Three-Rooted Permanent Mandibular First Molars: A Meta-Analysis of Prevalence

Abstract

Introduction. Although numerous amounts of high-level evidence were present, they solely emphasized the tooth-level prevalence of three-rooted permanent mandibular first molar. Global patient-level prevalence and bilateral symmetrical distribution of this type of teeth were needed to be tackled across the world. The research question was “What is the global prevalence of three-rooted permanent mandibular first molars?” Materials and Methods. In vivo epidemiological studies undergone with Cone Beam Computed Tomography (CBCT) were eligible. The proportions of the prevalence of three-rooted permanent mandibular first molars were presented in the forest plots by random effect model. The calculation was performed with MetaXL version 5.3. Subgroup analysis, sensitivity analysis, and publication bias method were also calculated. Results. Seventy-two studies from 31 countries were selected for both qualitative and quantitative analyses. 26302 patients and 37994 permanent mandibular first molars were included in the analysis. 9% of permanent mandibular first molars all over the world demonstrated 3 roots. These three-rooted teeth were found in 10% of the world population, more than 45% of which revealed bilateral symmetry of that anatomy. Right-side dominance and no sexual dimorphism were seen in the distribution of three-rooted permanent mandibular first molars. Global tooth-level prevalence of Radix Entomolaris and Radix Paramolaris was 12% and 0.1%, respectively. Conclusion. The prevalence of three-rooted permanent mandibular first molars (PMFMs) was influenced by different geographical locations across the world and also by widespread habitation of the Mongoloid descent. The authors postulate that globalization, together with blending among ethnicities, may have a great impact on the reduction or accentuation of the anatomical significance in some populations.

Bifid Mandibular Canal: A Proportional Meta-Analysis of Computed Tomography Studies

“…Tree formulas [26] for the corresponding objectives (Ι, ΙΙ, and ΙΙΙ) were (number of patients with BMCs/total number of patients) × 100 for objective Ι, (number of hemi − mandibles with BMCs)/(total number of hemi − mandibles) × 100 for objective ΙΙ, and (number of patients with bilateral presence of BMCs/total number of patients with BMCs) × 100 for objective ΙΙΙ.…”

“…Ten, we categorized the identifed articles into three subgroups: JBI score (8, 7, and 6), (5 and 4), and (≤3). JBI 8, 7, and 6 were consistent with low risk of bias, 5 and 6 were consistent with moderate risk of bias, and less than or equal to 3 was consistent with high risk of bias [26]. Te percentage of JBI score gained by each category was calculated by the following formula: (the summation of JBI scores obtained from each study/total JBI scores) × 100.…”

Root and canal morphology of the mandibular first molar: A micro-computed tomography-focused observation of literature with illustrative cases. Part 1: External root morphology

“…On average, RP was present in 0.1% of teeth ranging between 0% and 2%. 65 There was also a rare clinical case of a fi rst molar that had both RE and RP. 66 In Africa there were a few reports on RE or RP.…”