Effect of APF gel on micromorphology of resin modified glass–ionomer cements and flowable compomers

Abstract

The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.

Surface degradation of composite resins by acidic medicines and ph-cycling

“…This finding could be due to the filler particle characteristics of this material. Previous studies have shown that resin materials that have larger filler particles presented greater surface micromorphology changes when submitted to acidulated phosphate fluoride (APF) gel, i.e., a fluoride compound that has a low pH 5 , 29 . Among the resin materials analyzed in this study, TPH presents the largest filler particles, 0.8 μm, ( Table 1 ), which has probably contributed to the increase of its roughness after pH-cycling.…”

Effect of pH Variations in a Cycling Model on the Properties of Restorative Materials

“…13 This interaction may be better presented when the surface conditions are observed with scanning electronic microscopy, a widely used method. [14][15][16] This methodology may, however, submit the specimens to adverse conditions inside the equipment as they become dehydrated, resulting in small cracks and fractures. 16 This aspect can be minimized when the evaluation is carried out on a larger surface and in more than one specimen.…”

<b>Influência da aplicação tópica de géis de flúor na rugosidade superficial de cimentos de ionômero</b>

“…Segundo alguns pesquisadores o gel de flúor fosfato acidulado forma mais fluoreto de cálcio no esmalte do que o gel neutro, sendo mais eficiente em reduzir a desmineralização do esmalte e, portanto, sendo preferíveis à aplicação de géis neutros (11).…”