With three-dimensional (3D) analyses, every step of the CAD/CAM process chain can be assessed, from intraoral digitizing or impression-making to the resulting dental restoration. The individual errors can cancel or mutually reinforce each other. CAM precision also depends on the quality of the machining components 1,31.Įvery step in the CAD/CAM process chain can add to the resulting manufacturing error. Regardless of the digitizing technology applied, digitization quality affects precision in the CAD/CAM process
Furthermore, extraoral digitization always includes the errors introduced by impression and gypsum model-making in addition to the error resulting from digitization 27. However, conventional impressions of the full arch are also subject to greater deviation than those of single teeth. This process, termed matching, will always introduce a small systematic error to the data of any measuring system. As a result, several digital data sets must be obtained and combined to capture more than two to three neighboring teeth when using intraoral digitizing devices. Because of space restrictions, intraoral digitizing devices have a smaller measuring area than extraoral digitizers. These factors, which include moisture (saliva, blood), movement of patient and dentist, and restricted space in the oral cavity, can also impede intraoral digitizing. Clinical parameters have the greatest impact on the quality of dental impressions Both methods of data capture have advantages and disadvantages. An ever more widely applied alternative is intraoral digitization 7, 28, which allows practitioners to dispense with conventional impressions and gypsum model fabrication. The resulting gypsum model can be digitized extraorally Subsequently, dental stone is poured into these impressions. Conventionally, high-precision condensation-curing or addition-curing impression materials are used to make dental impressions.
The CAD/CAM process chain starts with taking an impression of the clinical situation, for example, by capturing a patient’s prepared tooth or teeth. Sophisticated high-strength materials, such as zirconium oxide, which can only be processed using CAD/CAM technologies, and generative (additive) technologies, such as rapid prototyping, require digital data as the key to apply any CAD/CAM process Computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies allow the use of a range of manufacturing methods and materials for dental restorations.
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