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The production of dental inlays and crowns requires precise information on patients’ teeth morphology. The conventional method is the preparation of impressions using mold materials, e.g. a silicone impression material. The disadvantage of this technique is the human choke impulse and the flavor of the material. These discomforts can be avoided by methods where a three-dimensional scanner is used for recording the teeth morphology. The present study reveals the accuracy of three model types, namely conventional impression, rapid prototyping using an oral scanner C.O.S., 3M (Schweiz) AG and milling from a proprietary resin using the oral scanner iTero, Straumann Holding AG. For each method five models were fabricated from a steel reference (standard). Using a nanotom m (phoenixǀx-ray, GE Sensing and Inspection Technologies GmbH), three-dimensional micro computed tomography data sets of the standard and the 15 models were recorded and landmark distances within the data sets were measured with sub-pixel accuracy. To verify these results a coordinate measuring machine (Leitz PMM 864, Hexagon Metrology GmbH) based on tactile detection was used for the measurement of the landmark distances, and a correction of the distances measured by the nanotom m was arranged. The nanotom data sets of the 15 models were also compared to the standard by means of a non-rigid registration algorithm. The calculated deformation field exhibited mean pixel displacement values of (0.19 ± 0.09) mm for the C.O.S. models, (0.12 ± 0.07) mm for the gypsum models and (0.19 ± 0.12) mm for the i-Tero models.

ISBN:978-3-86624-476-4

ISBN:3-00-011419-X

We firstly review some approaches to recover the 3D shape of human figures and the related movements. Then we present an improved and reliable version of an easy approach to recover 3D model of humans using just one frame or a monocular video sequence. A simplification of the camera model based on the collinearity condition is required, due to the absence of stereo view. This leads to a perspective or orthographic projection and requires additional information or constraints to solve the problem. The human figure is reconstructed in a skeleton form and visualized with the portable VRML language. Moreover a surface fitting is performed using a predefined 3D model obtained from laser scanner measurements.