Determination of Surface Hardness of Refractory Cast Investment Materials Before and After Dipping in Wax Hardening Agents

Abstract

Abstract Background: Phosphate-bonded investments resulted in a brittle cast model with a pores surface. Dental Surface hardening agents are then applied to refractory investment materials to enhance its properties. Objective of the study: evaluate the effects of different hardening agents on surface hardness of refractory model investment materials. Material and Methods: Thirty specimens prepared from commercially available phosphate bonded investment material, specimens were evaluated for hardness test before dipping in hardening wax and then divided into three groups according to the type of wax in which they were immersed (Bee’s wax, Carnauba wax, and Ceresin wax). (Each group have10 specimens). Surface hardness test was done by a Micro Vickers hardness device and three readings were taken, the mean was evaluated for the hardness value for all specimens before and after dipping in waxes. Results: The hardness value increased in all specimens after dipping in different waxes, (P value < 0.001 HS highly significant). Conclusion: Conclusion was derived that hardening agents' addition significantly affects hardness of the specimen surface of refractory investment materials.