molars presented with a higher MB2 prevalence than 2-rooted molars. The MB2 proportions ranged from 48.0%–97.6% among the regions, with a worldwide global prevalence of 73.8%.

Acknowledgments

The authors deny any conflicts of interest related to this study.

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