Layer-based abrasive computer tomography techniques for custom dental restoration

Fixed partial denture produced by conventional method is greatly relied on the skill and experience of dental technician. Its quality and accuracy depends mostly on the technician´s subjective judgment. In addition, the manual process involves many procedures which require a long time to complete. Most important, it does not preserve any quantitative information for future retrieval. In this paper, a new device for scanning denture images and reconstructing 3D digital information of dental model by abrasive computer tomography (ACT) was designed in-house and proposed. The fixed partial denture was then produced by the rapid prototyping (RP) and computer numerical control (CNC) machining methods based on ACT scanned digital information. A force feedback sculptor (FreeForm system, Sensible Technologies Inc., USA) accompany with 3D Touch technology was applied to modify the morphology or the design of denture. It enables the dentist to perform digital manipulation of denture profile with real-time and user-friendly human interactive operation without relying on CAD/CAM technician or dental technician. In this article, the comparison of conventional manual operation and digital manufacture using both RP and CNC machining technologies for denture production was presented. In addition, a digital custom denture manufacturing protocol integrating proposed computer abrasive teeth profile scanning, computer-aided denture design, 3D touchable force feedback feature modification and advanced denture manufacturing techniques were suggested. These proposed methods provide a solid evidence that digital design and manufacturing technologies may become a new avenue for custom-made denture design, analysis, and production in 21st century.