Influence of mechanical and chemical degradation on surface gloss of resin composite materials

To determine the changes in surface gloss of different composite materials after simulation of mechanical and chemical aging mechanisms.

36 specimens were fabricated for each material and polished with 120-, 220-, 500-, 1200-, 2400- and 4000- grit SiC abrasive paper, respectively. Gloss measurements were made with a glossmeter (Novo-Curve) prior to testing procedures. Specimens of each material were randomly divided into three groups. Group 1 was conditioned for 7 days at 37 degrees C in 75% ethanol aqueous solution. Group 2 was immersed in fluoride gel (Elmex Gelée) at 37 degrees C for 1 hour. Group 3 was subjected to simulated toothbrushing with an electric toothbrush while being immersed in toothpaste. Surface gloss measurements were made subsequently.

Significant difference between surface gloss of the composite materials tested were detected after simulated brushing (Kruskal Wallis, P < 0.05). With the exception of Filtek Silorane, all composite materials tested were significantly affected by immersion in Elmex Gelèe (Wilcoxon signed-rank test, P < 0.05). Immersion in 75% alcohol aqueous solution significantly affected surface gloss except natural enamel and Durafill (Wilcoxon signed-rank test, P< 0.05).