安氏Ⅰ类错病例前磨牙拔除模式的选择

Choice of premolar extraction patterns in ClassⅠ patients

目的通过对拔除第一前磨牙和第二前磨牙的安氏Ⅰ类错病例治疗前颌面部软硬组织的比较,探寻影响前磨牙拔除模式的因素,为临床提供参考。方法选取疗效满意、中轻度拥挤、非双颌前突的安氏Ⅰ类病例153例,分为两组,其中拔除4个第一前磨牙组96例,拔除4个第二前磨牙组57例。对两组治疗前的头颅侧位X线片进行测量(软硬组织共118项指标),组间比较,选取其中有统计学差别的指标进行逐步判别分析。结果逐步判别分析得到判别公式:IS=0.092A.P.D.I+0.065FM IA-0.049颏沟倾角-0.352下唇厚度+0.188颏部软组织厚度-6.465,判别临界值为0.17。拔除第一前磨牙组回代率为77.1%,拔除第二前磨牙组回代率为77.2%。结论在进行前磨牙拔除模式的选择上,治疗前软组织的形态,特别是下唇的厚度必须有所考虑。

Objective To find the pretreatment factors influencing the premolar extraction pattern and provide some clinical and academic reference for the premolar extraction choice before treatment. Methods In the study 96 patients involved the extraction of first premolars and 57 patients involved the extraction of second premolars. Both groups of patients were Class I without protruding maxillary and the crowding was less than 8mm and the treatment effects were satisfactory. The lateral cephalometric radiographs taken before and after treatment were traced and measured. 118 typical values of hard tissue and soft tissue were measured in Winceph 7.0 software and statistical analysis was carried by Spss10. 0 software. After the statistically significant differences were searched, stepwise discriminant a- nalysis was applied to identify the key factors for discriminating the two groups. Results IS = 0. 092A. P. D. I ＋ 0. 065FMIA - 0. 049 ∠Pos - B＇- FH -0. 352 [ Lower lip thickness] ＋0. 188 [ soft tissue thickness of chin] - 6.465. The critical score was 0. 17. The patient with an individual score higher than the critical score will be treated with the second premolar extraction. When the values were taken back to the formula,the percent age was 77. 1 in the first premolar extraction group and 77.2 in the second premolar extraction group. Conclusions In the choice of premolar extraction pattern before treatment, we must think of the soft tissue profile, especially the thickness of lower lip.