JOURNAL OF ADVANCED PROSTHODONTICS, vol.7, no.2, pp.108-114, 2015 (SCI-Expanded)
PURPOSE The aim of this study was to evaluate effect of different surface treatment methods on the bond strength between aged composite-resin core and luting agent. MATERIALS AND METHODS. Seventy-five resin composites and also seventy-five zirconia ceramic discs were prepared. 60 composite samples were exposed to thermal. aging (10;000 cycles, 5 to 55 degrees C) and different surface treatment. All specimens were separated into 5 groups. (n=15): 1) Intact specimens 2) Thermal aging-air polishing 3) Thermal aging- Er:YAG laser irradiation 4) Thermal aging- acid etching 5) Thermal-aging. All specimens were bonded to the zirconia discs with resin cement and fixed to universal testing machine and bond strength testing loaded to failure with a crosshead speed of 0.5 mm/min. The fractured surface was classified as adhesive failure, cohesive failure and adhesive-cohesive failure. The bond strength data was statistically compared by the Kruskal-Wallis method complemented by the Bonferroni correction Mann-Whitney U test. The probability level for statistical significance was set at alpha=.05. RESULTS. Thermal aging and different surface treatment methods have significant effect on the bond strength between composite-resin cores and luting-agent (P<.05). The mean baseline bond strength values ranged between 7.07 +/- 2.11 and 26.05 +/- 6.53 N. The highest bond strength of 26.05 +/- 6.53 N was obtained with Group 3. Group 5 showed the lowest value of bond strength. CONCLUSION. Appropriate surface treatment method should be applied to aged composite resin cores or aged-composites restorations should be replaced for The optimal bond strength and the clinical success.