Entwicklung und Charakterisierung eines neuartigen introralen 3D-Scanners (IOS) für die restaurative Zahnheilkunde

Abstract

In this work, the development and characterization of a novel intraoral scanner (IOS) is presented, which allows a powder-free direct measurement of teeth without moving parts in the IOS. According to the current state of knowledge, this work demonstrates for the first time that it is possible to realize a practicable and competitive IOS on the basis of chromatic confocal distance measurement. In this thesis, the basic operation of the chromatic confocal distance measurement as well as the methodology for the design of a chromatic confocal multispotsensor is explained. The measurement accuracy and reproducibility of the IOS prototype is determined by 3D-comparison of IOS 3D-data and reference 3D-data (µCT, CMM) taken on a gypsum jaw model with embedded real human teeth and an epoxy resin jaw model with ceramic reference structures. The average accuracy on the jaw model with human teeth is -2.8 μm ± 48.3 μm for a single tooth and between -13.1 μm ± 57.6 μm and -17.9 ± 73.1 μm for three unit bridges. The reproducibility is -0.3 μm ± 23.1 μm (single tooth) and 0.04 μm ± 20.6 μm or 0.2 μm ± 17.6 μm (three unit bridge). The average measurement accuracy ceramic balls +5.9μm ± 23.3μm. The distance deviations of the reference structures on the epoxy resin model are 31.22 microns ± 26.22 microns (four teeth) and 40.85 microns ± 29.72 microns (five teeth). Based on the determined 3D measurement accuracy and precision the conclusion can be taken that the digitization quality of single teeth and three unit bridges fulfills the clinical requirements. This thesis shows that it is possible to realize a chromatic confocal IOS with a very good potential for the use in restorative dentistry.