偏颌畸形患者的牙弓特征

目的　分析偏颌畸形患者的牙弓特征,为临床矫治提供参考。方法　采用三维坐标测量仪在20例偏颌 畸形患者(试验组)和20例正常人(对照组)的牙模型上测量上下颌尖牙、前磨牙和磨牙牙尖的三维坐标值,分 析牙弓矢向和横向的对称性、上下牙弓的协调性和牙齿倾斜度,采用SAS 6·03进行统计学检验。结果　试验组上 颌尖牙和第一前磨牙距腭中缝的距离偏向侧大于偏离侧(P<0·05),下颌从尖牙到第二磨牙偏向侧距中线的距离 小于偏离侧(P<0·05);上颌尖牙和第一前磨牙的牙弓宽度比率较对照组小(P<0·05),而上颌第二前磨牙和第一 磨牙的牙弓宽度比率与正常无统计学差异(P>0·05);上颌后牙偏向侧颊向倾斜度大于偏离侧,下颌后牙偏向侧 舌向倾斜度大于偏离侧(P<0·05);上颌偏向侧和偏离侧牙齿的矢向位置无统计学差异(P>0·05)。结论　偏颌畸 形患者上牙弓前部窄于下牙弓,上颌牙齿矢向位置无差别,而上下颌两侧后牙颊舌向倾斜度存在明显差异。

Dental Arch Characteristics of the Facial Asymmetry

Objective To study the characteristics of dental arches in the patients with facial asymmetry.Methods 20 facial asymmetrical patients were chosen as the study subjects.They were 8 boys and 12 girls,aged from 12_year to 16_year old.20 normal occlusion persons without signs of facial asymmetry were chosen as control.Dental casts were measured by 3_dimension measuring machine.Dental arch asymmetry,coordination between upper and lower dental arch,and dental inclination were measured.SAS 6.03 was used in statistical analysis.Results The distance from cuspid and the first bicuspid to the median palatal raphe in the side of crossbite was larger than that of contralateral side in maxilla.The distance from cuspid,bicuspids and the first molar to the midline in the side of crossbite was smaller than that of contralateral side in mandible(P<0.05).The dental arch width of cuspid and first premolar in maxilla was smaller than that of mandible(P<0.05).Significant buccal inclination of the maxillary posterior teeth coupled with lingual inclination of the mandibular posterior teeth was found on the crossbite side.In contrast,significant lingual inclination of the maxillary posterior teeth coupled with buccal inclination of the mandibular posterior teeth was found on the contralateral side(P<0.05).Conclusion The width of upper anterior dental arch was smaller,and the inclination of upper and lower posterior teeth between crossbite side and counterside was different in facial asymmetry patients.