上颌快速扩弓联合前方牵引对替牙期骨性Ⅲ类错牙合畸形的矫治疗效

Orthodontic effects of rapid maxillary expansion combined with maxillary protraction on skeletal Class Ⅲ malocclusion during the mixed dentition

目的通过锥形束断层扫描技术(cone beam computed tomography,CBCT)研究评价上颌快速扩弓联合前方牵引对替牙期骨性Ⅲ类错牙合横向不足的治疗效果。方法选择替牙期骨性Ⅲ类错牙合患儿19例,平均(8.47±0.70)岁。分别于上颌快速扩弓联合前方牵引治疗前(T_(1))及扩弓结束3个月后(T_(2))拍摄CBCT,测量上颌第一磨牙倾斜度、上颌前磨牙段及第一磨牙牙冠宽度、牙槽突宽度、上颌基骨宽度、牙槽嵴高度、第二前磨牙牙胚在牙槽骨中的位置等,比较治疗前后各测量项目的差异。结果从T_(1)到T_(2)阶段,上颌第一前磨牙牙冠宽度增加(2.37±3.47)mm(P=0.008),第二乳磨牙牙冠宽度增加量中位数为3.37 mm(P=0.009),第一磨牙牙冠宽度增加(2.60±2.53)mm(P<0.001),上颌第一前磨牙、第二乳磨牙、第一磨牙对应牙槽突宽度分别增加(1.63±2.45)mm(P=0.010)、(2.12±2.59)mm(P=0.002)、(1.98±2.10)mm(P<0.001),第一磨牙腭根根尖宽度、第一磨牙阻抗中心宽度分别增加(2.00±2.40)mm(P=0.002)、(2.00±2.07)mm(P<0.001),差异具有统计学意义;上颌第一磨牙倾斜度(P_(左)=0.196、P_(右)=0.251)、上颌基骨宽度(P=0.192)、下颌基骨宽度(P=0.266)及第一磨牙根分叉宽度(P=0.678)、上颌第一前磨牙牙槽骨高度(P=0.136)、第二乳磨牙牙槽骨高度(P=0.638)、第一磨牙牙槽骨高度(P=0.274)、第二前磨牙牙胚在牙槽骨中的相对位置(P=0.058)治疗前后差异均无统计学意义。结论上颌快速扩弓联合前方牵引可明显改善替牙期骨性Ⅲ类错牙合患儿中后段牙弓及颌骨横向不调,治疗对前磨牙牙胚在牙槽骨中的相对位置无影响。

Objective To evaluate the therapeutic effect of rapid maxillary expansion combined with anterior traction on maxillary transverse deficiency in patients with skeletal Class Ⅲ malocclusion during the mixed dentition period using cone beam computed tomography(CBCT)technology.Methods A total of 19 mixed dentition patients(average age 8.47±0.70 years old)with skeletal Class Ⅲ malocclusion were selected.CBCT was taken before maxillary protraction combined with rapid maxillary expansion(T_(1))and 3 months after treatment(T_(2)),respectively,to measure the inclination of the first maxillary molar,the crown width and alveolar width of the first maxillary premolar,the second primary molar and the first molar,the width of the maxillary basal bone,the height of the alveolar crest and the location of the second maxillary premolar germ in the alveolar bone.The differences in various measurement items before and after treatment were compared.Results The crown width of the first maxillary premolar increased by(2.37±3.47)mm(P=0.008),the median increase in crown width of the second primary molar was 3.37mm(P=0.009)and the crown width of the first molar increased by(2.60±2.53)mm(P<0.001)from T_(1) to T_(2).The alveolar width of the maxillary first premolar,the second primary molar and the first molar increased by(1.63±2.45)mm(P=0.010),(2.12±2.59)mm(P=0.002)and(1.98±2.10)mm(P<0.001)respectively.The width of the apex of the palatal root and the width of resistance center of the first molar increased by(2.00±2.40)mm(P=0.002)and(2.00±2.07)mm(P<0.001)respectively,with statistically significant differences.There was no statistically significant difference in.the tipping of the first maxillary molar(P=0.196,P=0.251),the width of the maxillary basal bone(P=0.192),the width of the mandibular basal bone(P=0.266)and the width of the center of resistance of the first molar(P=0.678),the height of the alveolar bone of the first maxillary molar(P=0.136),the second primary molar(P=0.638)and the first molar(P=0.274)and the location of the germ of the second premolar in alveolar bone(P=0.058)before and after treatment.Conclusion Rapid maxillary expansion combined with maxillary protraction can significantly improve the transverse deficiency of the middle-posterior arch and maxillary bone in mixed dentition patients with skeletal ClassⅢmalocclusion.The treatment has no effect on the relative position of the premolar tooth germ in the alveolar bone.