Evaluation of Linear Dimensional Stability of Various Combinations of Dental Stone and Plaster
Background: It has been observed that due to the cheaper cost of dental plaster compared to dental stone, casts on which most of the dental prostheses and appliances were being fabricated in various laboratories were often mixtures of dental stone and dental plaster in order to reduce production cost. Objective: To evaluate the dimensional stability of various combinations of Dental Stone and Dental Plaster mixtures used to make dental casts. Methods: Alginate impressions of a master model of truncated metal cones were made and casts were produced by pouring with various combinations of dental stone and dental plaster mixtures. The linear dimensional differences between the inter-abutment distances on the casts were measured with an electronic calliper. One sample t-test and percentage differences were calculated. Results: Dimensional variations for the distances measured using either 50% dental stone or 25% dental stone with plaster were statistically significant (p d" 0.05). Mixture of 75% dental stone and 25% dental plaster produced casts with no statistically significant dimensional variation from the master model (p en0.05). Conclusion: A mixture of 75% dental stone and 25% dental plaster could be used for procedures not requiring very accurate replica like mounting of teeth for dental training and for study models.