Influence of Al2O3/ Y-TSZ Mixture as Filler Loading on the Radiopacity of PMMA Denture Base Composites

The radiopacity of alumina/yttrium stabilizer zirconia (Al₂O₃/Y-TSZ) particles with nitrile butadiene rubber (NBR) dispersed in PMMA denture base material has been investigated. PMMA matrix without filler was prepared from PMMA powder with 0.5% benzoyl peroxide (PBO) as the control material. The similar PMMA matrix was mixed with Al₂O₃/Y-TSZ (1:1) together with NBR particles as the reinforcement. The amount of NBR was fixed at 7.5 wt %, however, Al₂O₃/Y-TSZ varied from 1 to 10 wt %, respectively. Samples with 4 mm thickness for each composition were irradiated using 60 KV, 10 mA, 0.4 s to examine their radiopacity. This radiopacity was compared to radiopacity of aluminum plate which having the same thickness. The result shows that the radiopacity (i.e. the lower optical density the higher radiopacity) of reinforced PMMA matrix slightly increased from 1.40 to 1.05, respectively, with the increased of filler loading compared to unreinforced PMMA matrix.