The superstructure desing of a newly developed one-stage zirconia implant

本研究旨在探讨一种新型一段式氧化锆种植体的上部结构设计对骨界面骨界面的影响，为一段式氧化锆种植体的上部结构设计提供参考。在7只雌性恒河猴(Macaca Fuscata)下颌磨牙和前磨牙无牙区的左右两侧预备骨槽内分别植入2颗氧化锆种植体。种植体植入3个月后，在种植体上粘接3种金属上层建筑。按上层建筑设计将种植体分为3组。第1组(G1组)：将单个金属全冠粘结于种植体近中；在第2组(G2)，左侧种植体用金属桥粘接。第3组(G3)用粘固剂粘结金属桥接右侧种植体远中与邻接第二磨牙。加载12个月和24个月后，处死动物，制备涉及种植体的不脱钙切片，进行光镜观察。同时进行组织形态计量学分析。组织学上，所有种植体骨-种植体界面均为直接界面，三组间无明显差异。在为期12个月的组织形态计量学分析中，G1组种植体的骨接触率低于其他组。然而，在24个月的研究中，三组之间的骨接触率没有显著差异。这些结果表明，无论哪种种植体是由上层建筑连接的，与邻牙相连的一期氧化锆种植体都可以获得比单一立式种植体更高的骨接触率。

The purpose of this study was to examine effects of superstructure designs on bony interface of a newly developed one-stage zirconia implant, and to present useful informations on the superstructure design of one-stage zirconia implant. Two zirconia implants were placed by tapping insertion into the prepared bone socket at left and right sides of molar and premolar edentulous areas of the mandible of each of seven female adalt monkeys (Macaca fuscata). Three months after implant placement, three kinds of metal superstructure were cemented on the implants. The implants were divided into 3 groups according to superstructure designs. In group 1 (Gl), a single metal crown was cemented on the reight mesial implant. In group 2 (G2), a metal bridge was cemented connecting left two implants. In group 3(G3), a metal bridge was cemented connecting right distal implant and neighboring second molar. After 12 months and 24 months of loading, the animals were sacrificed and undecalcified sections involved implants were prepared and examined by light microscopy. Histomorphometric analyzes were also performed. Histologically, direct bone-implant interface was generally achieved in all implants, and there was no clear difference among three groups. In histomorphometric analyzes of a 12-month study, bone contact ratio of the implant in G1 was lower than others. However, in 24-month study, no significant difference of bone contact ratio was obtained among three groups. These results suggest that one-stage zirconia implant connected with neighboring tooth could achieve higher bone contact ratio than single standing implants whichever they were connected by superstructure.