Leached components from dental composites in oral simulating fluids and the resultant composite strengths

Abstract

The aim of this study was to analyse the leached moieties of dental composites after storage in ethanol and organic acids of plaque and further evaluate the resultant effect on the diametral tensile strength (DTS) of the composites. Three commercial composites were used: Bis-GMA-based Z100, Bis-GMA/UDMA-based Heliomolar, and Bis-MPEPP-based Marathon One. The solutions used were: 99.9% acetic acid, 99% propionic acid and 75% ethanol. Specimens (4 mm diam. x 2 mm thick) were stored at 37 degrees C in 3 mL of solution for up to 30 days. Gas chromatography/mass spectrometry was used to characterize the leached moieties and DTS of the specimens after immersion was evaluated. Data were analysed using ANOVA and Tukey LSD test. The eluted substances were not all the same in different solutions and composites but mostly increased with immersion time, and included diluents (TEGDMA and decamethacrylate) and some additives, such as an ultra-violet stabilizer (TINUVINP), plasticizers (dicyclohexyl phthalate and bis(2-ethylhexyl) phthalate), initiator (triphenyl stibine), coupling agent (gamma-methacryloxypropyl trimethoxysilane), and phenyl benzoate. The chief polymerizing monomers were not found. More kinds of components were found in the acetic acid and ethanol groups studied. The fewest kinds and quantities of leached moieties were found for Bis-GMA specimens and then Bis-GMA/UDMA ones, most of which are diluent agents. Bis-MPEPP specimens leached the most substances, which were composed mostly of a short phenyl group chain structure. The BisGMA composite showed the highest DTS (54.8 +/- 5.7 MPa), which was not greatly affected by the length of storage. Bis-GMA/UDMA (36.2 +/- 6.8 MPa) and Bis-MPEPP (26.1 +/- 4.5 MPa) composites were significantly reduced (P < 0.05) after 30 days storage in the ethanol (35-50%), in the propionic acid (25-30%), and in the acetic acid (40-60%). Irreversible processes such as the leaching of components occur in fluids simulating an oral environment, which may contribute to irreversible material degradation, especially for non-Bis-GMA-based composites.

Effects of food-simulating liquids on the mechanical properties of a silorane-based dental composite

“…Therefore, in the case of RBCs, degradation typically occurs because of these two reasons: (1) hydrolytic breakdown of the bond between the silane and filler particles and the fillerresin matrix, resulting in debonding ultimately; and (2) the softening of dental resins through the plasticizing action of water 9) . As for the effects of solvents on dental composites, many factors come into play -such as the hydrophilicity of polymers andthecrosslinkingdensityofthenetwork 10) . Recently, Weinmann et al 11) reported on the synthesis of a new monomer system named "silorane", which is obtained from the reaction of oxirane and siloxane molecules.…”

Sorption and solubility of luting cements in different solutions

“…Several factors contribute to the elution of components from resin-based materials -namely amount of unreacted monomers, size and chemical composition of elutable species, and chemistry of the solvent 16,27) . Many mouthrinses include ethanol in their composition, and ethanol may accelerate the hydrolytic degradation of resin-based materials 28) . On this ground, subsurface and surface degradation of resin composites can be reproduced in the laboratory by storage in 50:50 ethanol:water solution 29,30) , which is listed as a food-simulating liquid in the U.S. Food and Drug Administration (FDA) Guidelines.…”

An AFM evaluation of the effect of 37.5% hydrogen peroxide on sealed and unsealed aged composite materials

“…The degradation process can also be influenced by powers on the radical formation of bleaching materials and their PH alongside their contact time. (17,20,22,23) The effect of each prescribed reason can affect the results of different studies, and different results for surface roughness are not affected only by one main factor.…”