Evaluation of the roughness of composite resins submitted to different surface treatments

The aim of this study was to evaluate the surface roughness of restorative composite resins after polishing with aluminum oxide discs and applying an adhesive layer The following composite resins were used: Filtek Z250 (hybrid, 3MESPE, A2) and Filtek Supreme XT (nanofilled, 3M ESPE, A2E). Thirty specimens of each composite were made using a condensation silicone mold (5.0 x 2.0 mm) into which the composites were inserted and submitted to light pressure. After polymerization using the halogen light source Curing Light 2500 (3M) for 40 seconds, the specimens were assigned to the following groups: G1-Z250/CO- control, did not receive any treatment; G2-Z250/SL--the specimens underwent finishing and polishing with Sof-Lex discs; G3-Z250/ADE, application of an adhesive layer on the top of the specimen and light curing for 20 seconds. Groups G4, G5 and G6 followed the same treatment sequence, but using Filtek Supreme XT The specimens were stored in deionized water at 37 degrees C for 24 h. Three readings of surface roughness were made for each specimen. The results were submitted to variance analysis by Two-Way ANOVA Test and Tukey HSD Test. The mean values obtained were: G3 (0.2325 +/- 0.1484 microm) and G6 (0.2266 +/- 0.0463 microm), which were higher than the other groups and did not differ statistically from each other. Groups G1 (0.1023 +/- 0.0464 microm), G4 (0.1083 +/- 0.0241 microm), G5 (0.1160 +/- 0.0252 microm) and G2 (0.1360 +/- 0.0131 microm) had the lowest average roughness and did not differ statistically among each other. It was concluded that the Sof-Lex discs performed better for the surface treatment of the composites resins tested, producing similar values of surface roughness for both composites. Covering with dentin adhesive increased the surface roughness in both composites.