IADR Abstract Archives
Flexural Properties of UDMA Dentures are Unaffected by Water Storage
Objectives: One of the most common reasons for premature physical failure of complete dentures is due to flexural failure at the midline. Consequently, any newly developed denture base materials must be evaluated in terms of its flexural properties to ensure that it performs at least as the most commonly used material, heat-cured polymethylmethacrylate(PMMA). In this study we evaluated the flexural properties of recently developed light-curable urethane dimethacrylate(UDMA)denture base material, comparing the results with heat-cured and cold-cured PMMA.
Methods: Bar specimens (n=15, 70x10x 3.5 mm) were produced from heat-cured PMMA (HC, John Winter &Co Ltd), cold-cured PMMA (CC, John Winter &Co Ltd), and Eclipse(Dentsply International). HC and Eclipse samples were made following manufacturer’s instructions. CC samples were made using 2:1 g/ml mixing ratio and cured at 3 bar pressure for 15 minutes at room temperature(RT). After polishing, samples were stored in distilled water at RT for 2days, and at 37°C for 1week, 1month, 3months and 6months.Samples were subjected before and after storage to 3-points bend testing using a universal testing machine(Instron 5567, Berks, UK) following ISO 20795-1:2013.
Results: There was no significant change in flexural strength for Eclipse or HC specimens over 6-months storage, while that of the CC specimens dropped significantly with increasing storage time(P<0.05).The Eclipse specimens were the strongest at each time period(P<0.05, Kruskal Wallis test) with the HC specimens being stronger than the CC specimens. In general the Eclipse specimens exhibited the highest flexural modulus, which is sometimes significantly different and sometimes not significantly different.
Conclusions: Within the limitations of the current study:
Eclipse is a potential alternative denture base material to HC in terms of flexure.
There is no significant effect of water storage on Eclipse and HC flexural strength within 6months, while it reduced CC strength .
Eclipse is not much stiffer than HC and CC.
Methods: Bar specimens (n=15, 70x10x 3.5 mm) were produced from heat-cured PMMA (HC, John Winter &Co Ltd), cold-cured PMMA (CC, John Winter &Co Ltd), and Eclipse(Dentsply International). HC and Eclipse samples were made following manufacturer’s instructions. CC samples were made using 2:1 g/ml mixing ratio and cured at 3 bar pressure for 15 minutes at room temperature(RT). After polishing, samples were stored in distilled water at RT for 2days, and at 37°C for 1week, 1month, 3months and 6months.Samples were subjected before and after storage to 3-points bend testing using a universal testing machine(Instron 5567, Berks, UK) following ISO 20795-1:2013.
Results: There was no significant change in flexural strength for Eclipse or HC specimens over 6-months storage, while that of the CC specimens dropped significantly with increasing storage time(P<0.05).The Eclipse specimens were the strongest at each time period(P<0.05, Kruskal Wallis test) with the HC specimens being stronger than the CC specimens. In general the Eclipse specimens exhibited the highest flexural modulus, which is sometimes significantly different and sometimes not significantly different.
Conclusions: Within the limitations of the current study:
Eclipse is a potential alternative denture base material to HC in terms of flexure.
There is no significant effect of water storage on Eclipse and HC flexural strength within 6months, while it reduced CC strength .
Eclipse is not much stiffer than HC and CC.