Effect of Two Surface Treatments of Lithium Disilicate on the Flexural Strength after De-bonding by Er,Cr:YSGG Laser Irradiation

Abstract

All ceramic restorations have become more popular as a result of increase patients demands for esthetic restorations for more pleasant appearance. Recent advances in optical and mechanical properties, techniques of fabrication of all ceramic material in addition to new adhesive systems aid in increasing the use of ceramic materials. All ceramic restorations are frequently used not only for anterior teeth, but also for posterior teeth. Using all ceramic restorations for posterior teeth requires high mechanical properties for longevity under functional loading. Therefore, production of ceramic material made from lithium disilicate which has high flexural strength that can be used as an alternative for metal ceramic restorations. Lithium disilicate is commonly used to produce monolithic restorations through pressing or milling through computer-aided design/computer-aided manufacturing (CAD/CAM). This study was performed to evaluate the effect of Er,Cr:YSGG on the flexural strength of lithium disilicate using two different surface treatments hydrofluoric acid etching and Laser irradiation. The most common technique for removal of all ceramic restorations is cutting through the restorations which are a time consuming process due to high bond strength between the tooth structure and the restoration. Also, the difficulty in differentiation between the bonded restoration and the tooth structure during cutting will be difficult because the restoration, resin cement and tooth will almost have the same color.