Nanotubes/Polymethyl Methacrylate Composite Resins as Denture Base Materials
- 1.8k Downloads
Denture resin base fracture is not uncommon for clinicians. The purpose of this study was to examine the effect of multi-walled carbon nanotubes (MWCNTs) on properties of a commonly used polymethyl methacrylate (PMMA) denture resin.
Four groups of denture resin (Luciton-199, DENTSPLY Inc.) specimens were fabricated as control, 0.5, 1, and 2 wt% of MWCNTs. MWCNTs were dispersed to monomer by sonication. Seven specimens per group without thermocycling (TC) were subjected to a three-point bending test monotonically. Another set of four groups underwent 5000 thermocycles from 20 to 80 °C at 1 min intervals. Knoop microhardness evaluations were performed on the control and the experimental groups before and after thermocycles. Two-way analysis of variance (ANOVA) and Tukey’s honest significant difference (HSD) post hoc analysis were used to identify significant differences.
Flexural strength, resilience, flexural modulus, yield stress, and yield strain were calculated. Fracture surfaces were analyzed by scanning electron microscopy (SEM). Statistical analyses revealed that there was a significant adverse effect of TC on mechanical properties of the MWCNT/PMMA composite. Two-percent MWCNT/PMMA was the weakest among the groups in terms of mechanical strength.
Without TC, 0.5 and 1 wt% MWNCT/PMMA composite groups had a significant improvement of mechanical properties compared with the control group because of retardation of crack growth. MWCNTs dispersed in PMMA more than 1 wt% was not beneficial. SEM analysis showed sporadic agglomerations presented on fracture surface of 2 % WMCNT/PMMA composite that might have adverse effects on mechanical properties. Further study is needed to improve the dispersion of MWCNTs into commercial denture base systems.
KeywordsFlexural Strength Flexural Modulus Denture Base PMMA Matrix Denture Resin
- 1.J. Chai, Y. Takahashi, M. Kawaguchi, The flexural strengths of denture base acrylic resins after relining with a visible-light activated material. Int. J. Prosthodont. 91, 121–124 (1998)Google Scholar
- 9.L.T. Smith, J.M. Powers, D. Ladd, Mechanical properties of new denture resins polymerized by visible light, heat, and microwave energy. Int. J. Prosthodont. 5, 315–320 (1992)Google Scholar
- 22.P. Harris, Carbon nanotubes and related structures, (Cambridge University Press, New York, 2002)Google Scholar