Method for making a numerical three-dimensional model of a structure of soft and hard parts, three-dimensional model and carrier

A method for making a numerical three-dimensional model of a chewing system and the parts surrounding the chewing system, comprising hard parts formed by a bone structure of jawbones and elements of the chewing system and soft parts formed by the gums of the chewing system, wherein the gums have an outer surface, comprising:

• making at least two sections of the chewing system located at a mutual distance by means of penetrating radiation and numerically representing the absorption for the radiation;
• storing in a memory the at least two sections numerically representing the absorption;
• and
• constructing a numerical three-dimensional model of the chewing system on the basis of the at least two sections stored in the memory,
• wherein the step of making the at least two sections comprises:
• custom fitting a form-retaining carrier to a chewing system of a patient such that a geometry contour of the carrier matches at least a geometry of the soft parts of an outer chewing system of the patient, wherein the carrier is manufactured from a material with a low absorption coefficient for the penetrating radiation;
• applying with the carrier a layer of contrast agent to at least a part of the outer surface of the gums of the chewing system of the patient, wherein the contrast agent has an absorption coefficient for the radiation differing substantially from that of the gums, and wherein the contrast agent is mixed with a non-hardening paste and applied in a thin layer to the outer chewing system of the patient, including the portion thereof adjacent to the gums;
• irradiating by the penetrating radiation parts of the chewing system with the thin layer of contrast agent applied to the outer surface of the gums;
• determining the absorption of irradiated parts of the chewing system, the carrier, and the contrast agent from the radiation emerging from the chewing system, the at least two sections numerically representing the absorption of the irradiated parts being determined from the absorption of the irradiated parts;
• and
• subsequently removing the carrier with the layer of contrast agent.