正畸治疗对错畸形患者牙弓形态的影响

Effects on arch form after orthodontic treatment for malocclusion patients

目的分析比较拔牙与不拔牙矫治对安氏Ⅰ类错畸形患者牙弓形态的影响。方法42例拔除4个第一前磨牙和27例未拔牙的安氏Ⅰ类错畸形患者,测量治疗前后的牙颌模型,记录上、下颌牙弓尖牙间和磨牙间宽度,以及上、下颌牙弓前牙段牙弓长度,将测量数据进行统计学分析。结果安氏Ⅰ类错畸形拔牙矫治后,上下颌牙弓尖牙间宽度增大(分别为1.08 mm和1.43 mm),变化值与不拔牙矫治差异无显著性(P>0.05);上颌牙弓磨牙间宽度减小(为1.63 mm),下颌牙弓磨牙间宽度增大(为1.34 mm),变化值明显大于不拔牙矫治(P<0.01);上下颌前牙段牙弓长度增大(分别为1.31 mm和1.01 mm),变化值明显大于不拔牙组(P<0.05)。不拔牙矫治后上下颌牙弓尖牙间宽度无明显增大,但磨牙间宽度增大(分别为0.99 mm和0.46 mm)。结论与不拔牙矫治相比,拔牙矫治不会减小尖牙间牙弓宽度和前牙段牙弓长度而影响面部美观;但拔牙和不拔牙矫治都能引起磨牙间牙弓宽度的改变,可能影响疗效的长期稳定性。

Objective To examine the dental arch form changes after extraction and nonextraction treatment in class Ⅰ malocclusion patients. Methods The study was performed on pretreatment and posttreatment class Ⅰ malocclusion casts of 42 patients with 4 flrst-premolar extraction and 27 patients with no extraction. Intercanine and intermolar arch widths and anterior arch depths of the maxillary and mandibular arches were measored. Results The maxillary and mandibular intercanine arch widths of the extraction group increased significantly （1.08 mm and 1.43 mm, respectively） ; the maxillary intermolar widths of the extraction group decreased （1.63 mm）and the mandibular intermolar widths had increased（1.34mm）;the maxillary and mandibular anterior arch depths of the extraction group increased significantly （1.31 mm and 1.01 mm, respectively）. The maxillary and mandibular intercanine arch widths of the nonextraction group did not increase significantly, but the intermolar arch widths increased significantly（0.99 mm and 0.46 mm, respectively）. Conclusion To compare with the nonextraction treatment, the extraction treatment does not result in narrower dental arch widths and shallower anterior arch depths , it dose not have the detrimental effects on facial esthetics. Both the extraetion and nonextraetion treatment can result in ehanging posterior dental areh widths and affeet the permanent stability.