[The conventional and the digital impression method for single-unit and multi-unit fixed dental prostheses].

To manufacture single-unit and multi-unit fixed dental prostheses, an accurate cast is required. Casts can be obtained either by the conventional or the digital impression method. For both methods, dry tooth surfaces and a well exposed finish line of the tooth preparation are required. The conventional impression method requires an elastic impression material. Elastomers have a high detail accuracy, which can produce, in combination with a good fitting and rigid impression tray, an impression with reliable dimensional stability. Based on the number of different impression material consistencies used and the number ofphases of the impression procedure, several options of the conventional impression method can be distinguished. For the digital impression method, teeth or implants are scanned to produce a digital cast which can be used directly with the help of computer technology to produce single-unit or multi-unit fixed dental prostheses. The digital impression method has a number of advantages when compared to the conventional impression method, but is not applicable for all prosthetic cases.