安氏Ⅰ类错牙合不同垂直骨面型患者下颌骨骨密度的测量分析

Analysis and measurement of bonemineral density of mandible of class Ⅰ malocclusion with different vertical facial types

目的探讨安氏I类错牙合不同垂直骨面型患者的下颌骨骨密度的差异,为不同骨面型患者的正畸治疗提供临床参考。方法选择面部基本对称安氏I类患者88例,其中均角患者32例(男性12例,女性20例,平均年龄21.0岁)作为正常对照,高角患者27例(男性10例,女性17例,平均年龄22.5岁)、低角患者29例(男性15例,女性14例,平均年龄21.0岁)作为两实验组,88例患者均拍摄数字化全颌曲面断层片,采用曲面体层下颌指数(PMI)为测量指标分析样本的下颌骨骨密度。结果正常对照组s PMI值为0.280±0.035,i PMI值为0.348±0.052;高角组患者s PMI值为0.248±0.033,i PMI值为0.313±0.044;低角组患者s PMI值为0.285±0.038,i PMI值为0.361±0.061。3组的PMI指数差异有显著性(P<0.05)。结论高角组患者下颌骨骨密度值较正常组低,低角组患者下颌骨骨密度值较正常组高。PMI指数反映了下颌骨皮质骨量的变化,间接反映了下颌骨的骨密度,为检测下领骨骨密度提供了简便、直观的方法。同时,下颌骨骨密度的测定结果可能提示全身骨密度情况,可以使其得到早期防治。

Objective To investigate the difference of mandibular bone mineral density in class I malocclusion patients with different vertical facial types, and to provide clinical reference for orthodontic treatment of patients with different facial types. Methods Eighty-eight patients with class I malocclusion were selected.Among those, 32 patients with average-angle （ 12 males and 20 females, with an average age of 21 years old） were divided in normal control group, and 27 patients with high-angle （10 males and 17 females, with an average age of 22.5 years old） and 29 patients with low-angle （15 males and 14 females, with an average age of 21 years old） were divided to two experimental groups.All the 88 patients took the digital panoramic radiography photos.Bone mineral density of the mandible was analyzed using panoramic mandible index （ PMI） .Results In control group, sPMI was 0.280 ±0.035, and iPMI was 0.348 ±0.052.In the group with highangle, sPMI was 0.248±0.033, and iPMI was 0.313 ±0.044.In the group with low-angle, sPMI was 0.285 ±0.038, and iPMI was 0.361 ±0.061.PMI index was statistically different among the three groups （P〈0.05）.Conclusion The mandible bone mineral density in high-angle group is lower than that in normal group.The mandible bone mineral density in low-angle group is higher than that in normal group.PMI reflects the change of bone mass in the cortial bone.It reflects bone mineral density of the mandible bone indirectly.It provides a convenient and intuitional method to measure bone mineral density of the mandible.Meanwhile, the result of bone mineral density in the mandible can indicate bone mineral density of the whole body, which may prevent osteoporosis earlier.