Development and verification of a novel device for dental intra-oral 3D scanning using chromatic confocal technology

The presented work describes the development and verification of a novel optical, powder-free intra-oral scanner based on chromatic confocal technology combined with a multifocal approach. The proof of concept for a chromatic confocal area scanner for intra-oral scanning is given. Several prototype scanners passed a verification process showing an average accuracy (distance deviation on flat surfaces) of less than 31μm ± 21μm and a reproducibility of less than 4μm ± 3μm. Compared to a tactile measurement on a full jaw model fitted with 4mm ceramic spheres the measured average distance deviation between the spheres was 49μm ± 12μm for scans of up to 8 teeth (3- unit bridge, single Quadrant) and 104μm ± 82μm for larger scans and full jaws. The average deviation of the measured sphere diameter compared to the tactile measurement was 27μm ± 14μm. Compared to μCT scans of plaster models equipped with human teeth the average standard deviation on up to 3 units was less than 55μm ± 49μm whereas the reproducibility of the scans was better than 22μm ± 10μm.