拔牙矫治与非拔牙矫治对牙槽骨宽度影响的比较研究

目的 研究拔牙矫治与非拔牙矫治对牙槽骨宽度的影响。方法选正畸临床非拔牙病例和拔除四颗第一双尖牙病例各32例，分别对其矫治前和矫治后模型的下颌尖牙间、上颌尖牙间、下颌第二磨牙间及上颌第二磨牙间牙槽骨宽度进行测量，测量点为牙根牙槽部之最突点，测量数据经统计学分析。结果矫治后，拔牙组比非拔牙组下颌、上颌前部宽度分别增加了1．57mm、1．64mm（P均〈0．01），而后部宽度的差异无统计学意义。矫治前后，非拔牙组牙槽骨前后部宽度变化不明显（P均〉0，05）；而拔牙组下颌前部宽度增加了2．47mm（P〈0，001），上颌前部宽度增加了2．07mm（P〈0．01），而后部宽度的变化不明显（P均〉0.05）。结论非拔牙矫治对牙槽骨前、后部宽度无影响；拔牙矫治对牙槽骨后部宽度也无影响，但对前部宽度不但未引起降低，反而有明显的增宽。拔牙矫治导致牙弓缩窄、从而影响美观的结论有待探讨。

Comparison of the arch width between extraction and nonextraction orthodontic treatments

Objective To investigate the effect of orthodontic tooth extraction and nonextraction on the dental arch widths.Methods Thirty-two patients treated without extraction and 32 patients treated with extraction of 4 first-premolars were selected. The study models of the patients were measured before and after the treatment and compared statistically. Measurements were made in the mandibular and maxillary canine regions and the second molar regions from the most labial aspect of the buccal surfaces of the roots.Results After treatment, the anterior width of mandibular arch in the extraction group was 1.57mm larger than that in the nonextraction group (P<0.01); meanwhile the anterior width of maxillary arch in the extraction group was 1.64mm larger (P<0.01). There were no statistical differences in both mandibular and maxillary posterior regions. In nonextraction group, there were no statistical differences in both anterior and posterior regions of mandible and maxilla between pre-treatment and post-treatment. In extraction group, mandibular anterior arch width of post-treatment was 2.47mm larger than that of pre-treatment (P<0.001), maxillary anterior arch width of post-treatment was 2.07mm large(P<0.01). There were no statistical differences in posterior regions of mandible and maxilla between pretreatment and post-treatment.Conclusion Non extraction treatment does effects on neither anterior nor posterior arch width. Extraction treatment does not effect on posterior arch width, but it can increase anterior arch width. The view that orthodontic extraction results in narrower arch widths and unesthetic faces is untenable.