<prompt> Material causing minimum tissue distortion is:PolysulphideSiliconeImpression plasterZinc oxide eugenol paste  <response>: Impression plaster is a β-calcium sulfate hemihydrate used at a waterpowder ratio of approximately 0.5 to 0.6. Its fluidity makes it suitable for making impressions of soft tissues in the uncompressed state, a characteristic of mucostatic impression material.Ref: Phillips Science of Dental Materials ed 12 pg 177 