Birooted Mandibular Canine: A Systematic Review and Meta-Analysis

Background/Objectives: Birooted mandibular canines are a rare but clinically significant variation that is often underdiagnosed and may complicate dental treatment. The aim of this review was to conduct a comprehensive meta-analysis to estimate the prevalence of birooted and multirooted mandibular canines, and to address the research question of whether geographical region, sex, or side predilections significantly influence these anatomical variations. Methods: A systematic search was performed on 4 September 2025 across five databases: BASE, Scopus, PubMed, DOAJ, and Scielo. Studies on permanent mandibular canines with at least 10 cases, assessed radiologically or in vitro, were included. Reports without detailed root number data or based only on two-dimensional imaging were excluded. Meta-analysis estimated prevalence and odds ratios by sex and geographic region, with results shown in tables and graphs. Risk of bias was assessed using the Joanna Briggs Institute appraisal tools. Results: Eighteen studies met the inclusion criteria, of which seventeen were classified as population studies and one case as a series. The pooled prevalence of birooted mandibular canines was 2.71%. A female predilection was statistically significant in four modern cohorts. Only one case of a three-rooted mandibular canine was documented. No clinical outcome data were available regarding endodontic success or extraction complications. Conclusions: Birooted mandibular canines represent a relatively common anatomical variant, especially in females and on the right side of the jaw. However, clinical implications related to treatment outcomes remain underreported, emphasizing the need for future clinical and radiological investigations.