As the accuracy of an impression affects the accuracy of the cast, a precise impression is needed in order to create prosthesis with optimal fitting. A misfit in the prosthesis influences the pattern and magnitude of stress distribution in the prosthesis itself. Minimizing the misfit and optimizing the passive fit through variation in impression techniques and impression materials is an important aim in prosthesis science and dental implants. Digital impressions offer speed, efficiency, ability of storing captured information indefinitely and transferring digital images between the dental office and the laboratory. The advantages of the digital impressions and scanning systems are improving patient acceptance, reducing the distortion of impression materials, 3D pre-visualization of tooth preparations, and potential cost- and time-effectiveness.This topic will focus mainly on the digital impression techniques in prosthodontics, working principles of the scanners and data aquisation.