ABSTRACT
Increase in surface free energy of tooth activates enamel and dentin to enhance surface wettability and optimize adhesion. The purpose of this study was to evaluate the effect of different surfactant solutions with and without EDTA during preparation on dentin surface free energy. In this in vitro study, 88 selected molar teeth were cut in occlusal one-third of the crown and a flat dentin surface was obtained. Surfactant solutions with five different HLB [Hydrophil-Lipophil Balance] were selected and the flat dentin surfaces were abraded with a commercial high-speed cylindrical diamond bur while rinsing with the solutions. Two control groups were selected, including negative control [cutting with air-water spray], positive control [cutting with air-water spray and etching with phosphoric acid]. The study was carried on by depositing drops of two different liquids including distilled water [polar liquid] and methylene iodide [non-polar liquid] on the different treated surfaces and taking photographs of the drops by means of a digital camera. The contact angles were measured with AutoCad software. The surface free energy of dentin was then calculated using Fowkes equation. After selection of the most effective solution, a higher concentration was applied to determine the effect of concentration on surface free energy. After determining the effective concentration, the combined solution of surfactant and EDTA was evaluated. Data analysis was done by ANOVA and Duncan test with 95% signifieance level. The SEM study was done to evaluate smear layer formation in the specimens. The results revealed that use of surfactant on dentin surface decreased the surface energy while the surfactant with EDTA caused a significant increase in the surface energy compared to surfactant solution alone [Pvalue<0.05]. This increase in energy was equal to that of negative control. SEM study revealed that using surfactant with or without EDTA, removes the smear layer incompletely. 1] Surfactant solutions without EDTA decrease dentin surface energy at the same level of positive control group. 2] The result of measuring surface energy in negative control group and in the groups using this combined solution was identical with surface tension of water [72.8 j/m[2]]
Subject(s)
Dentin/drug effects , Edetic Acid/pharmacology , Surface Tension , Wettability/drug effectsABSTRACT
A desinfecçäo de todo e qualquer molde obtido é medida de biossegurança obrigatória na atividade clínica. Täo importante quanto a desinfecçäo é a seleçäo do método e da soluçäo desinfetante a ser utilizada para cada material de moldagem. É imperativo que a capacidade de reproduçäo de detalhes, a estabilidade dimensional e o grau de umedecimento (ou "molhabilidade") näo sejam criticamente afetados. O propósito deste trabalho foi avaliar o grau de umedecimento de uma marca comercial de poliéter (Impregum F) por três diferentes marcas comerciais de gesso tipo IV (Herostone, Durone e Polirock), após sua desinfecçäo por aerossóis de hipoclorito de sódio 1 por cento (líquido de Milton) ou glutaraldeído 2 por cento (Glutalabor II). Foram confeccionados 45 moldes de poliéter, os quais, em grupos de 15, receberam aerossóis de água (Grupo Controle), Líquido de Milton ou Glutalabor II. Em seguida, sobre a superfície dos moldes foram confeccionados modelos de gesso tipo IV, em número de 5 para cada marca de gesso. Após seu seccionamento mediano e preparo da superfície de corte, os modelos foram levados ao microscópio Carl Zeiss para leitura do ângulo de contato. Os resultados obtidos permitiram concluir que: a) a capacidade de umedecimento do poliéter por diferentes marcas comerciais de gesso tipo IV variou para os gessos estudados; b) o gesso Durone adaptou-se melhor aos moldes de poliéter do que os gessos Herostone e Polirock; c) a desinfecçäo dos moldes com aerossóis de hipoclorito de sódio 1 por cento (líquido de Milton) ou glutaraldeído 2 por cento (Guatalabor) näo afetou a adaptaçäo entre os gessos e o poliéter