Anti-demineralization Ability of the Denture-base Resin containing S-PRG filler

Objectives: We have reported that the denture-base resin containing surface pre-reacted glass ionomer (S-PRG) filler had abilities of the initial fluoride release (0.007-0.029mg/mm²) and fluoride release (0.081-0.74mg/mm²) after being recharged with 9,000ppmF fluoride solution. In this study, we evaluated the dentin demineralization adjacent to these resins using transversal microradiography (TMR) in vitro. Methods: 0, 5, 10, 20 and 30wt% of S-PRG filler was added to heat-polymerizing PMMA denture-base resin blocks (11x14x4mm). The resins blocks were polished with 2,000 grit waterproof abrasive paper and cleaned ultrasonically. Dentin thin sections (300mm) were prepared from bovine root dentin, and covered with the bonding agent. A final cut for the test surface was made to remove the outer 200-300mm of the original root surface. The sections were sandwiched with the experimental resin blocks and fixed to vessels. Demineralization test was performed by immersing into 0.1mol/l lactic acid (pH4.8) and 8% MC gel for one week at 37°C. TMR was taken and the integrated mineral loss (IML) based on the mineral profile of each section was measured. IML was analyzed statistically using ANOVA and Tukey test at p<0.05 (n=5). Results: The mineral vol% of dentin surface and subsurface lesions increased with S-PRG filler contents. Particularly, the surface mineral vol% notably increased at 20 and 30wt% S-PRG filler contents groups. IML of dentin specimens adjacent to resin blocks with 20 and 30wt% S-PRG filler (2,039.8 and 1,787.7vol%xmm) were significantly less than these of 0, 5 and 10wt%(4,328.8, 3,198.6 and 2,497.5vol%xmm) at p<0.05. Conclusions: Heat-polymerizing PMMA denture-base resin containing S-PRG filler inhibit the dentin demineralization effectively, and it may contribute to prevent root caries progression of the abutment teeth.