Post and core fabrication beneath an existing crown

Post and core fabrication George Priest, D.M.D.,” Fort

Gordon,

Ga.,

and

Fort

and Albert Goerig, Knox,

beneath an existing

crown

D.D.S. **

Ky.

11 acement of a post and core within an endodontically treated tooth can contribute to the strengthening of that tooth and the preservation of the restoration placed upon it.‘, ’ Although a post is normally inserted before fabrication of fixed prostheses, methods have been developed to construct and insert a post and core beneath an existing crown or fixed restoration.“-’ The following technique demonstrates an approach to repairing an abutment fractured prior to final insertion of an already fabricated fixed partial denture (Figs. 1 and 2). It is additionally applicable to fractured endodontically treated teeth with existing crowns where posts and cores had not been previously inserted.

TECHNIQUE 1. Prepare the root of the fractured tooth and obturate it with gutta percha. 2. With a heated endodontic plugger, remove sufficient gutta percha to provide a post at least one-half the length of the root. 3. Taper and smooth the dentinal walls using Gates Glidden burs? (Fig. 3). Form an opening that is irregular in outline which will prevent rotation of the post. 4. Prepare the occlusal portion of the tooth flat and perpendicular to the canal to create a positive seat for the post (Fig. 4). Keep the design simple to ensure an accurate fit of the casting. Grooves in the canal or coronal steps increase the likelihood of a discrepancy in seating and may result in an open crown margin. The opinions or assertions of the authors and are reflecting the views of D epartment of Defense. *Captain, DC, U.S. Army. **Major, DC, U.S. Army. TUnion Broach Co., Long

contained herein are the private views not to be construed as official or as the Department of the Army or the

Island

City,

N. Y.

Fig. 1. During insertion of a mandibular fixed partial denture, the canine abutment fractured, leaving the incisal segment within its retainer. 5. Select a Wilkinson plastic tapered pin* (or a plastic sprue) that will loosely fit to the depth of the canal (Fig. 5). Roughen the pin (or sprue) to retain the Duralay resin? that will be applied. 6. Remove the pin and, using a paper point, coat the canal w,ith lubricant. 7. Using the brush technique, apply Duralay resin onto the pin and into the canal, then insert the pin into the canal (Fig. 6). A lubricated endodontic plugger may be used to force more resin into the opening. Before the pattern has completely polymerized, grasp the plastic pin, moving it occlusogingivally to prevent the post from binding. 8. Reduce the protruding pin until the retainer seats fully on the abutment. Notch the pattern with a *The Wilkinson Co., Westlake Village, Calif. tReliance Dental Mfg. Co., Worth, Ill.

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645

PRIEST

Fig. 4. Abutment

is prepared

AND

GOERiC

to receive a post and core

Fig. 5. One of the three Wilkinson fitted to the depth of the preparation.

plastic pins will be

pattern from the crown. Place the pattern back on the abutment anid correct seating interferences (Figs. 8 and 9). 11. Sprue the pattern and cast it into gold (Fig. 10). 12. Return the casting to the abutment and remove seating interferences (Fig. 11). 13. Simultaneously cement the post and core and the crown with z:inc phosphate cement (Figs. 12 and 13).

SUMMARY A technique has been described post and core for a tooth fractured

646

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1979

for constructing a prior to insertion

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POST

AND

CORE

FABRICATION

BENEATH

EXISTING

CROWN

Fig. 6. Duralay resin is painted into the lubricated canal and onto the roughened Wilkinson pin, which is then placed within the canal.

e

Fig. 9. Cross-sectional view of completed pattern. a, the pattern; b, the notched Wilkinson pin; c, the retainer :; d, the abutment; and e, the gutta percha.

Fig. 7. Internal surface of the retainer filled with Duralay resin.

Fig. 8. Post and core pattern is returned for final adjustments.

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is lubricated

and

to the abutment Fig. 10. Pattern is cast in gold.

647

PRIEST AND

Fig. 11. Casting is placed on the abutment interferences are removed.

and seating

Fig. 13. One year postoperative ment.

Fig. 12. Cemented fixed prosthesis 1 year postoperatively. Avow denotes the fractured abutment.

of a fixed partial denture. In selected patients, method of repair offers an acceptable alternative more costly and time-consuming refabrication fixed prosthesis.

this to a of a

Baraban, North

648

criteria

3.

Shirdel, K., Azarmehr, P., and Raoufi, M.: Consrrurtion of a post and core to fit a completed restoration. .J I’HO:.PHBT DENT 38:229. 1977. Henry, P. J., and Bower, R. C.: Secondary and core. Ausi Dent J 22:128, 1977.

5.

Harris,

6.

dure. Texas Dent J 94:15, Goldstein, R. ;E.: Esthetics

W.

E.: A single-visit

7.

1976, J. B. Lippincott Asawa, G. N.: Cast Dent

Sun;

and

intrntmn

endodonticipost 1976. in Dentistry,

Co.. pp 292-295. dowel core fabrication 48:36,

for posts

crown ed

prbst proce-

I Philadelphia, oo a preexisting

1972.

Reprmt requeststo: D. J,: The

Am,

F. I.: Clinical 28~405. 1972.

of the abut-

Perel, cores.

4.

M. L., and Muroff, J PROSTHET DENT

radiograph

2.

crown.

REFERENCES 1.

COERIG

Nov.

restoration

1967,

pp

of pulpless 633-653.

teeth.

Dent

Clin

CAPTAIN CEVRCE PRIEST, DC. US ARMY HEADQUARTERS, DENTAL COMPANY FORT GORDON, GA. 30905

DECEMBER

1979

VOLUME

42

NUMBER

6