• Paijit Humpanont
• Piyawat Phankosol
• Kussalee Thongpussa
• Nantaya Samyod
• Porntipa Ounmee

Acrylic denture base is likely to be continuously immersed in water or aqueous environment. This can lead to the change of its mechanical properties. The objective of this study is to compare the strength of heat-cured and self-cured acrylic resin when subjected to moisture desorption and water absorption after moisture desorption. 50 bar specimens of each resin were fabricated and divided in 2 groups. The first group was subjected to dry in a desiccator for 1, 3, 7 and 14 hour with their control group. The second group was subjected to dry in a desiccator for 7 hour then immersed in water for 1 hour, 6 hour 1 day and 7 day with their control group. The weight of the specimen was measured before and after the process. The transverse strength and the deflective rupture were conducted on a L1oyd universal testing machine. The data were statistically analyzes using Mann-Whitney U test and Kruskal-Wallis test (P=0.05).

                It was found that when dried out, the transverse strength of both acrylic resins were significantly increased while the deflective rupture was decreased. Conversely, when the resins were immerse in water after dried out, the transverse strength decreased and the deflective rupture increase. The rate of moisture desorption is faster than the water absorption. Furthermore, self-cured acrylic resin tend to have weight change and absorp water more than heat-cured acrylic resin.

(CU Dent J 2002;25:131-7)