基于遗传算法优化青少年下颌磨牙后区生长潜力预测方法研究

 目的　探讨影响青少年下颌磨牙后区生长潜力的因素，并分析基于遗传算法（genetic algorithms，GAS）优化青少年下颌磨牙后区生长潜力非线性预测方程的准确性。方法　选取2017-2019年于吉林大学口腔医院正畸科就诊的符合纳入标准的初诊患者306例。通过头颅定位侧位片测量下颌磨牙后间隙及颈椎测量指标，采用多元线性回归分析下颌磨牙后间隙与年龄、下颌第三磨牙牙龄、颈椎骨龄等的相关性，选取最强相关因子构建线性回归方程和基于GAS优化的非线性方程，并比较两个预测方程的准确性。结果　（1）不同矢状骨面型患者下颌磨牙后间隙不同，骨性Ⅰ类错牙合畸形组［（9.99 ± 2.53）mm ］与骨性Ⅲ类错牙合畸形组［（10.53 ± 3.53）mm ］比较，差异无统计学意义（P > 0.05）；而骨性Ⅱ类错牙合畸形组患者下颌磨牙后间隙［（8.98 ± 2.71）mm］小于骨性Ⅰ类和Ⅲ类错牙合畸形组，差异均有统计学意义（均P < 0.05）。故将所有患者分为骨性Ⅰ+Ⅲ类错牙合畸形组和骨性Ⅱ类错牙合畸形组。（2）下颌磨牙后间隙（RMS）与下颌第三磨牙牙龄（YL）呈正相关关系，两组分别构建线性回归方程和基于GAS优化的非线性方程如下。骨性Ⅰ+Ⅲ类错牙合畸形组：RMS = 1.489YL + 3.891；RMS = 2.36YL0.81 + 2.686。骨性Ⅱ类错牙合畸形组：RMS = 1.464YL + 1.961；RMS = 2.36YL0.81 + 0.723。基于GAS优化的非线性方程误差值低于线性回归方程，但其差异无统计学意义（P > 0.05）。结论　临床正畸医生进行青少年患者正畸方案设计时，应着重结合患者第三磨牙牙龄及矢状骨面型。应用基于GAS优化的非线性方程预测下颌磨牙后区生长潜力具有较高的预测精度和准确性。

Analysis of the survey on oral health behavior in 639 physical examinees

Abstract：Objective To investigate the oral health behavior of people in the neighbourhood of Beijing Huangsi Aesthetic Plastic Surgery Hospital and analyze their influencing factors. Methods Questionnaire survey was conducted among 639 physical examinees on the purpose and frequency of toothbrushing， methods of dental cleaning and the selection of toothpaste. The results were statistically analyzed. Results The females were much better than the males in frequency of toothbrushing and use of dental floss and fluoride toothpaste（P < 0.01）. There were significant differences among the people from different growing places on the purpose of toothbrushing（P < 0.05）， frequency of toothbrushing（P < 0.01） and use of dental floss and fluoride toothpaste （P < 0.01）. At toothbrushing， the purpose affected the frequency（P < 0.05）. Conclusion The department of stomatology of basic-level hospitals and dental clinics should adjust oral health promotion strategy according to the people they serve.