Polytetrafluorethylene added to acrylic resins: mechanical properties

Abstract

The addition of different polymers, such as polytetrafluorethylene (PTFE), to denture base resins could be an option to modify acrylic resin mechanical properties. This study evaluated the surface hardness, impact and flexural strength, flexural modulus and peak load of 2 acrylic resins, one subjected to a long and another subjected to a short polymerization cycle, which were prepared with or without the addition of 2% PTFE. Four groups were formed according to the polymerization cycle and addition or not of PTFE. Forty specimens were prepared for each test (10 per group) with the following dimensions: hardness (30 mm diameter x 5 mm thick), impact strength (50 x 6 x 4 mm) and flexural strength (64 x 10 x 3.3 mm) test. The results of the flexural strength test allowed calculating flexural modulus and peak of load values. All tests were performed in accordance with the ISO 1567:1999 standard. Data were analyzed statistically by ANOVA and Tukey's test with the level of significance set at 5%. No statistically significant differences (p>0.05) were found for surface hardness. Flexural strength, impact strength and peak load were significantly higher (p<0.05) for resins without added PTFE. The flexural modulus of the acrylic resin with incorporated 2% PTFE polymerized by long cycle was significantly higher (p<0.05) than that of the other resins. Within the limits of this study, it may be concluded that the addition of PTFE did not improve the mechanical properties of the evaluated acrylic resins.

Effect of conventional water-bath and experimental microwave polymerization cycles on the flexural properties of denture base acrylic resins

“…The results of this study exceeded the recommended minimum values in all experimental conditions and may not have clinical relevance. Nevertheless, the values were in agreement with results obtained in the literature for heat-polymerized resins based on polymethyl methacrylate 11,[22][23][24] . However, as pointed out above, the results must be interpreted with caution, because different performance can be obtained when these materials are under fatigue loads when in function 25) .…”

Chemical Characterization and Flexural Strength of a Denture Base Acrylic Resin with Monomer 2‐Tert‐Butylaminoethyl Methacrylate

“…Each specimen was prepared for chemical characterization by investing glass slides measuring 25 × 75 mm in a plastic flask supported by dental stone (α‐hemihydrate of calcium sulfate; Herodent, Vigodent S.A. Ind. Com., Rio de Janeiro, Brazil) .…”

“…Poly(methyl methacrylate) (PMMA) resins have been successfully used in the manufacture of partial and complete dentures since the late 1930s because they are easy to handle and process, do not need special equipment, have a lower density, and provide the possibility of mixing colors . However, PMMA resins have certain disadvantages, such as low resistance and thermal conductivity, porosity, water sorption and solubility, in relation to their physical and mechanical properties . Another important limitation is the deposition and formation of biofilm on the surface of PMMA resins.…”

“…This might also cause damage to their mechanical properties. Nowadays, antimicrobial polymers or monomers represent a plausible alternative to solve such problems, since they are potentially resistant to microbial adhesion, they provide adequate mechanical properties, and they may remain attached to the acrylic resin polymer chains by means of copolymerization with the methacrylate monomers …”

Tensile Bond Strength between Soft Liners and Two Chemically Different Denture Base Materials: Effect of Thermocycling

“…Over the past century, polymethyl methacrylate (PMMA) denture base resin has been the first choice of clinicians for denture fabrication due to its low cost, adequate esthetic properties, and ease of manipulation . In the 1980s, to overcome contact allergies and to eliminate flasking, boiling out, packing, and water‐bath polymerization, light‐activated urethane dimethacrylate (UDMA) denture base resin was developed as an alternative to PMMA .…”