上颌拔牙矫治对骨性Ⅲ类错畸形正颌术前牙弓宽度影响研究

Effect of extraction of the maxillary first premolars on arch-width changes before orthodontics for skeletal Class Ⅲ malocclusion

目的评价骨性Ⅲ类错畸形患者正颌术前正畸治疗中拔除与不拔除上颌第一前磨牙对牙弓横向宽度的影响,为是否在术前正畸中拔除上颌前磨牙提供一个参考指标。方法选择2007年1月至2012年7月在大连市口腔医院接受正畸-正颌联合治疗的骨性Ⅲ类错畸形患者28例,其中12例术前正畸采取拔牙矫治(拔牙组),16例采取不拔牙矫治(非拔牙组)。对两组病例正畸治疗前后的模型进行牙弓宽度对比研究。结果经过术前正畸治疗,拔牙组较非拔牙组的上颌后段牙弓宽度减小明显,差异有统计学意义(P<0.05);拔牙组与非拔牙组的下颌牙弓中段及后段宽度均有增加,但两组差异无统计学意义(P>0.05)。结论在骨性Ⅲ类错畸形的正畸-正颌外科联合治疗中,拔除上颌第一前磨牙有利于术前正畸有效去除后牙代偿,协调上下牙弓间横向关系,为正颌手术创建良好条件。

Objective To compare arch-width changes between maxillary premolar extraction and non-extraction mo- dalities, and to provide an additional indication for presurgical maxillary premolar extraction according to the transverse dental arch characteristics of Class Ⅲ surgical-orthodontic patients. Methods Pretreatment and preoperative dental cases of 28 adult Class Ⅲ patients（ 16 non-extraction, 12 extraction）who underwent surgical-orthodontic treatment were collected. The changes in maxillary and mandibular dental arch widths were measured. Results Statistical analyses showed that the maxillary posterior dentitions arch-width changes of the premolar extraction group were significantly greater than that of the non-extraction group. The mandibular dentition arch-width changes had no significant differenc- es between two groups. Conclusion Maxillary premolar extraction in Class Ⅲ presargical orthodontic treatment might be benefitial for intermaxillary arch width coordination and decompensate posterior teeth.