AVALIAÇÃO DA APLICAÇÃO SÔNICA DE RESINA INFILTRANTE EM ESMALTE DENTÁRIO SUBMETIDO A PROCESSO DE DESMINERALIZAÇÃO

Abstract

The aim of this study was to evaluate the sonic application of infiltrating resin on dental enamel subjected to demineralization process. Forty-eight human molar teeth were used, being defined an area on the buccal (V) and lingual (L) surfaces, and induced to a white spot lesion with gel demineralizing acid. Thereafter, the teeth were divided into 6 groups according to the application technique and conditioning: AC - hydrochloric acid (AC) 15%; AF + AC - phosphoric acid (AF) 37% + AC; ACU - AC + applying ultrasonic (U) waves; ACS - AC + applying sonic (S) waves; AFACS - AF + AC + and S waves and AFACU - AF + AC + U waves, where n = 24 for bond strength test (BS) and n = 24 for evaluation of penetration depth (PP). Prior to the process of infiltration protocols, for PP test the crowns were etched with AC for 120 s, applying the infiltration protocol according to the manufacturers of Icon® resin (DMG) and subjected to washing with water for 60 s. The crowns were then stained with 0.1% tetrametilrhodaminaetanólica isothiocyanate of submerged for 12 h at 37 °C, and then the infiltration protocols previously described were made without application of AC; AF was only conditioned to the corresponding groups, after infiltration the crowns were cut in cemented-enamel junction and in the U and V directions obtaining slices of 1 mm ± 0.1 mm thickness, and the slices were subject to hydrogen peroxide at 30% for 12 h at 37 °C to bleach the dye flours not penetrated, washing was done by 60 s with water and applied ionized sodium fluorescence to obtain the images in Microscopy Confocal Laser; then the measurements of PP in microns (μm) were performed. To test the BS (MPa), the microshear test was made at a speed of 0.5 mm/min. Data from PP and BS were analyzed by two-way ANOVA (application technique vs conditioning) and Tukey (α = 0.05). For BS, the cross-product interaction, as well as the main factors were not significant (p> 0.05). For PP, again the cross-product interaction was not significant; but the main factors application technique (p <0.001) and conditioning (p = 0.003) were. With regard to application technique, the worst results of PP were found for conventional application (manual), and the highest for U waves, while the S waves had intermediate result. In relation to conditioning, the prior application of AF showed superior results for isolated application of AC. It was concluded that the 11 sonic and ultrasonic application associated with acids conditioning did not show improved on the adhesion; but improved the infiltration of low molecular weight resin; and the best results were found when phosphoric acid was used previously to hydrochloric acid, and when the infiltrating resin was applied by means of ultrasonic waves.