未萌尖牙和双尖牙总冠宽预测值表的建立

Establishment of orthodontic predictive charts for the sum crown widths of unerupted canine and two bicuspids

目的:建立适合乌鲁木齐汉族青少年未萌尖牙双尖牙总冠宽可信的预测表。方法:按 Morrees方法用数显式游标卡尺测量了 144例恒牙列期汉族正常牙合青少年石膏模型上第一恒磨牙间所有牙的近远中宽度 ,利用这些数据研究计算下颌切牙总冠宽与上下颌单侧尖牙双尖牙近远中宽度的相关性 ,建立回归方程。 结果 :形成适合乌鲁木齐汉族青少年未萌尖牙双尖牙的预测表。男性 :(1)上颌 Y=15 .0 5 19+0 .34 0 2 X(X为下颌切牙总冠宽 ,r=0 .415 1,Sy.x=0 .90 5 6 ) ,(2 )下颌 Y=13.972 8+0 .35 79X(r=0 .45 0 1,Sy.x=0 .86 2 5 )。女性 :(1)上颌 Y=13.36 93+0 .392 5 X(r=0 .42 6 4,Sy.x=1.0 30 5 ) ,(2 )下颌 Y=13.92 2 3+0 .34 33X(r=0 .35 85 ,Sy.x=1.10 6 8)。

Objective: To establish predictive charts about the size of unerupted canine and two bicuspids in Urumqi Hans' adolescents. Methods: 144 normal occlusion adolescents were gained complete permanent dentition plaster models. Their mesiodistal widths of ten teeth between two first molars were measured following the Morrees's criteria with a digital sliding calliper. These data were then utilized to establish regression equations for both maxillary and mandibular arches according to the calculating the correlation coefficients between the sum widths of the four lower incisors and those of the canine and two bicuspids on side of the upper or lower arch. Results: The predictive charts for the size of unerupted canine and bicuspids for the Hans' adolescents in Urumqi were formulated. The following formulas (Y), correlation coefficients (r) and standard deviation of Y for fixed X (Sy.x) were gained. Males: (1) Upper arch Y= 15.051 9 +0.340 2X (X equals the total widths the four lower incisors, r=0.415 1, Sy.x=0.905 6). (2) Lower arch Y=13.972 8+0.357 9X (r=0.450 1, Sy.x=0.862 5). Females: (1) Upper arch Y=13.369 3+0.392 5X (r=0.426 4, Sy.x=1.0305 ). (2) Lower arch Y=13.922 3+0.342 2X (r= 0.358 5, Sy.x=1.106 8). Conclusion: It is envisaged that the proposed charts would be more suitable for the Hans' adolescents in Urumqi.