歯科

概要

Effect of Margin Level Setting in Abutments Created by CAD/CAM on Residual Cement

Yusuke Taniguchi, Kae Kakura, Takashi Tsuzuki, Masahide Baba, Ippei Hamanaka, Tomohiro Kawaguchi, Masahiro Yoneda and Hirofumi Kido

Background: Various complications of dental implants have been reported as cases with long-term implant use increase with its spread of use. It has been reported that residual cement is involved in approximately 80% of the peri-implantitis cases, and prompt management of residual cement is important. This study examined cementation of the superstructure and how the level of gingival margin of abutments affected the amount of residual cement. The study also examined the level of abutment margin to avoid residual cement.
Materials and Methods: Working models were prepared using epoxy resin. Implants were placed in one part of the maxillas. Silicone rubber was used to simulate peri-implant gingiva. Morphological designing was performed for the abutments and superstructures on the prepared models. The examination was performed on four levels of abutment margins: the same level as the margin of the gingiva (ML0), 1 mm subgingival (ML-1), 2 mm subgingival (ML-2), and 3 mm subgingival (ML-3). Temporary cement was placed in each superstructure which was then placed on the abutment. An access hole was created on the superstructure, and the abutment and superstructure were removed from the model. Observations were made on the cement remaining subgingivally (residual cement). The cement above the margin and residual cement were collected.
Results: If the margin level was subgingival, there was a tendency for residual cement to adhere to the entire subgingival area regardless of the margin depth. The residual cement weight percentage was significantly higher for the ML-2 and ML-3 margins than for ML-0 margins. The percentages of supragingival cement did not differ significantly among different abutment margins.
Discussion and Conclusion: The results of this study suggest that when the abutment margin is ML-2 or lower, the cement does not extrude supragingivally and tends to remain subgingivally.