Effect of food simulating liquids on bulk-fill composites: A dynamic analysis approach / Ahmed Hesham Ahmed Mohamed Eweis
Objective: To determine the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. Material and Methods: Four dental composites were evaluated which included a conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (...
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Format: | Thesis |
Published: |
2017
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Online Access: | http://studentsrepo.um.edu.my/10419/4/ahmed.pdf http://studentsrepo.um.edu.my/10419/ |
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Summary: | Objective: To determine the effect of food simulating liquids on visco-elastic properties
of bulk-fill restoratives using dynamic mechanical analysis.
Material and Methods: Four dental composites were evaluated which included a
conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill
[FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative
[BB]). Test specimens (12 x 2 x 2mm) were fabricated using customized stainless steel
molds. The specimens were light-cured, removed from their molds, finished, measured
and randomly divided into six groups. The groups (n=10) were conditioned in the
following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled
water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were then
assessed using dynamic mechanical testing in flexural three-point bending mode and
their respective mediums at 37°C and a frequency range of 0.1 to 10 Hz. The distance
between the supports were fixed at 10mm and an axial load of 5N was employed. Data
for elastic modulus, viscous modulus and loss tangent were subjected to
ANOVA/Tukey’s tests at significance level p<0.05.
Results: Significant difference in visco-elastic properties was observed between
composite materials and conditioning mediums. With the exception of bulk-fill giomer
restorative (BB), the highest elastic modulus was observed after conditioning in
heptane. For BB, conditioning in air gave the highest elastic modulus. Excluding FB,
the lowest elastic modulus was noted after exposure to ethanol. FB showed the lowest
elastic modulus after conditioning in distilled water. No apparent trends were noted for
viscous modulus. Excluding BB where exposure to citric acid gave the greatest values,
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loss tangent was the highest when the composites were conditioned in ethanol. For all
materials, air and heptane had the lowest loss tangent values.
Conclusion: The effect of food simulating liquids on the visco-elastic properties of the
evaluated bulk-fill composites was material and medium dependent. The UDMA-based
bulk-fill composite (FB), however, appeared to be more resistant to degradation effects
of ethanol when compared to BisGMA-based conventional and bulk-fill composites. |
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