Effects of occlusion on mandibular morphology and architecture in rats
Effects of occlusion on mandibular morphology and architecture in rats
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咬合对大鼠下颌形态和结构的影响
DOI：
10.1016/j.jss.2015.09.025
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发表时间：
2016-02-01
影响因子：
2.2
通讯作者：
Chen, Yong-Jin
中科院分区：
文献类型：
--
作者：
Liu, Jia;Liu, Shi-Yu;Chen, Yong-Jin
背景：啮齿动物咬合功能减退模型在颌骨相关研究中已被广泛建立。然而，完全消除磨牙接触的咬合刺激及其康复对下颌重塑的影响尚不清楚。材料与方法：选用5周龄Sprague-Dawley雄性大鼠48只。24只实验大鼠通过插入咬合提升器进行咬合功能减退。24只大鼠不给药（对照组）。2周后处死半数实验大鼠（咬合功能减退组）；剩余的实验大鼠（恢复组）在杀死前再将器械取出两周。对照动物每两周宰杀一次。测量体重和咬肌重量，并对下颌骨进行显微计算机断层扫描，以评估下颌骨形态和皮质骨特征。采用定量聚合酶链反应检测成骨细胞和破骨细胞相关基因的表达。结果：实验组大鼠与对照组大鼠体重无明显差异。咬合功能低下组咬肌较轻，下颌切牙冠、下颌骨体和支较短，下颌牙槽突和第一磨牙窝较高。此外，与成骨细胞和破骨细胞相关基因表达相关的皮质骨特征在咬合功能低下组的中、后下颌骨中存在显著差异。在咬合刺激后2周的恢复时间点，咬肌和下颌骨的改变参数恢复到正常水平。结论：通过骨转换的下颌重塑对改变的咬合刺激具有区域特异性。正常咬合是下颌形态和结构的重要决定因素。(C) 2016 Elsevier Inc.版权所有。
Background: A rodent occlusal hypofunction model has been widely established in jawbone-related studies. However, the effects of occlusal stimuli, with total elimination of molar contacts, and its rehabilitation on mandibular remodeling remain unclear.Materials and methods: Forty-eight 5-wk-old Sprague-Dawley male rats were used. Twenty-four experimental rats underwent occlusal hypofunction by insertion of a bite-raising appliance. Twenty-four rats received no treatment (control group). Two weeks later, half the experimental rats (occlusal hypofunction group) were killed; the appliance was removed from the remaining experimental rats (recovery group) for two additional weeks before killing. Control animals were killed biweekly. Body weight and masseter muscle weight were measured, and the mandibles were subjected to micro-computed tomography to evaluate the mandibular morphology and cortical bone characteristics. The expressions of osteoblast-and osteoclast-related genes were evaluated with quantitative polymerase chain reaction.Results: No significant body weight differences were observed between the experimental and control rats. However, lighter masseter muscle, shorter mandibular incisor crown, mandibular body and ramus, and higher mandibular alveolar process and first molar fossae were observed in the occlusal hypofunction group. Moreover, the cortical bone characteristics associated with the expression of osteoblast-and osteoclast-related genes were remarkably different in the central and posterior mandible in the occlusal hypofunction group. At the 2-wk recovery time point after occlusal stimuli, the altered parameters in the masseter and mandible returned to normal levels.Conclusions: Mandibular remodeling via bone turnover is region specific for altered occlusal stimuli. Normal occlusion is an important determinant of the mandibular morphology and architecture. (C) 2016 Elsevier Inc. All rights reserved.