In vitro abrasion of resin-coated highly viscous glass ionomer cements: a confocal laser scanning microscopy study

Objectives The aim of this study was to evaluate the effect of resin coating on the wear depth of highly viscous glass ionomer cements (HVGICs) after 40,000 cycles, corresponding to over 8 years of tooth brushing. Materials and methods A resin composite (Gradia Direct Posterior), two HVGICs (EQUIA Fil and Riva Self Cure), a resin coating (EQUIA Coat) and a conventional varnish (Fuji Varnish) were used in the study. The control groups were the resin composite group and the non-coated HVGICs groups. Samples ( n = 8) were produced in flat plastic moulds at 23 ± 1 °C and stored in artificial saliva sodium acetate-acetic acid-glycerine formalin (SAGF medium) for 7 days at 37 ± 1 °C. The abrasion test was carried out in a toothbrush simulator (Willytec) with a load of 1 N using abrasive toothpaste slurry. Vertical loss was measured at different cycles under confocal laser scanning microscopy (CLSM). Data were analysed using one-way ANOVA, Tukey’s HSD test, repeated measures ANOVA and Bonferroni tests ( p