早期阻断矫治后乳前牙反患者在替牙列期的颅颌形态特征

目的:探讨乳前牙反早期矫治后替牙列期的颅颌形态特征,进一步认识乳前牙反的发生和发展。方法:对接受早期阻断矫治的49例(男19例,女30例)乳前牙反患者进行追踪观察至替牙阶段的Hellman’s IIIA期病例,根据上、下颌恒切牙的覆盖情况将患者分为稳定组(37例;男14例,女23例)和复发组(12例;男5例,女7例)。对患者的头颅定位侧位片进行测量分析,比较两组患者牙、颌、面测量值之差异。结果:在矢状骨性关系中,复发组患者的SNA、ANB、Wits值、A-NPog及Co-A显著小于稳定组患者;在垂直骨性关系中,复发患者的蝶鞍角(N-S-Ar)较小,下颌角(Ar-Go-Me)较大。复发组患者的下切牙倾斜度(IMPA)显著小于稳定组患者。与稳定组相比,复发组患者的软组织面角(G-Sn-Pog′)较大。复发组患者的上唇位于审美平面之后,而稳定组患者的上唇位于审美平面之前。结论:在替牙列阶段的Hellman’s IIIA期,乳前牙反早期矫治后复发患者的颅面特征,与乳牙列期和恒牙列期安氏III类错患者均有所差别。

Cranifacial morphology in the mixed dentition of the deciduous anterior crossbite individuals after early interceptive treatment

Objective： The purpose of this study was to investigate the craniofacial morphology in the mixed dentition of the deciduous anterior crossbite individuals after early interceptive treatment. Method： Forty-nine subjects （19 males, 30 females） with a deciduous anterior crossbite who had been treated interceptively in the deciduous dentiton were followed up to the mixed dentition at the Hellman＇s development stage IIIA and the lateral cephalograms of all subjects were obtained. The patients were assigned to either a stable （n=37~ 14 males, 23 females） or relapse （n=12; 5 males, 7 females） group according to the amount of overjet. The differences in craniofacial morphology between the two groups were compared with in- dependent sample t-test. Result.. Among the sagittal skeletal measurement, the SNA angle, ANB angle, Wits appraisal, facial convexity （A-Npog） and maxillary length （Eo-A） of the relapse subjects were smaller than those of the stable subjects. As for the vertical skeletal measurement,the relapse subjects had a smaller saddle angle （N-S-Ar） and a more obtuse gonial angl （Ar-Go-Me）. Compared with the stable subjects, IMPA of the relapse subjects was significantly smaller. The facial angle （G-Sn-Pog＇） of the relapse subjects was significant larger. The value of UL to E-plane was positive in the relapse group and vice versa in the stable group. Conclusion： At the Hellman＇s stage IIIA of dentition development, the craniofacial patterns of the relapse individuals of deciduous anterior crossbite after early treatment are diffrerent from those of individuals with Class III malocclusion at deciduous or permanent dentition.