Digital analysis of mouthrinses' staining characteristics on provisional acrylic resins

Provisional restorations are expected to be both aestethically and physically durable during the preparation of permanent restorations. In this study, the staining properties of mouthrinses containing chlorhexidine gluconate, benzydamine hydrochloride and a hybrid mouthrinse were investigated on light and dark shades of a provisional acrylic resin. Totally 80 specimens were prepared and were photographed digitally to obtain the baseline L*, a*, b* values. Each sample was immersed in test solutions for 12 h which was equivalent time to 1 year of mouthrinse use, and the post-treatment images of the test materials were acquired. All L*, a*, b* values were analysed by a graphic software, and the total colour change (DeltaE*) of each specimen was calculated. Also the same colour analyses were performed on all test solutions to establish their colour parameters. Analysis of variance and Tukey's tests were used for statistical analyses and alpha was 0.05. All test solutions produced perceptible staining on the provisional material, with DeltaE values over 3.7. In both shades, hybrid rinse caused the highest staining (DeltaE=5.705), and was followed by chlorhexidine gluconate rinse, with DeltaE value of 4.120. The third highest staining was observed with benzydamine hydrochloride rinse (DeltaE=3.959), whereas the control caused the least staining (DeltaE=3.095). The lighter shade provisional material resulted with clinically observable staining even when immersed in distilled water; however, the dark shades showed clinically perceptible staining solely with the hybrid mouthrinse. In this study, the shade of the acrylic material was the determinator of the staining process.