Determine the effect of humidity on dimensional stability of duralay acrylic resins

Abstract

With regard to the extensive application of Acrylic Duralay in preparing a direct pattern from the inside part of the channel and with regard to the vagueness of the effects of passing time and the environment on the dimensions of Acrylic Duralay' the aim of this research was to investigate the effects of moisture on the dimensional stability of Acrylic Duralay in two different environments, water and dry environment and on the stability of the post and core dimensions made from Acrylic Duralay. Materials and methods: In this experimental study, In order to collect the data the techniques of observation and filling forms were used. The samples included 60 patterns of Acrylic Duralay, The control group was help in the dry environment for 7 days and the experimental group was help in incubator at 37 degree centigrade distilled water. After this period the dimension; weight and the volume of the samples were measured and recorded in the forms, then the collected were analyzed by the use of pared T-Test and independent sample T-test. Results: The recent research showed that the volume and the dimensions of the Acrylic Duralay deoreased in the dry environment and regarding the volume and diameter was meaningful at %1 but the decrease in length was not meaning ful In addition in the dry environment the weight of Acryl Duralay decreased and it was not meaningful statistically. In the wet environment the volume and the dimensions as well as the weight of Acrylic Duralay increased and this was not meaningful. The comparison of the wet and dry methods showed that the changes in the dimension and volume of the Acrylic Duralay was meaningful in these two environments statistically but the changes in weight of the Acryl Duralay were not meaningful. Conclusion: Based on research findings, acryl Duralay after seven days storage in dry environment contraction and expansion in humid environments finds so acryl Duraly dimensional changes after 7 days storage in dry environments than the dimensional changes in the environment is wet.