Abstract
Forty recently extracted teeth with Class II amalgam restorations with overhangs were divided in four groups of ten teeth each. The overhangs were removed using one of the following instruments in each gruop: trimmer, chisel, surgical blade and reciprocating.motor.driven diamond tip. Instrumentation was performed until no irregularity could be detected clinically with a nº 3 explorer. The tooth.amalgam interfaces were examined by combined use of a surface measuring instrument and a scanning electron microscope. Four tracings from each specimen were recorded and the vertical discrepancy at the tooth.restoration interfaces measured. The mean score for tooth was determined, and the results were photographed aí 140 magnification with the SEM. The results indicated that all instruments tested were effective in removing overhangs, since none of the discrepancies registered after instrumenntation exceeded 4 Um. The surgical blade, and especially the reciprocting-motor.driven diamond tip eliminated overhangs better than the chisel. Both SEM photographs and the profilometric tracing revealed gaps at the tooth amalgam interface, rancing from 10 t o 50 Um in width.
Highlights
Class II amalgam restorations with overhangs were divided in four groups o! ten teeth each, The overhangs were removed using one of the following instruments in each gruop: trimmer, chisel, surgical blade and reciprocating-motor-driven diamond tip
The toothamalgam interfaces were examined by combined use of a surface measuring instrument and a scanning electron mieroscope
A. — Effect of silicate cement and amalgam on the gingiva, J.Am, Dent, Assoc, 55:11, 1957
Summary
Terface dente-restauração, com o auxílio dos traçados em papel calibrado, foi possível determinar a eficiên. Após a obtenção dos escores perfilométricos, os dentes foram desidratados e montados em cilindros plásticos e cobertos com uma liga de ouro e paládio para observá-los num microscópio eletrônico de varredura (Super II Internacional Scientific Instruments). Cais obtida na altura das interfaces dente restauração variaram de 1 um a 4Um em todos os espécimes testados, A tabela 1 mostra o número de dentes em cada categoria de acordo com as médias das discrepâncias e com os instrumentos usados, O teste do qui quadrado mostrou diferenças significantes entre os resultados conseguidos com diferentes instrumentos (P
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