JOURNAL OF PROSTHETIC DENTISTRY THE

Vol. 100 No. 1      July - 2008

ISSN: 0022-3913      UBIC: 171

SUMMARY

Statement of problem: Mechanical properties of denture acrylic resins are important for the clinical success of multiple types of prostheses. Acrylic resins must be strong and resilient so as to withstand impact. Few studies utilize cyclic loads to characterize material response to repeated stress. Purpose: The purpose of this study was to evaluate static and dynamic flexure properties of a variety of acrylic resins utilized in the fabrication of prostheses: (1) heat-polymerized polymethyl methacrylate (PMMA), powder-liquid type, and (2) a newly introduced, visible light-polymerized urethane dimethacrylate dough type. Material and methods: Twenty rectangular bars each of 4 PMMA acrylic resin materials (Diamond D, Fricke Hl-l, Lucitone 199, Nature-Cryl Hl-Plus) and 1 urethane dimethacrylate (Eclipse) were fabricated and stored in 100% humidity for 30 days. Half of the specimens for each group were submitted to a static 3-point flexure test. The other half was submitted to cycling loading at 5 Hz for 1 0 cycles. Data were analyzed using 1-way ANOVA and 2-way ANOVA, followed by Tukey HSD or Bonferroni post hoc tests when necessary (α=.05). Results: Mean static flexure strength (SDs) in MPa were: Eclipse, 127.11(5.83); Diamond D, 84.92 (5.10); Lucitone199, 83.96 (11.96); HI-I, 79.54 (5.84); and Nature-Cryl Hi-Plus, 75.82 (6.96). Mean flexural strengths (SDs) in MPaPostcycling were: Eclipse, 113.36(31.29); Diamond D, 88.26 (5.46); Nature-Cryl Hi-Plus, 81.86(4.93); HI-l, 79.18(6.60); and Lucitone 199, 74.34 (4.95). Conclusions: The visible light-polymerized urethane dimethacrylate resin (Eclipse) showed greater flexure strength than all PMMA heat-polymerized resins for both static and cycled groups (P<.001). Yet the Eclipse material had lower load limits, and demonstrated brittle-type behavior and greater standard deviations. The heat-polymerized PMMA materials did not significantly differ from each other after static or cyclic testing. (j Prosthet Dent 2008;1 00:47-51)

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