Scanning dental impressions
Systems and methods are provided for scanning a dental impression to obtain a digital model of a patient's dentition as an input to computer aided design (CAD) and computer aided manufacturing (CAM) methods for producing dental prostheses.
1. A computer-implemented method of designing a dental restoration for a patient, comprising:
providing a physical negative impression of at least a portion of the patient's dentition, the physical negative impression comprising an impression tray containing impression material previously molded to the at least a portion of the patient's dentition;
using a computed tomography (CT) scanner system, scanning the physical negative impression to create a three dimensional (3D) virtual image corresponding to the physical negative impression, the 3D virtual image comprising a volumetric density file;
using the 3D virtual image of the physical negative impression, directly constructing a surface image of the at least a portion of the patient's dentition from the 3D virtual image of the physical negative impression without constructing a surface image of the physical negative impression; and
designing a dental restoration for the patient based upon the surface image of the at least a portion of the patient's dentition,
wherein the step of directly constructing a surface image of the at least a portion of the patient's dentition from the 3D virtual image of the physical negative impression further includes:
defining isosurfaces having the same volumetric density value within the 3D virtual image; and
identifying density gradient vectors from the defined isosurfaces.
2. The computer-implemented method of claim 1 , wherein the CT scanner system includes a source of x-ray radiation, an x-ray detector, and a processor connected to the detector, and wherein the step of scanning the physical negative impression further includes:
locating the physical negative impression between the source of x-ray radiation and the x-ray detector; and
rotating the physical negative impression in place as a series of images is captured by the CT scanner system.
3. The computer-implemented method of claim 2 , further including a step of reconstructing the series of images to create the 3D virtual image.
4. The computer-implemented method of claim 1 , wherein the step of directly constructing a surface image further includes constructing a surface image that corresponds with void spaces of the physical negative impression.
5. The computer-implemented method of claim 4 , wherein the surface image includes an upper dentition surface image, a lower dentition surface image, and bite registration information between the upper dentition and lower dentition.
6. The computer-implemented method of claim 5 , wherein the surface image is in .STL file format.
7. A system for designing a dental restoration for a patient, the system comprising:
a source of x-ray radiation;
an x-ray detector;
a processor; and
a non-transitory computer-readable storage medium comprising instructions executable by the processor to perform steps comprising:
reconstructing a series of two dimensional (2D) images collected by the x-ray detector to create a three dimensional (3D) virtual image comprising a volumetric density file corresponding to a physical negative impression of at least a portion of the patient's dentition;
using the 3D virtual image of the physical negative impression, directly constructing a surface image of the at least a portion of the patient's dentition from the 3D virtual image of the physical negative impression without constructing a surface image of the physical negative impression; and
designing a dental restoration for the patient based upon the surface image of the at least a portion of the patient's dentition,
wherein the step of directly constructing a surface image of the at least a portion of the patient's dentition from the 3D virtual image of the physical negative impression further comprises:
defining isosurfaces having the same volumetric density value within the 3D virtual image; and
identifying density gradient vectors from the defined isosurfaces.
8. The system of claim 7 , wherein the step of directly constructing a surface image further includes constructing a surface image that corresponds with void spaces of the physical negative impression.
9. The system of claim 8 , wherein the surface image includes an upper dentition surface image, a lower dentition surface image, and bite registration information between the upper dentition and lower dentition.
10. The system of claim 9 , wherein the surface image is in .STL file format.