[Setting expansion of dental stone in hydrophilic addition type silicone impression]

The setting expansion of a dental stone poured in addition silicone impression materials was evaluated. Impressions were made of two different addition silicones (hydrophilic and hydrophobic) that had three different consistencies (injection, regular and putty). A dental stone which did not contain any additives was poured in the impressions and the setting expansion of the stone was automatically measured using an electric micrometer and a computer. The setting expansion of the stone that was poured in the impression did not significantly vary with the consistency of the silicones. On the other hand, the setting expansion of the stone in the hydrophilic silicone was significantly larger than that in hydrophobic silicone.