A method of refacing cemented veneered crowns

A method

of refacing

cemented

veneered

crowns

Aliza Rehany, D.M.D.,* and Noah Stern, D.M.D., M.S.D.** Hebrew University-Hadassah School of Dental Medicine, Jerusalem,

Israel

A

crylic resin facings sometimes become detached from the gold crowns, creating discomfort and embarrassment to the patient. When the restoration can be removed, the repair is simple. A new facing is fabricated and the restoration recemented. However, when it is impossible to remove the restoration without damaging it, the problem of refacing is more difficult. This article describes a simple method of replacing a facing without removing the existing restoration. MATERIALS

AND

METHODS

An exact impression of the region of the veneer including the adjacent teeth must be obtained. Any material suitable for making impressions for indirect gold procedures can be used (Fig. 1) . Before making the impression, the length, width, and contours of the crown are examined, paying special attention to undercuts in the region to be veneered. Any remnants of old acrylic resin are removed, and undesirable or unesthetic gold margins or other surfaces that affect the contour or appearance are reshaped.l An “individual tray” is fabricated to cover all of the facial and occlusal surfaces or incisal edges of the crown being refaced and of adjacent teeth. If impression plaster is used as the primary material, the vestibular undercut should be removed. When a putty-like tray-forming material is used, undercuts may be removed using a sharp instrument after the impression is withdrawn. The primary impression should be checked to see if it includes the necessary oral structures and if it can be accurately re-placed in the mouth. The final impression is completed using a wash material to reproduce the fine details and undercuts of the region. When the final impression has completely set, it is removed and checked again for accuracy. The shade of the facing is then selected. Supported in part by a grant Hadassah School of Dental Medicine, *Department

of Oral

**Senior Lecturer Professor, Department Medicine, Philadelphia,

158

from the joint Research Jerusalem, Israel.

Fund

of the

Hebrew

University-

Rehabilitation.

in Prosthodontics, of Restorative Pa.

Department of Oral Rehabilitation; Dentistry, University of Pennsylvania,

Visiting School

Associate of Dental

Volume Number

38 2

Refacing

Fig. 1. The completed impression a low-consistency material. Fig.

2. The

stone

made

by

veneered

cemented

use of a high-consistency

putty-like

crowns

material

159

and

cast of the impression.

Fig.

3. The

facing

attached

on the crown

in the mouth.

The impression is poured in a die stone to fabricate a master cast (Fig. 2). The laboratory procedures are the same as for placing a facing on a gold crown except that they are completed on a stone cast instead of on the crown itself. The completed facing should be examined for adequate retention, marginal coverage, contour, and occlusion. If occlusal interferences are present, they should be corrected so the facing will not be dislodged. There must be enough retention in the gold to retain the facing. When necessary, retentive sites are added by undercutting the gold with a high-speed carbide bur. * Carelessly added retention will elevate fragments of the gold and make exact placement of the facing difficult. The facing is attached using cold-curing acrylic resin at a doughy consistency. The inner surface of the facing is wetted with monomer, then the acrylic resin is placed in the veneer portion of the crown and also on the inner surface of the facing. The facing is placed on the crown and held with finger pressure for several minutes. Excess acrylic resin can be removed while it is still soft. After the acrylic resin has set, occlusal interferences should again be examined and carefully adjusted (Fig. 3). *Mid-West

American,

friction-grip

No.

1558,

Melrose

Park,

111.

160

Rehany

J. Prosthet. Dent. August, 1977

and Stern

DISCUSSION

Two main factors may cause the detachment of the facing from the restoration: ( 1) lack of mechanical retention for the acrylic resin and (2) occlusal interference on the facing material. When the detachment is causedby lack of mechanical retention, undercuts should be added in the region of the veneer, preferably after the facing has been fabricated. It would be impossible to seat the processedfacing on a stone cast which includes these undercuts. When attaching the facing, the self-curing acrylic resin will be pressedinto the undercuts in the gold to supply good mechanical retention. When there are sufficient retentive sites in the gold and the facing has been broken as a result of occlusal interference, the undercuts should be blocked out in the cast prior to fabricating the facing to allow its placement. SUMMARY

A simple and efficient method has been described for refacing restorations without removing them from the mouth. The impression technique, fabrication of the facing, and its attachment to the crown were described. Reference 1.

Pietrokovski, J., and Sorin, S.: Clinical J. PROSTHET. DENT. 34: 503-507, 1975. HEBREW UNIVERSITY-HADASSAH P.O.B. 1172 JERUSALEM, ISRAEL

ARTICLES Flat-plane

occlusion

E. J. Neiburger,

Comparison amination Carl

Ira Franklin

for

OF DENTAL

IN FUTURE

in the development

Improving

Veneered

Metal

Crowns,

MEDICINE

ISSUES of man

D.D.S.

of the efficacy of a questionnaire, oral history, and clinical exin detecting occlural and TMJ dysfunction signs and symptoms

E. Rieder,

Acquired

TO APPEAR

SCHOOL

Procedures

D.D.S.

mesio-occlusion Ross, D.D.S.

in the adult:

Treatment

without

orthodontics