Effect of Nano Filled Protective Coating and Dentin Bonding Agent on the Microleakage Resistance of A Hybrid Composite During Bleaching Treatment- An In Vitro Study

Abstract

Activation of bleaching agents containing hydrogen peroxide or carbamide peroxide results in their transformation into low molecular weight reactive free radicals which infiltrate dental hard tissues. These, in turn, remove the discolouration in the dental tissue. However, they may have undesired consequences on the dental tissues, restoration materials, and tooth restoration interfaces. Microleakage at restoration margins is a significant consequence which can lead to numerous clinical issues. Some of these are pulpal damage, secondary caries, surgical sensitivity, marginal discolouration, and bacterial buildup. Surface coating agents or protective coating materials can be considered as an alternative for minimizing microleakage, to prevent these clinical adverse effects. The materials are applied to the cavosurface margins of completed restorations, where they penetrate into structural microdefects and marginal gaps formed during the finishing and polishing operations via capillary action. This study examined the effects of a nanoparticle-loaded covering material on the hybrid composite resin's marginal integrity after bleaching. Class V cavities were created in the middle third of human premolar buccal surfaces and were restored with hybrid composite resin for three groups (n = 30). Group A-restored and coated with G coat plus and bleached using 35 % H₂O₂ . Group B-restored and coated with dentin bonding agent & bleached using 35 % H₂O₂. Group C-restored with hybrid composite resin, without any coating \& was bleached using H₂O₂.  All specimens were dyed with 0.5 % fuschin stain & observed under the stereomicroscope for assessing the marginal gap and microleakage. Group A showed maximum resistance to microleakage in this study.