The Dental Labouratory is led by Josef Schweiger, who is the author of more than 50 international and 300 national publications, including a 2022 report on the application of 3D-printed, coloured models for the fabrication of full ceramic restorations using Stratasys Polyjet technology. Schweiger, who has been interested in additive manufacturing for more than 20 years, focused on ceramics and implant restorations as a Certified Dental Technician (CDT) before becoming the head of the Dental Labouratory at LMU University Hospital in Munich in 1999.
Schweiger began using Stratasys technology in 2013 when his team at LMU, with the help of Gerhard Kräutner, M.Sc.Eng., produced a multilayer tooth for the first time using multi-material 3D printing.
Today, Schweiger said, with the new 3Shape Colour Workflow there are vast possibilities to produce esthetically-pleasing, natural-looking dental restorations because of the ability to record geometry-related colour information of individual points with intraoral 3D scanners.
“Colour models give dental technicians the ability to provide intraoral colour information in addition to three-dimensional information on the jaw’s geometry,” Schweiger said. “They are a ‘killer application’ that can’t be produced using a traditional analog physical impression with a plaster model.”
Traditional plaster models, which are produced by pouring analog jaw impressions, cannot convey colour information. The colour is specified by the manufacturer, so it bears no relation to other conditions in the mouth, including the gingival areas, Schweiger said. He also pointed out a few more opportunities for error in the traditional analog workflow, which starts with taking a physical impression of the patient’s mouth, compared to the 3D printing process.
“If areas of the impression weren’t moulded correctly, or if bubbles and pulls can be seen, the impression must be repeated,” Schweiger said. “This is uncomfortable for the patient, plus, repeating an impression costs time and money, and it’s not uncommon to take multiple physical impressions.”
Schweiger and his team members use the 3Shape colour workflow and Stratasys PolyJet printers to create true-colour, realistic, 3D models when manufacturing restorations where colour is important, including crowns, inlays, onlays, veneers, and bridges. With this workflow, users can scan and capture every part of a patient’s mouth.
“The 3Shape colour workflow delivers unparalleled added value for labouratories and patients,” Schweiger said. “It’s important that the colour of dental restorations matches a patient’s actual teeth so that it integrates naturally into the oral cavity. Patients don’t want teeth that look ‘fake,’ so dentists and dental technicians need to create highly-accurate colours for dental restorations. 3D printed colour models offer unprecedented possibilities for natural-looking dental restorations.”
The future value of colour in digital dentistry
As it becomes easier to transmit photorealistic information about the colour of the teeth and gingiva, Schweiger said, it will also become possible to consider more aspects of dental restorations that can be improved.
“In the future, intraoral optical scanning technologies will be able to record the tooth layers — like the dentine area and outer enamel surface — three-dimensionally, and then provide the data for multilayer, 3D-printing of dental restorations,” Schweiger said. “In addition to producing highly esthetic crowns and bridges, excellent solutions will also be possible in the area of full and partial dentures, for example.”
Seamless colour workflow for 3D printing dental models
Stratasys has partnered with 3Shape, the market-leading developer and manufacturer of 3D scanners and CAD/CAM software solutions for the dental industry, to develop an end-to-end colour workflow for dental models. This new interface and the power of PolyJet printing allow users to easily colour match the restoration to the patient’s teeth by accurately replicating teeth, stump, and gingiva shades from an intraoral scan.
Hands off, end-to-end solution: Once the lab receives the scans, users can program their printer to automatically produce coloured models without spending any additional hands-on time at the printer.
Patient-specific models: This new workflow automatically matches colours with intraoral scans to produce the most realistic, patient-specific models.
Better communication: Colour models facilitate communication between dental labs, dentists, and patients, and make it easier for dental technicians to complete high-aesthetic restorations like crowns and bridges.
