成人骨性Ⅲ类错[牙合]患者第三磨牙与磨牙后间隙及[牙合]平面的相关性

Analysis of the correlations between the third molar and retromolar space and occlusion plane with skeletal Class Ⅲ malocclusion in adults

目的探讨成人骨性Ⅲ类错[牙合]第三磨牙与磨牙后间隙及[牙合]平面的相关性,为正畸、正颌治疗提供策略依据。方法选取90例成人骨性Ⅲ类正畸患者治疗前的锥体束CT作为观察组,同时选取90例个别正常[牙合]的锥体束CT作为对照组。测量两组的磨牙后间隙及[牙合]平面数据,并进行比较分析,对成人骨性Ⅲ类错[牙合]患者第三磨牙的测量数据与磨牙后间隙及[牙合]平面数据进行Pearson相关分析。结果与正常[牙合]相比,成人骨性Ⅲ类错[牙合]的URMS较小,LRMS较大,OP-FH较小;U8-PP与URMS呈正相关(P<0.01),与OP-FH呈负相关(P<0.05),U8s-FHs、U8c-FHc与URMS、OP-FH无显著相关关系,L8-MP与LRMS呈正相关,L8s-UMPs、L8c-MPc与LRMS无显著相关关系。结论正畸医师在对成人骨性Ⅲ类错[牙合]患者进行间隙分析时,可以通过第三磨牙的萌出高度评估磨牙后间隙的大小,决定是否进行磨牙远移的治疗;如果上颌第三磨牙过度萌出,提示[牙合]平面变平,在设计治疗方案时,需重视[牙合]平面的重建,利于错[牙合]畸形的纠正和疗效的稳定。

Objective To investigate the correlations between the third molar and the retromolar space and occlusion plane,and to provide a strategic basis for orthodontics and orthognathic treatment with skeletal Class Ⅲ malocclusion in adults.Methods Ninety skeletal Class Ⅲ patients were selected as the observational group,and 90 cases of individual normal occlusion patients was selected as control group.The data of retromolar space and occlusion plane space were measured and compared between the two groups.Linear analysis was used to analyze the correlations between the third molar and retromolar space and occlusion plane.Results As compared with the control group,the retromolar space of maxillary with skeletal Class Ⅲ malocclusion was significantly smaller;the retromolar space of mandible was larger;the angle between occlusion plane and Frankfort plane was significantly smaller;the distance from the third molar to the maxillary plane was significantly positively correlated with retromolar space of maxillary(P<0.01),significantly negatively correlated with the angle between occlusion plane and Frankfort plane(P<0.05),and the distance from the third molar to the mandible plane was significantly positively correlated with the retromolar space of mandible.There was no significant correlation between the inclination angle of the third molar and the retromolar space or occlusion plane.Conclusion When analyzing the space of skeletal Class Ⅲ malocclusion patients,orthodontists can evaluate the size of the retromolar space by the eruption height of the third molar,and decide whether to carry out the treatment of molar distalization;if the maxillary third molar excessively erupts,it indicates that the occlusion plane becomes flat.When designing the treatment plan,we should pay attention to the reconstruction of occlusion plane,which is beneficial to the correction and curative effect of malocclusion stable.