Surface tridimensional topography analysis of materials and finishing procedures after resinous infiltration of subsurface bovine enamel lesions

Objective: To evaluate the effects of materials and finishing procedures on the surface roughness of infiltrated subsurface bovine enamel lesions. Method and Materials: Eighty enamel specimens were prepared from 80 bovine incisors and partially varnished (control). The nonvarnished areas were demineralized (pH 4.95, 28 days) and etched with phosphoric acid gel (20%, 5 seconds). Specimens were randomly divided into two groups, which were each split into four subgroups (each n = 10): E1/E2 (Excite, Ivoclar Vivadent), F1/F2 (Fortify, Bisco), G1/G2 (Glaze & Bond, DMG), and I1/I2 (Icon, DMG). In group 1, resin materials were polymerized and polished using finishing strips by means of a polishing device; in group 2, excess material was removed with a rubber cup before polymerization (without polishing). The surface roughness (Sa) of control, demineralized, and treated surfaces were evaluated topometrically using a focus variation 3D scanning microscope. Results: Demineralized surfaces were significantly rougher than sound enamel (P .0005, t test). Etching increased Sa significantly to more than 450% of demineralization values (P .0005). Surfaces of nonpolished infiltrated lesions were significantly rougher than demineralized enamel (P .0005), while no significant differences could be found among infiltrated subgroups (P = .067), nor between polished and nonpolished groups (P = .359). Application of Glaze & Bond (G2) appeared to reduce Sa values of etched lesions (P .0005), while with all other subgroups Sa values improved only marginally. Conclusion: Regarding surface roughness, the use of finishing strips after infiltration of subsurface lesions does not seem to be advantageous. Excess material should be removed before light curing, but surface quality of nonprocessed infiltrants seems to be perfectible. Keywords: bovine enamel, caries infiltration, focus variation, initial caries, minimum intervention dentistry, polishing procedures, resin infiltration, surface metrology, surface roughness