INTRAORAL SCANS FOR CAD / CAM APPLICATION
2 . Material and methods The Department of Prosthodontics , Faculty of Dentistry , Semmelweis University has been working with digital impression-taking systems since 2011 . Digital technologies and their novel materials have been introduced into the department ’ s undergraduate dental curricula . A Bachelor of Science digital dental designer training program is also aimed at the Faculty of Dentistry SU in cooperation with the Neumann University of Technology and Economics to modernizate the classic profession of dental technician . A series of articles has been published in the Hungarian dental paper in 2017 as part of the continuing education program to educate Hungarian dentists about digital dentistry . This paper gives a summary of the digital dentistry series .
3 . Results In 2018 all four Hungarian dental schools teach digital technology , they give lectures and demostrations and 50 % have also practical training . All four dental laboratories of those schools use some digital techniques ( Fig . 1 ). Dental technology educational programs are faced with serious challenges , including rapid changes in technology , inadequate funding for educational programs , and the need to develop curricula that reflect current industry needs [ 3 ]. The high cost to purchase equipment and the investment of time and expense in staff training encourages nonuniversity educational systems and trainings . Manufacturers and commercial dental laboratories offer a selection of continuing education courses for international dentists . Some courses are accredited by universities and the participants are awarded certificates and European Credit Transfer System ( ECTS ) credits [ 4 ]. Online knowledge centers and webinars provided by manufacturers offer promising new opportunity for self-education [ 5 ]. Digital technology introduced new nomenclature for dental procedures : digital workflow , CAD / CAM systems , indirect CAD / CAM impression technique , direct CAD / CAM impression technique , digital impressions , virtual casts , intraoral scanners , close or open systems , charside or labside systems . These elements are drafted in italics in the following text .
3.1 . Digital workflow 3.1.1 . Indirect CAD / CAM method The digital workflow starts with a device which is suitable for mapping real forms . Indirect CAD / CAM method is built on conventional impressions . The virtual cast is created by digitizing the gypsum cast ( or the conventional impression ) with a laboratory scanner [ 6 ] ( Fig . 2 ). The virtual cast is a realistic , colorful digital model of the patient ’ s oral cavity . This method has some distorting effects enclosed : conditions of impression-taking , material properties of alginate , silicone or gypsum ( shrinkage of impression material , dilation or shrinkage of gypsum ) and sectioning of casts . Furthermore , the laboratory scanner has some degree of distortion . The laboratory scanner creates a 3-dimensional set of points based on information of the sectioned cast .
Figure 1 . Dental students practice digital impression taking at the Department of Prosthodontics of Semmelweis University , Budapest .
Figure 2 . Laboratory scanner creates a 3-dimensional set of points by information of sectioned cast or impression .
Figure 3 . CAM ( Computer-Aided Manufacturing ) machine milled crowns from zirconia block .
The computer makes the virtual cast that serves as basis for CAD / CAM workflow . During CAD ( Computer- Aided Design ) the dental technician designs dental restorations , most often crowns , veneers , inlays or onlays and bridges . The CAD software enables the technician to design the framework of the restorations or the anatomical , final form . Applying CAM ( Computer- Aided Manufacturing ) the restorations are milled from solid blocks with dental milling CNC machines ( Fig . 3 ). There are different types of materials to mill : ceramics , zirconia , PMMA , metal alloys or titanium .
3.1.2 . Direct CAD / CAM method The Direct CAD / CAM method means that the digital
Original Article
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