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

本研究的目的是检查上部结构设计对新开发的一段式氧化锆种植体骨界面的影响，并提供有用的信息，一段式氧化锆种植体的上部结构设计。在7只雌性成年猴（Macaca fuscata）的下颌骨的磨牙和前磨牙缺牙区的左侧和右侧，通过攻丝插入制备的骨槽中放置两个氧化锆种植体。种植体植入3个月后，将3种金属上部结构骨水泥固定在种植体上。根据上部结构设计将种植体分为3组。在第1组（G1）中，在右侧近中种植体上粘固单个金属冠。在组2（G2）中，用骨水泥固定金属桥连接左侧两个种植体。第3组（G3），右侧远中种植体与相邻第二磨牙之间用骨水泥固定一个金属桥。分别于负重12个月和24个月后处死动物，制备种植体不脱钙切片，光镜观察。还进行了组织形态计量学分析。在组织学上，所有种植体均实现了直接骨-种植体界面，三组之间无明显差异。在12个月研究的组织形态计量学分析中，G1中种植体的骨接触率低于其他种植体。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，一阶段氧化锆种植体与相邻牙连接可以达到更高的骨接触率比单一的常设种植体，无论他们是通过上部结构连接。

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.