With CAD/CAM technology, the restorative challenge can be much more easily addressed with one simple and predictably successful extra step. The process is called “copy milling” which is precisely what is done. The doctor must first take an accurate VPS type (or digital) impression of the tooth or crown before removal or preparation, (if part of the tooth has fractured away it should be restored with wax or composite to the desired contour) being sure to include several adjacent teeth along with the ridge areas in the impression. Then complete the preparation of the tooth to be restored and take the new master impression for laboratory fabrication. In the lab, we scan in the original tooth contours which fit under the partial, and merge the files with the prepared tooth scan to fabricate the new restoration within tenths of millimeters of the original. The “copy” can be almost perfect if both impressions are accurate. We recommend full contour High Translucency pre-shaded zirconia for this type restoration. The pre-shaded HT zirconia looks very much like premium denture teeth and there is minimal adjusting necessary if copied properly.
The other benefits are significant:
- No additional chairside time is required other than the impression of the existing tooth before preparation
- The patient does not have to go without the partial
- The “copy milling” is an exact process within microns of accuracy chairside adjustments should be almost zero if both impressions were accurate
- No additional lab fee is required