Leaching and mechanical properties characterization of dental composites

Abstract

The objective of this study was to determine the leaching of Ba, Si, and Sr from four dental composites: Restolux (RX), Micronew (M), Renew (RW), and Choice (C) and to correlate the effects of such leaching with flexure strength and modulus of elasticity. The specimens were 3 x 3 x 25-mm bars, polished with 120- and 240-grit SiC paper, and were aged for 4, 6, and 8 months in artificial saliva, distilled water, and a 50/50 mixture of ethanol and distilled water. Inductively coupled plasma with mass spectroscopy (ICP/MS) was used to determine the ion concentrations after aging. The greatest release of Ba and Sr occurred after aging in 50/50 volume fraction mixture of ethanol/water and for Si in artificial saliva. The 50/50 solution caused a breakdown of the resin and glass matrix, resulting in an increase of Ba and Sr, whereas aging in artificial saliva resulted in an ion charge balance, which allowed an elevated and continuous release of Si. The flexure strength and the elastic modulus showed a gradual decrease over time, with the greatest decreases occurring following aging in the 50/50 water/ethanol solution, but little correlation with the leaching of the filler ions.

Investigation of Mechanical Properties of Modern Dental Composites After Artificial Aging for One Year

“…[2][3][20][21][22] Some previous studies found that the release of particular filler particles, such as strontium or barium, were different after aging in ethanol, artificial saliva and distilled water. 4,[23][24] However, as only little correlation has been observed between filler leaching and flexural strength, Drummond and others assumed that the deterioration of dental composites is more closely related to degradation of the resin matrix and the matrix-filler bonds than degradation of the glass fillers, 25 which is in accordance with other reports. 20 Zhang reported that storage of specimens in a mixture of ethanol and water led to a significantly higher decrease in FS than did immersion in distilled water or artificial saliva.…”

“…[4][5]8,16 With regard to this aspect, the findings of this in vitro study indicate that the aging medium has a negligible influence on mechanical performance, such as FS and VH. Generally, aging in aqueous solutions or the oral cavity may contribute to the leaching of composite components, degeneration of the cross-linked resin matrix and fostering hydrolysis of the filler-matrix interfaces.…”

“…Numerous in vitro studies have focused on the mechanical performance of dental composite materials after artificial aging. [3][4][5][6][7] Generally, the artificial aging of dental composites accelerates degradation of the material, [8][9] which causes a significant decrease in mechanical properties. However, the comparability of studies dealing with artificial aging of dental composite materials is rather low, as very different aging conditions and durations have been applied and there is only limited evidence as to how far different aging protocols account for differences in the mechanical performance of a specific material.…”

Surface and bulk properties of dental resin- composites after solvent storage

“…Several studies demonstrated a significant influence of different aging media and aging times on the mechanical properties of resin-based composites [12,26,[40][41][42]. Hahnel and others demonstrated a significant effect of the composite materials and the storage times on the surface hardness and flexural strength; on the other hand Drummond showed a significant influence of the resin-composites and the storage media but not the storage times [18,40].…”

“…Their low filler loading indicates high resin contents which is based on UDMA and EBADMA. UDMA-based monomer system have shown less resistance to solvent degradation compared to the BIS-GMA-based materials [41,43]. Moreover, the increased plasticity of these bulk fill materials may led to the increased softening effect of the solvents [51].…”