Abstract
The fundamental relationship between the hydrophilicity of rubber impression materials and the setting expansion of dental stones set in contact with the impression materials was examined using α -calcium sulfate hemihydrate, a commercial dental stone and twenty-two commercial rubber impression materials including condensation silicone, hydrophobic addition silicone, hydrophilic addition silicone, polysulfide, and polyether families. The contact angle of water on the sample of the impression material, the weight change of the sample of the impression material after immersion in water, and the dimensional change of the sample of the impression material in water were measured. Moreover, the setting expansion of the dental stone set on the sample of the impression material was recorded, and compared with the measured values. A very significant negative correlation was found between the contact angles and the setting expansions. On the other hand, neither the weight changes nor the dimensional changes correlated with the setting expansions significantly. The relationship between the hydrophilicity of rubber impression materials and the setting expansion of dental stones were examined in detail based on the obtained multiple-linear-regression equations and other results.
