Effect of surface prereacted glass ionomer nanofillers on fluoride release, flexural strength, and surface characteristics of polymethylmethacrylate resin.

Abstract

Dentures should have proper fluoride release and physical properties. We evaluated how surface prereacted glass ionomer (S-PRG) nanofillers influenced fluoride release, flexural strength, and surface characteristics of polymethylmethacrylate (PMMA) resin. PMMA resin disc (n=14) and rectangular (n=5) specimens containing 0, 20 wt% microparticles, and 20 wt% nanoparticles of S-PRG were prepared. Six-disc specimens were examined for surface roughness; eight-disc specimens were immersed in 5ml of deionized water for 24 h before analyzing the fluoride levels on days 1-3, 12, and 15. They were recharged with 1000 ppm fluoride solution for 24 h and stored in deionized water for five cycles. Fluoride release was examined. The flexural strength of the rectangular specimens was determined using a three-point bending test. Data were analyzed by two-way repeated-measures ANOVA. S-PRG nanofiller had the highest fluoride exchange rate and did not significantly change the surface roughness compared with the microparticle and control groups; however, the nanofillers agglomerated and reduced the flexural strength to below 65 MPa. Incorporating 20 wt% nanofillers into resin enhanced the fluoride exchange property greater than microfillers at the same content, but diminished the mechanical properties of the resin. Incorporating 20 wt% S-PRG nanofillers in resin denture base can improve the fluoride releasing property without affecting the surface roughness.