The evaluation of shear bond strengths of porcelain laminate veneers to tooth surfaces prepared with acid, Er,Cr: YSGG laser system and combined system etching

Ceramic laminates are a conservative treatment method and used to achieveexcellent esthetic results on malpositioned, discolorated, traumatised , broken orabraded anterior teeth. Superficial preparation of the healthy enamel ensures minimaltooth loss. Laminate restorations used in conjuction with adhesive systems are aimedto correct discolorated , malformed and malpositioned anterior teeth.Acid etching is the first step to achieve an adhesion in restorative dentistry.There is a need an adhesive bonding between composite resins and tooth structures inorder to reduce microleakage, dentinal hypersensitivity and excessive tooth loss.Acid etching on the enamel and dentin surface promotes the formation of cavitiesand penetration of the resins in these cavities ensures the adhesive bonding. Acidetching is a routine and a common application of modern dentistry and proved tosuccessful results in clinical dentistry.Recent studies are shown that acid etching has some disadvantages, although, laser etching is an alternative to conventional rotary intruments and comes intoquestion in last years about their non-hazardous properties to surrounding structures.In our study we were aimed to evaluate the shear strengths of the porcelainlaminate veneers applied to etched tooth surface with acid, Er,Cr:YSGG laser andcombine system. In this study, we were used 60 extracted incisor teeth forperiodontal reasons. Teeth were non carious, healthy, and lack of enamel defects andcracks. Collected teeth were divided into 4 main groups according to etchingmethods. (only acid etch, first acid etch then laser etch, first laser etch then acid etch,only laser etch) In this study, we were used %37 phosphoric acid and Er,Cr:YSGGlaser. In the laboratory conditions, 60 IPS?Empress II cylindrical blocks wereprepared in 2 mm. height and 5 mm. diameter in order to apply etched tooth surface.First, IPS?Empress II blocks were bonded to teeth with dual cured resin cement andthen shear tests were performed. Finally, SEM photographs of the applied toothsurface were taken at X3800 magnification level after the shear test.Overall, there is no statistical significant correlation found between theetching methods. Despite laser etching is easy to apply, modern and less timeconsuming, acid etching is an economical application and as successful as laseretching.Keywords: Er,Cr:YSGG Laser, Acid etching, Porcelain laminate veneer, Shearstrength, SEM