The impact of extraction vs. non-extraction orthodontic treatment on the angulation of third molars on panoramic radiographs: a systematic review and meta-analysis.
Systematic Review
The angulation of third molars is a critical factor influencing the likelihood of impaction. Orthodontic premolar extractions have been hypothesized to affect the eruption path of developing third molars by modifying available space and mesial drift patterns./r/nThis systematic review and meta-analysis aimed to assess whether premolar extraction during orthodontic treatment alters the angulation of developing third molars compared to non-extraction protocols./r/nObservational studies comparing angular measurements of third molars between extraction and non-extraction orthodontic treatments were included. Studies without a control group or adequate cephalometric data were excluded./r/nA comprehensive literature search was conducted across two electronic databases (MEDLINE, Scopus) up to November 2024, following PRISMA 2020 guidelines./r/nRisk of bias was evaluated independently by two reviewers using the ROBINS-I tool. A random-effects meta-analysis was conducted, and the certainty of the evidence was assessed using the GRADE approach./r/nNine studies (865 participants) were included. For mandibular third molars, extraction was significantly associated with improved angulation (SMD = - 0.37; 95% CI: - 0.59 to - 0.15; p = 0.004). Significant differences were found in M3L/M2L (MD = - 1.31; 95% CI: - 1.76 to - 0.85; p = 0.003) and M3L/PP (MD = - 4.85; 95% CI: - 8.50 to - 1.21; p = 0.02). No statistically significant difference was observed in the M3L/MP angle. In the maxilla, only the M3U-PP angle showed a significant change (MD = - 5.79; 95% CI: - 11.53 to - 0.04; p = 0.049). Meta-regression revealed no association with age, sex, or premolar type. Certainty of evidence ranged from low to moderate.
