Macromolecular leakage beneath full cast crowns. Part I: The diffusion of lipopolysaccharide and dextran

Abstract

Fifteen extracted molars were prepared for crowns. Crowns with access ports (one facial, one lingual) were cast in gold. Teeth and crowns with filters inserted into the ports were immersed in solutions of different concentrations of labeled and unlabeled macromolecules (fluorescein isothiocyanate-dextran, tetramethylrhodamine isothiocyanate-lipopolysaccharide [LPS], unlabeled LPS) and were evaluated for leakage. Retrieved filters were analyzed with fluorescent microscopy. At 10 micrograms/ml, only LPS leaked beneath the crowns in 24 hours (p = 0.0002), but after a 1-week immersion, both LPS and dextran leaked beneath the crowns. LPS scores were higher (p = 0.0002) than dextran scores. Slightly more LPS leakage occurred at 1 week than at 24 hours. LPS appeared to inhibit dextran diffusion beneath the cast crowns. Neither LPS nor dextran influenced LPS diffusion. Factors other than molecular size and weight may play a more important role in the microleakage occurring beneath crowns.

Cytotoxicity and sealing properties of four classes of endodontic sealers evaluated by succinic dehydrogenase activity and confocal laser scanning microscopy

“…Teeth with gutta-percha root-end fills have been shown to permit leakage of LPS, as shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis (20). Conventional fluorescence microscopy has shown that rhodamine-B-labeled LPS leakage occurs under cemented crowns, but the sensitivity of conventional microscopy for detecting the fluorescent tracer has not been adequate (21).…”

Influência da ciclagem com cargas dinâmicas na microinfiltração de coroas metalocerâmicas cimentadas com três tipos de cimento

“…A multiplicidade de estudos na literatura acerca da avaliação da microinfiltração corrobora para a inexistência de um modelo ideal 3,18,29,44,48,51,53,60 11,12,13,18,25,29,31,38,44,66,79,104,106,110 não contribui para uma análise qualitativa . 8,61,79,104,107,108,120,127,128,129…”

“…Uma das maneiras utilizadas para verificar tal relação consiste na avaliação da microinfiltração marginal em função da penetração de um corante na interface dente-cimento-restauração. Porém, estudos "in vitro" ou "in vivo" mostram resultados variados entre cimentos e materiais restauradores devido a falta de padronização do corante, tempo de aplicação, técnica de avaliação empregada, presença ou não de ciclagem térmica e ou mecânica, estabelecimento de escores variados de penetração e do tipo de análise realizada na interface dente-cimento (quantitativa ou qualitativa) 11,12,13,27,34,35,43,61,66,92,97,106,107,120,127,128,141 . Como consequência, muitas dúvidas e contradições têm sido apontadas na literatura em função da dificuldade de se obter resultados semelhantes de microinfiltração, tanto "in vivo" como "in vitro".…”