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Effect of aging and a tooth defect on the shape of mandible

衰老和牙齿缺损对下颌骨形状的影响

基本信息

批准号：
08457519
负责人：
OHYAMA Takashi
金额：
$ 4.8万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08457519/
关键词：
aging tpptj extraction bone mineral density mandible maxilla osteoporosis エストロゲン欠乏ラット下顎骨 DEXA

项目摘要

Bone mass is a key factor for success of various dental and oral treatment, and we consider about bone loss when applying dentures and dental implants to alveolar ridge. Despite the high risk for osteoporotic bone loss among the post menopausal elderly, effect of estrogen depletion on oral bones has been ambiguous. To determine if estrogen depletion and tooth extraction affects mandibular bone volume, we conducted the following experiments, using ovariectomized (OVX) rats. The first right molars of OVX and sham operated rats were extracted. 109 days postovariectomy, the rats were sacrificed and measured the bone mineral density of right mandibles with dual energy X-ray absorptiometry (DEXA) and peripheral Quantitative Computed Tomography (pQCT). Significant difference between OVX rats and sham rats was not detected when whole mandible bodies were scanned by DEXA.However, there was significant difference when the condyle was scanned. Further, trabecular bone mineral density and cortical bone mineral density around molars in the mandibles were separately measured with pQCT.In a limited area around the molars, trabecular bone mineral density was significantly decreased in the OVX group although cortical bone mineral density was not significantly different. By contrast, the maxillary molar extraction led to decrease in BMD though dit was not significant. In this study, the BMD of he condyle which is abound with trabecular bone and trabecular bone mineral density around molars were decreased in OVX rats. These results suggest that estrogen depletion mainly affects the trabecular bone in mandible. It will be necessary to conduct further experiments to clarify the effect of tooth extraction. Furthermore, we established a primary culture system dirived from rat bone marrow cells and have investigated anabolic or catabolic factor for bone.

骨量是各种牙科和口腔治疗成功的关键因素，我们在将义齿和牙种植体应用于牙槽嵴时考虑到了骨质流失。尽管绝经后老年人骨质疏松性骨丢失的风险很高，但雌激素耗竭对口腔骨的影响尚不明确。为了确定雌激素耗竭和拔牙是否影响下颌骨体积，我们使用卵巢切除（OVX）大鼠进行了以下实验。拔除去卵巢大鼠和假手术大鼠的右第一磨牙。术后109天处死大鼠，采用双能X线骨密度仪（DEXA）和外周定量计算机断层扫描（pQCT）测量大鼠右下颌骨骨密度。DEXA扫描下颌骨体部时，OVX大鼠与Sham大鼠之间无显著性差异，而扫描髁状突时，两者之间有显著性差异。此外，松质骨矿物质密度和皮质骨矿物质密度周围的磨牙在下颌骨分别测量与pQCT。在磨牙周围的有限区域，骨小梁矿物质密度显着降低，在OVX组，虽然皮质骨矿物质密度没有显着差异。而拔除上颌磨牙后骨密度降低，但差异不显著。本研究中，OVX大鼠髁突骨密度和磨牙周围骨小梁密度均降低。提示雌激素缺乏主要影响下颌骨的松质骨。有必要进行进一步的实验来阐明拔牙的效果。此外，我们还建立了大鼠骨髓细胞的原代培养体系，并对骨合成代谢因子和分解代谢因子进行了研究。