Objective: To evaluate the flexural modulus, surface hardness and fluoride release of S-PRG fillers incorporated in heat-polymerizing polymethylmethacrylate (PMMA).
Method: Specimens were packed in 2 layers of PMMA. The first layer was prepared with PMMA resin containing S-PRG filler at 0, 5, 10, 20 and 30 wt% for 1.5 mm of thickness. The same resin without S-PRG was placed over the final 2 mm of thickness. The resin was prepared according to ISO 20795-1:2008 standard.
The flexural moduli of the specimens were tested according to ISO standardization and ADA specification No. 12. Surface hardness tests were performed on the same groups via Barcol Hardness test weekly for 6 weeks. Fluoride release was measured in four phases up to 60 days on disk specimens (n=8/group, 15mm diameter; 3mm thickness).
Result: Flexural modulus (GPa): 0%: 2.8; 5%: 3.1; 10%: 3.1; 20%: 3.2; 30%: 3.3. Barcol Hardness (Week 1; Week 6): 0%: 40.7; 32.3, 5%: 41.7; 33.1, 10%: 39.7; 36.7, 20%: 40.9; 36.4, 30%: 41.3; 39.5. Fluoride release data showed 30wt% group having the highest amount released and recharging was effective for all groups except 0%. Results are analyzed with ANOVA with Tukey HSD Test (α=0.05). SEM photographs of the five groups were taken for comparison. There is no statistical difference with flexural modulus among the five groups. Surface hardness of the 30wt% group is statistically higher than 0 and 5wt% groups at week 6 (P<0.05)
Conclusion: There is no change in flexural modulus and fluoride release when of S-PRG fillers are incorporated in PMMA. The S-PRG filled resin is viable as a denture resin alternative.