To evaluate the effect of coating enamel and dentin with a calcium phosphate powder, a calcium fluoride silicon polymer, an oxalate and a functionalized tricalcium phosphate, on marginal adaptation of class V cavities restored with a universal adhesive containing the adhesive monomer with chemical bonding potential 10-MDP (Clearfil Universal Bond) and a hybrid composite (Clearfil APX).

Class V cavities with margins located in enamel and dentin were coated with the different bioactive materials prior to the application of the adhesive and composite. After restoration polishing, the samples were subjected to a thermo-mechanical fatigue test. Gold coated resin-based replicas were readied to analyze the percentages of continuous margins (%CM) before and after loading to evidence differences between different enamel/dentin pre-treatments (Kruskal-Wallis, Duncan post hoc test).

The highest %CM was observed in the group in which enamel and dentin were coated with calcium phosphate powder prior to the application of the 10-MDP-containing adhesive. This was also the most stress-resistant group.

The adhesive interface formed between 10-MDP-containing universal one component adhesive and enamel/dentin with enriched mineral content may improve the quality of restoration margins.