Third molar agenesis: An updated systematic review and meta-analysis.

Abstract

Third molars (M3s) are the teeth most frequently affected by agenesis in modern human permanent dentition. Despite extensive research, reported prevalence rates vary considerably across populations and study designs. The present systematic review and meta-analysis aimed to provide an updated global estimate of the prevalence and patterns of M3 agenesis by incorporating evidence published since the previous comprehensive review by Carter and Worthington (2016). A systematic search was performed in PubMed, Scopus, Virtual Health Library, SciElo, and Open Access Theses and Dissertations to identify relevant studies reporting radiographically diagnosed M3 agenesis in individuals aged ≥ 11 years. Random-effects meta-analyses were performed to estimate pooled prevalence and to examine differences according to sex and jaw. A total of 125 data points comprising 87,282 individuals were included. The pooled global prevalence of M3 agenesis was 23.07% (95% CI: 21.2-25.0%), with substantial heterogeneity across studies (I² =97.6%). No significant difference was observed between prevalence estimates from the earlier dataset and newly included studies (2015-2025). Sex stratified analysis indicated slightly lower odds of agenesis in males compared to females (OR = 0.84, 95% CI: 0.71-0.99). Jaw-specific analysis revealed higher odds of agenesis in the maxilla than in the mandible (OR = 1.56, 95% CI: 1.12-2.18). These outcomes confirm that agenesis of at least one M3 affects approximately one quarter of the global population - a finding that can be relevant and should be considered by professionals in clinical, forensic, and academic contexts.