The relationship between third molar agenesis and craniofacial morphology: a systematic review and meta-analysis

Abstract

Summary Background Agenesis of third molar agenesis has a higher incidence than other tooth development anomalies. Previous research identified a potential correlation between third molar agenesis and specific craniofacial morphology; however, no systematic review and meta-analysis on this topic currently exists. Objective The objective of this systematic review and meta-analysis was to evaluate the association between third molar agenesis and craniofacial sagittal and vertical morphology. Search methods An electronic search was conducted on PubMed, Embase, Web of Science, and the Cochrane Library without restrictions on publication year or language; this was supplemented by the manual retrieval of relevant literature. Selection criteria Cross-sectional studies that compared craniofacial morphology using angular and linear measurements obtained from lateral cephalography between patients with third molar agenesis and those without were included. Data collection and analysis The quality assessment of the enrolled articles was evaluated by the Joanna Briggs Institute critical appraisal tool. Meta-analysis and sensitivity analysis were performed by Review Manager software (The Cochrane Collaborative, version 5.4, Cochrane IMS). Results A total of seven studies were included. Meta-analysis demonstrated that the ANB (mean differences (MD) = –0.75, 95% CI: –1.31 to –0.19, P < 0.01), palate length (ANS–PNS, MD = –1.68, 95% CI: –2.24 to –1.11, P < 0.01), and mandibular length (Go-Pog, MD = –0.36, 95% CI: –0.59 to –0.13, P < 0.01) were smaller in patients with third molar agenesis. With regard to vertical craniofacial morphology, the mandibular plane angle (MP-FH; MD = –1.88, 95% CI: –3.45 to –0.31, P = 0.02), gonial angle (gonial angle; MD = –1.73, 95% CI: –2.69 to –0.77, P < 0.01) and lower face height (lower face heigh angle; MD = –1.36, 95% CI: –1.94 to –0.77, P < 0.01) were smaller in patients with third molar agenesis, indicating a flatter or brachyfacial skeletal pattern. Conclusions The results of this study suggest that third molar agenesis maybe associated with a reduced maxillary length and a flatter mandible. However, these findings need to be interpreted with caution due to inconsistencies in the certainty of evidence. Clinical Trial Registration PROSPERO (CRD42023448226).