2023 年 57 巻 1 号 p. 191-195
A 22-month prognostic study covering a total of 180 CAD/CAM crowns reported that 9 (5.0%) of them came off and 1 (0.6%) fractured.1 The purpose of this study was to clarify the effect of plasma treatment on the bond strength between resin blocks used for fabrication of CAD/CAM crowns that had contaminants, and the adhesive resin cement used to place them in the patient. Cerasmart Prime was used as the resin block, Panavia V5 as the cement, and Clearfil Ceramic Primer Plus as the primer. Silicone oil and machine oil were used as the contaminants. The materials were divided into those subjected to and not subjected to alumina blasting and plasma treatment. The resin blocks were bonded to stainless steel blocks. And shear bonding tests were then conducted. Two-way analysis of variance was performed for statical analysis. Plasma treatment and the type of contaminant were considered factors. There was a significant difference attributable to plasma treatment, but no difference for the contaminant factor. Specimens contaminated with machine oil and treated with plasma had the highest adhesive strength. Cohesive failure was observed within the block, indicating that plasma treatment is effective in removing the surface contaminants. (J Osaka Dent Univ 2023; 57: 191-195)
