Histological Analysis of the Periodonitium-like Tissues around Hydroxyapatite Implant

本研究的目的是探讨羟基磷灰石陶瓷作为牙髓-骨内种植体的可能性。我们初步观察了种植体周围的组织，这些组织从根尖向外推。本研究使用的是猴子的上门牙。为了准备种植腔体，拔除牙齿，用钢钻从牙尖钻出。然后，将长10mm，最大直径2mm，锥形1/20的致密羟基磷灰石植入体从根尖插入腔内。我们立即重新植了牙齿。这些牙齿被用夹板固定在相邻的牙齿上一个月。术后5个月，剥离牙齿及周围组织，用10%福尔马林酒精固定。它们被包埋在聚酯树脂中，制备了未钙化的切片。切片采用甲苯胺蓝染色，光镜、透射电镜观察。结果：1)5个月时，未见牙齿强直。2)种植体表面有新形成的硬组织从根骨质向外延伸。3)种植体周围有纤维束将新形成的硬组织与周围的骨连接起来。这些组织与完整的牙齿非常相似。在本研究中，牙周组织在羟基磷灰石种植体周围能够分化。结果表明，羟基磷灰石陶瓷作为牙髓-骨内种植体是有效的。

The purpose of this study was to investigate the possibility of applying hydroxyapatite ceramics as endodontic-endosseous implants. We preliminarily observed the tissues around the implants, which were pushed out from the root apexes. The upper medical incisors of monkeys were used for this study.To prepare the implant cavities, the teeth were extracted and drilled from the apexes by steel bur. Then, dense hydroxyapatite implants, 10mm in length, 2mm in maximum diameter and 1/20 tapered, were inserted into the cavity from the apexes. Immediately we replanted the teeth. The teeth were splinted to the neighbouring teeth for a month. Five months after the operation, the teeth with surrounding tissues were dissected and fixed by 10% formalin alcohol. They were embedded in polyester resin and undecalcified sections were prepared. The sections were stained with toluidin blue and obsereved under light microscope and transmission electron microscope.Results : 1)At 5 months, no teeth ankylosis was observed. 2)There was newly formedhard tissue which extended from the root cementum, on the surface of the implant, 3)Fiber bundles were observed around the implants which connected the newly formed hard tissue to the surrounding bone. These tissues were very similar to a intact tooth.In this study, peridontal tissues were able to differentiate around hydroxyapatite implants. So these findings indicate that the application of hydroxyapatite ceramics as an endodontic-endosseous implant is effective.