The Worldwide Prevalence of Radix Molaris in Mandibular Second Molars Assessed by Cone Beam Computed Tomography: Systematic Review and Meta-analysis.

Introduction: This study aimed to investigate the worldwide prevalence of radix entomolaris (RE) and paramolaris (RP) in mandibular second molars via cone beam computed tomography.

Methods: The electronic databases MEDLINE, Web of Science, Scopus, and Embase were searched using related MeSH keywords. In vivo cone-beam computed tomography-based studies that evaluated the prevalence of RE and RP in mandibular second molars were retrieved and assessed. The included studies were quantitatively analyzed via a meta-analysis to determine the pooled prevalence rates of RE and RP. Furthermore, the studies were qualitatively assessed using the Newcastle‒Ottawa quality assessment scale.

Results: Twenty-six studies were eligible for this review and a meta-analysis of 21,383 mandibular second molars was performed. All the studies involved were ranked as high quality with no evidence of publication bias. The global prevalence of RE was 0.72% (95% confidence interval: 0.45% to 1.04%) and that of RP was 0.17% (95% confidence interval: 0.004% to 0.36%). Sex and geographical location did not significantly influence RE or RP incidence.

Conclusion: The prevalence of radix molaris is not infrequent. The incidence of RE is higher than that of RP, and neither sex nor country influences the incidence rate of either presentation.