Anti-plaque effect of a surface pre-reacted glass-ionomer-based prophylactic paste under cariogenic challenge: a randomized in situ study

Objectives To evaluate the anti-plaque effect of a prophylactic paste containing Surface Pre-Reacted Glass-ionomer (S-PRG) fillers under cariogenic challenge using a randomized in situ model. Materials and methods This randomized, double-blind study involved 18 volunteers; both the participants and the outcome assessor were blinded to the prophylactic agent allocation. The prophylactic agents were the S-PRG-based Pro-Care Gel (Shofu Inc.; test), Herjos (Vigodent; conventional comparator), and pumice and water (negative control). The other factors were cariogenic challenge (presence or absence) and time of plaque accumulation (24 h and 7 days). During 8 days, volunteers wore intraoral appliances with enamel blocks divided into 2 rows (split-mouth design), in one of them a cariogenic challenge was applied (20% sucrose, 8x/day). Prophylaxis was performed at baseline and again after the 24-hour assessment. The three agent phases were separated by 7-day washout periods. Plaque accumulation was evaluated by quantitative digital image analysis of plaque-covered area (mm²) and adapted Simplified Oral Hygiene Index (OHI-S) scores. Results Three-way repeated-measures ANOVA showed significant main effects of Time, Cariogenic Challenge, and Prophylactic Agent (all p < 0.001). A significant Time × Prophylactic Agent interaction ( p = 0.022) indicated different temporal patterns among agents. Plaque accumulation increased from 24 h to 7 days in all groups, while Pro-Care Gel showed the lowest plaque-covered area at both evaluations; the OHI-S analysis showed the same overall group/time pattern. Conclusions Under the conditions of this short-term in situ study, the tested S-PRG-based prophylactic paste (Pro-Care Gel) resulted in lower stainable plaque accumulation than the tested conventional paste (Herjos) and pumice/water. These findings are specific to the products and outcomes evaluated. Clinical relevance S-PRG prophylactic paste exhibits a sustained anti-plaque effect, markedly reducing dental plaque accumulation relative to the two comparators during the 7-day evaluation period. This strategy could particularly be effective for high-caries-risk patients, as the material’s efficacy is not compromised by frequent sucrose exposure.