PENGARUH LAMA APLIKASI BAHAN BLEACHING HIDROGEN PEROKSIDA 40% TERHADAP KEBOCORAN MIKRO RESTORASI RESIN KOMPOSIT HIBRIDA

Bleaching is a treatment to whiten the teeth. One of bleaching materials is hydrogen peroxide. Hybrid composite resin is a restorative material which commonly used in dentistry due to it�s aesthetic and good strength. Hydrogen peroxide is known to have a negative impact on the tooth and composite resin restoration such as proteins denaturation that may cause inorganic structure alteration of the teeth. There is a residue of hydrogen peroxide which can cause microleakage of composite resin restorations. The aim of this study was to determine the effect of time application 40% hydrogen peroxide bleaching materials towards microleakage of hybrid composite resin restorations. The object of this research were 34 maxillary premolar which were prepared with class I cavity on buccal side with 3mm diameter, and 2mm depth. The cavity were etched (35% Scotchbond phosphoric acid, 3M ESPE) and were applied with bonding materials (Adper Single Bond 2, 3M ESPE) then filled with hybrid composite resin (Filtek Z100, 3M ESPE). The object were divided into two groups. Group 1 was applied with 40% hydrogen peroxide (Opalescense Boost) for 20 minutes. Group 2 was applied with 40% hydrogen peroxide (Opalescense Boost) for 60 minutes. Both groups were immersed with artificial saliva (pH 6.8) and were incubated (37 o C) for 24 hours. Then, both groups were thermocycled with 5 o C and 55 o C. The object were coated with nail polish and sticky wax, then immersed in 2% methylene blue solution for 24 hours. The teeth were split from buccal to palatal and were observed under digital computer microscope with 60 magnification. Furthermore, the data were analyzed with Mann-Whitney U test (p