The effect of artificial ultraviolet light on the gloss of composite resin surface sealants

This study evaluated how exposure to ultraviolet (UV) light affected the gloss of composite resins following application of resin-based surface sealants (SSs). Thirty composite resin discs were fabricated using cylindrical molds and randomly assigned to 1 of 5 SS groups (n = 6 each). Both sides of each disc received a polyester film clear matrix surface finish, and then rotary finishing and polishing procedures were performed on 1 side only. Six baseline measurements for each disc surface were performed using a 60-degree-angle gloss meter. The finished and polished side then received an SS application and was polymerized with an LED light through a polyester film matrix. Gloss measurements were then obtained. All specimens were then exposed to an artificial UV light source for a total of 382 hours, after which final gloss measurements were made. A 2-way repeated-measures analysis of variance and Student-Newman-Keuls pairwise multiple comparison tests revealed statistically significant differences between the SS materials and surface treatments (P < 0.05). No statistically significant (P > 0.05) differences were found between the surfaces that were mechanically finished and polished and those that only received a polyester film finish. However, all specimens exhibited significantly (P < 0.0001) higher gloss readings after SS application. Following UV exposure, all SS specimens exhibited significantly (P < 0.0001) lower gloss readings. The study results suggest that application of SSs to composite resin discs increases the gloss on a short-term basis; however, long-term exposure of SSs to an artificial UV light source might have a negative effect on the surface properties. Thus, dentists need to periodically evaluate composite resin restorations.