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An experimental study on histopathological changes of alveolar bone around hydroxyapatite during orthodontic tooth movement.

正畸牙移动过程中羟基磷灰石周围牙槽骨组织病理学变化的实验研究。

基本信息

批准号：
62570858
负责人：
HARA Yoshitaka
金额：
$ 1.34万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

It the been unclear whether M.T.M. is acceptable in the cases treated with bone graft using hydroxyapatite(HAP), which is not bio-degradable. So we examined histological changes of bone among HAP during orthodontic tooth movement. HAP was implanted into artificial bone defects adjacent to second premolars in beagie dogs, and as control no materials was implanted into them. Three months after implantation, the second premolars were moved with orthodontic force. Then they were observed histopathologically. The results obtained were as follows.Amount of movements of the teeth in implanted sites were smaller than control. At pressure zone : Resorptions of bone by osteoclasts were observed both in implanted and control sites, in addition, root resorptions occured adjacently to HAP. Further mutinucleated giant cells closely attached to HAP surrounded by bone and connective tissue. In retention period there was ankylosis between roots and bone around HAP. At tension zone : additional bone from HAP was observed. Bone defects were filled with bone in implanted sites, on the other hand, with connective tissue in control.These results suggested that bone among HAP was resolved by osteoclasts. Clinically, HAP implantation for pressure zone should be avoided because of the occurence of root resorption and ankylosis. But for tension zone it seems to be effective because HAP implantation produces more repaired bone.

目前还不清楚M.T.M.在使用不可生物降解的羟基磷灰石（HAP）进行骨移植治疗的病例中是可以接受的。因此，我们研究了HAP在正畸牙移动过程中的骨组织学变化。将羟基磷灰石植入比格犬第二前磨牙附近的人工骨缺损中，作为对照，不植入任何材料。种植3个月后，用正畸力移动第二前磨牙。然后进行组织病理学观察。结果表明：种植牙的移动量小于对照组。在压力区：在植入部位和对照部位均观察到破骨细胞对骨的吸收，此外，在HAP附近发生牙根吸收。更多的多核巨细胞紧密附着在HAP上，被骨和结缔组织包围。在保留期，HAP周围的根与骨之间存在强直。在张力区：观察到HAP的额外骨。结果表明，HAP中的骨缺损被破骨细胞所解决，植入部位的骨缺损被骨组织所填充，而结缔组织则未被填充。临床上应避免压力区种植HAP，以免发生牙根吸收和强直。但对于张力区，由于HAP植入产生更多的修复骨，因此似乎是有效的。