【摘要】 目的 通过对成年人下颌第三磨牙(mandibular third molar,M3)生长情况的回顾性横断面研究，探索M3生长及萌出情况与下颌牙列拥挤度之间的相关性，为临床处理下颌第三磨牙的方案选择提供依据。方法 随机选择221例成人患者记录其M3情况，利用Dolphin软件对所有患者的CBCT进行测量，记录包括下颌全牙列拥挤度在内的多项牙弓测量项目，分析M3生长及萌出情况与下颌牙列各项测量项目之间的相关性。结果 M3近中阻生的角度与下颌全牙列拥挤度呈正相关(P<0.05)，与磨牙后间隙呈负相关(P<0.01);其中近中中位阻生的M3可显著增加下颌全牙列拥挤度(P<0.01)，垂直正位萌出的M3可显著增加磨牙后间隙(P<0.01)。结论 对于存在近中中位阻生的M3或磨牙后间隙不足的患者，临床可考虑预防性拔除M3，或可有利于减少拥挤产生及预防正畸术后复发。更多还原

【Abstract】 Objective To explore the association between the growth condition of mandibular third molars( M3) and the parameters of mandibular dental arch through a retrospective cross-sectional study on M3 in adults,and to provide a basis for the selection of clinical treatment of M3. Methods A total of 221 adult patients were randomly selected for our study. Dolphin software was used to analyze the CBCT of all the patients. Parameters of the mandibular dentition including the entire dental crowding( EDC) were recorded. Then the association between M3 growth condition and these parameters was analyzed. Results The mesio-impacted angle of M3 was positively correlated with EDC( P<0.05),and negatively correlated with the retromolar space( RMS,P<0.01). It was worth noting that median mesio-impacted M3 significantly increased EDC( P<0.01),and the erupting M3 in the vertical orthotopic position significantly increased RMS( P<0.01). Conclusion For patients with median mesio-impacted M3 or insufficient RMS,preventive removal of M3 may be considered clinically,which may help to reduce crowding and prevent relapse after orthodontic treatment.更多还原