Efficacy of S-PRG Filler Varnishes on Enamel Caries Prevention

Objectives: The aim of this study was to evaluate the efficacy of different concentrations of S-PRG filler in experimental varnishes versus fluoride varnish on enamel demineralization prevention.

Methods: Ninety polished sound enamel specimens were prepared and the baseline Knoop microhardness was measured. They were randomly assigned into 6 different varnish treatments (n=15), prepared by Shofu Inc. (Kyoto, Japan), according to the concentration of S-PRG filler added: 10%, 20%, 30% and 40%. A non-treated group was used as negative control (NC), and 5% sodium fluoride varnish (F) was the positive control. The varnishes were applied on specimens’ enamel surface according to the manufacturer’s instructions, followed by immersion in artificial saliva for 24h. They were then submitted to a pH-cycling (4h in the demineralizing solution and 20h in the remineralizing solution) for 8 days. Knoop microhardness of the treated area was assessed again. The data after treatment were statistically analyzed using one-way ANOVA and Tukey’s test (alfa=5%). The data before and after treatment for each group were compared using t-test for dependent samples.

Results: All the varnishes tested showed significant protection against demineralization compared to the negative control (p=0.0001). No differences were observed among the S-PRG filler treated groups, but 40% S-PRG varnish promoted significantly enhanced protection compared to fluoride varnish group. The results of Tukey’s test were: NC – 174.35 (± 29.22)a, F – 286.12 (± 56.82)b, 10% – 306.58 (± 57.63)bc, 20% – 307.62 (± 41.04)bc, 30% – 319.59 (± 53.89)bc, 40% – 352.74 (± 69.45)c (different letters mean significant differences). For the comparison between baseline and after treatment, only the group 40% did not show significant differences (p=0.5544).

Conclusions: All varnishes tested were able to protect enamel against demineralization. However, 40% S-PRG filler varnish was the most effective in preventing enamel demineralization compared to sodium fluoride varnish, completely avoiding demineralization.