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Microwave Disinfection: Cumulative Effect of Different Power Levels on Physical Properties of Denture Base Resins
Author(s) -
Senna Plinio M.,
Jose Da Silva Wander,
Faot Fernanda,
Antoninha Del Bel Cury Altair
Publication year - 2011
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/j.1532-849x.2011.00770.x
Subject(s) - materials science , composite material , flexural strength , distilled water , izod impact strength test , surface roughness , elastic modulus , polymerization , microwave irradiation , irradiation , modulus , microwave , ultimate tensile strength , chemistry , polymer , physics , chromatography , quantum mechanics , nuclear physics
Purpose: This study evaluated the cumulative effects of different microwave power levels on the physical properties of two poly(methylmethacrylate) (PMMA) denture base resins. Materials and Methods: Eight sets of four PMMA specimens each (two polymerized in a water bath and two using microwave energy) were immersed in beakers containing 200 ml of distilled water. Each beaker was subjected to microwave irradiation for 3 minutes at a power level of 450,630, or 900 W. The surface roughness, surface hardness, linear stability, flexural strength, elastic modulus, impact strength, and fractographic properties were evaluated after either 6 or 36 simulated disinfection cycles. The data were statistically analyzed using ANOVA and the Tukey post hoc test (α= 0.05). Results: The polymerization method did not influence any property ( p > 0.05) except linear stability. The surface roughness ( p < 0.001) and hardness ( p = 0.011) increased after 36 irradiation cycles at 630 or 900 W. The resin polymerized using microwave energy exhibited greater linear distortion ( p = 0.012), and there was a cumulative effect on linear stability for both resins ( p < 0.001). No significant change ( p > 0.05) was observed in flexural strength; however, the elastic modulus decreased ( p = 0.008) after 36 disinfection cycles. The impact strength and crack propagation angles displayed no significant differences ( p > 0.05). Conclusion: Within the limitations of this study, it can be concluded that microwave disinfection at 450 W to 630 W for 3 minutes is safe for PMMA.