Effect of acidulated phosphate fluoride solution on veneering particulate filler composite

Purpose: The objective of the current study was to investigate the surface morphologic characteristics of prosthodontic composite materials treated wi th an acidulated phosphate fluoride (APF) agent. Materials and Methods: Sev en composite materials (Artglass, Axis, Belleglass, Cesead II, Dentacolor, Solider, and Targis) were examined. Each material was packed into a split p lastic mold and was polymerized with a laboratory photo-curing unit. Half o f each composite disk surface was coated with a varnish, and the entire sur face of the sample was treated with an APF agent. After removal of the varn ish, surface roughness values (Ra) for the treated and untreated (ie, previ ously varnish coated) sides of all specimens were recorded with a surface a nalyzer and observed with a scanning electron microscope. Results: Ra value s for Cesead II, Solider, and Targis showed a significant increase as a res ult of treatment with the APF solution. Microphotographs demonstrated that the macroinorganic fillers in the Cesead II and Solider materials showed su bstantial dissolution caused by the APF agent. There were no significant st atistical differences in the Ra values between the treated and untreated ha lves for any of the materials containing inorganic fillers composed entirel y of diameters up to 1.0 mum. In particular, microphotographs of prepolymer ized silica composite (classified as microfilled materials in Axis and Dent acolor) did not reveal any change of the specimen surfaces. Conclusion: The APF agent attacked inorganic fillers in the composite materials. Microfill ed material surfaces were insensitive to the agent in comparison with macro inorganic filled material surfaces.