Efeito do uso simulado de bebidas ácidas na alteração de cor, topografia de superfície e propriedades mecânicas de resinas compostas convencional e bulk-fill

Abstract

The aim of this in vitro study was to investigate the effect of acidic drinks on the shade matching, surface topography and mechanical properties of conventional and bulk-fill composite resins. One conventional nanofilled composite resin Z350 (Filtek Z350 XT, 3M ESPE); and two bulk-fill composite resins: TNC (Tetric-N-Ceram Bulk-Fill, Ivoclar Vivadent) and X-TRA (X-Tra Fil, VOCO) were used to prepare disc-shaped specimens according to the manufacturers instructions. The degree of conversion (DC) of the specimens was monitored immediately and after 24 h storage in dried and dark recipient at 37oC, using Fourier Transformed Infrared Spectroscopy (FTIR) (n = 5). Shade matching was done using Vitapan Classic Shade Guide by three different examiners. The surface topography analysis was performed using 3D Laser Interferometry (n = 5). The amplitude parameters (Sa, Ssk and Sku) and hybrid parameter (Sdq) were extracted in the area of 1 x 1 mm using cut-off length of 0.25 mm. The elastic modulus (E) and Vickers hardness (VH) at different composite resin depths were determined by microhardness dynamic indentation (n = 5). The diametral tensile strength (DTS) was determined at 0.5 mm per min (n = 5). The specimens from control group were held in artificial saliva in dark recipient at 37oC for 24 h. Additional specimens of each composite resin were randomly divided into 4 groups according to tested solution: artificial saliva, acai juice, red wine or Coca-Cola. The specimens were acidic drinks challenged in 3 immersion baths of 15 min per day and after tests were performed again. The Sa, Ssk, Sku and Sdq parameters, E, VHN and DTS were statistically analyzed using two-way analysis of variance followed by Tukey s HSD test (∝ = 0.05). The shade matching data were analyzed using Kruskall- Wallis test. DC was similar at immediate evaluation or after 24 hours, irrespective of composite resin tested. After the acidic drinks challenge acidic drinks challenge, the E, VH and DTS data were reduced for all composite resins tested and the surface roughness increased significantly, mainly for Coca-Cola. The acai juice and red wine produced more surface staining than Coca-Cola. The acidic drinks have negatively influenced the physical and mechanical properties and surface quality of conventional and bulk-fill composite resins tested. Bulk-fill composite resins used had similar performance to conventional composite resin for all parameters evaluated.