Kazanopoulos Nikolaos, Xanthakis Ioannis, Vastardis Heleni, Sifakakis Iosif, Konstantonis Dimitrios
Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
Department of Biostatistics and Health Data Science, Medical School-Department of Mathematics, National and Kapodistrian University of Athens, Athens, Greece.
Prog Orthod. 2025 Jul 17;26(1):25. doi: 10.1186/s40510-025-00573-3.
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.
This 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.
Observational 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.
A comprehensive literature search was conducted across two electronic databases (MEDLINE, Scopus) up to November 2024, following PRISMA 2020 guidelines.
Risk 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.
Nine 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.
第三磨牙的倾斜度是影响阻生可能性的关键因素。正畸减数前磨牙被认为会通过改变可用空间和近中漂移模式来影响发育中第三磨牙的萌出路径。
本系统评价和荟萃分析旨在评估正畸治疗期间减数前磨牙与非减数方案相比，是否会改变发育中第三磨牙的倾斜度。
纳入比较减数正畸治疗与非减数正畸治疗中第三磨牙角度测量的观察性研究。排除没有对照组或足够头影测量数据的研究。
按照PRISMA 2020指南，截至2024年11月，在两个电子数据库（MEDLINE、Scopus）中进行了全面的文献检索。
两名评价者使用ROBINS-I工具独立评估偏倚风险。进行随机效应荟萃分析，并使用GRADE方法评估证据的确定性。
纳入9项研究（865名参与者）。对于下颌第三磨牙，减数与倾斜度改善显著相关（标准化均数差=-0.37；95%可信区间：-0.59至-0.15；p=0.004）。在M3L/M2L（均数差=-1.31；95%可信区间：-1.76至-0.85；p=0.003）和M3L/PP（均数差=-4.85；95%可信区间：-8.50至-1.21；p=0.02）方面发现显著差异。在M3L/MP角度上未观察到统计学显著差异。在上颌中，只有M3U-PP角度显示出显著变化（均数差=-5.79；95%可信区间：-11.53至-0.04；p=0.049）。Meta回归显示与年龄、性别或前磨牙类型无关。证据确定性范围为低到中等。
