Hardness and Roughness of Flexible Denture Base at Different Injection Time and Different Temperature

Most problems with heat cured acrylic are difficult to address, in recent time flexible dentures have become more popular, although the search for the ideal option is still on, so this study was conducted to study the effect of different temperature and different injection time to study the effect on the hardness and roughness of flexible denture. 60 specimens from metal pattern were prepared with dimension (60mm, 10mm, 3mm) length, width and thickness respectively. Specimens were allocated into two group;30 specimens for surface roughness measure(groupI)and 30 specimens for hardness measure(group II), these two group subdivided into three subgroups according to time of injection and temperature (10 specimens for each subgroup), group A: injection at (270°C) in (14 min.) (control). group B: injection at(300°C) in (10 min.) and group C: injection at (250°C) in (24 min.). For hardness measure all specimens were tested by (shore D device DINISO electrometer). All specimens were tested for roughness measure by surface roughness tester (profilometer, digital) the result expressed in micrometer. Result showed there were no significant differences in hardness and roughness measures between both group B and group C with control group (A) P0.05. The max. mean value of roughness was recorded by group(A)which was the control group and group (B) recorded the min. mean value of roughness. While for the hardness the min. mean value was recorded by group(B), while group(C) recorded the max. mean value of hardness, however there were no significant different(P0.05) between three groups A, B and C both in hardness and roughness measures.