Comparative Evaluation Of Diametral Tensile Strength Of Phosphate Bonded Investment Materials After Drying By Various Methods”–An Invitro Study

The study is to evaluate and compare the Diametral Tensile strength of Phosphate bonded Investment materials (Wirovest, Cromocasting Fast and Accuvest) after drying by Air dried method, Conventional Hot air oven method and Microwave oven method. A total of 90 cylindrical specimens were prepared from three different commercially available phosphate bonded investment materials. Thus 30 samples for each material were prepared and 10 of each were Air dried for 60 minutes, 10 were dried in a Conventional Hot air oven for 60 minutes t 265 c to 300 c nd 10 were dried in Microw ve oven with 600 w tts t frequency of 2450 MHz for 10 minutes. All the samples were subjected to diametral compression test using a computer coordinated Universal testing machine at 2 hour interval at a crosshead speed of 0.5 cm/min. The results illustrate that the method of Microwave drying of the samples of all the materials could withstand high compressive loads when compared to the other two methods i.e., Air dried and Hot air oven dried methods respectively .And the material Wirovest is considered to be the one with high diametral tensile strengths of all the compared phosphate bonded investment materials. Within the limitations of this study, the Mean Diametral tensile strengths of the Microwave oven dried samples were highest, followed by the Hot air oven dried samples and Air dried samples. The Mean Diametral tensile strengths of the Wirovest material show highest values than Cromocasting fast investment material and Accuvest material.