الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The success or failure of resin composite restoration in clinical observations and laboratory investigations determines by the quality of the adhesive system at the tooth/restoration interface. So, good adhesion to tooth structure is required for clinical success and restoration longevity. This study was designed to evaluate the effect of etching method and time on surface roughness and shear bond strength of universal adhesive to ground enamel. Three etching agents PPA, PLA and PPM with one universal adhesive (G-Premio Bond) were used in this study. Fifty sound human molars were decoronated and sectioned mesiodistally to obtain 100 buccal and lingual halves. Each half was fixed in self-cure acrylic resin. Ten specimens were selected as a control group (no etching) whereas, the remaining (n=90) was equally assigned into three tested groups (n=30) according to the etching agents. Every tested group was subdivided into three subgroups (n=10) regarding to the etching time (5, 10, 15 seconds). Tested groups were treated with acids and surface roughness was measured using a Profilometer. The universal adhesive was applied to all groups. Resin composite block (Tetric N-Ceram, Ivoclar Vivadent) was incrementally built up using a plastic mold. All the specimens were subjected to shear bond strength test. Current study results showed that surface roughness of enamel treated by PPA was the highest followed by PPM and PLA. Shear bond strength of universal adhesive to enamel etched with PPM and PPA for 5 to 15 seconds, and PLA for 15 seconds was significantly higher than other groups. It was concluded enamel surface micro-morphology and bonding durability are etching protocol dependent. Enamel treatment with PPA increases surface roughness more than PLA and PPM. High SBS can be obtained by using PPM and PPA etching protocols.