for a post-core William

E. Jacoby,

for the fabrication

of a direct


restoration Jr., D.D.S.

Ridgewood, N. J.

1 he pulp chambers of teeth vary considerably in their mesiodistal-labiolingual sections1 Preparation of these pulp chambers, particularly those of the canines and premolars, to receive a cylindrical prefabricated post will mean unjustifiable removal of tooth structure or relying on the cementing medium alone to offset the lateral forces of mastication. An accurate and manageable technique for a cast core post should be part of a restorative dentist’s armamentarium. The following is a direct-pattern technique for posts and cores made with a cold-curing acrylic-resin* and prefabricated plastic posts.? This technique is a modification of those already reported in the literature.2M8 PROCEDURE (1) Prepare the post by using Peeso reamers$ to a minimal depth of one-half the length of the root (Figs. 1 to 3). (2) Use a reduction torque handpiece at low rotary speed to remove all undercuts from the prepared canal. (3) Lubricates the post preparation. (4) Choose a plastic post that loosely fits the canal. (5) Using a brush and the powder-liquid technique, flow DuraLay into the prepared canal, and insert the selected post into the canal. In a multirooted tooth (e.g., premolar or molar), only the major or largest canal need be prepared to one half of the length of the root. However, the other roots or minor canals should be entered and prepared as far as possible to maintain a path of insertion of approximately one quarter to one third of the length of the root. If the roots are too divergent, the pattern may be split and a male-female interlock fabricated for separate cementing (Fig. 4).

l DuraLay,



Mfg. Company,

tStar plastic post, Star Dental $.Peeso reamers, Henry §DuraLay


Schein Inc., Flushing, Reliance


Mfg. Company, Dental


Inc., Conshohocken,


N. Y.

Mfg. Company,


Ill. 357


J. Prosthet. Dent. March, 1976


Fig. 1. A post is prepared with a Peeso reamer and reduction torque handpiece. Fig. 2. Prepared post canals. Fig. 3. DuraLay pattern before preparation with the handpiece.

Fig. 4. DuraLay pattern after preparation. not been reduced at this time.

Note the full collar of tooth structurt

which has

(6) Restore the missing part of the clinical crown by adding and building the DuraLay to the approximate size and contour desired. (7) Allow the pattern to completely set. (8) Prepare the built-up crown, while still in the tooth, with high-speed instruments. During the preparation, the pattern may loosen, and finishing of the preparation may then be done by hand. No attempt should be made to duplicate the margin of the root in the acrylic resin pattern. Rather, a complete collar of tooth structure should exist around the pattern. The clinical crown portion of the core can be modified to suit the tooth. It is advisable to notch the buccal surface (especially on molars) for ease of fit and cementation (Figs. 5 and 6).



Fig. 5. The gold post is in place. Note the buccal notch to facilitate casting in before cementation. Fig. 6. Try in of the gold post before before finishing.


of the sprue. Note

Fig. 7. The gold post is cemented. The collar of the tooth structure Fig. 8. A temporary crown is cemented on the gold post.


a post-core


when trying

the excellent



the fit

has been prepared.

(9) Invest and cast the DuraLay pattern. ( 10) Cement the post in place (Fig. 7). ( 11) Prepare the cervical collar, make the final impression, and fabricate the final restoration. (12) Cement the final restoration, and finish the margins on the tooth structure (Fig. 8). ADVANTAGES ( 1) The acrylic resin pattern is accurate9 and stable and is easier to handle than a wax pattern. (2) The pattern requires 45 minutes for setting of the investment and 45 minutes for the burnout. The pattern may be started and completed on the same day if necessary. (3) The technique and materials are inexpensive and easy to use. (4) The technique can be used in a single canal or for multiple canals. (5) The mesiodistal-buccolingual dimensions of the canal are not of concern.



J. Prosthet. Dent. March, 1976

References 1. Wheeler, R. C.: Textbook of Dental Anatomy and Physiology, ed. 3, Philadelphia, 1960, W. B. Saunders Company, pp. 252-278. 2. Rosen, H.: Operative Procedures on Multilateral Endodontically Treated Teeth, J. PROSTHET. DENT. 11: 973-986, 1961. 3. Silverstein, W. H.: The Reinforcement of Weakened Pulpless Teeth, J. PROSTHET. DENT. 14: 372-381, 1964. 4. Baraban, D. J.: The Restoration of Pulpless Teeth, Dent. Clin. North Am., Nov., 1967, pp. 633-653. 5. Sheets, C. E.: Dowel and Core Foundations, J. PROSTHET. DENT. 23: 58-65, 1970. 6. Baraban, D. J.: A Simplified Method For Making Posts and Cores, J. PROSTHET. DENT. 24: 287-297, 1970. 7. Shillingburg, H. T., Jr., Fisher, D. W., and Dewhirst, R. B.: Restoration of Endodontically Treated Posterior Teeth, J. PROSTHET. DENT. 24: 401-409, 1970. 8. Stern, N.: A Direct Pattern for Post and Cores, J. PROSTHET. DENT. 28: 279-283, 1972. Study of Dimensional Changes 9. Galan, J., Jr., Mondelli, J., and Vieira, D. F.: Comparative of Castings Obtained From Wax on Acrylic Patterns-Their Influence on the Fit of Castings, Estomatol. Cult. 4: 157-174, 1970. 40 W. RIDGEWOOD AVE. RIDDEWOOD, N. J. 07450

ERRATUM In the article by Payne entitled “The Future of Prosthodontics,” J. PROSTHET. DENT. 35: 3-5, 1975, the second sentence of the second paragraph on p. 5 should read: “Deans and curriculum committees must realize that you cannot practice dentistry with your mouth, even though a few try!”

Practical technique for the fabrication of a direct pattern for a post-core restoration.

Practical technique for a post-core William E. Jacoby, for the fabrication of a direct pattern restoration Jr., D.D.S. Ridgewood, N. J. 1 he...
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