In contrast to the imprint, optically based techniques are nontactile and hence they allow measuring the same area multiple times to reduce the measurement uncertainty. Optical measurement techniques can drastically reduce the time and risk of measurement errors. 1 The first step toward digital dentistry is already well established by scanning the plaster models that originate from the conventional impression, and manufacturing the restorations with an automated computer-aided manufacturing process (CAD/CAM). It is easy to understand that, between all these steps, many sources for possible errors may occur. The conventional process of impression-taking requires many steps to finally get to the restoration, which is cemented in the patient’s mouth.
In that manner, the production process of a tooth implant is based on a two-step process, which is both very time-consuming and likely to be affected by artifacts when removing the imprint (e.g., incomplete removal of the imprint, mechanical deformation), material inhomogeneities, shrinkage, and errors caused in the casting process.
The impression process can take some minutes, in which the patient, as well as the impression material, should remain in the same position to ensure a good reproduction. The negative imprint is then used to produce a positive copy of the tooth. In the conventional intraoral restoration process, a negative imprint of the tooth, which is also known as a dental impression, is taken by using self-curing elastomers.
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