Comparative study on the fit of Maxillary Complete Denture Bases at the Posterior Palatal Border Made by Heat Cure Acrylic Resin Processed on High Expansion Stone and Type III Dental Stone

Background: The advent of acrylic resins in 1937 was a major breakthrough in the annals of modern dentistry. Their recognition and acceptance in prosthodontics was indeed incredible as they were found to be more aesthetic, easy to manipulate both in the clinic as well as in the laboratory. Aims: To determine the effect of high expansion stone (type V) in compensating the acrylic resin shrinkage compared to type III dental stone. Materials and Methods: A total of 30 edentulous maxillary casts were made from this master mold, out of which 15 were made with type-V high expansion dental stone and another 15 were made from type-III dental stone. These 30 edentulous casts were used for processing the maxillary denture bases. Each acrylized denture base was recovered, trimmed, polished and numbered before its adaptation on the master cast for reading. Results: Analysis of the data revealed that the maxillary denture bases processed on high expansion dental stone casts produced openings along the posterior palatal border that were substantially 39% smaller compared with the denture bases processed on type-III dental stone. Conclusion: The use of high expansion dental stone can be recommended to compensate for the acrylic shrinkage.