Casting accuracy with noncarcinogenic ring liner for dental casting

Abstract

The necessity of safe casting with the use of low-biotoxic materials has increased since the carcinogenicity of ceramic fibers was reported. We evaluated the use of noncarcinogenic biosoluble fibers as ring liners for dental casting. We previously used plate-like biosoluble fibers as ring liners, adjusted the amount of setting expansion to that of commercially available ring liners and performed a tension test, scanning electronic microscopic observation, element analysis employing energy dispersive X-ray spectroscopy (EDX), and crystal structure analysis using X-ray diffraction. In this study, we performed a compression test of the ring liner, measurement of the thermal expansion of investing materials, and a fitness tested the fit of the cast crowns for clinical application. The amount of displacement of the experimentally-produced ring liner was lower than that of a commercially available ring liner, showing that the buffering ability was slightly greater with the commercially available liner. However, the thermal expansion of the investing materials were similar. The fit of cast crowns produced using the biosoluble fibers was better than that of cast crowns produced using a commercially available ring liner. Therefore, we concluded that the ring liner of biosoluble fibers was acceptable for clinical application.