KMID : 1023820130050020153
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The Journal of Advanced Prosthodontics 2013 Volume.5 No. 2 p.153 ~ p.160
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Mechanical and thermal properties of polyamide versus reinforced PMMA denture base materials
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Koray Soygun
Giray Bolayir Ali Boztug
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Abstract
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PURPOSE : This in vitro study intended to investigate the mechanical and thermal characteristics of Valplast, and of polymethyl methacrylate denture base resin in which different esthetic fibers (E-glass, nylon 6 or nylon 6.6) were added.
MATERIALS AND METHODS : Five groups were formed: control (PMMA), PMMA-E glass, PMMA-nylon 6, PMMA-nylon 6.6 and Valplast resin. For the transverse strength test the specimens were prepared in accordance with ANSI/ADA specification No.12, and for the impact test ASTM D-256 standard were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n=7) test instrument (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength (n=7). All of the resin samples were tested by using thermo-mechanical analysis (Shimadzu TMA 50, Shimadzu, Japan). The data were analyzed by Kruskal-Wallis and Tukey tests for pairwise comparisons of the groups at the 0.05 level of significance.
RESULTS : In all mechanical tests, the highest values were observed in Valplast group (transverse strength: 117.22 ¡¾ 37.80 MPa, maximum deflection: 27.55 ¡¾ 1.48 mm, impact strength: 0.76 ¡¾ 0.03 kN). Upon examining the thermo-mechanical analysis data, it was seen that the E value of the control sample was 8.08 MPa, higher than that of the all other samples.
CONCLUSION : Although Valplast denture material has good mechanical strength, its elastic modulus is not high enough to meet the standard of PMMA materials.
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KEYWORD
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PMMA, Polyamide, Mechanical and thermal properties, Reinforced
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