Effects of Different Concentrations of Bleaching Agent on the Micro hardness of Restorative Materials”– An In Vitro Study

Abstract

Background: Today‟s society dictates that it is the norm for people to have straight, white teeth. The demand therefore for tooth whitening in dental practice has increased exponentially over the last decade. A common approach to achieving this goal is by bleaching. Aim: The aim was to evaluate the effect of bleaching with carbamide peroxide agents at concentrations 10%, 21% on the Micro hardness of Nano Composites and Nano hybrid Composite Restorative materials. Material and Methods: 60 pellets were prepared with both types of composites of 30 each using brass molds of inner diameter 4 mm and a height of 2 mm. For Micro hardness evaluation, samples of both were subdivided into control group (stored in artificial saliva), Experimental groups bleached with 10% carbamide peroxide and those bleached with 21% carbamide peroxide. Following 2 weeks of bleaching treatment, Vickers‟s hardness number was recorded for each test specimen using a Micro hardness meter. Results: One way Analysis of Variance (ANOVA) was used for multiple group comparisons followed by Tukey‟s test for pair wise comparison. Bleaching with carbamide peroxide at concentrations 10% and 21% caused reduction in Micro hardness of Composite Restorative materials. Conclusion: On the basis of the present findings, it can be suggested that there was a significant reduction in the Micro hardness of restorative materials observed after exposure to Carbamide Peroxide agents under a clinically simulated bleaching regimen. Key words: Aesthetics, Carbamide peroxide, Developmental defects, Discoloured enamel, Micro hardness