EOS GmbH recently showcased a new Additive Manufacturing (AM) process at the IDS 2013 (35th International Dental Show), Cologne, Germany, for producing removable partial dentures (RPD). The technique uses 3D data sourced directly from the patient’s mouth as the basis for the manufacturing process.
Data created by intraoral scanners or from scanning an impression or model is processed without any loss of accuracy using the customised software functions of the new CAMbridge 2012 RPD module from 3Shape. The resulting virtual model is sliced and the digital information is utilised to direct a focussed laser beam to fuse metal powder in successive layers until the prosthesis is complete.
For a dental laboratory, the conventional manufacture of cast prostheses involves a lot of work. The preparation of a cast model and subsequent wax modelling often takes more than an hour and the entire casting procedure including finishing is laborious and time-consuming.
The digital AM production method, by contrast, saves a lot of time, as the design for the RPD is ready in around 15 minutes. Due to the flexibility of design possible with Direct Metal Laser-Sintering (DMLS), the manufacturing process does not restrict the capabilities of the modelling software. High strength, rigid parts are produced.
The production of RPD’s via DMLS is very accurate, making laboratory work easier. The denture is produced to an accuracy of ± 20 µm and is of a consistently high quality. Around 48 units can be produced within 24 hours, corresponding to an average build time of around 30 minutes per unit, making the process economical.
RPDs are made in the established EOSINT M 270 machine from EOS. Certified for use in the dental industry (CE 0537), EOS CobaltChrome RPD is the powder metal used. It is a fine grained, biocompatible material free from nickel, beryllium and cadmium. Its mechanical properties including density, resilience and elongation at break satisfy the requirements of the standard EN ISO 22674:2006 Type 5.
Martin Bullemer, Business Development Manager Medical at EOS, stated, “A dental laboratory using EOS AM for manufacturing removable partial dentures will gain a commercial advantage over a competitor using the conventional approach.”
“The time saving, design-led method offers a more precise manufacturing route using an economical and certified process chain employing a material exclusively developed for this application, allowing RPDs to be produced at comparatively low cost.”