11. Align the denture parts on the cast and hold them in place with sticky wax at the posterior edges (step F).

12. Prepare the self-curing acrylic resin.

13. Moisten the brush with monomer and dip it into the polymer (powder), and apply it to the fractured area. Repeat this procedure until the fracture is covered and slightly overfilled.

14. Allow the denture to stand for a few minutes until the sheen of the resin disappears from the surface.

15. Place the denture and the cast in a pneumatic curing unit (step G).

16. Cover the denture with lukewarm water (115°F) and secure the lid.

17. Attach the rubber tubing to the air valve on the lid and till with compressed air to 20 psi.

18. The curing process will take 30 minutes. Note: If a pneumatic curing unit is not available, place denture and cast in a bowl of lukewarm water for 30 minutes or until the resin hardens. This is not the recommended procedure but may be used in emergencies.

19. Gradually turn the air release valve on the lid to relieve the inside pressure. When the pressure gauge reads zero, carefully remove the lid.

20. Remove the repaired denture base from the pressure pot.

21. Using a denture bur, trim all excess acrylic from the denture (step H).

22. Polish the external surfaces with pumice and a muslin or brush wheel that is mounted on a bench lathe. If a lathe is not available, you may use a mandrel- mounted wheel on a straight handpiece.

23. Disinfect and place denture in a prosthetic bag with water for delivery.

DENTURE TOOTH REPAIRS

The original tooth can be reattached if it is still intact, but some repairs will require a new denture tooth. The following procedures describe simple denture tooth repairs that do not involve the facial denture base plastic (complex fracture). The example given is of an anterior tooth that fell out. If the facial denture base plastic needs repair, a prosthetic technician or a dental officer will perform the repair. To accomplish a denture tooth repair, perform the following steps (A-F) as shown in figure 8-41:

1. Roughen the lingual aspect of the acrylic teeth to guarantee good chemical bonding with the repair material. Use an inverted bur to undercut a hollow opening in the lingual aspect of the acrylic tooth.

2. Make a box preparation (step A) in the denture base, lingual to the tooth to be repaired.

3. Position the tooth (step B) in its seat and sticky wax it in place from the lingual.

4. Construct a plaster cast facial matrix to hold the tooth in position during repair. It should include the tooth that is being repaired and the tooth on each side (step C).

3. After the plaster has set, remove the matrix and clean all wax from the box preparation (step D).

6. Paint the matrix with a tinfoil substitute (step E).

7. Reassemble the denture, the tooth, and the matrix in correct aligment. Sticky wax the tooth to the matrix, and the matrix to the denture (step F).

8. Place self-curing resin to the repair area in the same manner as described in the denture base repair section. Build up the repair resin slightly higher than the surrounding denture base.

9. Place the tooth repair in a pneumatic curing unit and follow the same steps as described in the denture base repair section for curing, finishing, and polishing.

10. Disinfect and place the repaired denture in a prosthetic bag with water.

PROSTHODONTIC CHAIRSIDE ASSISTING

The basic clinical procedures are essentially the same as in all direct patient care in dentistry. The prosthodontic procedures, sequence of treatment, and materials required vary with the specific treatment requirements for the patient and the individual dentist. This section covers the basic chairside duties a prosthodontic assistant performs with a dentist. In-depth techniques and procedures should be learned from on-the-job training.

Most prosthodontic cases require a series of appointments. It is your duty as the assistant to schedule these appointments. Two basic factors influence the scheduling of prosthodontic patients:

The procedures to be done during the appointment