Computer aided design and manufacturing of dental restorations - “computerized impression” technology

Abstract

CAD/CAM technology (Computer Aided Design / Computer Aided Manufacturing) in the matter of fact helps in design and development of two-dimensional or three-dimensional models and their realization on numerical controlled machines. The key to direct or indirect CAD/CAM dental restorations is the measurement of dental preparation in the mouth or on the plaster die. The aim of this paper is to describe the possibilities and the way of function of different computer aided inspection (CAI) systems as a first part of CAD/CAM systems. Different researchers have presented several approaches of methods for three dimensional (3D) measurement. Today, for chairside dental treatment, only the optical method of measurement has lead to satisfactory results in practice. Laboratory CAD/CAM systems use mechanical and optical technologies for 3D measurement. Optical impression grows as a leader of CAI segment of almost every new CAD/CAM system. The most important properties of 3D scanners are: accuracy, volume and speed of measurement and ergonomy of instrument.

A New 3D Contour Extraction Method for Tooth Cavity in a Dental CAD/CAM System

“…Nowadays, Dental CAD/CAM is an attractive research issue with some successful clinical applications [1][2][3][4][5], in this system, the missing crown or inlay restorations have to be accurately designed and fitted to the tooth articulation after insertion into the tooth cavity [6,7]. Usually, a reasonable approach for the tooth surface design is by picking an appropriate standard tooth from database, then through suitable transformation and adjustment, the missing surface can be reconstructed [7,8].…”

In vitro Comparison of Accuracy of Two Scanners Used in Dental Medicine

“…These scanners are faster than contact scanners, but are affected by the optical properties of the scanned material and require the application of a titanium dioxide powder or spray in order to prevent surface glare, similar to intraoral scanners [12]. Although intraoral scanners directly capture the topography of dental arches, eliminating the need for a conventional impression and/or plaster cast, and thus eliminating the errors induced by these clinical and technical steps, the accuracy of the digital models generated with these scanners may be altered by the complex factors in the oral environment, such as optical properties of teeth, saliva, or the presence of bleeding, but also by the lower resolution of these scanners compared to their laboratory counterparts [13].…”