Digitization procedure of creating 3D model of dental bridgework reconstruction

Purpose: The still growing patient requirements is concerned with aesthetics but also with strength of the prosthetic restorations. Resistance on stresses depends among others on the shape, so it is necessary to transfer the dentures of a physical model to a computer environment and a simulation of the work conditions. The aim of that work was to study the methodology of digitization of a plaster model into a numerical model, using CAD/CAM dental system and CAD application, which can be in a next step imported to ANSYS application in order to realize stress analysis. Design/methodology/approach: To realize the transfer of a physical model of the dental bridge to a computer environment the 3i Incise Renishaw scanner which saved the plaster model by a probe about 1 or 3 mm diameter, moved in the scanner arm and contacted with it was used. A scanned plaster mode was exported into STL file and then opened in DentCAD Delcam application. Using the CAD module the preparation line was marked, a pontic was orientated in a right position and connectors of the pillar teeth and the pontic. Geometry and the cross section of the connectors depend on the bridgework strength. A designed bridge reconstruction was imported to CAD application and there curves were firstly drawn, then changed into NURBS surfaces and finally surfaces were merged into one solid model. A ready model can be imported up to ANSYS software in order to realize the stress analysis. Findings: A prepared dental case from a physical one was changed into a numerical model in following steps: scanning a plaster model by a contact scanner, designing the bridgeworks in CAD dental software environment, importing in CAD application, building the solid model and at the end importing in ANSYS software. Selected digitization procedure let to make all engineering calculations and analysis without manufacturing the physical model, what considerably reduce cost of the research investigations. Practical implications: A realized work gave an information about possibilities of verification for a physical model of restoration and a numerical model which can be compared to results from software simulation of behaviour of the bridgework in different load cases. Originality/value: The paper presents that it is not necessary to have a physical reconstruction model, to check the resistance on stress because it is possible to use the CAD/CAM dental system to design the dentures and then modelling the boundary conditions and observe the stress analysis.