Surface changes in denture soft liners with and without sealer coating after mechanical brushing abrasion

Aim: To evaluate the surface alterations of soft liners with or without sealer coating after mechanical brushing abrasion. Methods: Thirty specimens were made of a methacrylate(Coe-Soft) and a siloxane-based material (Ufi-Gel SC), and 15 received two coatings of surface sealer. The specimens were submitted to a mechanical brushing-dentifrice assay under 200 g of force at 250 cycles/min. Mechanical brushing was simulated for a period of 1 (1,250 cycles) and 6 months (5,000 cycles). Surface roughness (Ra parameter) was measured, and SEM images were obtained. Ra data were analyzed by ANOVA for repeated measures and Bonferroni’s test (alpha=0.05). Results: Ra increased from baseline to six months of mechanical brushing abrasion regardless of sealer coating. At baseline, only Coe-Soft without sealer had higher Ra than the other groups. After one month, the Ra of Coe-Soft with sealer was three-fold higher than the Ra at baseline; the other groups showed no significant increase of Ra. SEM images showed degradation of the soft liners over time, except for the Ufi-Gel SC with sealer, which displayed minimum alteration of surface texture. Conclusion: Sealer coating reduced the surface degradation of the tested soft liners, but the protective effect was more pronounced for the siloxane-based material.