RESUMO
PURPOSE: To evaluate, in vitro, the obliteration of dentin tubules promoted by different desensitizing methods, before and after pH cycling. METHODS: Human dentin blocks of 4x4 mm were randomly divided into: control group (n = 20): no treatment; Group GH (n = 20): surface treatment with a solution containing glutaraldehyde (5.1%), HEMA (36.1%), sodium fluoride (NaF), and deionized water; Group NP (n = 20): surface treatment with a calcium phosphate gel containing nanostructured hydroxyapatite crystals, NaF and NK; and Group ARG (n = 20): surface treatment with a paste containing CaCO3 and 8% arginine. After treatment, 10 samples of each group were evaluated in scanning electron microscopy (SEM) while another 10 were included in a pH cycling procedure for 48 hours, and then analyzed in the SEM. All SEM images were evaluated by three calibrated examiners regarding dentin tubular obliteration. Mann-Whitney and Kruskal-Wallis tests were used for data analysis (P < 0.05). RESULTS: The GH, NP, and ARG groups promoted immediate obliteration higher than the control group (P < 0.05) with NP and ARG groups superior to GH group (P < 0.05). After pH cycling, an increase in tubular obliteration in the GH group was observed, which was similar to the NP and ARG groups (P > 0.05), even though all groups promoted higher obliteration than the control group (P < 0.05). All treatments were effective in a tubular obliteration.