An a c c e l e r a t e d t e c h n i q u e for c a s t i n g p o s t and core restorations W a y n e V. C a m p a g n i , D M D , a a n d M i c h a e l M a j c h r o w i c z , D M D b
University of Pittsburgh, School of Dental Medicine, Pittsburgh, Pa.; and Elmendorf Air Force Base, Anchorage, Alaska An a c c e l e r a t e d technique for c a s t i n g a direct-pattern post and core restoration is presented. The entire clinical and laboratory procedure m a y be completed w i t h i n 1 hour. The n e c e s s i t y for two appointments for completion of the restoration as well as the n e c e s s i t y of m a k i n g two provisional restorations m a y be eliminated. (J PROSTHET DENT 1991;66:155-6.)
V a r i o u s methods are available for making cast post and core restorations. These restorations may be produced by indirect techniques or by making a direct pattern. 1 A problem attendant with the making of a cast post and core is the necessity for two appointments because of the laboratory time. The conventional laboratory process involves a minimum of 21/~ hours of laboratory time: sprueing and investing, 10 to 15 minutes; investment setting, 45 to 60 minutes; and staged burnout and casting, a minimum of 60 to 75 minutes. 2The patient is normally dismissed and
The views expressed herein are those of the authors and do not necessarily reflect the viewsof the United States Air Force or the Department of Defense. Presented before the Carl O. Boucher Prosthodontic Conference meeting, Columbus, Ohio. aAssociate Professor and Acting Chairman, Department of Restorative Dentistry, University of Pittsburgh, School of Dentistry. bCaptain, U.S. Air Force, DC, Elmendorf AFB. 10/1/28819
given another appointment because of the fabrication time for the casting. An interim restoration must be placed until completion of the casting. This provisional restoration is difficult to retain and often will dislodge before the next appointment, causing aggravation to both dentist and patient. After cementation of a cast post and core, a new provisional restoration must be made, necessitating more time. The accelerated casting technique was suggested by Marzouk and Kerby 3 and has resulted in clinically excellent results. A direct pattern is advocated in this technique because it may be made in approximately the same time that an impression is made for making an indirect restoration. The pattern is made by means of an acrylic resin core buildup over a prefabricated plastic burnout post. 2 The pattern is invested while the patient remains in the office, and the casting is delivered in the same appointment. The entire investing, burnout, and casting technique can be accomplished within 45 minutes. Final preparations and impressions could be made at the same appointment. Only one appointment and one provisional restoration are necessary.
Fig. 1. Buildup of direct pattern core on prefabricated post with acrylic resin.
Fig. 2. Sprued resin pattern ready for investing. Full ring liner is used.
THE JOURNAL OF PROSTHETIC DENTISTRY
CAMPAGN'I AND MAJCHROWICZ
Fig. 3. Completed castings of posts and cores. Fig. 4. Multiple one-appointment post and core restorations. TECHNIQUE 1. Make a direct pattern 1 by using a plastic burnout post for the dowel (ParaPost, Whaledent Int., New York, N.Y.) and building the core to ideal tooth preparation form with acrylic resin (G. C. Pattern Resin, G. C. Intl. Corp., Scottsdale, Ariz.) (Fig. 1). 2. Sprue andinvest the pattern with Complete phosphatebonded investment (Jelenko Dental Health Products, Armonk, N.Y.). A full ring liner is used and the special liquid is diluted with water using a 50/50 ratio (Fig. 2). 3. Let the investment set until firm and at its peak thermal setting temperature, which occurs in 12 to 15 minutes. 4, Place the ring in an oven preheated to 1300 ° F and burn out for 12 to 15 minutes, depending on the ring size and number of patterns. 5. Cast in a type III or type IV gold alloy. 6. Cool, quench, devsst, clean, and deliver the resultant casting by conventional methods (Fig. 3). CONCLU~ON This technique has been used successfully to produce multiple restorations in one appointment (Fig. 4). Research
is being conducted for a scientific rationale for the technique, which challenges traditional methods for handling phosphate-bonded casting investments. REFERENCES 1. ShiUingburg HT, Kessler JC. Restoration of the endodonticalty treated tooth. 1st ed. Chicago: Quintessence Publishing Co, 1982:45-74; 75-122; 163-204. 2. Jelenko Dental Health Products. Complete investment technique. Atmonk, N.Y., 1988. 3. Marzouk MA, Kerby J. The exothermic casting procedure: a comparative study of four thermal treatments. Chicago: Quintessence Yearbook 1988:177-85. Reprint requests to: DR. WAYNEV. CAMPAGNI SCHOOLOF DENTALMEDICINE UNWF~SITYoF PrrTsBUR~H 3501 TERRACEST. PITTSBURGH, PA 15261