Worldwide Anatomic Characteristics of the Mandibular Canine—A Multicenter Cross-Sectional Study with Meta-Analysis
Jorge Martins, Pablo Ensinas, Francis Chan, Narin Babayeva, Murilo von Zuben, Luiza Berti, Ernest W.N. Lam, Marcia Antúnez, Fan Pei, Catalina Méndez de la Espriella, Walter Vargas, Juan Carlos Izquierdo Camacho, Moataz-Bellah A.M. Alkhawas, Tiago Pimentel, Fábio Santiago, H Herrmann, A. Chaniotis, Gergely Benyőcs, Magnús F. Ragnarsson, Jojo Kottoor, Avi Shemesh, Raffaella Castagnola, Sriteja Tummala, Satoru Matsunaga, A. Yu. Мaksimova, Hani Ounsi, Abhishek Parolia, Rubén Rosas Aguilar, O H Oderinu, Muhammad Rizwan Nazeer, Carlos Heilborn, Christian Nole, Sergiu Nicola, Elena Lipatova, Hussam Alfawaz, Hussein C. Seedat, Seok Woo Chang, José Antonio González Sánchez, Zaher Altaki, Raweewan Arayasantiparb, Ali Keleş, Iliana Modyeievsky, Adam Monroe, Carlos Bóveda, Emmanuel João Nogueira Leal Silva, Michael Solomonov, Joe Ben Itzhak, Marco A. Versiani
Abstract
INTRODUCTION: This study aimed to examine the global prevalence of root and root canal morphologies in mandibular canines and analyze potential influences of region, ethnicity, sex, and age on the proportion of a second root and root canal configuration. METHODS: Observers from 44 countries screened 13,200 canines using cone-beam computed tomographic exams and gathered data on the percentages of 2 root canal morphologies and 2-rooted configurations (primary outcomes), as well as the root canal configurations (secondary outcome). Demographic factors (ethnicity, sex, and age) were collected for each participant. Primary outcomes were represented as odds ratios and untransformed proportions accompanied by 95% confidence interval (CI) forest plots. Meta-analysis compared subgroups and identified sources of heterogeneity. Intra- and inter-rater tests were conducted. Statistical significance was set at 5%. RESULTS: The worldwide prevalence of a second canal was 7.5% (95% CI, 6.3%-8.7%), ranging from 0.7% in Nigeria to 17.7% in Uruguay. The meta-analysis also revealed significant variations when comparing ethnicity, gender, and age (P < .05). The global prevalence of a second root was 1.9% (95% CI, 1.5%-2.3%), with the highest proportion observed in Spain (6.7%). Caucasian and Indian (south Asian) ethnic groups, females, and older patients exhibited higher proportions of 2 roots (P < .05). Meta-regression excluded side, voxel size, and field of view as sources of heterogeneity (P > .05). CONCLUSIONS: The prevalence of 2 root canals and 2-rooted configurations in the mandibular canine exhibited variations based on geographic location, ethnicity, sex, and age. The global prevalence of 2 root canals and 2-root configuration was 7.5% and 1.9%, respectively.