Evaluation of the changes in water sorption, surface roughness and color parameters of resin compositesfollowing the storage in staining solutions and home bleaching material applications

In this in vitro study, the aim is to analyze the change of water sorption,surface roughness and color parameters, in which the discs of 3 different compositebrands (Supreme XT, Ceram x duo, Artemis) prepared with 2 different layeringtechniques, were immersed in various solutions followed by home bleaching materialapplication.Stainless steel molds were used to prepare the 8mm diameter & 2mm widthdiscsout of 3 different composite materials. All the composites have A2 equivalentcolor codes on the vita scale. For each composite material, 2 layering techniques wereused; single layer of 2 mm enamel composite and double layer of total 2mmcomposite discs consisting of 1 mm enamel and 1mm dentine composite wereprepared.Each group having 15 samples, were formed under 6 main groups. Baselinemeasurements of initial weight, surface roughness and color parameters werecompleted. All the samples were kept in artificial saliva for 24 hours at 37°Cdessicator. For staining experiment, the samples were immersed in artificial saliva,diet coke and tea as 3 sub-groups. Following 6 hours of immersion, the sampleswere washed with distilled water, dried with air spray and immersed in artificial salivafor 18 hours. This cycle continued for 14 days and same measurements wereperformed in 1st, 7th and 14th day of the staining experiment. Then, for bleachingexperiment, bleaching material (Opalescence PF%10) was applied on all the samplesfor 6 hours, washed with distilled water, dried with air spray and immersed inartificial saliva for 18 hours. For 14 days, same cycle continued (6 hours bleachingmaterial, 18 hours in artificial saliva) and measurements of water sorption, surfaceroughness and color were performed at 1st, 7th and 14th day of bleaching experiment.During the whole experiment protocols, the samples were kept in 37°C dessicator toimitate the oral environment.The statistical analysis of the results were calculated by ?one way ANOVA?and post hoc ?Tukey? tests.In conclusion, among all the groups which were immersed in tea, diet cokeand artificial saliva followed by application of bleaching material, the maximumamount of water sorption was examined in Supreme XT composite. There is nostatistical meaning for the change in the surface roughness. Single layered Artemistea groups have shown significantly more color(a) change than double layeredArtemis tea groups. As a result of staining experiement between the tea groups, themost significant color(a) change was observed in single layered Ceram x duocomposite. Comparing the measurements of staining and bleaching experiments, themost significant color(b) change was again observed in this group. In terms of colorparameters (L, E) , the maximum color change was observed in tea groups whichthe staining was removed after bleaching application.Keywords: Nano- composite, water sorption, surface roughness, staining,bleaching