减小后牙▉平面倾斜度对安氏Ⅱ类高角畸形髁突位置影响的研究

目的: 研究在安氏Ⅱ类高角畸形正畸治疗中,减小后牙平面倾斜度对髁突位置的影响。方法: 15例安氏Ⅱ类高角畸形患者,年龄15~30岁。治疗前ANB>5°,下颌平面角FH-MP>32°,磨牙关系为双侧远中关系。常规排齐整平及适当扩弓后,利用多曲唇弓导下颌向前,并使后牙平面平坦化。利用锥形束CT（cone-beam CT,CBCT）测量治疗前、后颞下颌关节前、上、后间隙及后牙平面的改变情况。采用SPSS19软件包对变化量进行t检验;并利用相关性分析,进一步探讨髁突位置改变量与后牙平面倾斜度减小量之间的相关性。结果: 所有患者磨牙尖牙关系均调整到中性,侧貌改善明显,髁突后间隙平均增加(0.88±0.17)mm,变化有统计学意义(P<0.001);髁突上间隙平均增加(0.45±0.20)mm,变化也具有统计学意义(P<0.05)。后牙平面变平坦,POP-SN及POP-FH平均减小3.59°±2.31°及2.31°±3.62°,变化具有统计学意义(P<0.001)。髁突前间隙变化量无统计学意义,髁突位置改变量与后牙平面倾角的变化量之间无显著相关性。结论: 在安氏Ⅱ类高角畸形患者的正畸治疗中,通过正畸减小后牙平面倾斜度,可使髁突的位置发生适当的前下改变,有利于关节症状的改善。

Influence on the condyle position by decreasing posterior occlusal plane angle in Class II high angle cases

PURPOSE: To investigate the changes of condyle position by decreasing posterior occlusal plane angle in Class II high angle cases. METHODS: Fifteen Class II high angle patients, aged from 15 to 30, were treated. Before treatment, ANB>5°, FH-MP>32°, molar relationship was Class II bilaterally. The treatment began with aligning and leveling the upper and lower dental arch, then the upper arch was expanded when necessary. Multiloop edgewise arch wire (MEAW) was used to guide the mandible forward and flatten the posterior occlusal plane. Cone-beam CT(CBCT) was taken for each patient before and after treatment. The anterior, superior and posterior spaces of temporomandibular joint(TMJ) were measured respectively, and the posterior occlusal plane angle was also measured. Paired t test was used to evaluate the changes of condyle position and posterior occlusal plane angle, and pearson correlation coefficients was used to determine the correlation between changes of condyle position and posterior occlusal plane angle using SPSS 19 software package. RESULTS: Class II molar relationship of all patients was improved to Class I, and the profile was improved. Posterior and superior space of TMJ increased by 0.88 mm±0.17 mm and 0.45 mm±0.20 mm on average respectively, and both increases were significant. Posterior occlusal plane was flattened, POP-SN and POP-FH decreased by 3.59°±2.31° and 2.31°±3.62°, respectively, and the decreases were significant. Pearson's correlation test showed no significant correlation between changes of condyle position and posterior occlusal plane angle. CONCLUSIONS: In orthodontic treatment of Class II high angle cases, the condyle can be changed to anterior and inferior position by decreasing posterior occlusal plane angle.