Effect of Surface Treatment of Different Ceramic Materials by Er, Cr : YSGG Laser Irradiation on The Shear Bond Strength to Resin Cement : A Comparative in-Vitro Study /

Abstract

People’s interests for a beautiful smile have been greatly increased lately which led to the appearance of veneers. The high outstanding esthetic properties of all ceramic restorative materials that simulate the appearance of natural teeth, plus its high mechanical properties that can tolerate and protect the teeth against different occlusal forces inside the mouth for long time, makes it number one material used for veneers restorations. Although ceramics have the best esthetic proper ties, high wear resistance, and are biocompatible and can retain their color for long time, they are brittle and can get fractured. Additionally, ceramics may cause severe wear of the opposing natural teeth. A new novel material polymerinfiltratedrestor ation called (hybrid ceramics) combines the positive properties of both the ceramic and resin composite restorations composed of mainly ceramic network of (86 wt%) and reinforced with an acrylate polymer network of (14 wt%) and can be used for veneer rest orations. The surface treatment of the ceramic surface has been a major breakthrough owing to its significance in increasing the surface roughness of ceramics to enhance the micromechanical bond with adhesive resin cement. With the introduction of erbium lasers (Er:YAG and Er,Cr:YSGG) in dentistry, many studies have been performed to test the effect of laser in changing the surface texture of ceramic materials Clinically, due to many variable factors inside oral cavity, chipped or fractured veneers are one of the most frequently reported problems. In cases of small fracture it is not necessary to totally replace chipped veneers. Due to the high cost and difficulty of total replacement, many studies suggested that intra oral repair with composite resin is m ore conservative and cause less trauma to teeth and surrounding tissues. Different intra oral repair methods have been applied and developed to improve the fractured surface and optimize its bond strength with composite resin. However, the traditional meth ods containing acid are hazardous for both patient and clinicians, as the acid may cause damage to eyes and the skin, so special protective equipment is needed. Therefore, another more biofriendly technique is preferred. Nowadays, since the introduction o f the idea of laser for ceramic surface treatments many authors studied the effect of Nd:YAG and Er:YAG lasers for increasing surface roughness of some ceramic materials. However, Er,Cr:YSGG laser still needs more studies to prove its efficiency to be used as an alternative surface treatment method to improve bonding of etched ceramic with adhesive resin. The effect of Er,Cr:YSGG laser in producing surface roughness of glass ceramics and composite materials is still questionable. So, in the current study th e effectiveness of Er,Cr:YSGG laser as an alternative method to the traditional ceramic surface treatment techniques was to be examined to prove if the Er,Cr:YSGG laser irradiation could enhance the shear bond strength of different ceramic materials with a dhesive resin cement. This would be more beneficial and less harmful to oral tissues during intra repair of fractured ceramic restorations.