اثر زمانهای آلودگی بزاقی سطح اچ شده بر استحکام اتصال برشی براکت با دندان

Introduction: Salivary contamination of etched surfaces is an important cause of resin and composites bond strength reduction. The aim of this study was to evaluate the relationship between the duration of saliva exposure on the etched surface and the shear bond strength of braces and the enamel of the tooth . Materials and Methods: This was an experimental study which included 50 premolar intact teeth. After mounting the specimens, they were randomly divided into 5 groups of 10 teeth. In the first group used as our control, the braces were bonded without any saliva contamination. In the remaining four groups, samples were contaminated with saliva prior to resin application and the etched surfaces were cleaned after 1, 5, 10 and 15 seconds and then the resin was applied. After thermocycling, samples were subjected to shear force and the loads were recorded. The collected data were analyzed through ANOVA and Duncan post hoc tests using SPSS. (α = 0.05) Results: The groups showed significant differences (P < 0.001). Pair wise comparison showed that there was no statistically significant difference only between groups IV and V. Conclusion: Contamination of etched surface with saliva reduces the bonding strength of braces. However, there was no significant difference between the contamination durations of 10 and 15 seconds . Key words : Shear bond strength, Brace, Saliva contamination, Enamel.