Effects of thermal cycling on surface roughness, hardness and flexural strength of polymethylmethacrylate and polyamide denture base resins.
BACKGROUND
The purpose of this study was to evaluate the effects of thermal cycling on the surface roughness, hardness and flexural strength of denture resins.


METHODS
Polyamide (PA; Deflex and Valplast) and polymethylmethacrylate (PMMA; QC-20 and Acron MC) denture materials were selected. A total of 180 specimens were fabricated and then divided into 3 groups. The first group (group 1) acted as a control and was not thermocycled. The second group (group 2) was subjected to thermocycling for 10,000 cycles in artificial saliva and 5,000 cycles in distilled water. The last group (group 3) was thermocycled for 20,000 cycles in artificial saliva and 10,000 cycles in distilled water. The surface roughness were measured with a profilometer. The hardness of the resins were measured with a Vickers Hardness Tester using a 100-gf load. The flexural strength test was performed using the universal test machine with a crosshead speed of 5 mm/min. Data were analyzed using statistical software. The results of the measurements in the 3 different tests were analyzed by Kruskal-Wallis test with Bonferroni correction. Multiple comparisons were made by Conover and Wilcoxon tests.


CONCLUSIONS
There was a significant difference between the PMMA and PA groups in terms of surface roughness, hardness and transverse strength before and after thermal cycling (p&lt;0.001). Thermal cycling did not change the surface roughness, hardness and flexural strength values of either the PMMA or PA group (p&gt;0.001).
Department of Prosthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon - Turkey.
Elif Aydoğan
EA
Ayaz
Department of Prosthodontics, Faculty of Dentistry, Katip Çelebi University, İzmir - Turkey.
Bora
B
Bağış
Department of Prosthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon - Turkey.
Sedanur
S
Turgut
D003819:Denture Bases; D006244:Hardness; D009757:Nylons; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
D009757:Nylons; D012117:Resins, Synthetic; D019904:Polymethyl Methacrylate