安氏Ⅲ类错(牙合)畸形治疗方法的早期预测初探

目的 试探讨可用于判别手术与非手术治疗安氏Ⅲ类错(牙合)畸形患者替牙期颅面牙(牙合)特征的方法. 方法 早期治疗组为28例替牙期解除前牙反(牙合)的安氏Ⅲ类错(牙合)畸形患者(男性16例,女性12例),替牙期拍摄头颅侧位片的平均年龄为(9.1±1.4)岁, 在恒牙期采用非拔牙矫治.手术治疗组为21例随生长发育成为严重骨性安氏Ⅲ类错(牙合)畸形患者(男性12例,女性9例),替牙期拍摄头颅侧位片的平均年龄为(10.0±2.0)岁,最终接受正颌手术治疗.结果 早期治疗组与手术治疗组上下齿槽座点连线与下颌平面的夹角(AB-MP)分别为65.1°和61.2°,差异有统计学意义(P＜0.05);上颌切牙长轴与上下齿槽座点连线的夹角(U1-AB)分别为23.1°和27.3°,差异有统计学意义(P＜0.05). 结论 个体指数(IS)＝0.164×(AB-MP)-0.15×(U1-AB)-6.675.当安氏Ⅲ类错(牙合)畸形患者的IS＞0时,其较适合在替牙期进行早期矫治;IS＜0,患者更适合进行手术矫治.

Early identification of non-surgical and surgical intervention of class Ⅲ malocclusion

OBJECTIVE: To establish a model of cephalometric variables for identification of indication of early treatment of class III malocclusion in mixed dentition. METHODS: Cephalograms taken in the mixed dentition were available for twenty-eight patients (16 males, 12 females, mean age: 9.1 +/- 1.4 years) in early treatment group and twenty-one patients (12 males, 9 females, mean age: 10.0 +/- 2.0 years) in orthognathic surgery group. Patients in early treatment group received successful treatment to correct anterior crossbites in mixed dentition and later received non-extraction comprehensive treatment in permanent dentition. Patients in orthognathic surgery group received orthognathic surgery after growth ceased. RESULTS: The mean value of AB-MP in early treatment and orthognathic surgery groups was 65.1 degrees and 61.2 degrees, respectively (P < 0.05). The mean value of the angle between upper incisor inclination and AB line was 23.1 degrees in early treatment group and 27.3 degrees in orthognathic surgery group (P < 0.05). CONCLUSIONS: The resulting equation was: individual score (IS) = 0.164 x (AB-MP)-0.15 x (U1-AB)-6.675. When IS > 0, greater success in early treatment of class III malocclusion in mixed dentition was expected and when IS < 0, delayed treatment with orthognathic surgery is recommended.