Document Type : Original Article
Authors
1
Assistant Professor, Department of Dental Biomaterials, Director of Research Lab, Faculty of Dentistry, Tanta University, Tanta, Egypt.
2
Lecturer, Department of Dental Biomaterials, Faculty of Dentistry, Tanta University, Egypt
3
Professor, Department of Chemistry, Director of Technology Transfer office, Faculty of Science, Tanta University, Tanta, Egypt.
Abstract
Objective: The objective of the study was to assess surface roughness, microhardness, color
stability, water sorption and water solubility of polymethyl methacrylate (PMMA) denture base resin
reinforced with inorganic {silanized ZrO2}, organic {Bisphenol A diglycidyl ether dimethacrylate
(Bis-GMA)+Triethylene glycol dimethacrylate (TEGDMA)+Polyethylene glycol dimethacrylate
(PEGDMA)} and hybrid {silanized ZrO2+Bis-GMA+ TEGDMA} Nanofibers.
Materials and Methods: The study was divided into four groups according to the added
nanofibers (6wt%) to heat curing PMMA denture base material; Control group: PMMA denturebase
material without reinforcing nanofibers, Inorganic group: PMMA denture-base material with
silanized ZrO2 nanofibers, Organic nanofibers group: PMMA denture-base material with Bis-GMA/
TEGDMA/PEGDMA nanofibers and, Hybrid nanofibers group: PMMA denture-base material with
silanized ZrO2/Bis-GMA/TEGDMA nanofibers. For each group, 10 specimens were prepared and
tested for surface roughness, microhardness, water sorption and water solubility. For each group
11 specimens were prepared and tested for color stability. Surface roughness was measured by
optical method. Digital Microhardness tester was used to measure Vickers microhardness. Color
stability was evaluated according to ISO/FDIS 20795-1 and ISO 7491, using a Portable Reflective
Spectrophotometer. Water sorption (WSP) and water solubility (WSL) were performed according
to ISO/FDIS 20795-1. One-way ANOVA was used for comparison between groups and Post-Hoc
test (Tukey’s tests) was used for multiple comparisons. P-value different.
Results: One-way ANOVA revealed insignificant differences between the studied groups in
surface roughness (p=0.168) and color stability (p=0.806). Significant differences were found in microhardness (p=0.000), WSP (p=0.000) and WSL (p=0.000). Post-Hoc (Tukey’s test) revealed
that: 1) microhardness means of nanofibers-reinforced groups were markedly significantly higher
than control group (p=0.000). 2) WSP of organic nanofibers reinforced group was significantly
lower than that of control (p=0.008), hybrid (p=0.001) and inorganic (p=0.000) groups that were
not significantly different from each other (p≥0.243). 3) WSL of ZrO2 nanofibers reinforced group
was significantly higher than control, organic, and hybrid groups (p=0.000). However, the control
group was not significantly different from organic (p=0.992) and hybrid (P=0.018) groups. Organic
group was significantly lower than hybrid group(p=0.009).
Conclusions: Addition of 6% nanofibers prepared by electrospinning technique to PMMA
denture resin significantly enhanced microhardness. Surface roughness and color stability were not
affected. Water sorption was significantly reduced with organic nanofibers, but was not affected with
ZrO2 and hybrid nanofibers. The highest water solubility for nanofibers reinforced groups recorded
in this study was (0.46±0.04μg/mm3) which is nearly one third of the ISO limit (1.6μg/mm3).
Keywords
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