610 the journal of prosthetic dentistry volume 81 number 5
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Microleakage of Class V resin modified g
CLINICAL IMPLICATIONS
The findings of this in vitro study suggest that Fuji II LC glass ionomer cement pro- vided a better marginal adaptation than Dyract composite in Class V restorations, and the amount of resin content and filler particles of the materials may influence the degree of microleakage. tive materials to composites for the conservative restoration of these lesions because of their adhesion to tooth structure, fluoride release, biocompatibility, lower shrinkage values, reduced microleakage, and acceptable esthetics. 7-11 Light-cured resin-modified glass ionomer cements were developed to improve the handling and working characteristics of the original glass ionomer formulation. 12,13 Improved adhesion to dentin is probably caused by both a chemical bond from the polyacrylic acid component and formation of a hybrid layer from the hydrophilic HEMA. 14-21 Favorable adhesive and fluoride-releasing properties of glass ionomer cements have lead to their widespread use as restorative, lining, and luting materials. To over- come the problems of moisture sensitivity and low early mechanical strengths associated with the conventional glass ionomer cements (GICs) and at the same time maintain their clinical advantages, some hybrid versions of GIC were introduced that are light-cured, because of their small quantity of resin components such as HEMA or BIS-GMA. In some situations, the polyacid also has been modified with side chains that can be polymerized by light-curing mechanisms. The actual formulations vary between manufacturers, but the amount of resin in the final set restoration is between 4.5% to 6%, such as for Fuji II LC and Vitremer glass ionomer cements. The addition of a resin component to GIC and its effects on the development of the ionic crosslink and the subsequent marginal seal against the tooth structure needs further evaluation. To overcome technique-sensitive mixing and han- dling properties of the resin-modified glass ionomer cements, new materials containing acid-decomposable glass and acidic polymerizable monomers substituting the polyalkenoic acid polymer were developed. These materials were termed polyacid-modified resin compos- ites , 22-26 commonly called compomers. Dyract poly- acid-modified resin composite belongs to the new materials that have either been marketed as multipur- pose materials, or contain both of the essential compo- nents of a glass-ionomer cement but at levels that are insufficient to produce an acid-base reaction. 13 With this material, the resin content is approximately 28%. The purpose of this study was to compare the microleakage of Class V restorations produced with the 3 materials, which differ in their resin content, to test the hypothesis that resin content affects microleakage. Download 62.61 Kb. Do'stlaringiz bilan baham: |
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