Infiltração marginal em restaurações de compositos com diferentes viscosidades polimerizados sob intensidade gradual da luz visivel

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The purpose this study was to evaluate the marginal leakage of cavities restored with resin composites of different viscosities. Composites with high viscosity (Sure FiI), low viscosity (Tetric Flow) and medium viscosity (TPH Spectrum), and polyacid modified resin (Dyract AP) were evaluated. Sixty-five class V cavities were prepared on freshly extracted human molars and randomly divided into Control and Experimental Groups. The cavities were positioned either one half above and one half below the cementum-enamel junction. The entire cavity was conditioned with 35% phosphoric acid, rinsed and the excess of water removed, and Prime &Bond 2.1 applied according to the manufacturer s instructions. In the Control Group, restorations were made with each composite in two 1.5mm increments, and polymerized by the conventional technique, with a normal light activating unit (XL 3000-3M) for 40 seconds. In the Experimental Group, each increment was polymerized first for 10 seconds with 30% light total intensity (150 mW/cm2), followed by a final cure using 100% intensity of light during 30 seconds. After 24 hours in water at 37°C, the restorations were polished with Sof-Lex disks (3M). The teeth were coated with nail varnish leaving a 1-mm window around the margins, immersed in a 50% aqueous silver nitrate solution for 24 hours, rinsed for 1 minute, and immersed in a photo-developing solution for 8 hours. The teeth were cut longitudinally through the center of the restorations and leakage length at each cavity was measured with a microscope. The leakage results were calculated as the whole percentage of silver nitrate leakage into the cavity as: global leakage score = length of silver nitrate penetration I total length of cavity wall X 100. The specimens were observed on the scanning electron microscopy with variable pressure (SEM-VP LEO 435). The data were analyzed using ANOVA and Tukey s test (p<0.05). The average results in %, from Control and Experimental Groups were, respectively: Sure Fil (21.91 e 19.04 %), TPH (17.31 e 17.38 %), Tetric Flow (16.78 e 14.76 %) and Dyract AP (16.80 e 17.48 %). Silver penetration was not found at the enamel-restoration interface. However, at the dentin-composite, ali the interfaces showed marginal gaps and silver penetration. Only the composite Tetric Flow showed the lowest values of the infiltration (p<0.05), when it was submitted to intensity of light decreased at the first 10 seconds. Silver penetration was observed along the dentin-adhesive interface for medium and low viscosity composites, and it was observed at the composite-adhesive interface for high viscosity composite

ASSUNTO(S)

viscosidade polimerização resinas compostas restaurações (odontologia)

ACESSO AO ARTIGO

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