Patent EP-1782756-B1 (EP)
Inventor: WEBER GERHARD
IPC: A61C13/08
Filed: 2005-06-10
Granted: 2011-11-30
Abstract: Production of denture parts is effected by using digitally-obtained data of the corresponding tooth space and using such surface and mold data to design the three-dimensional required mold, such procedure taking into consideration a number of specified aspects. Independent claims are also included for: (1) designing web constructions between the tooth stumps and production of the corresponding mold data; (2) graphically representing surface data obtained from a bite impression and, using a gypsum model, forming the denture part; (3) creating the 3-D molding from a combination of geometrical data; (4) creating an implant stud from the surface data; (5) applying on an implant stud a wax model of an abutment using a scanning process controlled by the data so as to form an abutment with jointed upper and lower sides; (6) applying a mark to a graphic representation of the surface data and constructing the mold data for the denture part based on the surface data and taking into consideration the mark; (7) making a rough assembly on the gypsum model using wax, again scanning the assembly and then accurately correlating the two scans; (8) distinguishing variations in the wall thickness of the restoration in a visual display by color gradations or by partially rendering transparent; (9) scanning a cavity to detect the edges, modelling in wax, scanning again, superimposing the two data sets by 3-D matching and deriving a differential data set; (10) proceeding as per the process immediately above but then obtaining the differential data set by overlaying the two scans and filtering out the deviation relevant to the inlay; (11) using a volume differential formation; (12) determining the position of implant studs or screws in a gypsum model by scanning, importing the geometrical data of the implant studs and matching it with the 3-D-determined data and displaying visually and, finally, constructing crown or bridge based on the previous steps and transferring to a CNC machine; (13) arranging primary crowns and their data sets by selecting a visible friction line on a visual display, marking a position or point on the friction line, selecting from this point a range and also the breadth of a position to be altered, drawing the friction line at this point over the selected range above, below, internally or externally and so producing a new topography of the primary cone by retaining the parallel relationship to the plug-in direction or retaining the cone angle; (14) producing primary crowns by 3 + 1 or angular axis milling or grinding; (15) avoiding undercutting using an additional plug-in direction and a milling device; (16) achieving an optimal alignment of the blank to the milling part by 'uphill/downhill' milling; and (17) scanning a modelling wax using a wax with at least 1/3 to 4/5 weight parts of zirconium oxide powder. An independent claim is also included for an apparatus for the above process or processes including in coupled form data processing units, data stores, a visual display unit, feed and output units, data transfer units and a material processing device.