De Lange G L, De Putter C, De Groot K, Burger E H
Department of Oral Cell Biology, Academic Center for Dentistry Amsterdam, The Netherlands.
J Dent Res. 1989 Mar;68(3):509-18. doi: 10.1177/00220345890680031601.
A clinical, histological, and radiographic examination was performed on 77 permucosal dental implants, made of dense sintered hydroxylapatite: 34 solid cylinders and 43 hollow cylinders. The hollow cylinders were pre-compressed between two titanium caps. The implants were placed in partly edentulous mandibles of dogs, and were physiologically loaded. Healing was clinically and radiographically evaluated during a six-month to five-year period. At various times, implants with their surrounding tissues were removed and prepared for light and electron microscopy. All implants showed a good initial fit and were maintained in place without undercut or mechanical stabilization. After 18 months, 76% of the solid cylinders had fractured at the implant/bone junction due to fatigue. However, the submerged portions of the solid cylinders were preserved without clinical problems, and became entirely embedded in bone. The pre-stressed implants did not fracture, and 91% were functioning 24 months after placement. The average scores of pocket depths and gingival bleeding showed no significant differences between implants and surrounding natural teeth. Bone deposition occurred on the entire surface of the implant below the crest of the alveolar bone, and intimate bone contact was confirmed by electron microscopy. It was also observed that a layer of bone tissue was deposited on the implant surface in the permucosal area just above the alveolar bone level. Embedding of gingival fibers in this layer resulted in gingival attachment to the implant, comparable with that of natural teeth.
对77颗由致密烧结羟基磷灰石制成的穿黏膜牙种植体进行了临床、组织学和影像学检查：34颗实心圆柱体和43颗空心圆柱体。空心圆柱体在两个钛帽之间进行了预压缩。将种植体植入犬的部分无牙下颌骨中，并进行生理加载。在6个月至5年的时间内对愈合情况进行了临床和影像学评估。在不同时间，取出带有周围组织的种植体并制备用于光镜和电镜检查。所有种植体均显示出良好的初始贴合度，并且在没有倒凹或机械固定的情况下保持在位。18个月后，76%的实心圆柱体由于疲劳在种植体/骨交界处发生骨折。然而，实心圆柱体的植入部分没有出现临床问题，并完全嵌入骨中。预应力种植体没有骨折，91%在植入后24个月仍在发挥功能。种植体与周围天然牙之间的牙周袋深度和牙龈出血平均得分没有显著差异。牙槽骨嵴以下的种植体整个表面都有骨沉积，电镜证实有紧密的骨接触。还观察到在牙槽骨水平上方的穿黏膜区域的种植体表面有一层骨组织沉积。牙龈纤维嵌入该层导致牙龈与种植体附着，与天然牙相当。
