正常下颌骨生长活性的核素骨显像研究

A study on the development of normal mandible in children by skeletal scintigraphy

目的 研究正常下颌骨生长发育期生长活性的变化特点及规律。方法 对 2 0例 40侧生长发育期正常下颌骨进行99Tcm 亚甲基二膦酸盐 (MDP)显像 ,测定吸收值 ,并以第 4腰椎的99Tcm MDP吸收值作为参照 ,计算下颌骨各部位的吸收比值 ,以排除个体间差异。结果 5岁时儿童的髁状突、升支、体部吸收比值分别为 1 6 6 ,0 79,0 70。随年龄升高逐渐递减 ,2 0岁时分别为 0 6 5 ,0 44 ,0 5 9。生长发育期正常下颌骨髁状突、升支、体部的生长活性随年龄的增长逐渐递减 ,且呈直线相关关系。其回归方程分别为 :髁状突 ^Y =- 0 0 5 2 2X + 1 792 8,下颌升支 ^Y =- 0 0 15 1X + 0 76 6 7,下颌体部 ^Y =- 0 0 142X + 0 7410。下颌骨髁状突、升支、体部双侧99Tcm MDP吸收比值差异无显著性 ,男女下颌骨99Tcm MDP吸收比值差异无显著性。结论 生长发育期下颌骨髁状突、升支、体部的生长活性随年龄的增长逐渐递减 ,其变化以髁状突最为显著。下颌骨发育的稳定期在 2 0岁左右 。

Objective To study the developmental characters of the normal mandible in growing children Methods Twenty growing children undergoing skeletal scintigraphic study for isolated bone disease other than bones of the head and neck at hospital and turned out with normal results finally were studied The 99 Tc m MDP uptakes in the mandibular condyle, ramus, body and the fourth lumbar vertebra in these cases were quantitated and a ratio of the uptake in the three mandibular regions to that in the fourth lumbar vertebra was obtained Results The analysis results showed that the 99 Tc m MDP uptake ratios of the three mandibular regions decreased in linear fashion with age increasing and leveled off after age of 20 The regression equations are: the mandibular condyle, =-0 052 2X+1 792 8; the mandibular ramus, =-0 015 1X+0 766 7; the mandibular body, =-0 014 2X+0 741 0 There was no significant difference of the 99 Tc m MDP uptake ratio between the two sides of the mandible and between the male and female Conclusion The results suggest that the ideal time to undergo orthognathic surgery should be at the age of 20 or so if the circumstance of the deformity is not quite clear