Constructing cast crowns to fit existing removable partial denture clasps

FIXED PROSTHODONTICS OPERATIVE DENTISTRY DAVID WILLIAM

E. BEAUDREAU, LEFKOWITZ,

SAMUEL

Constructing partial Albert Louisiana

cast

denture T. Goldberg, State

E. GUYER,

Section editors

crowns

to fit

existing

removable

clasps D.D.S., M.S.,*

University,

School

and

Rex D. Jones,

of Dentistry,

New

D.D.S.** Orleans,

La.

E

scalating costs in today’s economy obligate dentists to encourage patients to maintain their restorative dental care and avoid unnecessary additional expense. For example, proper fabrication of cast crowns under existing serviceable removable partial dentures obviates modifying or remaking the denture.’ This article presents a simple, precise method for making a cast crown that fits an existing partial denture clasp. The crowns can be completed in two visits without depriving the patient of his denture. Before proceeding, an examination must be made to determine that ( 1) the oral tissues adjacent to the partial denture are healthy, (2) the partial denture is serviceable, and (3) the abutment tooth is periodontally sound.’ FIRST APPOINTMENT (1) If necessary, recontour the clinical crown to better accept the partial denture clasp. Use a diamond cutting instrument to adjust rest seats, guiding planes, and retentive surfaces of the crown. Use a basing material to repair voids in the natural crown resulting from decay, fracture, or breakdown of existing restorations. (2) With the removable partial denture out of the mouth, make a quadrant rubber-base impression of the recontoured tooth (Fig. 1) . This impression is used to form a temporary acrylic resin crown and serves as a rubber mold for shaping the final crown pattern. (3) Prepare the recontoured tooth for a cast crown (Fig. 2), and check for sufficient tooth reduction by placing the removable partial denture in the mouth. (4) Retract the gingiva, and make a second quadrant rubber-base impression of the prepared tooth (Fig. 3). Th is impression will be used during the laboratory phase to pour both a stone die and master cast for fabrication of the crown pattern. (5) Use the first rubber-base impression to make a temporary acrylic resin crown *Associate Professor, Department of Fixed Prosthodontics. **Assistant Professor, Department of Fixed Prosthodontics. 382

$d~m&6 u

Cast crowns

Fig.

1. A quadrant

Fig.

2. The

rubber-base

completed

Fig. 3. Rubber-base Fig. 4. A temporary

crown

impression preparation

impressions acrylic

that after

includes pin

of the recontoured resin

crown

fitted

to fit existing denture

the recontoured

amalgam

tooth under

the

clasps

383

tooth.

buildup.

and partial

(Zeft) prepared denture

tooth

clasp.

to be worn under the patient’s partial denture (Fig. 4). Ney indicating spray” aids in adjusting the temporary crown into the partial denture clasp. LABORATORY

PHASE

( 1) Make two pours of hard die stone into the second rubber-base impression. The first pour is sectioned and trimmed into an individual die for carving the gingival margins of the crown pattern. The second pour is sectioned so that the prepared tooth has at least one tooth on either side. This is the master cast that will be placed into the rubber impression (Fig. 5). (2) Lubricate the individual die, master cast, and rubber impression. Place Duralayt or melted inlay wax into that part of the rubber impression that records *The

J. M.

tReliance

Ney Dental

Company, Manufacturing

Bloomfield,

Conn.

Company,

Worth,

111.

384

Goldberg

and Jones

.J. Prosthet. October,

Dent. 1976

Fig. 5. The second rubber-base impression, stone master die, and master cast. Fig. 6. The rubber-base impression with melted inlay wax in the location of the prepared tooth.

Fig. 7. The master cast seated into the rubber-base impression containing the master die for pattern finishing. Fig. 8. The final wax pattern finished on the stone master die.

melted inlay wax and

the prepared tooth (Fig. 6), and quickly seat the master cast into it, Hold these securely together until the Duralay or wax is set (Fig. 7). (3) Separate the master cast from the rubber impression. The pattern will be retained either in the rubber impression or on the master cast. (4) Complete the contour of the pattern by placing it on the individual die, adding more inlay wax to the gingival margins and repairing all voids (Fig. 8). Care must be taken not to disturb occlusal or axial surfaces involved with retention or support of the partial denture clasp. (5) Sprue the completed pattern on a proximal surface not contacted by the denture clasp. Invest the pattern, burn out the mold, and cast. Semifinish the casting with a rubber lvheel before trying it in the patient’s mouth.

ifzkE2

Cast

crowns

to fit existing

Fig. 9. The casting seated with the occlusion and proximal contacts Fig. 10. The crown sprayed with Ney indicating spray during

denture

clasps

385

adjusted. trial

seating

denture

clasp.

of the

partial

denture.

Fig. 11. The completed

crown

fitted

to the partial

SECOND APPOINTMENT ( 1) Seat the casting on the prepared tooth, and adjust the proximal and occlusal contacts (Fig. 9). (2) With the partial denture in place, adjust the fit of the casting into the denture clasp (Fig. 10). Ney indicating spray is helpful for adjusting the fit of the crown into the denture clasp. (3) Give the cast crown a final polish, and cement (Fig. 11).

SUMMARY A step-by-step procedure has been presented for fabrication of a cast crown to fit an existing partial denture clasp. The procedure can be accomplished in two appointments, and the patient need not be subjected to the inconvenience of being without the partial denture between office visits. It is an accurate and easy technique

386

Goldberg

J. Prosthet. October,

and Jones

Dent. 1976

which gives uniform results and eliminates the need for remaking an adequate removable partial denture. References 1. 2.

Thurgood, B. W., Thayer, K. E., and Lee, R. E.: Complete Crowns Constructed isting Partial Denture, J. PROSTHET. DENT. 29: 507-512, 1973. McCracken, W. L.: Partial Denture Construction, Principles, and Techniques, Louis, 1973, The C. V. Mosby Company. LOUISIANA SCHOOL NEW

Infiltration

TO APPEAR

A clinical W.

D.D.S.,

evaluation Dale,

Significance Girard

IN FUTURE

of a radioactive

Simonides Consani, Stolf, D.D.S., MS.

solution MS.,

Luiz

D.D.S.,

D.D.S.,

and James

of the edentulous Ph.D.,

H. Enlow,

Heat treatment J. R. Eshleman,

alloys

A magnetically

light-weight

gold

alloys

Gettleman,

angle

Wolney

Luiz

and cores Moser,

MS.,

Ph.D.

to prosthodontics

Jr., D.D.S.

and

and Stephen

Eklund,

P. C. Moon,

MS.,

D.D.S.

Ph.D.

D.D.S.

maxillary

obturator

M.Sc.D.

RTV silicone

Effect of rapid

John

and

Part I. A review

interim

D.M.D.,

N. Firtell,

D.D.S.,

and Jon H. Wetz,

retained

D. Federick,

plane

R. Moergeli,

D.D.S.,

restoration.

and

MS.,

mandible

J. R. Svitzer,

D.D.S.,

D.D.S.,

for dowels

F.R.A.C.D.S.,

J. Bianco,

of laser-welded D.D.S.,

The pin-amalgam R. Evans,

Henry

silver amalgam

Ruhnke,

of the Frankfort-mandibular

J. DiPietro,

Lawrence son, M.S.

into joined

M.D.S.,

The remodeling

David

ISSUES

Antonio

of semiprecious

B.D.S.,

Donald

David

ed. 4, St.

LA. 70119

ORLEANS,

r-

Joseph

an Ex-

STATE UNIVERSITY OF DENTISTRY

ARTICLES

John

for

for maxillofacial

D.D.S.,

Michael

curing

procedures

D.M.D.,

L. Donnan,

M.S.D.,

prostheses and

Charles

on polymer Dan

Nathanson,

Ray

implant D.M.D.,

Anderson

materials and

Richard

L. Myer-