Objectives: the objective of the investigation was to evaluate the flexural strength of all ceramics layered with paste porcelain (PP). This porcelain has been developed for easier fabrication of metal-ceramic restorations. Since PP is supplied as paste state, no condensation is needed, only a flat plastic is necessary for build-up. Physical properties and the bond strength for metal-ceramics have previously been reported elsewhere. Methods: the experimental method followed ISO 6872:1995 Dental ceramics. This study determined the flexural strength of all ceramic specimens, In-Ceram Alumina (ICA) and Spinell (ICS) layered with PP comparing to those layered with conventional powder porcelain, Vitadur Alpha(VA). Twenty specimens were cut from all ceramic blocks for CAD/CAM with a uniform 0.5-mm-thickness as core ceramics and were infiltrated with glass in a furnace. They were divided into four groups, and were layered with conventional or paste porcelains. The experimental groups were: 1.ICA + VA, 2.ICS +VA, 3.ICA +PP, 4. ICS+PP. After firing, each specimen was adjusted and polished to a final dimension of 20mm in length x4mm in width x1.2mm in thickness. The glazed specimens were then subjected to a three-point bending test using a universal testing machine (SHIMADZU HGS-50, Japan) and the flexural strength was calculated. Results: the flexural strength obtained (mean (SD),MPa) for group 1, 2, 3 and 4 was 216.7(18.7), 225.6(36.4), 250.9(26.2), and 239.5(44.5), respectively. No significant difference was found both in the type of layering porcelain and all ceramics (p<0.05) by ANOVA. Conclusions: we conclude that all ceramics layered with paste porcelain possesses similar or slightly higher flexural strength comparing to that of conventional powder porcelain. This study was supported in part by Grant-in-aid for exploratory research #13877325 from Japan Society for the Promotion of Science.

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