Studies on mechanisms of controlling the extracellular matrix molecules in periodontal tissue regeneration and dental ankylosis

I.深低温保存对牙齿移植的影响大鼠磨牙在移植到背部皮下组织前，先深低温保存一晚。然后对牙齿进行组织学检查。结果表明，冷冻保存延长了牙周再生期，而冷冻保存组牙周再生过程与对照组相似。II.去卵巢大鼠牙槽骨三维结构的变化。结果显示，含骨髓的牙槽骨有明显的骨丢失，而不含骨髓的牙槽骨数量无明显差异，提示绝经后骨质疏松症患者的骨质丢失主要发生在下颌骨的骨内表面。III.羟基磷灰石植入牙窝周围形成钙化基质。结果显示，两组患者牙槽窝内新生骨数量无明显差异。然而，在植入釉质基质蛋白的羟基磷灰石周围观察到一层薄薄的钙化基质。此外，胶原纤维被插入到较薄的基质层中，表明釉质基质蛋白具有促进羟基磷灰石周围牙骨质样和牙周韧带样结构再生的潜力。

I.Effect of cryopreservation on tooth transplantationRat molars were cryopreserved for a night before transplantation into the back subcutaneous tissue. Then the teeth were histologically examined. Results showed that cryopreservation elongated the period of periodontal regeneration, however the process of the regeneration in cryopreserved group was similar as the control non-cryopreserved group.II.Changes of the alveolar bone in the ovariectomized ratThe changes of three dimensional structure in alveolar bone of ovariectomized rats were examined by micro-CT. Results showed that significant bone loss in the alveolar bone that contain bone marrow, while no significant difference in the amount of alveolar bone that did not contain bone marrow, suggesting bone loss in postmenopausal osteoporosis occurs mainly at the endosteal surface in mandible.III.Calcified matrix formation around the hydroxyapatite placed in tooth socketThe hidroxyapatite particles were placed with/without enamel matrix protein in tooth sockets and histologically examined. Results showed that the amount of newly formed bone in the socket was not different in both group. However, a thin layer of calcified matrix was observed around the hydroxyapatite placed with enamel matrix protein. Furthermore, the collagen fibers were inserted into the thin matrix layer, suggesting enamel matrix protein has potential to promote the regeneration of cementum like and periodontal ligament like structures around hydroxyapatite.