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Direct core buildup using a preformed crown and prefabricated zirconium oxide post
DENTAL TECHNOLOGY
Kenneth D. Rudd
Direct core buildup using a preformed crown and prefabricated zirconium oxide post M. Zalkind, DMD,a and N. Hochman, DMDb Hadassah School of Dental Medicine, Hebrew University, Jerusalem, Israel This article describes a procedure that can produce a post and core in a reasonable chair time during a single session. With a preformed crown for core buildup, and being relatively rapid, this is a fairly simple procedure that has good results. (J Prosthet Dent 1998;80:730-2.)
E
ndodontic therapy allows patients to retain severely damaged teeth. The restoration of endodontically treated teeth involves complex procedures. Numerous post systems and techniques have been described. Coronoradicular stabilization techniques include custom-made metal posts and cores or commercially prefabricated intraradicular posts that retain core reconstructions consisting of silver amalgam, composite, glass ionomer cement, or modified glass ionomer cement.1 Nonmetallic posts in combination with all-ceramic crowns are esthetically preferable for the restoration of endodontically treated anterior teeth with fractured or discolored coronal aspects. A prefabricated all-ceramic post with good mechanical and biocompatible properties, in combination with novel adhesive technology, will allow direct bonding of the post to the root and core buildup with composite. Composites offer several advantages and have therefore become popular for core reconstruction. These advantages include strength, bonding capability, ease of manipulation, and rapid setting time, as compared with silver amalgams.2,3 This allows the dentist to complete a bonded composite core preparation immediately after placement of a prefabricated post.4
Fig. 1. Coronal portion of tooth prepared for receiving post and core.
PROCEDURE 1. Prepare the coronal part of the tooth (Fig. 1). 2. Remove gutta-percha to the desired length of the root canal with a hot instrument. 3. Prepare the root canal with specific cylindrical burs in accordance with the manufacturer’s instructions. 4. Select an appropriately sized zirconium oxide (Biopost-Incermed, SA, Lausanar, Switzerland) or other type of prefabricated post. 5. After roughening and sandblasting the surface of the zirconium oxide post, cement it with Bond-it material (Jeneric Pentron Inc, Wallingford, Conn.) (Fig. 2). aSenior
Lecturer, Department of Prosthodontics. Professor, Department of Prosthodontics.
bAssociate
730 THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 2. Zirconium oxide post fitted, seated, and cemented in place.
6. Select a preformed polycarbonate crown closely adapted to the prepared tooth. 7. After lubrication with petroleum jelly, fill the polycarbonate crown with Build-it composite (Jeneric Pentron Inc, Wallingford, Conn.) and place it on the cemented post (Fig. 3). 8. After polymerization, cut a vertical groove and then remove the preformed crown (Figs. 4 and 5). VOLUME 80 NUMBER 6
ZALKIND AND HOCHMAN
THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 3. Preformed polycarbonate crown filled with composite tightly placed on cemented post.
Fig. 5. Core immediately after removal of preformed crown.
Fig. 4. Vertical groove cut in preformed polycarbonate crown.
Fig. 6. Preparation of core and tooth to receive appropriate crown.
9. Prepare the core to receive the appropriate crown (Fig. 6).
zirconium oxide post, thereby increasing the retention of the luted components. The use of a preformed crown for core buildup is a simple 1-stage procedure, which allows almost immediate preparation of the final crown. Thus, the procedure is less expensive and less time-consuming than conventional procedures, and results in good esthetics. Building the core free-hand would be more difficult. By using a preformed crown, the composite can be compacted, which leaves no voids in the material. The new bonding systems enhance the usefulness of the composite.10,11 This technique of post-and-core reconstruction is best used in combination with all-ceramic crowns to take full advantage of the proper illumination of the tissues.4 All types of posts should be of an adequate length and strength and should fit well into the canal. Therefore, with direct systems, precision drilling and matching of the post can be carried out.3 However, the use of a cast post and core is sometimes neces-
DISCUSSION Prosthetic restoration of nonvital anterior teeth often requires making a post and core to support a crown and restore the remaining tooth structure. Many techniques are available for post and core reconstruction.3,5-7 A composite resin core and a prefabricated allceramic post seem to be the esthetic treatment of choice for anterior teeth when they are to be restored with an all-ceramic restoration. The core is tooth-colored and the post does not show through.4,8 The short setting time of composites and glass ionomer renders them suitable as core build-up materials, and their advantages and disadvantages have been documented.9 The bond between the zirconium oxide post and the composite material (Bond-it) was achieved mechanically by roughening and sandblasting the surface of the DECEMBER 1998
731
THE JOURNAL OF PROSTHETIC DENTISTRY
sary. Metal posts and cores are the most commonly used, but the metallic gray poses an esthetic problem in anterior all-ceramic restorations.3,12 REFERENCES 1. Morgano SM, Hashem AF, Fotoohi K, Rose L. A nationwide survey of contemporary philosophies and techniques of restoring endodontically treated teeth. J Prosthet Dent 1994;72:259-6. 2. Cohen BI, Pagnillo MK, Condos S, Dentsch AS. Four different core materials measured for fracture strength combination with five different designs of endodontic posts. J Prosthet Dent 1996;76:487-95. 3. Hunt PR, Gogarnoiu D. Evaluation of post and core systems. J Esthet Dent 1996;8:74-83. 4. Meyeberg KH, Luthy H, Scharer P. Zirconium posts. A new all-ceramic concept for nonvital abutment teeth. J Esthet Dent 1995;7:73-80. 5. Assif D, Gorfil C. Biomechanical considerations in restoring endodontically treated teeth. J Prosthet Dent 1994;75:565-7. 6. Morgano SM. Restoration of pulpless teeth: application of traditional principles in present and future contexts. J Prosthet Dent 1996;75:375-80. 7. Shillingburg HT Jr, Kessler JC. Restoration of the endodontically treated tooth. Chicago: Quintessence Publishing; 1982. p. 13-73.
Noteworthy Abstracts of the Current Literature
ZALKIND AND HOCHMAN
8. Zalkind M, Hochman N. Esthetic considerations in restoring endodontically treated teeth with posts and cores. J Prosthet Dent 1998;79:702-5. 9. Levartovsky S, Goldstein GR, Georgescu M. Shear bond strength of several new core materials. J Prosthet Dent 1996;75:154-8. 10. Hinoura K, Miyazaki M, Onose H. Dentin bond strength of light-cured glass ionomer cements. J Dent Res 1991;70:1542-4. 11. Waknine S, Gable P, Pernugondo B, Schulman A. Bond strength characterization of an experimental series of dentin adhesives. J Biomater Dent 1990;5:25-38. 12. Morgano SM, Milor P. Clinical success of cast metal posts and cores. J Prosthet Dent 1993;70:11-6. Reprint requests to: DR M. ZALKIND DEPARTMENT OF PROSTHODONTICS HEBREW UNIVERSITY–HADASSAH MEDICAL SCHOOL PO BOX 12272 91120 JERUSALEM ISRAEL Copyright © 1998 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/98/$5.00 + 0. 10/1/94012
Early and intermediate time response of the dental pulp to an acid etch technique in vivo. Gwinnett AJ, Tay FR. Am J Dent 1998;11:534-45.
Purpose. This special issue dealt with pulpal response to restorative techniques. This article presented the ultrastructural features of pulpal responses after the application of All-Bond 2 to acidconditioned, deep, unexposed coronal dentin and exposed pulps in human teeth. Material and methods. Cylindrical class V cavities approximately 4 mm in diameter were prepared on the buccal surface of 25 noncarious human premolars. The population was divided into a group where the preparation was approximately 0.5 mm from the pulp and the other with intentional pulp exposures. All teeth were etched with 10% phosphoric acid for 20 seconds, followed by rinsing for 20 seconds and left moist. Five coats of All-Bond primer was applied to the cavity preparation and light cured. Dentin-enamel bonding resin was applied and then preparations were light cured. Restorations were then completed by incremental placement of a hybrid composite. Specimens were divided into 3 categories according to the time of extraction (0-7, 28-35, and >90 days) and further into whether they were initially exposed. Sections were then evaluated histologically by light microscopy and transmission electron microscopy. Results. A characteristic connective tissue response to injury was noticed in a majority of specimens. Irreversible injury to the odontoblasts nearest to the site of the cavity preparations resulted in the death of these cells. That process was followed by an early neutrophilic response, a subsequent macrophage response, and a fibroblastic response that led to the deposition of reparative dentin or formation of a calcific bridge by odontoblast-like cells. Another consistent observation was that of resin particulates within the dentin-pulp complex. At times the presence of these resin particulates triggered a foreign body response, characterized by the presence of a mononuclear inflammatory infiltrate and the appearance of multinuclear giant cells. Persistence of unresolved chronic inflammation was associated with the lack of calcific bridge formation in these specimens. Conclusions. Although direct resin pulp capping can be a successful clinical procedure, a subacute, foreign body response can occur in the presence of resin particulates that were introduced into the pulp after a total etch technique. 76 References. —ME RAZZOOG
732
VOLUME 80 NUMBER 6
Kenneth D. Rudd
Direct core buildup using a preformed crown and prefabricated zirconium oxide post M. Zalkind, DMD,a and N. Hochman, DMDb Hadassah School of Dental Medicine, Hebrew University, Jerusalem, Israel This article describes a procedure that can produce a post and core in a reasonable chair time during a single session. With a preformed crown for core buildup, and being relatively rapid, this is a fairly simple procedure that has good results. (J Prosthet Dent 1998;80:730-2.)
E
ndodontic therapy allows patients to retain severely damaged teeth. The restoration of endodontically treated teeth involves complex procedures. Numerous post systems and techniques have been described. Coronoradicular stabilization techniques include custom-made metal posts and cores or commercially prefabricated intraradicular posts that retain core reconstructions consisting of silver amalgam, composite, glass ionomer cement, or modified glass ionomer cement.1 Nonmetallic posts in combination with all-ceramic crowns are esthetically preferable for the restoration of endodontically treated anterior teeth with fractured or discolored coronal aspects. A prefabricated all-ceramic post with good mechanical and biocompatible properties, in combination with novel adhesive technology, will allow direct bonding of the post to the root and core buildup with composite. Composites offer several advantages and have therefore become popular for core reconstruction. These advantages include strength, bonding capability, ease of manipulation, and rapid setting time, as compared with silver amalgams.2,3 This allows the dentist to complete a bonded composite core preparation immediately after placement of a prefabricated post.4
Fig. 1. Coronal portion of tooth prepared for receiving post and core.
PROCEDURE 1. Prepare the coronal part of the tooth (Fig. 1). 2. Remove gutta-percha to the desired length of the root canal with a hot instrument. 3. Prepare the root canal with specific cylindrical burs in accordance with the manufacturer’s instructions. 4. Select an appropriately sized zirconium oxide (Biopost-Incermed, SA, Lausanar, Switzerland) or other type of prefabricated post. 5. After roughening and sandblasting the surface of the zirconium oxide post, cement it with Bond-it material (Jeneric Pentron Inc, Wallingford, Conn.) (Fig. 2). aSenior
Lecturer, Department of Prosthodontics. Professor, Department of Prosthodontics.
bAssociate
730 THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 2. Zirconium oxide post fitted, seated, and cemented in place.
6. Select a preformed polycarbonate crown closely adapted to the prepared tooth. 7. After lubrication with petroleum jelly, fill the polycarbonate crown with Build-it composite (Jeneric Pentron Inc, Wallingford, Conn.) and place it on the cemented post (Fig. 3). 8. After polymerization, cut a vertical groove and then remove the preformed crown (Figs. 4 and 5). VOLUME 80 NUMBER 6
ZALKIND AND HOCHMAN
THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 3. Preformed polycarbonate crown filled with composite tightly placed on cemented post.
Fig. 5. Core immediately after removal of preformed crown.
Fig. 4. Vertical groove cut in preformed polycarbonate crown.
Fig. 6. Preparation of core and tooth to receive appropriate crown.
9. Prepare the core to receive the appropriate crown (Fig. 6).
zirconium oxide post, thereby increasing the retention of the luted components. The use of a preformed crown for core buildup is a simple 1-stage procedure, which allows almost immediate preparation of the final crown. Thus, the procedure is less expensive and less time-consuming than conventional procedures, and results in good esthetics. Building the core free-hand would be more difficult. By using a preformed crown, the composite can be compacted, which leaves no voids in the material. The new bonding systems enhance the usefulness of the composite.10,11 This technique of post-and-core reconstruction is best used in combination with all-ceramic crowns to take full advantage of the proper illumination of the tissues.4 All types of posts should be of an adequate length and strength and should fit well into the canal. Therefore, with direct systems, precision drilling and matching of the post can be carried out.3 However, the use of a cast post and core is sometimes neces-
DISCUSSION Prosthetic restoration of nonvital anterior teeth often requires making a post and core to support a crown and restore the remaining tooth structure. Many techniques are available for post and core reconstruction.3,5-7 A composite resin core and a prefabricated allceramic post seem to be the esthetic treatment of choice for anterior teeth when they are to be restored with an all-ceramic restoration. The core is tooth-colored and the post does not show through.4,8 The short setting time of composites and glass ionomer renders them suitable as core build-up materials, and their advantages and disadvantages have been documented.9 The bond between the zirconium oxide post and the composite material (Bond-it) was achieved mechanically by roughening and sandblasting the surface of the DECEMBER 1998
731
THE JOURNAL OF PROSTHETIC DENTISTRY
sary. Metal posts and cores are the most commonly used, but the metallic gray poses an esthetic problem in anterior all-ceramic restorations.3,12 REFERENCES 1. Morgano SM, Hashem AF, Fotoohi K, Rose L. A nationwide survey of contemporary philosophies and techniques of restoring endodontically treated teeth. J Prosthet Dent 1994;72:259-6. 2. Cohen BI, Pagnillo MK, Condos S, Dentsch AS. Four different core materials measured for fracture strength combination with five different designs of endodontic posts. J Prosthet Dent 1996;76:487-95. 3. Hunt PR, Gogarnoiu D. Evaluation of post and core systems. J Esthet Dent 1996;8:74-83. 4. Meyeberg KH, Luthy H, Scharer P. Zirconium posts. A new all-ceramic concept for nonvital abutment teeth. J Esthet Dent 1995;7:73-80. 5. Assif D, Gorfil C. Biomechanical considerations in restoring endodontically treated teeth. J Prosthet Dent 1994;75:565-7. 6. Morgano SM. Restoration of pulpless teeth: application of traditional principles in present and future contexts. J Prosthet Dent 1996;75:375-80. 7. Shillingburg HT Jr, Kessler JC. Restoration of the endodontically treated tooth. Chicago: Quintessence Publishing; 1982. p. 13-73.
Noteworthy Abstracts of the Current Literature
ZALKIND AND HOCHMAN
8. Zalkind M, Hochman N. Esthetic considerations in restoring endodontically treated teeth with posts and cores. J Prosthet Dent 1998;79:702-5. 9. Levartovsky S, Goldstein GR, Georgescu M. Shear bond strength of several new core materials. J Prosthet Dent 1996;75:154-8. 10. Hinoura K, Miyazaki M, Onose H. Dentin bond strength of light-cured glass ionomer cements. J Dent Res 1991;70:1542-4. 11. Waknine S, Gable P, Pernugondo B, Schulman A. Bond strength characterization of an experimental series of dentin adhesives. J Biomater Dent 1990;5:25-38. 12. Morgano SM, Milor P. Clinical success of cast metal posts and cores. J Prosthet Dent 1993;70:11-6. Reprint requests to: DR M. ZALKIND DEPARTMENT OF PROSTHODONTICS HEBREW UNIVERSITY–HADASSAH MEDICAL SCHOOL PO BOX 12272 91120 JERUSALEM ISRAEL Copyright © 1998 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/98/$5.00 + 0. 10/1/94012
Early and intermediate time response of the dental pulp to an acid etch technique in vivo. Gwinnett AJ, Tay FR. Am J Dent 1998;11:534-45.
Purpose. This special issue dealt with pulpal response to restorative techniques. This article presented the ultrastructural features of pulpal responses after the application of All-Bond 2 to acidconditioned, deep, unexposed coronal dentin and exposed pulps in human teeth. Material and methods. Cylindrical class V cavities approximately 4 mm in diameter were prepared on the buccal surface of 25 noncarious human premolars. The population was divided into a group where the preparation was approximately 0.5 mm from the pulp and the other with intentional pulp exposures. All teeth were etched with 10% phosphoric acid for 20 seconds, followed by rinsing for 20 seconds and left moist. Five coats of All-Bond primer was applied to the cavity preparation and light cured. Dentin-enamel bonding resin was applied and then preparations were light cured. Restorations were then completed by incremental placement of a hybrid composite. Specimens were divided into 3 categories according to the time of extraction (0-7, 28-35, and >90 days) and further into whether they were initially exposed. Sections were then evaluated histologically by light microscopy and transmission electron microscopy. Results. A characteristic connective tissue response to injury was noticed in a majority of specimens. Irreversible injury to the odontoblasts nearest to the site of the cavity preparations resulted in the death of these cells. That process was followed by an early neutrophilic response, a subsequent macrophage response, and a fibroblastic response that led to the deposition of reparative dentin or formation of a calcific bridge by odontoblast-like cells. Another consistent observation was that of resin particulates within the dentin-pulp complex. At times the presence of these resin particulates triggered a foreign body response, characterized by the presence of a mononuclear inflammatory infiltrate and the appearance of multinuclear giant cells. Persistence of unresolved chronic inflammation was associated with the lack of calcific bridge formation in these specimens. Conclusions. Although direct resin pulp capping can be a successful clinical procedure, a subacute, foreign body response can occur in the presence of resin particulates that were introduced into the pulp after a total etch technique. 76 References. —ME RAZZOOG
732
VOLUME 80 NUMBER 6