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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小梁结构的关系。方法 以 6月龄及15月龄雄性大鼠分别代表成年组和老年组大鼠 ,拔除大鼠右侧上颌全部磨牙使咀嚼 (左 )侧、非咀嚼 (右 )侧下颌骨分别处于相对的高低应力环境中 ;依此将老年和成年大鼠各 2 4只分为四组 ;①老年 +拔牙组 ;②老年 +非拔牙组 ;③成年 +拔牙组④成年 +非拔牙组 ;在实验 1.5个月和 3个月时对各组双侧下颌骨的组织切片进行骨组织形态计量学分析。结果 老年组大鼠下颌骨松质骨面积比 (Cn .Ar%)、骨小梁宽度 (Tb .Wi)较成年大鼠显著降低 ,骨小梁间隔宽度 (Tb .Sp)有部分增宽 ,但骨小梁数目 (Tb .N)无显著变化 ;对于成年大鼠 ,低应力和高应力侧以及非拔牙对照组相互间下颌骨Cn .Ar %、Tb .Wi、Tb .N和Tb .Sp均无显著差异 (P >0 .0 5 ) ;而对于老年组 ,实验 3个月时 ,低应力侧Cn .Ar%、Tb .Wi和Tb .N均比高应力侧及同期非拔牙对照组显著偏低 ,Tb .Sp则显著增宽 ;而高应力侧与同期对照组相比 ,两组间各值均无显著性差异。结论 咀嚼功能低下或缺失 (低应力环境 )可加速老年因素引起的下颌骨骨小梁吸收 ,对于老年患者应尽早恢复其咀嚼功能 ,减少颌骨骨丢失。
Objective To observe the relationship between mandibular stress environment and mandibular trabecular structure in adult and aged rats. Methods 6-month-old and 15-month-old male rats were used to represent the adult and aged rats, respectively. All the maxillary molars on the right side of the rats were removed, and the mandibular tissues at chewing (left) side and non-chewing Stress environment; accordingly, the 24 aged and adult rats were divided into four groups; ① old + extraction group; ② elderly + non-extraction group; ③ adult + extraction group ④ adult + non-extraction group; Bone histomorphometry was performed on the bilateral mandibular tissue sections of each group at month and 3 months. Results The mandibular cancellous bone area ratio (Cn. Ar%) and trabecular bone width (Tb .Wi) of the aged group were significantly lower than those of the adult rats, and the Tb (subscript Sp) However, there was no significant change in the number of trabecular meshwork (Tb .N). For adult rats, the mandibular CnAr%, Tb.Wi, Tb.N and Tb.Sp (P> 0.05). For the aged group, the Cn. Ar%, Tb .Wi and Tb .N on the low stress side were higher than those on the high stress side and the non-extraction control group Significantly lower, Tb. Sp was significantly broadened; and high stress side compared with the control group, the two groups had no significant difference between the values. Conclusions Mild malaise or absence (low stress environment) can accelerate the absorption of mandibular trabecular bone caused by geriatric factors. For elderly patients, masticatory function should be restored as soon as possible, and bone loss should be reduced.