The effect of topical APF foam and other fluorides on veneer porcelain surfaces

Some topical fluorides cause surface changes in dental materials. The purpose of this study was to compare the effects of a topical acidulated phosphate sodium fluoride (1.23% APF) foam with the effects of other topical fluorides on the surface of veneer porcelain. Forty porcelain specimens (Ceramco) were placed into eight groups (N = 5). Four groups were immersed in either 1.23% APF foam, 1.23% APF gel, 2.0% sodium fluoride (NaF) gel, or water (reference) for 1 min. The other four groups were immersed in one of the above agents for four 1-min immersions. The surface topography of two scanning electron micrographs of each specimen was scored visually by two raters and by computer digital analysis (CDA). Inter-rater reliability was r = 0.67 (intraclass correlation coefficient). There were no significant differences in the mean visual scores or CDA scores among any of the groups immersed for 1 min. Porcelain immersed 4 min in APF gel had significantly greater mean visual scores and CDA scores than the other treatments (P < or = 0.0001; one-way ANOVA and Tukey's Studentized Range Test). The average surface topography scores of veneer porcelain immersed for 1 min in 1.23% APF gel, 2.0% NaF gel, 1.23% APF foam, or water were not significantly different. Significantly greater surface topography scores occurred following 4 min of immersion in 1.23% APF gel than all other agents.