青少年安氏Ⅱ2类错畸形矫治后下颌骨的变化

目的: 探讨青少年安氏Ⅱ²类错矫治后下颌骨及下颌牙槽骨的改建。方法: 选择本院就诊患者36例,其中12例青春发育期安氏Ⅱ²类错患者作为试验组,12例成人安氏Ⅱ²类错患者作为对照Ⅰ组,12例青春发育期安氏Ⅰ类错患者作为对照Ⅱ组。治疗前、后拍摄锥形束CT（cone-beam CT, CBCT）或头颅侧位片,分析3组矫治前、后下颌骨及下颌牙槽骨各项测量指标的改变,探讨青少年安氏Ⅱ²类错矫治后下颌骨及下颌牙槽骨的改建。采用SPSS 21.0软件包对测量数据进行统计学分析。结果: 治疗后,青少年安氏Ⅱ²类患者下颌骨长度（GO-GN）、下颌支高度（Co-Go）、下颌骨突度（SNB）及下牙槽骨突度（SNId）、下面高（S-GO、ANS-Me、ANS-Me/N-Me）增加,颏凹陷减小（P<0.05）。成人安氏Ⅱ²类患者治疗后各项测量指标无显著变化（P>0.05）。矫治后,青少年安氏Ⅱ²类患者下颌骨突度（SNB）、下颌牙槽骨突度（SNId）及前下面高比（ANS-Me/N-Me）与安氏Ⅰ类患者的差异减小。结论: 及时矫治青少年安氏Ⅱ²类错,可释放下颌骨及下颌牙槽骨的生长潜力,促进其生长改建。

Study of the mandibular changes after treatment of Class Ⅱ division 2 malocclusion in adolescents

PURPOSE: To evaluate the mandibular and dentoalveolar changes in Class Ⅱ division 2 malocclusion adolescents after treatment. METHODS: Thirty-six patients treated in our hospital were selected. Twelve skeletal Class Ⅱ division 2 adolescents were served as the experimental group, while 12 skeletal Class Ⅱ division 2 adults were selected as the control group 1, 12 skeletal Class Ⅰ adolescents were selected from those who have undergone fixed orthodontic treatment as the control group 2. Cone-beam CT (CBCT) was taken before and after treatment. The lateral cephalometric radiographs generated from CBCT data were committed to explore the changes of the mandible and dentoalveolar bone before and after orthodontic treatment among three groups. Statistic analysis was completed by SPSS 21.0 software package. RESULTS: After orthodontic treatment, the mandibular length (Go-Gn), mandibular ramus height (Co-Go), mandibular protrusion (SNB), mandibular dentoalveolus protrusion (SNId), lower facial height (S-Go, ANS-Me, ANS-Me/N-Me) increased and the fossa of chin decreased significantly in Class Ⅱ division 2 adolescents (P<0.05). The differences of SNB, SNId, ANS-Me/N-Me between Class Ⅱ division 2 and Class Ⅰ adolescents decreased. CONCLUSIONS: The growth potential of the mandible is released after treatment of Class Ⅱ division 2 malocclusion adolescents, promoting mandibular growth and reconstruction.