Influence of different types of light curing and photoinitiators in surface roughness and gloss of composite resins after different challenges

Abstract

Recently, a new generation of LED was released in the dental market called third generation LED devices with multiple wavelengths. Therefore, the objective of this study will be to evaluate the surface roughness and gloss of resin composites for bleached teeth, using two types of LED before and after brushing and HCL immersion. Three resin composites will be selected: Filtek Z350XT (3M ESPE, color WD), a composite resin which uses camphorquinone as photoinitiator; Tetric N-Ceram (Ivoclar Vivadent, color A1) that have in their composition the photoinitiator lucirin-TPO and Vit-l-escence (Ultradent Products, color WO); that have in theis composition the canforoquinona, amina and lucerina-TPO. One hundred and e eighty disc shaped specimens will be made with dimensions of5 mm in diameter and 1.5mm thick. Forty disks will be photopolymerized by a LED apparatus of one wavelength (Poly Wireless, Kavo) and the remnants will be photopolymerized with a LED with several wavelengths (Valo, Ultradent), using two application modes. Initial analysis of surface roughness and gloss will be made. The specimens will be exposed to different challenges: brushing and HLC immersion. Then, surface roughness and gloss will be analyzed again. The mean values of roughness and gloss will be evaluated by analysis of variance (ANOVA) (p<0.05). Fisher's test will be used for multiple comparisons (p<0.05). Wilconxon's test will be used to compare the initial and final roughness and gloss evaluations (p<0.001). Spearman's test will verify the correlation between the surface roughness and gloss (p<0.05).