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

Abstract

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).

Keywords: craniofacial morpholpgy; dental agenesis; third molar.