Author/Authors :
Eghtedari Mehrdad نويسنده Assistance Professor of Prosthodontics, Department of Prosthodontics, School of Dental Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran , Ghanavati Saghar نويسنده Resident of Prosthodontics, Department of Prosthodontics, School of Dental Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran , Rohani Ali نويسنده Dentistry Student, School of Dental Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran , Parchami Mehdi نويسنده Dentistry Student, School of Dental Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran
Abstract :
Background and Objectives: 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, andetc. Recently, polyamidematerials 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.
Methods: 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.
Results: There is a significant difference between surface roughness of heat-cure acrylic resin with polyamide materials (P < 0.05),
however there is no significant difference between surface roughness of 2 types of polyamide materials (P > 0.05). The surface
roughness of all specimens was higher than the threshold level (0.2 ).
Conclusions: Due to the high surface roughness of polyamidematerials, 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.
