An evaluation of porcelain strength and the effect of surface treatment.

This investigation evaluated the flexural strengths of five porcelains commonly used in the all-porcelain margin technique and the effect of surface treatment on the flexural strength. Thirty samples were made by using each of five different porcelain margin systems. The five porcelain groups were subdivided into groups of 10 each to allow the evaluation of three surface treatments. A three-point flexural test was used to test the specimens on a universal testing machine. Crystar shoulder porcelain with distilled water as the binder was significantly stronger than the other porcelains tested, and porcelain treated with an overglaze was stronger than porcelain treated with autoglaze or autoglaze and polish.