The case involved a patient with a large amalgam on tooth #2 that had recurrent decay. Tooth #2 was an abutment with rest seat for an existing partial upper denture (PUD) that replaced some front teeth. Therefore, any new restorations must be retrofitted to the existing PUD, otherwise the new PUD is required. Typical procedure would require a final pickup impression, and the dental lab would hold on to the existing PUD for the duration of the fabrication (one to two weeks), in order to retrofit the new crown to the existing PUD.
However, patient is highly depended on the existing PUD for confidence and without PUD to replace the missing front teeth, it would be devastating to patient's social life. Due to this special situation, I communicated with our local PreTech Lab technician to make special arrangement for patient. The lab technician agreed to give priority to the fabrication of the master cast and give the existing PUD back to patient the same day; but the patient must also visit the PreTech again when the lab technician would be layering the porcelain. Because PreTech is a local dental lab that is only 10 minutes away, this arrangement was feasible.
A crown fabricated to retrofit an existing partial denture requires extraordinary precision and skill in comparison to a typical crown without existing partial denture. Not only must the inner surface fit to the tooth preparation, the outer surface of the crown must also fit to the existing PUD. Because this PUD has a flexible retentive clasp for retention, and so, the high of contour and amount of undercut must fit both the reciprocal clasp, the retentive clasp and the guide plane.
The final delivery of this case was a success. Careful adjustments were needed during the delivery appointment as expected. Nevertheless, our patient was happy and satisfied. Kudos to PreTech for the special arrangement which made this case possible.