A Comparative Study of Polyamide and PMMA Denture Base Biomaterials: I. Thermal, Mechanical, and Dynamic Mechanical Properties

Abstract

The fracture of denture base materials usually occurs due to accidental dropping and mishandling of these materials. Repeated fracture of denture base materials could be a problem for denture materials made of acrylic resins due to lack of toughness of PMMA-based denture materials. Use of a material with higher toughness might eliminate this problem. Properties of heat-polymerized poly(methyl methacrylate) (PMMA) and high-impact polyamide denture base biomaterials were compared. The test results showed that polyamide samples were more resilient and tougher. Polyamide biomaterials might be good candidate as an alternative to denture base PMMA materials for clinical situations of repeated fractures.

A Comparison of the Flexural and Impact Strengths and Flexural Modulus of CAD/CAM and Conventional Heat‐Cured Polymethyl Methacrylate (PMMA)

“…The CAD/CAM PMMA groups in this study demonstrated considerably higher impact strength values than the heat‐cured PMMA group did. Although statistical analysis revealed significant differences in impact strength among the tested groups, comparing our results with those in the literature is difficult, not only because of the absence of reports that have evaluated the impact strength of CAD/CAM dentures, but also because of the inherent differences in published reports in terms of the dimensions of the specimens, the cases where notched designs were used, and the adopted test configuration using Charpy or Izod approaches …”

“…From the load‐deflection curve, the bending modulus was also calculated according to the following formula: where E is the flexural (i.e., bending) modulus (MPa), Y is the recorded deflection corresponding to a certain load (f) for a point on a straight line segment on the load‐deflection curve, L is the span of specimen between the supports (50 mm), b is the width (10 mm), and d is the thickness of the specimen (3 mm).…”

“…Each specimen was placed horizontally and struck with a scaled pendulum (0 to 25 J) impact tester (WP 400; Gunt Hamburg, Barsbüttel, Germany). Corrected absorbed energy (Ec) was recorded, and the impact strength of each specimen was calculated according to the following formula: where I is the calculated impact strength kJ/m W is the specimen width (m), and T is the thickness (m).…”

Evaluation of flexural properties and dynamic mechanical analysis of glass fiber-reinforced polyamide resin

“…Denture base materials are subjected to various forces such as compression and shear during mastication. Mechanical properties of denture base resins are often evaluated with flexural strength, modulus of elasticity and impact strength ( 17 , 30 , 31 , 32 , 33 ). These tests have been approved to imitate the natural forces acting on the prosthesis in oral environment ( 34 ).…”

“…In the present study, the glass transition temperatures of PMMA, polyamide resin and glass fiber-reinforced polyamide resin were found as 144.53°C, 134.26°C and 134.22°C respectively. The Tg values are high because both the PMMA and the polyamide are amorphous materials ( 30 , 48 , 49 , 50 ). Decrease in the glass transition temperatures of materials after thermocycling shows that the mechanical properties of denture base materials may be affected at mouth temperatures ranging between 50C and 550C.…”