[Impressions].

The less hydrophobic addition reaction silicones and polyethers are preferable in taking elastomeric impressions for cast restorations. Hydrocolloid is the material of choice in case of a large number of preparations. An accurate impression requires a solid tray. A metal stock tray is money-saving compared to the expensive custom tray. Automix dispensing guns offer a number of practical advantages. Success in impression making rather depends on making proper preparations and correct processing than on impression techniques and the quality of the impression material. Crossinfection via impressions can be prevented by immersion in a sodium hypochlorite solution for ten minutes.