无牙下颌角大小与其皮质骨厚度和剩余牙槽骨高度的关系

目的　分析无牙下颌角角度的变化 ,探讨其角度与性别、年龄、下颌角骨皮质厚度、剩余牙槽骨高度及无牙颌时间的关系。方法　年轻有牙组 131例 ,女性 6 8例 ,男性 6 3例 (平均年龄 2 7岁 ) ,年长有牙组 97例 ,女性 5 9例 ,男性 38例 (平均年龄 6 5岁 ) ,老年无牙颌组 12 8例 (平均年龄 80岁 ,76岁者 5 8例 ,81岁者 39例 ,86岁 31例 )。 3组共拍摄 35 6张曲面断层片。分别测量曲面断层片下颌角角度、无牙下颌角区骨皮质厚度和剩余牙槽骨高度。用调查问卷收集无牙颌患者的病史资料。结果　年轻有牙组和年长有牙组的下颌角大小差异无显著性 ,但两组男性下颌角均小于女性下颌角 (P <0 0 5 ,P <0 0 0 1)。老年无牙颌组下颌角为 12 8 4 °± 6 6 °,大于年长有牙组 ( 12 2 8°± 6 6 °) ,二者间差异有极显著性 (P <0 0 0 1)。 76岁无牙女性组 ,下颌角的大小与下颌角区骨皮质厚度呈负相关 (P <0 0 1) ;无牙颌男性和女性下颌角大小均与剩余牙槽骨平均高度呈负相关 (P <0 0 1)。无牙下颌角角度与无牙颌时间无关。结论　无牙患者较有牙者下颌角增大以及剩余牙槽骨越低下颌角越大的结果说明 ,自然牙列和全口义齿的咀嚼功能可能对下颌角的角度有显著影响。无牙下颌角的大小与其骨皮质厚度的显著关系提示 ,系

Association of mandibular angle size with cortical thickness and residual ridge height of the edentulous mandible

Objective To evaluate the mandible angle and to investigate the relationship of angle size to gender, age group, cortical thickness at the mandibular angle (CTMA), height of mandibular residual body, and edentulous period in the elderly edentulous subjects. Methods A total of 356 panoramic radiographs of three groups of subjects were evaluated: the young dentate group, 131 subjects (mean age: 27); the older dentate group, 97 (mean age: 64); and the elderly edentulous group, 128 (ages 76, 81, or 86). Mandibular angle size, CTMA, and height of mandibular residual body were measured from panoramic radiographs. A structured questionnaire was used to determine the history of edentulousness. Results Difference in angle size was found between dentate men and women ( P <0 05, P <0 001), but not between the elderly edentulous men and elderly women. The elderly edentulous subjects had larger mandibular angles than did older dentate subjects ( P <0 001). The angle size was negatively related to CTMA only among 76 year old edentulous women ( P <0 01) and negatively associated with average height of the mandibular residual body in the edentulous men and women ( P <0 01). No association existed between angle size and duration of edentulousness. Conclusions Elderly edentulous subjects have large mandibular angles and the angle size is correlated with low height of the mandibular residual body, which suggests that masticatory function of natural dentition and complete denture may influence change of the mandibular angle. The significant relationship of mandibular angle size to CTMA probably indicates the effect of systemic factors on change in the mandibular angle.