应力环境影响老年大鼠下颌骨骨量变化的研究

The effects of local stress on bone mass of mandibles in aged rats

目的 :观察成年和老年大鼠下颌骨应力环境改变与下颌骨骨量的关系。方法 :选择健康老年及成年大鼠 ,拔除实验组大鼠右侧上颌全部磨牙使左右侧下颌骨分别处于相对的高低应力环境中。对各组大鼠双侧下颌骨进行单光子吸收骨密度测量并对比高应力与低应力侧骨密度的差别。结果 :老年因素可引起下颌骨骨量的丢失 ;单侧咀嚼引起的应力环境变化对成年大鼠下颌骨骨量变化无显著影响 ;高应力环境可减缓老年因素所引起的下颌骨骨量丢失 ,而低应力环境则加速其骨丢失进程。结论 :咀嚼功能对于保持下颌骨骨量有重要的作用 ,对于老年牙列缺损或缺失患者应尽早恢复其咀嚼功能。

Objective:To observe the relationship between the stress environment and bone mass of mandible in adult and aged rats. Methods:The rats of 6 months old were used in the adult group,those of 15 month in the senile. The high and low stress environment models of mandible were established by unilateral maxillary molar extraction.6 rats were used in each group The rats without teeth extraction were used as the control. The bone mineral density (BDM,g/cm 2) of mandibles were measured by single photon absorptiometry bilaterally 1.5 and 3 months after teeth extraction. Results: In the adult group,1.5 month after teeth extraction,BDM values of operated side and nonoperated side were 0.360±0.013 and 0.368±0.018 respectively ( P >0.05),while that of the control was 0.363±0.023;3 months after those were 0.355±0.015,0.375±0.017 and 0.364±0.027 respectively.In the senile group,1.5 month after teeth extraction BDM values of operated side and nonoperated side were 0.332±0.009 and 0.349±0.010 respectively ( P <0.05),while that in the control was 0.347±0.014;3 months after those were 0.327±0.011,0.346±0.010 and 0.338±0.016 respectively ( P <0.05 betweent each two groups).Conclusion:Masticatory function tends to conserve the mandibular bone mass in senitity.