Properties of experimental urethane dimethacrylate-based dental resin composite blocks obtained via thermo-polymerization under high pressure

摘要

Objectives. The aim of this study was to use high-pressure high-temperature (HP/HT) polymerization to produce urethane dimethacrylate (UDMA)-triethylene glycol dimethacry-late (TEGDMA) based resin composite blocks (RCB) suitable for dental computer-aided design/manufacture (CAD/CAM) applications and to compare their physical/mechanical properties to those of a commercial dental RCB. The null hypotheses tested were: (1) there are no differences in the physical/mechanical properties between HP/HT polymerized UDMA-TEGDMA RCB and a commercial RCB; (2) volume fraction filler (V_f) does not affect the physical/mechanical properties of HP/HT polymerized RCB. Methods. Four UDMA-based experimental RCB were manufactured under HP/HT conditions. A RCB manufactured under the same HP/HT conditions from a commercial resin composite (Z100) and its commercial counterpart CAD/CAM RCB (Paradigm MZ100) were used as controls. Flexural strength (σf), fracture toughness (K_(IC)), and hardness were determined. The results were analyzed using one-way ANOVA, Scheffe multiple means comparisons (a = 0.05), and Weibull statistics (for ay). Scanning electron microscopy was used to characterize fractured surfaces. Results. All HP/HT polymerized RCB had superior σf, K_(IC), and Weibull modulus compared to the commercial dental RCB. The experimental RCB had similar or superior properties compared to HP/HT polymerized Z100 RCB. Fewer and smaller porosities (not quantified) were apparent in HP/HT polymerized RCB. The experimental RCB that contained 65% V_f showed higher porosity, suggesting practical difficulties in filler incorporation beyond a certain V_f. Conclusions. The results of this study suggested that RCB suitable for dental CAD/CAM applications could be obtained by HP/HT polymerization of resin composites based on pure UDMA.