Characteristics of denture thermoplastic resins for non-metal clasp dentures

Abstract

Six thermoplastic resins and conventional acrylic resin were examined to characterize their mechanical and physical properties, water sorption, solubility, flexural strength, modulus of elasticity, tensile strength and color stability. Thermoplastic resins for nonmetal clasp dentures exhibiting low water sorption and solubility offer hygienic advantages. Since they have a low modulus of elasticity and are easily manipulated, these materials make it possible for larger undercuts to be used for retention compared to acrylic resin. Not all of the thermoplastic resins tested fractured after the bending test in contrast to the conventional denture base resin, which fractured when tested beyond its proportional limit. It was also found that clinically noticeable staining may occur on the polyamide resins and polyethylene terephtalate resins.

Comparative effects of denture cleansers on physical properties of polyamide and polymethyl methacrylate base polymers

“…The color of the specimens was measured using a portable colorimeter (Shade Eye-ex, Shofu, Japan) against a gray background with a lightness level of 5 Gray background was selected to make a standard for color measurements as performed in a previous study 12) . The diameter of the measurement window was 3 mm; the illumination and light beam angle was 90°.…”

“…In recent years, new-generation polyamide thermoplastic resins and butadiene styrene graft PMMA copolymer resins are more widely used than polyethylene methacrylate (PMMA)-based acrylic resins in production of removable dentures 11,12) .…”

“…Despite all these advantages, they have several important disadvantages, particularly due to their fibrous structure, as follows: difficulty in smoothing and polishing procedures and thus microbial contamination; mechanical retention with acrylic artificial teeth such as diatorics is required; mechanical connection with acrylic liner in nutrition operation 12) . Exact indications and contraindications of polyamide thermoplastic resins in clinical use were not determined.…”

Effect of fiber content on flexural properties of glass fiber-reinforced polyamide-6 prepared by injection molding

“…Patients today demand excellent esthetics as well as good function in prosthodontic restorations 1) . Removable partial dentures (RPDs) using resin-clasp retentive parts are defined as non-metal clasp dentures (NMCDs), and are often much more esthetically pleasing than conventional RPDs with metal clasps 2) .…”

Effect of Denture Cleansers on Flexural Strength, Color Stability and Surface Roughness of Flexible and Microwave cured Acrylic Resin

“…In recent years, new-generation polyamide thermoplastic resins (nylon) based material are more widely used than polyethylene methacrylate (PMMA)-based acrylic resins in production of removable dentures 10,13 . Nylon polymer has been attracting attention as a denture base material because of multiple advantages like favorable esthetic outcome, it does not contain allergic monomer, higher elasticity than conventional heat polymerized resins and sufficient strength for use as a denture base material and has low density 14 .…”