EFFECT OF PRESSURE CURING TECHNIQUE ON PROCESSING ' SOFT LINING MATERIAL

Abstract

This study was done to iiwestigate the effect of the pressure cunng technique on shear bond strength, surface hardness and roughness of the acrylic resin soft liner in comparison with conventional hot water curing technique. 50 samples of the acrylic resin soft liner bonded to the acrylic resin blocks were used for measuring shear bond strength in dry condition and after immersion in water for 48 hours, 1, 3 and 6 months. The mode of bond failure of the tested samples was examined visually. For measuring surface hardness of the soft liner, 40 samples of this material were prepared and immersed in water f<;Jr various periods. Shore-A hardness tester was used to measure the hardness of the soft lirier samples in dry and wet conditions. Another 50 samples of soft liner were constructed for measurmg the surface roughness of this material • by using laser scattering technique to determine Sa which is the arithmetic mean height deviation of the samples surface. Total number of the samples that were used for measunng shear bond strength, surface hardness and roughness were divided into two equal groups. The first group was cured by pressure curing technique and the other group was cured by conventional hot water curing technique. Each was subdivided into 5 subgroups, one group was used as a control (dry) and the other subgroups were immersed in water for 48 hours, l, 3 and 6 months. The effect of water on shear bond strength, surface hardness and roughness of this acrylic resin soft liner that cured by both techniques was identified. The result of this study revealed that the samples cured by pressure curing

technique had higher shear bond strength and smoother surface in coJ_nparison

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