Ultraviolet light stability of composite resins

Influence of surface sealing on color stability and roughness of composite submitted to ultraviolet‐accelerated aging

“…Studies using scanning electron microscopy (SEM) showed an increase on surface roughness of various composite resins after UV irradiation exposure attributed to wear, displaying internal porosities and microcracks with filler particle exposure. 14,19 In the present investigation, an increase on roughness values was observed for the experimental groups after UV aging, which agree with the results mentioned earlier, rejecting the third null hypothesis. We speculate that UV radiation is more related to a physical modification on the material surface, including loss of cohesion between fillers, pigment, and polymeric material, as stated by Kotnarowska.…”

“…Accelerated aging causes internal discolorations, as it does not consider the external stain influence . Thus, the color change of materials after UV irradiation has been related to chemical alterations in activators or the initiator system, and in the resinous matrix itself . Residual amine degradation and unreacted C=C oxidation result in the formation of yellowing compounds .…”

“…18 Thus, the color change of materials after UV irradiation has been related to chemical alterations in activators or the initiator system, and in the resinous matrix itself. 19 Residual amine degradation and unreacted C=C oxidation result in the formation of yellowing compounds. 11,20 A previous study reported that after 300 h of artificial accelerated aging, composites materials showed color change similar to those observed in a 24-month clinical evaluation.…”

Effect of Artificial Aging on the Roughness and Microhardness of Sealed Composites

“…The accelerated aging process involves UV exposure and temperature and humidity changes, simulating the effects of long‐term exposure to environmental conditions 18 . Scanning electron microscopy has shown an increased surface roughness of the various composite resins after UV irradiation exposure, 19 attributed to wear, exposure of interior porosities, 20 and microcracks with the exposure of the filler particles 19 . In the present study, although the microhardness decreased after 168 hours of UV irradiation, there was no significant difference in the roughness of the materials.…”

Effects of artificial accelerated aging on the optical properties of resin composites

“…Among them can be highlighted interaction with ambient light (WOZNIAK et al, 1985), thermal variations of the oral cavity, exposure to alcohol, acid or oily substances from the diet, or acids from bacterial metabolism. In the case of ambient light, exposure to the ultraviolet wavelengths present in natural and artificial light sources has been reported to be deleterious (DE OLIVEIRA et al, 2015.…”