The diffusion kinetics of a nanofilled and a midifilled resin composite immersed in distilled water, artificial saliva, and lactic acid

Abstract

This study investigated the diffusion kinetics of a nanofilled (Filtek Z350) and a midifill (Filtek P60) resin composite immersed in distilled water, artificial saliva and lactic acid. Resin composite specimens were desiccated, immersed in the media, weighed at suitable time intervals until they reached sorption equilibrium and were then desiccated again. Sorption and solubility (µg/mm(3)) were calculated based on ISO 4049:2000(E). The diffusion coefficient (m(2).s(-1)) was determined according to Flick's second law. The degree of conversion (DC%) was evaluated by FT-IR and the action of the media on the surfaces of the resin composite was evaluated by SEM. Z350 immersed in lactic acid presented the highest sorption (25.9 ± 1.3). The highest solubility was presented by Z350 immersed in lactic acid (5.6 ± 0.9), followed by P60 immersed in lactic acid (4.4 ± 0.5). The other groups presented no significant difference among them. The diffusion coefficients of both resin composites immersed in lactic acid and that of Z350 immersed in artificial saliva were significantly higher. The lowest diffusion coefficient was presented by P60 immersed in distilled water. The DC% was not significant, (p > 0.05). The SEM analysis showed that the effect of lactic acid on the resin composites was more deleterious than those of water and artificial saliva.

Influence of Curing Mode on the Surface Energy and Sorption/Solubility of Dental Self-Adhesive Resin Cements

“…The solvent diffuses into the resin network and reduces the intermolecular interaction of the polymer chains (swelling), yielding an increase in weight (sorption) [1]. Meanwhile, solubility in a resin-based composite reflects the amount of released residual or leachable monomers as well as filler particles from its surface, resulting in loss of weight [1,20]. The release of uncured monomers also presents a potentially sensitizing and irritating factor for the oral tissues [21].…”

Biological and mechanical degradation affecting the surface properties of aesthetic restorative

“…The hardness of the Z350 composite was lower than the Empress after the biological biodegradation, and this can be attributed to differences in size and distribution of the fillers on these materials 4,24 ; beyond the aforementioned factor, it can be speculated that this is the association of the consequent hydrolysis of the polymeric matrix with the inorganic framework differences of the studied composites 24 .…”

“…The nanofilled composite may be prone to absorbing liquids because of the greater contact area-load matrix, and this interface is more susceptible to fluid accumulation in the bacterial biofilm, or alternatively, the spaces resulting from the presence of the imperfect engagement of charged particles in the polymeric matrix. Spaces or "microvoids" in the polymeric matrix can increase the retention of acids and thereby increase the degradation of Z350 24 .…”

Effects of bleaching agent on physical and aesthetic properties of restorative materials

“…Apart from the type of bleaching agent, changes in the composition of the composite material depend on the differences in the composition of the organic matrix and the size and quantity of filler particles 33) . TECBF and TEC have the same resin in its composition (Bis-GMA, Bis-EMA, UDMA), but the difference in filler contain in TECBF which is 81/61 (wt%/vol%) compared to 76/55 (wt%/vol%) in TEC can affect the increased absorption of water and potentially lead to cracking of bonds between fillers and resins 35) thereby causing microhardness reduction. Our study reported a significant reduction in average surface microhardness after 45 min of bleaching with high concentrate of hydrogen peroxide, with the largest being recorded for nanohybrid composite TECBF.…”