计算机辅助数学模型分析Twin-block功能矫治后的组织相关性

背景：功能矫治器的观察对象郁是处于生长期的青少年．在研究功能矫治是否有效的问题时，必须要考虑儿帝本身的生长发育条件。目的：排除自然生长因素对实验结果的影响，采用计算机辅助数学分析Twin-block矫治器治疗后Ⅱ类错牙合]患者颅颁面软硬组织的相关性。方法：选择Hagg手腕骨片为FG-G期的安氏Ⅱ类1分类下颌后缩患者31例，其中接受Twin—block功能矫治的Ⅱ类错牙合患者17例，放弃正畸治疗的Ⅱ类错牙合]患者14例，2组患者年龄、性别相匹配。分别在治疗前后和自然生长前后拍摄头颅侧位片，观察Twin-block功能矫治前后和自然生长前后侧位片软硬组织头影测量值的变化规律，建立两组数学对比模型。结果与结论：通过数学对比模型发现，在Twin—block矫治后软组织测最项目Ls—EP、Pn—HP、NB—pg＇-Ls与硬组织测量项目ANB之间存在明显的曲线关系，方程为：NB-Pg’-Ls=-0．1191（ANB）2＋3．0029（ANB）＋6．1485，Pn—HP=0．0214（ANB）2—10267（ANB）＋0．3474，Ls—EP=0．1324（ANB）2-0．5364（ANB）＋1．5537。在自然生长前后，软硬组织的改变差异无显著性意义。提示Twin-block矫治后ANB的角度是改善Ⅱ类错牙合]患者软组织侧貌的决定性因素。

Mathematics model evaluation of soft tissue changes after Twin-block treatment

BACKGROUND： Because the subjects of functional appliance are young people in the growing period, children＇s growth and development need to be considered to study whether the functional appliance is valid. OBJECTIVE： To build a mathematical model to analyze the correlation between craniofacial soft and hard tissues after the correction of Class Ⅱ malocclusion with twin-block treatment. METHODS： Thirty-one Class Ⅱ Division 1 malocclusion subjects with hand-wrist radiographs in FG-G stage were selected. Among the 31 cases, 14 abandoned treatment. The remaining 17 subjects received Twin-block treatment. All the subjects were taken cephalometric radiographs before and after twin-block treatment as well as before and after natural growth of hard and soft tissue to observe the variation rule of soft and hard tissue cephatometric values so as to build the corresponding mathematical models. RESULTS AND CONCLUSION： Based on the mathematical models, the soft tissue indicators （Ls-EP, Pn-HP, NB-Pg＇-Ls） and hard tissue indicators （ANB） showed the curve relationships. The formula were： NB-Pg＇-Ls=-0.119 1（ANB）2 ＋3.002 9 （ANB）＋ 6.148 5; Pn-HP=0.021 4（ANB）2 -1.026 7（ANB）＋ 0.347 4; Ls-EP =0.132 4（ANB）2-0.536 4（ANB）＋1.553 7. The results of this study provided evidence that ANB angle was to the decisive factor to improve soft tissue profile of Class Ⅱ malocclusion patients after twin-block treatment.