Digital shape reconstruction and manufacturing for dental restoration

DESCRIPTION (provided by applicant): The goal of this project is to develop a complete digital shape reconstruction and manufacturing software system for dental restoration. More specifically, this research will deliver innovative algorithms to automatically generate patient-specific tooth shapes and occlusal surfaces. It will also provide computer guidance for high quality restoration through feedback on fit and undercuts. The result is expected to be superior to partial and manual systems in use or known today. It will make a fundamental impact in replacing the century-old craftsmanship by digital manufacturing processes for, inlays, onlays, crowns, bridges, veneers and implants. The benefits of the proposed project are measurable: (i) dentists will receive better quality products and reduce seat time; (ii) dental labs will reduce labor cost and control variability due to human skill; and (iii) patients will be happier with better fit and longer lasting restorations. We will evaluate our solution against state-of-the-art commercial systems and leading academic results. The success of this project will impact research in material science, laser sintering, optical scanning, and NC machining. Aim 1: Optimal preparation line creation. We will develop an algorithm to automatically segment the prepared tooth of a patient, which is represented by 3D scanned data. As a result, a smooth, optimally located, non-branching separation curve defining the preparation line will be obtained. Aim 2: Faithful tooth restoration using full 3D models. Overcoming the deficiencies of former 2.5D approaches, we develop a new, automatic 3D method that uses extended Iterative Closest Point algorithms and warping techniques. It is combined with special morphological steps such as detecting tooth cusps, matching dental features, and prescribing antagonist and proximal contact areas. The novelty of the approach is constrained correspondence between the reference and residual tooth that makes it possible to restore smoothly connected, natural occlusal surfaces. Aim 3: Constrained modification for personalized tooth restoration. We will provide a set of constraint based sculpting and warping tools to satisfy aesthetic or technical preferences. Dental morphology and anatomic rules will be embedded into a system with state-of-the-art shape deformation technology. Aim 4: Automatic shape adjustment for manufacturing and insertion. We will numerically analyze the surfaces of the patient's residual tooth and derive restoration surfaces without manufacturing defects; i.e., we will automatically remove preparation undercuts, add draft angles, compensate for cutter radii and determine angular insertion ranges.