Surface roughness of two Polyamide Material Types Used in the Manufacture of Denture Base Compared with a Type of Heat-cured Acrylic Resin

Some of the disadvantages of the heat-cured acrylic resins include high porosity, high water absorption, volume changes, and a lot of residual monomer. The development of polymer chemistry produced different kinds of materials such as polyamide, Acetal resins, and etc. Recently, polyamide materials are widely used in the manufacture of denture base. Denture bases made from this material are more flexible than conventional PMMA. There is a direct relationship between surface roughness (as a result of polishing) and the retention of microbial plaque. This study compared the surface roughness of 2 polyamide materials with a heat-cure acrylic resin.
A total of 60 wax samples (30 × 15 × 4 mm) were made. For preparation of PMMA specimens, 20 of the samples were heated in the 165°F water bath for 9 hours. Other 40 wax samples were used for the preparation of polyamide samples (TCS and VAL), according to the factory instructions. Polyamide samples were heated for 11 minutes at 274°C- 293°C and then, injection was done for them. After finishing and polishing, the thickness of the samples decreased to 3 mm. Roughness was measured by a stylus profilometer (the length of the cutoff = 0.8 mm and speed of pen movement 0.5mm/s randomly in 3 regions of each sample. The t-test was used for a statistical analysis.
There is a significant difference between surface roughness of heat-cure acrylic resin with polyamide materials (P 0.05). The surface roughness of all specimens was higher than the threshold level (0.2 µ).
Due to the high surface roughness of polyamide materials, the use of polyamide materials cannot be recommended for the construction of permanent appliance. Surface roughness of heat-cure acrylic resin of Meliodent (PMMA) was higher than the accepted standard.