Biodegradation of Dental Composites/ Glass-Ionomer Cements

Abstract

Studies of the degradation processes, types of tests, and measurements and analyses of substances leaching out from resin-based composite materials and glass-ionomer cements are reviewed. For both types of materials, the initial release rate rapidly decreases to a low, but nearly constant, level. For composites, various types of degradation processes have been demonstrated. Elements from filler particles and degradation products from the resin (e.g., formaldehyde) leak out. Many substances are not properly identified. It is, however, difficult for in vitro and in vivo degradation to be compared. For glass ionomers, a total disintegration of a surface layer is observed, together with a slow release of elements from the bulk. Of the elements released, fluoride is the most interesting. Marked differences have been shown between in vitro and in vivo solubility tests.

Investigation of Environmental Lead Contamination Caused by Thermo-Electric Power Plants

“…12 Lead is not used in dental restorative materials, but traces of lead have been found as contaminations in filler particles of glassionomer and composite fillings in insignificant concentrations habits. 23 In this study, findings similar to that of Lappalainen and Knuuttila 21 were obtained. Gomes et al, 24 determined the amount of lead in the superficial enamel of deciduous teeth from 4-and 5-year-old children both in industrialized and non-industrialized areas in Piracicaba, Brasilia.…”

Effect of Chemical and Mechanical Degradation on Surface Roughness of Three Glass Ionomers and a Nanofilled Resin Composite

“…31 While resin-based materials undergo the cleavage of polymer chains to form oligomers and monomers, the ionomeric cements present a complex process of absorption, disintegra- tion, and outward transportation of ions. 12 The acidic degradation begins with water absorption that diffuses internally through the matrix, filler interfaces, pores, and other defects, accelerated by a low pH and causing filler-matrix debonding or even hydrolytic degradation of the filler-matrix interface. 32,33 No statistically significant difference was found among the roughness values of all materials tested after the pH cycling (Table 2).…”

“…11 The resistance of dental restorations to superficial degradation has an appreciable influence on their clinical performance. 12 In the oral cavity, the degradation of restorative materials can be caused by low pH (due to cariogenic biofilm and acidic drinks), water sorption, erosion, and wear. [12][13][14] These factors involve degradation of the resin matrix, filler, or matrix-filler interface on the surface of the materials, leading to increased surface roughness and wear rate.…”

“…12 In the oral cavity, the degradation of restorative materials can be caused by low pH (due to cariogenic biofilm and acidic drinks), water sorption, erosion, and wear. [12][13][14] These factors involve degradation of the resin matrix, filler, or matrix-filler interface on the surface of the materials, leading to increased surface roughness and wear rate. 15,16 Laboratory studies assess the surface integrity of restorative materials using mechanical degradation tests, such as wear simulation and brushing abrasion, which evaluate the surface texture and wear/ abrasion resistance of materials.…”

"Efeitos de bebidas com baixo pH e da escovação dental simulada sobre os materiais restauradores utilizados em lesões cervicais não cariosas"

“…Convencionou-se chamar de degradação as alterações físico-químicas apresentadas pelos materiais. No meio bucal, a degradação dos materiais envolve um processo complexo que inclui desintegração e dissolução na saliva, desgaste, erosão causada por alimentos, atividade bacteriana (OILO, 1992).…”