Influência dos modeladores de resina sobre a propriedade superficial de uma resina composta

Abstract

The present study aimed to evaluate, in vitro, the influence of resin modeling agents on the surface roughness and microhardness of a composite resin. The null hypothesis tested was that the type of modeling agent does not affect the surface roughness and microhardness of the composite. After sample size calculation, 84 specimens (SP) were prepared, considering the modeling agents used (n=14): GC (control group, no modeling agent); A70 (70% alcohol); PB (Power Block® glycerin gel, Maquira, Maringá, Paraná, Brazil); SBMP (Scotchbond Multi-Purpose® adhesive, 3M Solventum, Sumaré, São Paulo, Brazil, bond only); SB (Single Bond 2® adhesive, 3M Solventum, Sumaré, São Paulo, Brazil); RM (Composite Wetting Resin® modeling resin, Ultradent, Indaiatuba, São Paulo, Brazil). Subsequently, the SP were identified and stored in amber flasks containing distilled water (37°C, for 24 h). Surface polishing of the SP was performed using the Sof-gloss® polyester disk sequence (American Burrs, Palhoça, Santa Catarina, Brazil). The specimens were then analyzed in an optical profilometer (Taylor Hobson, CCI MP, Leicester, England) to measure surface roughness (Ra, μm). For microhardness evaluation, a microhardness tester (HMV, Shimadzu, Kyoto, Japan) equipped with a Vickers diamond indenter was used, applying a load of 200 g for 15 seconds. For each SP, readings were performed in triplicate for both tests, and the mean values were used for statistical analysis. The results of the roughness and microhardness tests were statistically evaluated by one-way analysis of variance (ANOVA; p<0.05). Tukey’s test was applied for the microhardness data (p<0.05). The mean surface roughness values (Ra, μm) of each group were: GC: 0.29; A70: 0.40; PB: 0.34; SBMP: 0.36; SB: 0.28; RM: 0.44. ANOVA indicated no statistically significant differences in surface roughness between the experimental groups and GC. The mean microhardness values (kg/mm²) of each group were: GC: 156.9; A70: 120.8; PB: 156; SBMP: 30.7; SB: 127.3; RM: 73.3 (Tukey; p<0.05), with A70, SBMP, SB, and RM showing lower hardness compared to CG. We observed that the modeling agents evaluated in this in vitro study did not differ in their potential to provide adequate surface roughness. However, glycerin was the only modeling agent used that did not reduce hardness, similar to the control group.