CAD/CAM - international magazine of digital dentistry

36 I I industry report _ therapy splints a jaw movement analysis system (zebris TMJ, Schütz Dental) to the splint construction. In the following step, the vertical length of the splint is defined using a preparation margin (Fig. 5). The minimum thickness of the splint is specified individually. It is very important, how- ever, to create visible impressions in the occlusal areas. The dynamic occlusion (working and bal- ance contacts, as well as protrusive movements) is ground gradually by clicking on the mouse. Finally,anyexcessmaterialintheocclusalarea is removed, and the positioning of the incisors and canines is corrected if necessary. After- wards, the workflow can be closed (Figs. 6–9). The open STL (Surface Tessellation Language) interface enables the user to mill the generated file in-house with a five-axis milling system, for example with the Tizian Cut 5 smart (Schütz Dental). The material of choice for therapy splints is a transparent blank made of PMMA, for example a Tizian Transpa (PMMA) blank (Schütz Dental). I discourage the use of a three- or four-axis milling system because such sys- tems cannot provide the precision necessary for the production of a therapy splint. Anothersimpleoptionforproducingthesplint is sending the dataset to a milling centre to have the splint milled there. The finished splint will ar- rive at the laboratory only two working days after sending the STL dataset to the milling centre. The remarkably high precision of the splint becomes obvious when first placing it on to the situation model (Fig. 10)—no matter whether it was milled in-house or industrially, or whether it was printed. Nonetheless, all occlusal contacts and movements (laterotrusion, protrusion) must be checked with an articulator and corrected if necessary. Finally, the CAD/CAM-produced therapy splint is finished conventionally with polishing paste and a linen buff (Fig. 11)._ Figs. 9a & b_STL file of a finished therapy splint with occlusal contour. CAD/CAM 2_2013 Daniel Kirndörfer,DT Praxislabor edel & weiss Ludwigsplatz 1a 90403 Nuremberg Germany Tel.:+49 911 56836360 kirndoerfer@edelweiss-praxis.de www.edelweiss-praxis.de CAD/CAM_contact Fig. 11Fig. 10 Fig. 9bFig. 9a