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Fabrication of one-piece all-ceramic coronal post and laminate veneer restoration: A clinical report
Fabrication of one-piece all-ceramic coronal post and laminate veneer restoration: A clinical report C¸etin Sevu¨k, Dr Med Dent,a Hasim Gu¨r, Dr Med Dent,b and Begu¨m Akkayan, Dr Med Dentc Faculty of Dentistry, University of Istanbul, Istanbul, Turkey The procedure used for the restoration of maxillary right and left lateral incisors with all-ceramic onepiece coronal post and laminate veneer restorations is described in this clinical report. The proposed treatment technique conserves the remaining tooth structure, reestablishes function, offers satisfactory esthetics, and represents an alternative to traditional restoration procedures with the use of adhesive bonding techniques. (J Prosthet Dent 2002;88:565-8.)
A
common problem with the restoration of endodontically treated teeth complicated by total or partial loss of coronal tooth structure is deciding on the best restoration alternative. It has been suggested that root canal-treated teeth require restorations to prevent fracture.1,2 Studies reported the effect of decreased moisture content and subsequent brittleness of endodontically treated teeth,2-5 whereas Sedgley and Messer6 concentrated on the loss of both internal and external tooth structure as a cause of fracture. It therefore seems important to use a technique that minimizes these risks and best accommodates the clinical conditions and the patient’s desires. Although dentists are interested in the fracture resistance and marginal accuracy of the completed restorations to ensure clinical success, patients seem to be concerned primarily with improved esthetics.7-11 Because of this concern, all-ceramic restorations have been suggested as an alternative to solve the esthetic problems associated with metal-ceramic restorations.12-16 Porcelain laminate restorations have been proposed as a treatment modality, with conservative preparation design and excellent esthetics. It has been reported that a porcelain laminate veneer requires at least 50% of intact enamel surface area to maintain adequate resistance and retention.17 However, in this clinical report, the final preparation of the teeth did not exactly fit this criterion, because too much palatal and coronal tooth structure had been lost. Sorensen et al18 stated that in teeth where more than 50% of the intact enamel surface area has been lost because of excessive decay or access preparations for endodontic treatment, laminate veneer restorations would have some limitations with respect to retention and resistance. Because of this concern, the fabrication of postlike features called coronal posts, which hardly engage the root canal spaces, were planned to provide additional retention in this clinical situation. Moreover, a
Professor, Department of Prosthetic Dentistry. Associate Professor, Department of Prosthetic Dentistry. c Research assistant, Department of Prosthetic Dentistry. b
DECEMBER 2002
Fig. 1. View of maxillary right and left lateral incisors with defective composite restorations.
the need for adequate retention and resistance was fulfilled with the use of adhesive bonding techniques. This clinical report describes the fabrication of onepiece all-ceramic coronal post and laminate veneer restorations by use of the Celay copy-milling system (Mikrona AG, Spreitenbach, Switzerland) and Vita Celay Blanks (Vita, Bad Sa¨ckingen, Germany).
CLINICAL REPORT A 28-year-old female patient was referred to the clinic with esthetic concerns related to her defective composite restorations on the maxillary right and left lateral incisors (Fig. 1). The patient requested new, tooth-colored restorations that would also ensure satisfactory longevity. After the clinical and radiographic examination, it was detected that endodontic treatment had been completed on both lateral incisors. The defective restorations were removed, and the preliminary shades were selected before tooth preparation. Coronal tooth structure was prepared for porcelain veneer restorations, starting with a depth cutting diamond stone (Brasseler Laminate Veneer System Set; Brasseler, Savannah, Ga.). A low-speed hand-piece and finishing burs (7702-7103; Midwest Dental, Des Plaines, Ill.) were used to remove the caries extending THE JOURNAL OF PROSTHETIC DENTISTRY 565
THE JOURNAL OF PROSTHETIC DENTISTRY
¨ K, GU ¨ R, AND AKKAYAN SEVU
Fig. 2. Preparation of lateral incisors for one-piece all-ceramic coronal post and laminate veneer restoration. A, Right. B, Left.
Fig. 3. A, Direct build-up of resin patterns for coronal posts and laminate veneer restorations. B, Autopolymerizing resin patterns tried in mouth.
into dentin. The preparation included a rounded incisal edge terminating palatally with a heavy chamfer, and all the other line angles were slightly rounded. The canal orifices were enlarged with number 2 and 3 Gates Glidden drills (Maillefer, Ballaigues, Switzerland). The preparations were then completed for a resin-bonded, onepiece all-ceramic coronal post and porcelain laminate veneer restoration, with great attention to conserving the remaining tooth structure (Fig. 2). Retraction cord was placed and delicately deepened to the degree necessary to expose the subgingival finish line that extended facially and proximally below the tissue level. Patterns of the preparations were fabricated with autopolymerizing resin (Pattern Resin; GC Corp, Tokyo, Japan). The resin was mixed according to the powder/liquid ratio specified by the manufacturer and was immediately injected into the base of the preparation. To minimize the effects of polymerization shrinkage, the resin was applied in small volumes. After the polymerization of the first resin mix, a new mix was prepared and applied with a syringe along the entire 566
gingival and proximal finish lines. The resin patterns were then refined with new mixes of autopolymerizing resin until the patterns of the entire restorations were accomplished. The accurate fit of the resin patterns was checked under magnification. Resin patterns of the coronal post and laminate veneer preparations were thus modeled directly in the mouth (Fig. 3). One of the completed resin patterns was mounted to the copying chamber of the Celay machine, and the reference-scanning disc was placed. The appropriate size and shade of the porcelain blank was chosen and fixed to the tracing chamber accordingly. The reference disc acted as a scanning stylus moving across the surface of the resin pattern, while the diamond disc in the second chamber duplicated the exact movements of the scanner. Thus the resin pattern was surface-traced and copied in ceramic block (Fig. 4, A). The same procedure was applied for the other resin pattern (Fig. 4, B), and the restorations were then glazed and polished. The final restorations were checked for accuracy of fit in the mouth. VOLUME 88 NUMBER 6
¨ K, GU ¨ R, AND AKKAYAN SEVU
THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 4. One-piece all-ceramic coronal post and laminate veneer restoration milled from Vita Celay for lateral incisors. A, Right. B, Left.
The restoration was then inserted and the excess cement was removed. Total set of the resin cement was achieved by use of a polymerizing lamp applied for 60 seconds to each surface of the restoration. The excess hardened cement was removed from marginal areas with polishing disks (Soflex; 3M Dental, Duluth, Minn.) of decreasing coarseness. The final restorations provided the patient with a functional restoration that also accommodates her desires (Fig. 5). The patient was scheduled for maintenance every 6 months, and the restorations have been in place for 20 months. Fig. 5. Final restorations, facial view.
The restorations were cemented with an adhesive bonding technique (Variolink II; Vivadent, Schaan, Liechtenstein) according to the manufacturer’s guidelines. The inner surface of the ceramic restoration was etched with 4.9% hydrofluoric acid for 15 seconds (IPS Ceramic etching gel; Vivadent), rinsed for 10 seconds, and then dried for 5 seconds. A layer of silane compound (Monobond-S; Vivadent), used as a coupling agent on the porcelain restoration, was allowed to air dry. An unfilled resin-bonding agent (Heliobond; Vivadent) was applied with a brush and thinned with an air syringe for 5 seconds. The prepared tooth surfaces were etched for 45 seconds with 37% phosphoric acid (Total Etch; Vivadent), and the preparation was then washed under water for 60 seconds and dried with an air jet for 30 seconds. The primer (Syntac Primer; Vivadent) and the dentinal adhesive (Syntac Adhesive; Vivadent) were applied consecutively, and each was allowed to act for 15 seconds. An unfilled resin (Heliobond; Vivadent) was then applied with a brush and homogeneously sprayed with air. A dual-cure cement of the selected shade (Variolink II; Vivadent) was mixed and placed in the cavity. DECEMBER 2002
DISCUSSION The restorative material and the technique used for the restoration of severely damaged teeth can be particularly important in endodontically treated teeth, which frequently need coronal restorations. The restoration of anterior teeth with metal-ceramic restorations may lead to compromised esthetics because of the limited translucence of metal-ceramic porcelains and opaque metal substructures.12 Metal substructure may also shine through in the cervical root areas, thus altering the appearance of thin gingival tissue,13 and corrosion products may deposit in the gingival tissues.14 On the other hand, new developments on all-ceramic systems and adhesive bonding techniques have resulted in enhanced esthetics and have created new ways of looking at resistance and retention properties of the completed restorations. Moreover, the importance of conserving the remaining tooth structure has become an advocated concept. Vita Celay Blank ceramic blocks have been used for the fabrication of the restorations in this clinical report. It has been acknowledged that they offer high functional strength and display superb marginal fit.15,16 Marginal fidelity is in the range of 50 m, but should better marginal adaptation be desired or a discrepancy exist, 567
¨ K, GU ¨ R, AND AKKAYAN SEVU
THE JOURNAL OF PROSTHETIC DENTISTRY
the optimizer porcelain margin material (Optimizer; Vita) can be used to close the margins even further. The optimizer, a porcelain powder with a wax binder, is applied with an electronic waxer and then fired in a furnace.15 Vita Celay Blank ceramic blocks are available in 3 shades (A2, A3, A3.5) and various sizes.10 The translucency of the material is between that of dentin and enamel porcelain. It is possible to custom characterize the restoration with Delta stains (Vita) and Alpha porcelain (Vita).10,15 It is always imperative to remember the potential for fracture of ceramic veneers during cementation.10,11 The preliminary seating of the veneers should be performed from the incisofacial, with the porcelain incisal edge used as a guide to seating, and gentle finger pressure should be applied. After removal of the excess resin cement, the distal half of the facial surface of the veneer is covered with a finger, and light pressure is exerted upward and inward to ensure accurate placement before the resin cement is then light cured.11 The precise transfer of the details of the preparation is a critical step for ensuring the accuracy of fit of allceramic restorations. Distortion may result from dimensional changes of the impression material, as well as during the manufacture of the master cast. In this clinical report, patterns were fabricated directly on the prepared teeth by use of the autopolymerizing resin; with this direct technique, no other impression was needed. Use of this method reduced the number of appointments and the time spent on laboratory procedures, which was a great benefit for the patient, the dentist, and the dental technician.
SUMMARY The fabrication of one-piece all-ceramic coronal post and laminate veneer restoration with Celay copy-milling system provided this patient with satisfactory longevity, esthetics, and function. The procedure used suggested an alternative treatment modality by conserving the remaining tooth structure of the endodontically treated teeth and achieving an excellent result of replicating the natural state of dentition.
568
REFERENCES 1. Caputo AE, Standlee PJ. Biomechanics in clinical dentistry. Chicago: Quintessence; 1987. p. 185-203. 2. Walton RE, Torabinejad M. Principles and practice of endodontics. Philadelphia: WB Saunders; 1989. p. 249-62. 3. Cohen S, Burns CR. Pathways of the pulp. 5th ed. St Louis: CV Mosby; 1991. p. 640-81. 4. Huang TJ, Schilder H, Nathanson D. Effects of moisture content and endodontic treatment on some mechanical properties of human dentin. J Endod 1992;18:209-15. 5. Trope M, Ray HL Jr. Resistance to fracture of endodontically treated roots. Oral Surg Oral Med Oral Pathol 1992;73:99-102. 6. Sedgley CM, Messer HH. Are endodontically treated teeth more brittle? J Endod 1992;18:332-5. 7. ten Bosch JJ, Coops JC. Tooth color and reflectance as related to light scattering and enamel hardness. J Dent Res 1995;74:374-80. 8. Wasson W, Schuman N. Color vision and dentistry. Quintessence Int 1992;23:349-53. 9. Carossa S, Lombardo S, Pera P, Corsalini M, Rastello ML, Preti PG. Influence of posts and cores on light transmission through different allceramic crowns: spectrophotometric and clinical evaluation. Int J Prosthodont 2001;14:9-14. 10. Schmidseder J. Aesthetic dentistry: color atlas of dental medicine. Stutgart: Thieme; 2000. p. 225-34. 11. Rufenacht CR. Fundamentals of esthetics. Chicago: Quintessence; 1990. p. 360-6. 12. Pissis P. Fabrication of a metal-free ceramic restoration utilizing the monobloc technique. Pract Periodontics Aesthet Dent 1995;7:83-94. 13. Meyenberg KH. Dental esthetics: a European perspective. J Esthet Dent 1994;6:274-81. 14. Takeda T, Ishigami K, Shimada A, Ohki K. A study of discoloration of the gingiva by artifical crowns. Int J Prosthodont 1996;9:197-202. 15. McLaren EA, Sorensen JA. Fabrication of conservative ceramic restorations using copy-milling technology. Special reprint. Quintessence Dent Tech 1994;17:19-25. 16. Groten M, Girthofer S, Probster L. Marginal fit consistency of copy-milled all-ceramic crowns during fabrication by light and scanning electron microscopic analysis in vitro. J Oral Rehabil 1997;24:871-81. 17. Friedman MJ. The enamel ceramic alternative: porcelain veneers vs metal ceramic crowns. J Calif Dent Assoc 1992;20:27-33. 18. Sorensen JA, Strutz JM, Avera SP, Materdomini D. Marginal fidelity and microleakage of porcelain veneers made by two techniques. J Prosthet Dent 1992;67:16-22. Reprint requests to: DR HASIM GU¨R UNIVERSITY OF ISTANBUL, FACULTY OF DENTISTRY DEPARTMENT OF PROSTHETIC DENTISTRY 34390 C¸APASTANBUL TURKEY FAX: 90 212 534 4496 E-MAIL: [email protected] Copyright © 2002 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2002/$35.00 ⫹ 0 10/1/129376 doi:10.1067/mpr.2002.129376
VOLUME 88 NUMBER 6
A
common problem with the restoration of endodontically treated teeth complicated by total or partial loss of coronal tooth structure is deciding on the best restoration alternative. It has been suggested that root canal-treated teeth require restorations to prevent fracture.1,2 Studies reported the effect of decreased moisture content and subsequent brittleness of endodontically treated teeth,2-5 whereas Sedgley and Messer6 concentrated on the loss of both internal and external tooth structure as a cause of fracture. It therefore seems important to use a technique that minimizes these risks and best accommodates the clinical conditions and the patient’s desires. Although dentists are interested in the fracture resistance and marginal accuracy of the completed restorations to ensure clinical success, patients seem to be concerned primarily with improved esthetics.7-11 Because of this concern, all-ceramic restorations have been suggested as an alternative to solve the esthetic problems associated with metal-ceramic restorations.12-16 Porcelain laminate restorations have been proposed as a treatment modality, with conservative preparation design and excellent esthetics. It has been reported that a porcelain laminate veneer requires at least 50% of intact enamel surface area to maintain adequate resistance and retention.17 However, in this clinical report, the final preparation of the teeth did not exactly fit this criterion, because too much palatal and coronal tooth structure had been lost. Sorensen et al18 stated that in teeth where more than 50% of the intact enamel surface area has been lost because of excessive decay or access preparations for endodontic treatment, laminate veneer restorations would have some limitations with respect to retention and resistance. Because of this concern, the fabrication of postlike features called coronal posts, which hardly engage the root canal spaces, were planned to provide additional retention in this clinical situation. Moreover, a
Professor, Department of Prosthetic Dentistry. Associate Professor, Department of Prosthetic Dentistry. c Research assistant, Department of Prosthetic Dentistry. b
DECEMBER 2002
Fig. 1. View of maxillary right and left lateral incisors with defective composite restorations.
the need for adequate retention and resistance was fulfilled with the use of adhesive bonding techniques. This clinical report describes the fabrication of onepiece all-ceramic coronal post and laminate veneer restorations by use of the Celay copy-milling system (Mikrona AG, Spreitenbach, Switzerland) and Vita Celay Blanks (Vita, Bad Sa¨ckingen, Germany).
CLINICAL REPORT A 28-year-old female patient was referred to the clinic with esthetic concerns related to her defective composite restorations on the maxillary right and left lateral incisors (Fig. 1). The patient requested new, tooth-colored restorations that would also ensure satisfactory longevity. After the clinical and radiographic examination, it was detected that endodontic treatment had been completed on both lateral incisors. The defective restorations were removed, and the preliminary shades were selected before tooth preparation. Coronal tooth structure was prepared for porcelain veneer restorations, starting with a depth cutting diamond stone (Brasseler Laminate Veneer System Set; Brasseler, Savannah, Ga.). A low-speed hand-piece and finishing burs (7702-7103; Midwest Dental, Des Plaines, Ill.) were used to remove the caries extending THE JOURNAL OF PROSTHETIC DENTISTRY 565
THE JOURNAL OF PROSTHETIC DENTISTRY
¨ K, GU ¨ R, AND AKKAYAN SEVU
Fig. 2. Preparation of lateral incisors for one-piece all-ceramic coronal post and laminate veneer restoration. A, Right. B, Left.
Fig. 3. A, Direct build-up of resin patterns for coronal posts and laminate veneer restorations. B, Autopolymerizing resin patterns tried in mouth.
into dentin. The preparation included a rounded incisal edge terminating palatally with a heavy chamfer, and all the other line angles were slightly rounded. The canal orifices were enlarged with number 2 and 3 Gates Glidden drills (Maillefer, Ballaigues, Switzerland). The preparations were then completed for a resin-bonded, onepiece all-ceramic coronal post and porcelain laminate veneer restoration, with great attention to conserving the remaining tooth structure (Fig. 2). Retraction cord was placed and delicately deepened to the degree necessary to expose the subgingival finish line that extended facially and proximally below the tissue level. Patterns of the preparations were fabricated with autopolymerizing resin (Pattern Resin; GC Corp, Tokyo, Japan). The resin was mixed according to the powder/liquid ratio specified by the manufacturer and was immediately injected into the base of the preparation. To minimize the effects of polymerization shrinkage, the resin was applied in small volumes. After the polymerization of the first resin mix, a new mix was prepared and applied with a syringe along the entire 566
gingival and proximal finish lines. The resin patterns were then refined with new mixes of autopolymerizing resin until the patterns of the entire restorations were accomplished. The accurate fit of the resin patterns was checked under magnification. Resin patterns of the coronal post and laminate veneer preparations were thus modeled directly in the mouth (Fig. 3). One of the completed resin patterns was mounted to the copying chamber of the Celay machine, and the reference-scanning disc was placed. The appropriate size and shade of the porcelain blank was chosen and fixed to the tracing chamber accordingly. The reference disc acted as a scanning stylus moving across the surface of the resin pattern, while the diamond disc in the second chamber duplicated the exact movements of the scanner. Thus the resin pattern was surface-traced and copied in ceramic block (Fig. 4, A). The same procedure was applied for the other resin pattern (Fig. 4, B), and the restorations were then glazed and polished. The final restorations were checked for accuracy of fit in the mouth. VOLUME 88 NUMBER 6
¨ K, GU ¨ R, AND AKKAYAN SEVU
THE JOURNAL OF PROSTHETIC DENTISTRY
Fig. 4. One-piece all-ceramic coronal post and laminate veneer restoration milled from Vita Celay for lateral incisors. A, Right. B, Left.
The restoration was then inserted and the excess cement was removed. Total set of the resin cement was achieved by use of a polymerizing lamp applied for 60 seconds to each surface of the restoration. The excess hardened cement was removed from marginal areas with polishing disks (Soflex; 3M Dental, Duluth, Minn.) of decreasing coarseness. The final restorations provided the patient with a functional restoration that also accommodates her desires (Fig. 5). The patient was scheduled for maintenance every 6 months, and the restorations have been in place for 20 months. Fig. 5. Final restorations, facial view.
The restorations were cemented with an adhesive bonding technique (Variolink II; Vivadent, Schaan, Liechtenstein) according to the manufacturer’s guidelines. The inner surface of the ceramic restoration was etched with 4.9% hydrofluoric acid for 15 seconds (IPS Ceramic etching gel; Vivadent), rinsed for 10 seconds, and then dried for 5 seconds. A layer of silane compound (Monobond-S; Vivadent), used as a coupling agent on the porcelain restoration, was allowed to air dry. An unfilled resin-bonding agent (Heliobond; Vivadent) was applied with a brush and thinned with an air syringe for 5 seconds. The prepared tooth surfaces were etched for 45 seconds with 37% phosphoric acid (Total Etch; Vivadent), and the preparation was then washed under water for 60 seconds and dried with an air jet for 30 seconds. The primer (Syntac Primer; Vivadent) and the dentinal adhesive (Syntac Adhesive; Vivadent) were applied consecutively, and each was allowed to act for 15 seconds. An unfilled resin (Heliobond; Vivadent) was then applied with a brush and homogeneously sprayed with air. A dual-cure cement of the selected shade (Variolink II; Vivadent) was mixed and placed in the cavity. DECEMBER 2002
DISCUSSION The restorative material and the technique used for the restoration of severely damaged teeth can be particularly important in endodontically treated teeth, which frequently need coronal restorations. The restoration of anterior teeth with metal-ceramic restorations may lead to compromised esthetics because of the limited translucence of metal-ceramic porcelains and opaque metal substructures.12 Metal substructure may also shine through in the cervical root areas, thus altering the appearance of thin gingival tissue,13 and corrosion products may deposit in the gingival tissues.14 On the other hand, new developments on all-ceramic systems and adhesive bonding techniques have resulted in enhanced esthetics and have created new ways of looking at resistance and retention properties of the completed restorations. Moreover, the importance of conserving the remaining tooth structure has become an advocated concept. Vita Celay Blank ceramic blocks have been used for the fabrication of the restorations in this clinical report. It has been acknowledged that they offer high functional strength and display superb marginal fit.15,16 Marginal fidelity is in the range of 50 m, but should better marginal adaptation be desired or a discrepancy exist, 567
¨ K, GU ¨ R, AND AKKAYAN SEVU
THE JOURNAL OF PROSTHETIC DENTISTRY
the optimizer porcelain margin material (Optimizer; Vita) can be used to close the margins even further. The optimizer, a porcelain powder with a wax binder, is applied with an electronic waxer and then fired in a furnace.15 Vita Celay Blank ceramic blocks are available in 3 shades (A2, A3, A3.5) and various sizes.10 The translucency of the material is between that of dentin and enamel porcelain. It is possible to custom characterize the restoration with Delta stains (Vita) and Alpha porcelain (Vita).10,15 It is always imperative to remember the potential for fracture of ceramic veneers during cementation.10,11 The preliminary seating of the veneers should be performed from the incisofacial, with the porcelain incisal edge used as a guide to seating, and gentle finger pressure should be applied. After removal of the excess resin cement, the distal half of the facial surface of the veneer is covered with a finger, and light pressure is exerted upward and inward to ensure accurate placement before the resin cement is then light cured.11 The precise transfer of the details of the preparation is a critical step for ensuring the accuracy of fit of allceramic restorations. Distortion may result from dimensional changes of the impression material, as well as during the manufacture of the master cast. In this clinical report, patterns were fabricated directly on the prepared teeth by use of the autopolymerizing resin; with this direct technique, no other impression was needed. Use of this method reduced the number of appointments and the time spent on laboratory procedures, which was a great benefit for the patient, the dentist, and the dental technician.
SUMMARY The fabrication of one-piece all-ceramic coronal post and laminate veneer restoration with Celay copy-milling system provided this patient with satisfactory longevity, esthetics, and function. The procedure used suggested an alternative treatment modality by conserving the remaining tooth structure of the endodontically treated teeth and achieving an excellent result of replicating the natural state of dentition.
568
REFERENCES 1. Caputo AE, Standlee PJ. Biomechanics in clinical dentistry. Chicago: Quintessence; 1987. p. 185-203. 2. Walton RE, Torabinejad M. Principles and practice of endodontics. Philadelphia: WB Saunders; 1989. p. 249-62. 3. Cohen S, Burns CR. Pathways of the pulp. 5th ed. St Louis: CV Mosby; 1991. p. 640-81. 4. Huang TJ, Schilder H, Nathanson D. Effects of moisture content and endodontic treatment on some mechanical properties of human dentin. J Endod 1992;18:209-15. 5. Trope M, Ray HL Jr. Resistance to fracture of endodontically treated roots. Oral Surg Oral Med Oral Pathol 1992;73:99-102. 6. Sedgley CM, Messer HH. Are endodontically treated teeth more brittle? J Endod 1992;18:332-5. 7. ten Bosch JJ, Coops JC. Tooth color and reflectance as related to light scattering and enamel hardness. J Dent Res 1995;74:374-80. 8. Wasson W, Schuman N. Color vision and dentistry. Quintessence Int 1992;23:349-53. 9. Carossa S, Lombardo S, Pera P, Corsalini M, Rastello ML, Preti PG. Influence of posts and cores on light transmission through different allceramic crowns: spectrophotometric and clinical evaluation. Int J Prosthodont 2001;14:9-14. 10. Schmidseder J. Aesthetic dentistry: color atlas of dental medicine. Stutgart: Thieme; 2000. p. 225-34. 11. Rufenacht CR. Fundamentals of esthetics. Chicago: Quintessence; 1990. p. 360-6. 12. Pissis P. Fabrication of a metal-free ceramic restoration utilizing the monobloc technique. Pract Periodontics Aesthet Dent 1995;7:83-94. 13. Meyenberg KH. Dental esthetics: a European perspective. J Esthet Dent 1994;6:274-81. 14. Takeda T, Ishigami K, Shimada A, Ohki K. A study of discoloration of the gingiva by artifical crowns. Int J Prosthodont 1996;9:197-202. 15. McLaren EA, Sorensen JA. Fabrication of conservative ceramic restorations using copy-milling technology. Special reprint. Quintessence Dent Tech 1994;17:19-25. 16. Groten M, Girthofer S, Probster L. Marginal fit consistency of copy-milled all-ceramic crowns during fabrication by light and scanning electron microscopic analysis in vitro. J Oral Rehabil 1997;24:871-81. 17. Friedman MJ. The enamel ceramic alternative: porcelain veneers vs metal ceramic crowns. J Calif Dent Assoc 1992;20:27-33. 18. Sorensen JA, Strutz JM, Avera SP, Materdomini D. Marginal fidelity and microleakage of porcelain veneers made by two techniques. J Prosthet Dent 1992;67:16-22. Reprint requests to: DR HASIM GU¨R UNIVERSITY OF ISTANBUL, FACULTY OF DENTISTRY DEPARTMENT OF PROSTHETIC DENTISTRY 34390 C¸APASTANBUL TURKEY FAX: 90 212 534 4496 E-MAIL: [email protected] Copyright © 2002 by The Editorial Council of The Journal of Prosthetic Dentistry. 0022-3913/2002/$35.00 ⫹ 0 10/1/129376 doi:10.1067/mpr.2002.129376
VOLUME 88 NUMBER 6