Haptically enabled dental modeling system

A method for designing a three-dimensional dental restoration, the method comprising the steps of:

• (a) creating an initial 3D computer model from a scan of a dental stone made from an impression of a patient's mouth, or, alternatively, creating the initial 3D computer model from a direct scan of the patient's mouth;
• (b) automatically adding virtual block-out wax via a processor, or semi-automatically adding virtual block-out wax via a user interface, to an undercut portion of the initial 3D computer model based at least in part on a geometry of the initial 3D computer model and a direction of insertion of the three-dimensional dental restoration,
• (c) joining the initial 3D computer model and the added virtual block-out wax, thereby forming a virtual refractory model, wherein the initial 3D computer model and the added virtual block-out wax of the virtual refractory model are separately stored volumes that are combined with a volumetric union operation to produce the virtual refractory model;
• (d) adding virtual design wax onto the virtual refractory model to define a final 3D computer model of the dental restoration;
• wherein the undercut portion is automatically identified based at least in part on the geometry of the initial 3D computer model and the direction of insertion of the three-dimensional dental restoration.

An apparatus for preparing a virtual refractory model in a design of a three-dimensional dental restoration, the apparatus comprising:

• (a) memory that stores code defining a set of instructions;
• and
• (b) a processor that executes said instructions thereby to:
• (i) create an initial 3D computer model from a scan of a dental stone or a patient situation;
• (ii) automatically add virtual block-out wax via a processor, or semi-automatically add virtual block-out wax via a user interface, to an undercut portion of the initial 3D computer model based at least in part on a geometry of the initial 3D computer model and a direction of insertion of the three-dimensional dental restoration;
• and
• (iii) update the initial 3D computer model to incorporate the added virtual block-out wax upon a user command, thereby preparing a virtual refractory model onto which a virtual wax object corresponding to the three-dimensional dental restoration can be built, wherein the initial 3D computer model and the added virtual block-out wax of the virtual refractory model are separately stored volumes that are combined with a volumetric union operation to produce the virtual refractory model, wherein the undercut portion is automatically identified based at least in part on the geometry of the initial 3D computer model and the direction of insertion of the three-dimensional dental restoration.