Metal backings for denture teeth

Dental technology DANIEL

H. GEHL and

Metal

backings

S. HOWARD

for denture

PAYNE,

Associate

Editors

teeth

Horst Buckner, C.D.T., and William E. LaVelle, University Hospitals, Iowa City, Iowa

D.D.S.

S

ingle or isolated groups of denture teeth should be protected from excessive lateral or protrusive forces by cast metal backings to prevent fracture. Most commonly, interchangeable acrylic resin or porcelain facings are used. Platinum long-pin teeth are preferred in Europe for this purpose. The following is a simple and inexpensive procedure by utilizing readily available denture teeth. TECHNIQUE

FOR ACRYLIC

RESIN DENTURE

TEETH

1. Make upper and lower impressions in the usual manner. 2. Pour casts in the upper and lower impressions. 3. Make jaw relation records. 4. Mount the casts to these records in an articulator. 5. Choose the teeth according to shade, size, and contour. 6. Set up the teeth in wax, and try them in the mouth. 7. Secure the teeth in position in a plaster key. 8. Grind the lingual surface of each tooth according to the relationship of the antagonists and to the adjoining teeth. Allow enough space for metal backings. 9. Fill any undercuts on the lingual surface of the teeth with wax, and carve the wax according to the adjoining teeth. 10. Remove the plaster key. The denture teeth remain on the cast. 11. Survey the master cast, and duplicate it. 12. Pour a refractory cast. 13. Wax the removable partial denture framework on the refractory cast. 14. Adapt a 0.6 mm. wax sheet to the lingual surface of the duplicated denture teeth, and add more wax to create denture teeth anatomically similar to the adjoining teeth. 15. Invest, cast, and finish the partial denture framework. 16. Bend retention loops from 1.0 mm. round wire, and spot weld and solder the loops to the metal backings (Fig. 1). Polish the partial denture framework. 17. Place the denture teeth into the plaster key, and mark the loops with an indelible pencil. 579

580

Buckner

and Lavelle

Fig. 1. A sagittal section illustrates the cast metal backing, retention loop, and additional win* retention for pink acrylic resin. Fig. 2. A sagittal section of a porcelain denture tooth on the master cast illustrates the preparation of the lingual surface with wax before duplicating the cast.

Fig. 3. The finished removable partial denture.

18. Place the removable partial denture casting on the cast. 19. Press the plaster key with the teeth against the wire loops. 20. With a separating disc, grind slots into the lingual surfaces of the teeth at the indelible pencil marks. 21. Create undercuts in the slots with a small bur. 22. Cover the loops and the metal backings with a thin layer of cold-curing opaque acrylic resin to prevent discoloration of the teeth. 23. Paint the master cast with a separating medium. 24. Fill the slots and the retention loops with a thin mixture of tooth-colored cold-curing acrylic resin, and press the key in place. Polymerize the resin in a pressure pot.

Metal

backings

for

denture

teeth

581

25. Process the remainder of the denture in the usual manner with heat-curing acrylic resin. Additional bent retention wires may be soldered to the backings for the pink acrylic resin used to replace the resorbed ridge (Fig. 1). TECHNIQUE 1. 2. 3. 4. 5. acrylic 6.

FOR PORCELAIN

Follow steps No. 1 Fill any undercuts Cover the crampons Duplicate, cast and Fasten the denture resin. The finished partial

DENTURE

TEETH

through No. 7 for acrylic resin denture teeth. on the lingual surface of the denture teeth with wax. with wax, and carve as demonstrated in Fig. 2. finish the removable partial denture framework. teeth to the metal backings with tooth-colored cold-curing denture

is fitted on the master cast (Fig. 3).

SUMMARY A technique is described for the fabrication acrylic resin or porcelain denture teeth.

of protective

DEPARTMENT OF OTOLARYNGOLOGYAND MAXILLOFACIAL SURGERY UNIVERSITY HOSPITALS IOWACITY,IOWA 52240

metal

backings

for