A successful dental prosthesis or a restoration is mainly dependent on the accuracy of the dental impressions. An impression is an imprint produced by „the pressure of one thing upon or into the surface of another‟ or the negative likeness. It is not technically possible or desirable to fabricate prostheses or restorations directly in the patient‟s mouth. Therefore it is essential to obtain a cast or a model which must be accurate replicas of the denture bearing area or the prepared tooth/teeth in the mouth.
It is very important that the clinician selects an appropriate impression technique and materials to accomplish this task. The accuracy of the cast depends on the properties of the impression materials, impression techniques used and the properties of cast and die materials. Each technique and the material has its advantages and drawbacks. While an ideal material and the technique is yet to be developed it is apparent that the clinician is bound to select the most appropriate material and the technique based on evidence. This paper summarizes the techniques to be adopted in removable and fixed prosthodontics based on available evidence.