J Adv Prosthodont.  2013 May;5(2):153-160. 10.4047/jap.2013.5.2.153.

Mechanical and thermal properties of polyamide versus reinforced PMMA denture base materials

• Soygun K
• Bolayir G
• Boztug A

• KMID: 2284755
• DOI: http://doi.org/10.4047/jap.2013.5.2.153

Abstract

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 +/- 37.80 MPa, maximum deflection: 27.55 +/- 1.48 mm, impact strength: 0.76 +/- 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.

Keyword

PMMA; Polyamide; Mechanical and thermal properties; Reinforced

MeSH Terms

Caprolactam
Denture Bases
Dentures
Elastic Modulus
Glass
Nylons
Polymers
Polymethyl Methacrylate
Caprolactam
Nylons
Polymers
Polymethyl Methacrylate

Figure

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  Fig. 1 Stress-strain curves of the resin sample groups.

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  Fig. 2 Strain-temperature curves of the resin sample groups.

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  Fig. 3 LogE-Temperature curves of the resin sample groups.

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  Fig. 4 A: PMMA specimen without fiber (original magnifications ×100), B: Valplast specimen (original magnifications ×100).

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  Fig. 5 KCR4 fiber-added specimen (original magnifications ×3,000).

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  Fig. 6 N6.6 fiber-added specimen (original magnifications ×100).

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  Fig. 7 N6 fiber-added specimen (original magnifications ×300).

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