No abstract

Laboratory bond strength tests using standardized ground flat ceramic surfaces can be predictive of clinical situations where ceramic surfaces are irregular. SUMMARYIn vitro studies to assess bond strength between resins and ceramics have used surfaces that have been ground flat to ensure standardization; however, in patients, ceramic surfaces are irregular. The effect of a polished and unpolished ceramic on bond strength needs to be investigated. Sixty ceramic specimens (203532 mm) were made and divided into two groups. One group was ground with 220-to 2000-grit wet silicon carbide paper and polished with 3-, 1-, and ¼ ¼-lm diamond paste; the other group was neither ground nor polished. Each group was divided into three subgroups: treated polished controls (PC) and untreated unpolished controls (UPC), polished (PE) and unpolished specimens (UPE) etched with hydrofluoric acid, and polished (PS) and unpolished specimens (UPS) sandblasted with alumina. Resin cement cylinders were built over each specimen. Shear bond strength was measured, and the fractured site was analyzed. Analysis of variance (ANOVA) and Tukey post hoc tests were performed. PE (44.47 6 5.91 MPa) and UPE (39.70 6 5.46 MPa) had the highest mean bond strength. PS (31.05 6 8.81

Lower convergence angle combined with shoulder and a low-consistency luting cement is preferable to cement metal copings.