Physical properties of polyamide-12 versus PMMA denture base material

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials Science

Background:

• Polyamide-12 (PA) is a flexible polymer utilized in dental prosthetics, including denture bases and clasps.
• Understanding the aging effects on PA is crucial for its long-term clinical performance and patient satisfaction.

Purpose of the Study:

• To evaluate the effects of artificial aging on the surface roughness, color stability, and elasticity of Polyamide-12 (PA).
• To compare the aging resistance of PA with Polymethyl methacrylate (PMMA), a conventional denture base material.

Main Methods:

• PA (Valplast) and PMMA (Palapress) specimens were subjected to storage in air, water, coffee, and red wine.
• Color changes were quantified using the CIE L*a*b* system.
• Elasticity was assessed via three-point bending tests after thermocycling (1000, 3000, 7000 cycles).
• Surface roughness (Ra) was measured after liquid storage and thermocycling.

Main Results:

• PA demonstrated statistically significant color changes in red wine and coffee, unlike PMMA.
• The elastic modulus of PA remained unaffected by thermocycling, but elasticity decreased in dry conditions.
• No significant alterations in mean surface roughness were observed for PA or PMMA after aging protocols.

Conclusions:

• Polyamide-12 (PA) is more prone to discoloration than PMMA when exposed to staining agents.
• Artificial aging, including thermocycling and liquid immersion, did not adversely affect the surface roughness or elasticity of PA.
• PA's mechanical properties remain stable, but its color stability is a concern for prosthetic applications.