著者
伊藤 明彦 郭 明毅 劉 嘉東 細川 隆司 永富 勝広 村上 繁樹 内田 康也 帆鷲 郷一 内山 長司
出版者
九州歯科学会
雑誌
九州歯科学会雑誌 (ISSN:03686833)
巻号頁・発行日
vol.43, no.2, pp.351-359, 1989-04-25 (Released:2017-12-21)

In this study, we investigated the effects of the marginal surface configurations of different crown systems on the periodontal tissues. The morphology of the marginal surface of the crowns was examined by using a light- and a scanning electron microscope. In addition, biocompatibility of the materials used for crown margins was also examined by a subcutaneous implantation. The results were as follows : 1. The margins of the Ag-Pd-Au alloy full cast crowns fabricated by a conventional method were sharp and wavy with irregularities. 2. The modified method in which the margins of the Ag-Pd-Au alloy full cast crowns were rounded slightly with silicone rubber wheels was effective to make the margins smooth and round. 3. The glazed porcelain jacket crowns with metal foil copings produced sharp marginal openings because of the occurrence of a microfracture in a glass state of the ceramics. 4. The conventional ceramo-metal crowns displayed the irregularities of the surface adjacent to the boundary between metal collar and porcelain. One of the reason of this observation might be the exposure of a opaque porcelain of the crowns. 5. In the collarless ceramo-metal crowns, the marginal line configulations were totally rounded. 6. The DICOR crowns exhibited the smoothest marginal surfaces and the slightly rounded margins. 7. In the study of subcutaneous implantation, the porcelain (VMK 68) and the castable ceramic (DICOR) showed better histopathological findings than the gold alloy metal.