下牙弓后段可用间隙发育特征及其临床意义

A study on the available space of lower posterior arch and its clinic significance

目的 :研究下牙弓后段可用间隙生长变化特点。方法 :选取 188例下颌第一恒磨牙无近中移动及近中倾斜的初诊患者为研究对象 ,其中男性 76例 ,女性 112例。最小年龄 11岁 ,最大年龄 18岁。由同一技师按照同一头位拍摄X线全颌曲面断层片 ,在X线片上沿牙合平面测量下颌第一恒磨牙远中表面切线到升支前缘之间的距离 ,用SPSS/PC对测量值进行统计学处理。结果 :(1)可用间隙性别组差异有显著性 ,女性大于男性。 (2 )可用间隙生长量年龄组差异有显著性 ,14岁以上女性患者均值大于 14岁以下患者 ,差值为 1.12mm。 16岁以上男性患者均值大于 16岁以下患者 ,差值为 1.91mm。 (3 )可用间隙生长量在牙合发育阶段之间有高度显著性差异 ,在安氏错牙合类型之间差异无显著性。结论

objective: To study the development of available space of lower posterior arch. Methods: The sample consisted of 188 randomly selected subjects aged from 11 to 18 years, 76 males and 112 females. The distance from the distal surface of mandibular first molar to the anterior border of the ramus was measured on orthopantomography. All the data were analyzed statistically. Results: 1) The distance(mm) in female and in male was 14.45±3.54 and 13.29±4.17 respectively( P <0.01). 2) In the males aged 11～16 years the distance was 12.67±3.74, while in those aged 17～18 that was 14.58±2.94( P <0.05); in the famales aged 11～14 that was 14.76±2.66, in those aged 15～18 that was 15.88±4.16( P <0.05). 3) The significant difference of available space between developmental stages of occlusion was found( P <0.01), while no significant difference in Angle's malocclusion categories was shown.Conclusion: The present findings will help to make reasonable diagnosis and treatment planning.