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Fixed dental prostheses with vertical tooth preparations without finish lines: A report of two patients
CLINICAL REPORT
Fixed dental prostheses with vertical tooth preparations without finish lines: A report of two patients Rubén Agustín-Panadero, DMD, PhD,a María Fernanda Solá-Ruíz, DMD, PhD, MD,b César Chust, CDT,c and Alberto Ferreiroa, DMD, PhDd Treatment with tooth-supported ABSTRACT fixed dental prostheses (FDPs) Tooth abutments can be prepared to receive fixed dental prostheses with different types of finish remains one of the most lines. The literature reports different complications arising from tooth preparation techniques, commonly applied options for including gingival recession. Vertical preparation without a finish line is a technique whereby the replacing missing teeth and abutments are prepared by introducing a diamond rotary instrument into the sulcus to eliminate offers good long-term clinical the cementoenamel junction and to create a new prosthetic cementoenamel junction determined by the prosthetic margin. This article describes 2 patients whose dental abutments were prepared survival.1-5 However, FDPs can to receive ceramic restorations using vertical preparation without a finish line. (J Prosthet Dent suffer various complications, 2015;-:---) including gingival recession, which may compromise esThis preparation protocol without a finish line offers thetics in the anterior sector.6-8 The reasons for this type of several advantages. Clinicians can correct the position of complication include the relationship between the preparathe CEJ on both nonprepared and previously prepared tion of dental abutments and chronic gingival inflammation teeth, the latter eliminating the preexisting finish line. produced by inadequate marginal fit between the abutment At the same time, a new prosthetic CEJ is created by and FDP.4 placing the prosthesis so as to leave the gingival margin Traditionally, when clinicians prepare dental abutat the desired position (obtaining the optimal esthetic ments to receive FDPs, they create a finish line on the outcome in cases of compromised esthetics). Additiontooth on which the prosthetic restoration rests.9,10 This ally, this reorganization of the CEJ by means of the can be located supragingivally or subgingivally, with the prosthesis increases gingival thickness and generates latter being more likely to produce gingival inflammabetter soft tissue stability in the medium and long tion.11-15 These finish lines can be classified into 2 main term.7,16 The technique also improves prosthetic groups: horizontal finish lines, which include curved 6 retention, allows optimal fit between the tooth and chamfer, flat chamfer, and straight shoulder, or vertical restoration, preserves dental structure, and simplifies lines, which include feather or knife-edge margins. An the impression procedure as compared with dental alternative for dental preparation without a finish line, preparation with finish lines.7 known as the biologically oriented preparation technique 7 This clinical report describes 2 patients whose prep(BOPT), can be used for FDPs. The clinician removes the aration to receive FDPs was performed using the vertical emergence of the anatomic crown, which coincides with preparation protocol described by Agustín-Panadero and the cementoenamel junction (CEJ), to create a new Solá-Ruíz,16 reporting outcomes at 24 months after prosthetic junction situated according to the desired placement of the definitive restoration. location of the gingival margin.
a
Associate Professor, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain. Adjunct Professor, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain. c Laboratory technician, Valencia, Spain. d Associate Professor, Department of Buccofacial Prosthesis (Stomatology I), University Complutense of Madrid, Madrid, Spain. b
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Figure 1. Preoperative intraoral view.
CLINICAL REPORT Patient 1 A 45-year-old woman without medical problems came to a private dental clinic hoping to correct esthetic problems. Intraoral examination revealed Grade III mobility of the maxillary right lateral incisor (with a hopeless prognosis due to periodontal disease), absence of the maxillary right central incisor, and a thick gingival biotype (Fig. 1). After intraoral examination, the treatment plan was to provide a zirconia FDP from the maxillary right canine to the maxillary left central incisor, to extract the maxillary right lateral incisor, and to follow the vertical preparation protocol without finish line for the abutment teeth. Initially, a double probing was performed first to measure the depth of the gingival sulcus and then to measure the bone level and locate the CEJ, as this determines the limit of preparation of the dental abutment. Determining the location of the bone is also essential, as this must not be contacted during tooth preparation. Tooth preparation began by reducing the incisal edge of the dental abutments by 2 mm. The axial walls were reduced by 1 mm with a chamfer diamond rotary instrument (1.4 mm size) (ADO-881, G014; Ancladén SL) (Fig. 2A). Then the internal wall of the sulcus and the tooth were prepared at the same time with a conical diamond rotary instrument (862.514.012 BOPT drills; Sweden & Martina) with a particle size of 100/200 and a diameter of 1.2 mm. The diamond rotary instrument was introduced into the sulcus at an angle of 15 degrees (Fig. 2B).16 The purpose of this first stage was to eliminate 1 mm from the emergence of the anatomic crown. Then, in order to avoid creating a finish line, the diamond rotary instrument was situated parallel to the tooth axis between the root and crown so that it removed tooth structure with the instrument’s body rather than the tip. Both the tooth and gingiva were prepared at the same time (Fig. 2C). During BOPT, the rotary instrument interacted with the
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internal wall or the internal sulcus and the gingival epithelium up to the point where the CEJ was situated. This preparation step aims to eliminate the emergence area of the tooth crown while the soft tissues are prepared. The CEJ is located approximately at the level of the interface between the junctional epithelium and connective tissue. At this stage, the operator removed epithelial tissue from a controlled area of the free epithelial sulcus and junctional epithelium. In turn, the most coronal connective tissue was also prepared to a depth of 0.3 mm (Fig. 3). This procedure creates a blood clot at the apical level of the preparation which stabilizes in the presence of the interim restoration to stimulate fibroblast differentiation and gingival tissue growth. This process forms a new periodontal structure around the new emergence morphology of the interim restoration and subsequently around the definitive prosthesis (Fig. 4).16 Interim restorations fabricated by a dental laboratory technician were relined and adapted. Using the interim restorations, a CEJ was created with the new emergence profile (Fig. 5). The interim restorations were located at a depth of 0.5 to 1 mm into the sulcus, respecting biologic width (Fig. 6). For this patient, an ovoid pontic was used to remodel the soft tissues in the absence of teeth (Fig. 7). After 8 weeks, the soft tissues had a healthy aspect, and the interim restorations were removed (Fig. 8). Treatment proceeded with a 2-step impression technique with elastomers (Light Body and Virtual putty; Ivoclar Vivadent AG) and 2 gingival displacement cords (Ultrapack #000; Ultradent Products Inc). The definitive prosthesis was created on the basis of the biologic and functional parameters of the interim restorations. A zirconia framework (IPS e.maxZirCAD; Ivoclar Vivadent AG) was fabricated by computer-aided design/computer-aided manufacturing. After the zirconium dioxide framework (IPS e.maxCeram; Ivoclar Vivadent AG) had been placed, the esthetics, marginal and internal fit, interproximal contacts, and occlusion were evaluated at the bisque bake stage. Minimal occlusal adjustments were required. The internal surfaces of the zirconia FDP were airborne-particle abraded with tribochemical silicacoated 30 mm Al2O3 (CoJet Prep; 3M ESPE). A zirconia primer was then applied for 5 seconds (Z-PRIME Plus; Bisco) and air dried. The teeth were also treated with 35% phosphoric acid for 40 seconds, followed by a 30second application of a desensitizer (Gluma; Heraeus Kulzer). The FDP was then cemented with dualpolymerizing resin cement (RelyX Unicem 2 Automix; 3M ESPE) that was light polymerized. The patient was instructed in oral hygiene and the care of the new prosthesis. Follow-up evaluations were made at 3, 6, 12, and 24 months after the placement of the definitive prosthesis. No mechanical, esthetic, or biologic complications were Agustín-Panadero et al
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Figure 2. Simplified protocol for BOPT preparation. A, Preparation with supragingival finish line. B, Elimination of first millimeter of anatomic crown emergence (15 degrees’ angulation). C, Creation of vertical axial plane between crown and root.
Figure 3. Facial view of vertical abutment preparation.
Figure 4. Occlusal view of vertical abutment preparation.
Figure 5. Interim prosthesis after 8 weeks of gingival healing.
Figure 6. Facial view of gingival healing.
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Figure 7. Occlusal view of soft tissues with healthy status around dental abutments.
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Figure 8. Widening of gingival sulcus.
noted (Fig. 9). The periodontal status of the tooth abutments was assessed, showing probing depths within accepted ranges of periodontal health no more than 3 mm), no signs of inflammation, and no bleeding at the time of assessment. Patient 22 A 40-year-old man was referred from a private dental clinic to the University of Valencia dental clinic for assessment before being treated with fixed prostheses in the anterior sector. Clinical analysis observed extensive composite resin restorations of the maxillary central incisors with poor esthetics (Fig. 10). The patient presented a thick gingival biotype. The treatment plan was to use the vertical tooth preparation protocol to prepare dental abutments of the maxillary right central incisor and maxillary left central incisor to receive 2 zirconia crowns. The procedure began with the double probing technique as in patient 1. The teeth were prepared with a conical diamond rotary instrument (862.514.012 BOPT drills; Sweden & Martina) with a 100/200 particle size and a 1.2 mm diameter, which was used to penetrate the gingival sulcus following the same preparation protocol as in patient 1 (Fig. 11).16 After tooth preparation (Figs. 12, 13), interim restorations were then adjusted and relined with an autopolymerizable acrylic resin (Sintodent White; Sintodent). Relining the interim prosthesis allowed the acrylic resin to penetrate the gingival sulcus in an apical direction pushing tissue outward to reproduce maximum sulcus opening. This procedure reproduced 2 areas: a circumferential line that determined the extension of the gingival sulcus and an outer circumferential area that marked the position of the gingival margin. Between these areas, a groove is formed in the interim prosthesis, with its depth depending on the distance between the gingival margin and the margin-milling depth. The groove created will be filled with photopolymerizing
THE JOURNAL OF PROSTHETIC DENTISTRY
Figure 9. Postoperative intraoral view.
flowable composite resin (Filtek Supreme XTE flow; 3M ESPE) (Fig. 14). This union creates the interim restoration’s cervical emergence profile (Fig. 15). After 8 weeks, when gingival tissue maturation was almost complete, the interim restorations were removed (Figs. 16-18).10 The soft tissues were evaluated before
Figure 10. Preoperative intraoral view.
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Figure 11. Vertical preparation with diamond rotary instrument angled at 15 degrees in gingival sulcus.
Figure 12. Facial view of vertical abutment preparation.
Figure 13. Occlusal view of vertical abutment preparation.
Figure 14. Preparation sequence for interim restoration. Image on left shows 2 lines obtained in clinical relining procedure; white arrow indicates end of sulcus; yellow arrow indicates gingival margin. Central image shows union of 2 lines with photopolymerizable flowable composite resin. Interim restoration finished with knife-edge finish line, which is introduced 0.5 mm into sulcus.
making a 2-step impression with elastomers using 2 displacement cords (Ultrapack #000; Ultradent Products Inc). Two zirconia crowns were fabricated, and bonding was carried out in the same way as in patient 1. The patient returned for assessment at 3, 6, 12, and 24 months after definitive crown placement (Fig. 19). No mechanical, esthetic, or biologic complications were noted. The periodontal status of the tooth abutments was assessed, presenting probing depths of 1 to 3 mm, without bleeding or signs of gingival inflammation. DISCUSSION This protocol aims to stabilize gingival tissue in the medium and long term. In this technique, the restoration margin is located at subgingival level, but several studies have shown that restorations placed below the gingival margin are associated with periodontal inflammation and therefore possible gingival displacement.8,9 However, in the present patients, this dental abutment preparation protocol obtained good outcomes for soft tissue health and esthetics, free of any signs of inflammation. This Agustín-Panadero et al
technique respects biologic width dimensions10 by controlling the invasion of the sulcus without invading the epithelial attachment. This avoids complications related to the traditional preparation with finish line2-4 and produces a good periodontal tissue response. In this protocol for preparing dental abutments, the CEJ is reorganized by means of the prosthesis, which permits good management of new tooth contours. After tooth preparation, the process begins with fibroblast stimulation and their migration to the damaged area,11 which the dentist promotes by means of the vertical dental preparation; placement of the interim restorations stabilizes the resulting blood clot. The interim restoration is exploited to guide gingival remodeling by overcontouring or undercontouring the prosthesis. Overcontouring toothsupported restorations produce an apical displacement of the margin, while undercontouring produces the opposite
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Figure 15. Facial view of cervical area of interim restoration and soft tissues after 8 weeks.
Figure 16. Facial view of dental abutments with good appearance of papilla.
Figure 17. Occlusal view of gingival healing.
Figure 18. Widening of gingival sulcus.
effect.12 According to the particularities of the situation, the dentist can add or remove material from the interim restoration to guide soft tissue maturation. Furthermore, the margin of the interim restoration can be shortened or extended to reach different levels of the gingival sulcus. This establishes the position of the gingival margin, which will help balance soft tissue esthetics in terms of the margin position and the zenith position.13 Several studies have reported that overcontouring the restoration with a finish line on the dental abutment can produce inflammation and possible biologic complications.14 However, in spite of the known association between excessive overcontouring and gingival inflammation, no signs of inflammation were registered in the present patients. The technique is accompanied by increasing gingival tissue thickness, produced by reducing the dental abutment in the buccolingual direction.7 The soft tissues occupy this space and increase in thickness. Increased vascularization also takes place, decreasing the risk of gingival displacement, regardless of whether patients present thin or thick gingival biotypes. This situation is produced as a result of eliminating the CEJ and
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Figure 19. Postoperative facial view.
deepithelizing the gingival sulcus. The increase in soft tissues and increased vascularization also helps achieve long-term stability.15 The vertical preparation technique without finish line has drawbacks. The technique is complex and clinically more time-consuming. Situating the line of the prosthetic Agustín-Panadero et al
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margin adequately is difficult because there is no dental finish line to refer to. For the dentist or laboratory technician with little experience of the procedure, there is a risk of uncontrolled invasion of the sulcus. Excess cement is difficult to remove. The technique has not been backed by scientific evidence, and no published research is available. In our experience, vertical dental abutment preparation without a finish line does not appear to increase the risk of definitive prosthesis fracture. Using this protocol, not only can metal ceramic restorations be used for the definitive restoration but also zirconia and lithium disilicate crowns. Several studies have demonstrated that these ceramic materials offer sufficient fracture resistance to allow this type of vertical preparation without horizontal support on dental abutments in the anterior sector; they do not suffer mechanical complications.17 Furthermore, the technique adapts the crown to the dental abutment well. SUMMARY Vertical preparation without a finish line on the teeth is an alternative procedure for FDPs. It increases soft tissue thickness, achieves good esthetic results, and promotes healthy and stable soft tissues. No mechanical complications have been observed using this technique for ceramic restorations. Nevertheless, clinical studies are needed to confirm the results of these clinical reports and to validate the technique. REFERENCES 1. Walton TR. An up to 15-year longitudinal study of 515 metal-ceramic FDPs: part 1. Outcome. Int J Prosthodont 2002;15:439-45. 2. Walton TR. An up to 15-year longitudinal study of 515 metal-ceramic FDPs: part 2. Modes of failure and influence of various clinical characteristics. Int J Prosthodont 2003;16:177-82.
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3. Walton TR. Making sense of complication reporting associated with fixed dental prostheses. Int J Prosthodont 2014;27:114-8. 4. Podhorsky A, Rehmann P, Wöstmann B. Tooth preparation for fullcoverage restorations-a literature review. Clin Oral Investig 2015;19: 959-68. 5. Moretti LA, Barros RR, Costa PP, Oliveira FS, Ribeiro FJ, Novaes AB Jr, et al. The influence of restorations and prosthetic crowns finishing lines on inflammatory levels after non-surgical periodontal therapy. J Int Acad Periodontol 2011;13:65-72. 6. Tsitrou EA, Northeast SE, van Noort R. Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM. J Dent 2007;35: 68-73. 7. Loi I, Di Felice A. Biologically oriented preparation technique (BOPT): a new approach for prosthetic restoration of periodontically healthy teeth. Eur J Esthet Dent 2013;8:10-23. 8. Silness J. Periodontal conditions in patients treated with dental bridges. 3. The relationship between the location of the crown margin and the periodontal condition. J Periodontal Res 1970;5:225-9. 9. Orkin DA, Reddy J, Bradshaw D. The relationship of the position of crown margins to gingival health. J Prosthet Dent 1987;57:421-4. 10. Lanning SK, Waldrop TC, Gunsolley JC, Maynard JG. Surgical crown lengthening: evaluation of the biological width. J Periodontol 2003;74: 468-74. 11. Chiquet M, Katsaros C, Kletsas D. Multiple functions of gingival and mucoperiosteal fibroblasts in oral wound healing and repair. Periodontol 2000 2015;68:21-40. 12. Su H, Gonzalez-Martin O, Weisgold A, Lee E. Considerations of implant abutment and crown contour: critical contour and subcritical contour. Int J Periodontics Restorative Dent 2010;30:335-43. 13. Gracis S, Fradeani M, Celletti R, Bracchetti G. Biological integration of aesthetic restorations: factors influencing appearance and long-term success. Periodontol 2000 2015;68:21-40. 14. Creugers NH, Snoek PA, Vogels AL. Overcontouring in resin-bonded prostheses: plaque accumulation and gingival health. J Prosthet Dent 1988;59:17-21. 15. Kleinheinz J, Büchter A, Fillies T, Joos U. Vascular basis of mucosal color. Head Face Med 2005;24;1:4. 16. Agustín-Panadero R, Solá-Ruíz MF. Vertical preparation for fixed prosthesis rehabilitation in the anterior sector. J Prosthet Dent 2015;114:474-8. 17. Agustín-Panadero R, Román-Rodríguez JL, Ferreiroa A, Solá-Ruíz MF, FonsFont A. Zirconia in fixed prosthesis: a literature review. J Clin Exp Dent 2014;6:66-73. Corresponding author: Dr Maria Fernanda Solá-Ruíz University of Valencia C/ Gascó Oliag, 1 46021 Valencia SPAIN Email: [email protected] Copyright © 2015 by the Editorial Council for The Journal of Prosthetic Dentistry.
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Fixed dental prostheses with vertical tooth preparations without finish lines: A report of two patients Rubén Agustín-Panadero, DMD, PhD,a María Fernanda Solá-Ruíz, DMD, PhD, MD,b César Chust, CDT,c and Alberto Ferreiroa, DMD, PhDd Treatment with tooth-supported ABSTRACT fixed dental prostheses (FDPs) Tooth abutments can be prepared to receive fixed dental prostheses with different types of finish remains one of the most lines. The literature reports different complications arising from tooth preparation techniques, commonly applied options for including gingival recession. Vertical preparation without a finish line is a technique whereby the replacing missing teeth and abutments are prepared by introducing a diamond rotary instrument into the sulcus to eliminate offers good long-term clinical the cementoenamel junction and to create a new prosthetic cementoenamel junction determined by the prosthetic margin. This article describes 2 patients whose dental abutments were prepared survival.1-5 However, FDPs can to receive ceramic restorations using vertical preparation without a finish line. (J Prosthet Dent suffer various complications, 2015;-:---) including gingival recession, which may compromise esThis preparation protocol without a finish line offers thetics in the anterior sector.6-8 The reasons for this type of several advantages. Clinicians can correct the position of complication include the relationship between the preparathe CEJ on both nonprepared and previously prepared tion of dental abutments and chronic gingival inflammation teeth, the latter eliminating the preexisting finish line. produced by inadequate marginal fit between the abutment At the same time, a new prosthetic CEJ is created by and FDP.4 placing the prosthesis so as to leave the gingival margin Traditionally, when clinicians prepare dental abutat the desired position (obtaining the optimal esthetic ments to receive FDPs, they create a finish line on the outcome in cases of compromised esthetics). Additiontooth on which the prosthetic restoration rests.9,10 This ally, this reorganization of the CEJ by means of the can be located supragingivally or subgingivally, with the prosthesis increases gingival thickness and generates latter being more likely to produce gingival inflammabetter soft tissue stability in the medium and long tion.11-15 These finish lines can be classified into 2 main term.7,16 The technique also improves prosthetic groups: horizontal finish lines, which include curved 6 retention, allows optimal fit between the tooth and chamfer, flat chamfer, and straight shoulder, or vertical restoration, preserves dental structure, and simplifies lines, which include feather or knife-edge margins. An the impression procedure as compared with dental alternative for dental preparation without a finish line, preparation with finish lines.7 known as the biologically oriented preparation technique 7 This clinical report describes 2 patients whose prep(BOPT), can be used for FDPs. The clinician removes the aration to receive FDPs was performed using the vertical emergence of the anatomic crown, which coincides with preparation protocol described by Agustín-Panadero and the cementoenamel junction (CEJ), to create a new Solá-Ruíz,16 reporting outcomes at 24 months after prosthetic junction situated according to the desired placement of the definitive restoration. location of the gingival margin.
a
Associate Professor, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain. Adjunct Professor, Department of Stomatology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain. c Laboratory technician, Valencia, Spain. d Associate Professor, Department of Buccofacial Prosthesis (Stomatology I), University Complutense of Madrid, Madrid, Spain. b
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Figure 1. Preoperative intraoral view.
CLINICAL REPORT Patient 1 A 45-year-old woman without medical problems came to a private dental clinic hoping to correct esthetic problems. Intraoral examination revealed Grade III mobility of the maxillary right lateral incisor (with a hopeless prognosis due to periodontal disease), absence of the maxillary right central incisor, and a thick gingival biotype (Fig. 1). After intraoral examination, the treatment plan was to provide a zirconia FDP from the maxillary right canine to the maxillary left central incisor, to extract the maxillary right lateral incisor, and to follow the vertical preparation protocol without finish line for the abutment teeth. Initially, a double probing was performed first to measure the depth of the gingival sulcus and then to measure the bone level and locate the CEJ, as this determines the limit of preparation of the dental abutment. Determining the location of the bone is also essential, as this must not be contacted during tooth preparation. Tooth preparation began by reducing the incisal edge of the dental abutments by 2 mm. The axial walls were reduced by 1 mm with a chamfer diamond rotary instrument (1.4 mm size) (ADO-881, G014; Ancladén SL) (Fig. 2A). Then the internal wall of the sulcus and the tooth were prepared at the same time with a conical diamond rotary instrument (862.514.012 BOPT drills; Sweden & Martina) with a particle size of 100/200 and a diameter of 1.2 mm. The diamond rotary instrument was introduced into the sulcus at an angle of 15 degrees (Fig. 2B).16 The purpose of this first stage was to eliminate 1 mm from the emergence of the anatomic crown. Then, in order to avoid creating a finish line, the diamond rotary instrument was situated parallel to the tooth axis between the root and crown so that it removed tooth structure with the instrument’s body rather than the tip. Both the tooth and gingiva were prepared at the same time (Fig. 2C). During BOPT, the rotary instrument interacted with the
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internal wall or the internal sulcus and the gingival epithelium up to the point where the CEJ was situated. This preparation step aims to eliminate the emergence area of the tooth crown while the soft tissues are prepared. The CEJ is located approximately at the level of the interface between the junctional epithelium and connective tissue. At this stage, the operator removed epithelial tissue from a controlled area of the free epithelial sulcus and junctional epithelium. In turn, the most coronal connective tissue was also prepared to a depth of 0.3 mm (Fig. 3). This procedure creates a blood clot at the apical level of the preparation which stabilizes in the presence of the interim restoration to stimulate fibroblast differentiation and gingival tissue growth. This process forms a new periodontal structure around the new emergence morphology of the interim restoration and subsequently around the definitive prosthesis (Fig. 4).16 Interim restorations fabricated by a dental laboratory technician were relined and adapted. Using the interim restorations, a CEJ was created with the new emergence profile (Fig. 5). The interim restorations were located at a depth of 0.5 to 1 mm into the sulcus, respecting biologic width (Fig. 6). For this patient, an ovoid pontic was used to remodel the soft tissues in the absence of teeth (Fig. 7). After 8 weeks, the soft tissues had a healthy aspect, and the interim restorations were removed (Fig. 8). Treatment proceeded with a 2-step impression technique with elastomers (Light Body and Virtual putty; Ivoclar Vivadent AG) and 2 gingival displacement cords (Ultrapack #000; Ultradent Products Inc). The definitive prosthesis was created on the basis of the biologic and functional parameters of the interim restorations. A zirconia framework (IPS e.maxZirCAD; Ivoclar Vivadent AG) was fabricated by computer-aided design/computer-aided manufacturing. After the zirconium dioxide framework (IPS e.maxCeram; Ivoclar Vivadent AG) had been placed, the esthetics, marginal and internal fit, interproximal contacts, and occlusion were evaluated at the bisque bake stage. Minimal occlusal adjustments were required. The internal surfaces of the zirconia FDP were airborne-particle abraded with tribochemical silicacoated 30 mm Al2O3 (CoJet Prep; 3M ESPE). A zirconia primer was then applied for 5 seconds (Z-PRIME Plus; Bisco) and air dried. The teeth were also treated with 35% phosphoric acid for 40 seconds, followed by a 30second application of a desensitizer (Gluma; Heraeus Kulzer). The FDP was then cemented with dualpolymerizing resin cement (RelyX Unicem 2 Automix; 3M ESPE) that was light polymerized. The patient was instructed in oral hygiene and the care of the new prosthesis. Follow-up evaluations were made at 3, 6, 12, and 24 months after the placement of the definitive prosthesis. No mechanical, esthetic, or biologic complications were Agustín-Panadero et al
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Figure 2. Simplified protocol for BOPT preparation. A, Preparation with supragingival finish line. B, Elimination of first millimeter of anatomic crown emergence (15 degrees’ angulation). C, Creation of vertical axial plane between crown and root.
Figure 3. Facial view of vertical abutment preparation.
Figure 4. Occlusal view of vertical abutment preparation.
Figure 5. Interim prosthesis after 8 weeks of gingival healing.
Figure 6. Facial view of gingival healing.
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Figure 7. Occlusal view of soft tissues with healthy status around dental abutments.
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Figure 8. Widening of gingival sulcus.
noted (Fig. 9). The periodontal status of the tooth abutments was assessed, showing probing depths within accepted ranges of periodontal health no more than 3 mm), no signs of inflammation, and no bleeding at the time of assessment. Patient 22 A 40-year-old man was referred from a private dental clinic to the University of Valencia dental clinic for assessment before being treated with fixed prostheses in the anterior sector. Clinical analysis observed extensive composite resin restorations of the maxillary central incisors with poor esthetics (Fig. 10). The patient presented a thick gingival biotype. The treatment plan was to use the vertical tooth preparation protocol to prepare dental abutments of the maxillary right central incisor and maxillary left central incisor to receive 2 zirconia crowns. The procedure began with the double probing technique as in patient 1. The teeth were prepared with a conical diamond rotary instrument (862.514.012 BOPT drills; Sweden & Martina) with a 100/200 particle size and a 1.2 mm diameter, which was used to penetrate the gingival sulcus following the same preparation protocol as in patient 1 (Fig. 11).16 After tooth preparation (Figs. 12, 13), interim restorations were then adjusted and relined with an autopolymerizable acrylic resin (Sintodent White; Sintodent). Relining the interim prosthesis allowed the acrylic resin to penetrate the gingival sulcus in an apical direction pushing tissue outward to reproduce maximum sulcus opening. This procedure reproduced 2 areas: a circumferential line that determined the extension of the gingival sulcus and an outer circumferential area that marked the position of the gingival margin. Between these areas, a groove is formed in the interim prosthesis, with its depth depending on the distance between the gingival margin and the margin-milling depth. The groove created will be filled with photopolymerizing
THE JOURNAL OF PROSTHETIC DENTISTRY
Figure 9. Postoperative intraoral view.
flowable composite resin (Filtek Supreme XTE flow; 3M ESPE) (Fig. 14). This union creates the interim restoration’s cervical emergence profile (Fig. 15). After 8 weeks, when gingival tissue maturation was almost complete, the interim restorations were removed (Figs. 16-18).10 The soft tissues were evaluated before
Figure 10. Preoperative intraoral view.
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Figure 11. Vertical preparation with diamond rotary instrument angled at 15 degrees in gingival sulcus.
Figure 12. Facial view of vertical abutment preparation.
Figure 13. Occlusal view of vertical abutment preparation.
Figure 14. Preparation sequence for interim restoration. Image on left shows 2 lines obtained in clinical relining procedure; white arrow indicates end of sulcus; yellow arrow indicates gingival margin. Central image shows union of 2 lines with photopolymerizable flowable composite resin. Interim restoration finished with knife-edge finish line, which is introduced 0.5 mm into sulcus.
making a 2-step impression with elastomers using 2 displacement cords (Ultrapack #000; Ultradent Products Inc). Two zirconia crowns were fabricated, and bonding was carried out in the same way as in patient 1. The patient returned for assessment at 3, 6, 12, and 24 months after definitive crown placement (Fig. 19). No mechanical, esthetic, or biologic complications were noted. The periodontal status of the tooth abutments was assessed, presenting probing depths of 1 to 3 mm, without bleeding or signs of gingival inflammation. DISCUSSION This protocol aims to stabilize gingival tissue in the medium and long term. In this technique, the restoration margin is located at subgingival level, but several studies have shown that restorations placed below the gingival margin are associated with periodontal inflammation and therefore possible gingival displacement.8,9 However, in the present patients, this dental abutment preparation protocol obtained good outcomes for soft tissue health and esthetics, free of any signs of inflammation. This Agustín-Panadero et al
technique respects biologic width dimensions10 by controlling the invasion of the sulcus without invading the epithelial attachment. This avoids complications related to the traditional preparation with finish line2-4 and produces a good periodontal tissue response. In this protocol for preparing dental abutments, the CEJ is reorganized by means of the prosthesis, which permits good management of new tooth contours. After tooth preparation, the process begins with fibroblast stimulation and their migration to the damaged area,11 which the dentist promotes by means of the vertical dental preparation; placement of the interim restorations stabilizes the resulting blood clot. The interim restoration is exploited to guide gingival remodeling by overcontouring or undercontouring the prosthesis. Overcontouring toothsupported restorations produce an apical displacement of the margin, while undercontouring produces the opposite
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Figure 15. Facial view of cervical area of interim restoration and soft tissues after 8 weeks.
Figure 16. Facial view of dental abutments with good appearance of papilla.
Figure 17. Occlusal view of gingival healing.
Figure 18. Widening of gingival sulcus.
effect.12 According to the particularities of the situation, the dentist can add or remove material from the interim restoration to guide soft tissue maturation. Furthermore, the margin of the interim restoration can be shortened or extended to reach different levels of the gingival sulcus. This establishes the position of the gingival margin, which will help balance soft tissue esthetics in terms of the margin position and the zenith position.13 Several studies have reported that overcontouring the restoration with a finish line on the dental abutment can produce inflammation and possible biologic complications.14 However, in spite of the known association between excessive overcontouring and gingival inflammation, no signs of inflammation were registered in the present patients. The technique is accompanied by increasing gingival tissue thickness, produced by reducing the dental abutment in the buccolingual direction.7 The soft tissues occupy this space and increase in thickness. Increased vascularization also takes place, decreasing the risk of gingival displacement, regardless of whether patients present thin or thick gingival biotypes. This situation is produced as a result of eliminating the CEJ and
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Figure 19. Postoperative facial view.
deepithelizing the gingival sulcus. The increase in soft tissues and increased vascularization also helps achieve long-term stability.15 The vertical preparation technique without finish line has drawbacks. The technique is complex and clinically more time-consuming. Situating the line of the prosthetic Agustín-Panadero et al
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margin adequately is difficult because there is no dental finish line to refer to. For the dentist or laboratory technician with little experience of the procedure, there is a risk of uncontrolled invasion of the sulcus. Excess cement is difficult to remove. The technique has not been backed by scientific evidence, and no published research is available. In our experience, vertical dental abutment preparation without a finish line does not appear to increase the risk of definitive prosthesis fracture. Using this protocol, not only can metal ceramic restorations be used for the definitive restoration but also zirconia and lithium disilicate crowns. Several studies have demonstrated that these ceramic materials offer sufficient fracture resistance to allow this type of vertical preparation without horizontal support on dental abutments in the anterior sector; they do not suffer mechanical complications.17 Furthermore, the technique adapts the crown to the dental abutment well. SUMMARY Vertical preparation without a finish line on the teeth is an alternative procedure for FDPs. It increases soft tissue thickness, achieves good esthetic results, and promotes healthy and stable soft tissues. No mechanical complications have been observed using this technique for ceramic restorations. Nevertheless, clinical studies are needed to confirm the results of these clinical reports and to validate the technique. REFERENCES 1. Walton TR. An up to 15-year longitudinal study of 515 metal-ceramic FDPs: part 1. Outcome. Int J Prosthodont 2002;15:439-45. 2. Walton TR. An up to 15-year longitudinal study of 515 metal-ceramic FDPs: part 2. Modes of failure and influence of various clinical characteristics. Int J Prosthodont 2003;16:177-82.
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3. Walton TR. Making sense of complication reporting associated with fixed dental prostheses. Int J Prosthodont 2014;27:114-8. 4. Podhorsky A, Rehmann P, Wöstmann B. Tooth preparation for fullcoverage restorations-a literature review. Clin Oral Investig 2015;19: 959-68. 5. Moretti LA, Barros RR, Costa PP, Oliveira FS, Ribeiro FJ, Novaes AB Jr, et al. The influence of restorations and prosthetic crowns finishing lines on inflammatory levels after non-surgical periodontal therapy. J Int Acad Periodontol 2011;13:65-72. 6. Tsitrou EA, Northeast SE, van Noort R. Evaluation of the marginal fit of three margin designs of resin composite crowns using CAD/CAM. J Dent 2007;35: 68-73. 7. Loi I, Di Felice A. Biologically oriented preparation technique (BOPT): a new approach for prosthetic restoration of periodontically healthy teeth. Eur J Esthet Dent 2013;8:10-23. 8. Silness J. Periodontal conditions in patients treated with dental bridges. 3. The relationship between the location of the crown margin and the periodontal condition. J Periodontal Res 1970;5:225-9. 9. Orkin DA, Reddy J, Bradshaw D. The relationship of the position of crown margins to gingival health. J Prosthet Dent 1987;57:421-4. 10. Lanning SK, Waldrop TC, Gunsolley JC, Maynard JG. Surgical crown lengthening: evaluation of the biological width. J Periodontol 2003;74: 468-74. 11. Chiquet M, Katsaros C, Kletsas D. Multiple functions of gingival and mucoperiosteal fibroblasts in oral wound healing and repair. Periodontol 2000 2015;68:21-40. 12. Su H, Gonzalez-Martin O, Weisgold A, Lee E. Considerations of implant abutment and crown contour: critical contour and subcritical contour. Int J Periodontics Restorative Dent 2010;30:335-43. 13. Gracis S, Fradeani M, Celletti R, Bracchetti G. Biological integration of aesthetic restorations: factors influencing appearance and long-term success. Periodontol 2000 2015;68:21-40. 14. Creugers NH, Snoek PA, Vogels AL. Overcontouring in resin-bonded prostheses: plaque accumulation and gingival health. J Prosthet Dent 1988;59:17-21. 15. Kleinheinz J, Büchter A, Fillies T, Joos U. Vascular basis of mucosal color. Head Face Med 2005;24;1:4. 16. Agustín-Panadero R, Solá-Ruíz MF. Vertical preparation for fixed prosthesis rehabilitation in the anterior sector. J Prosthet Dent 2015;114:474-8. 17. Agustín-Panadero R, Román-Rodríguez JL, Ferreiroa A, Solá-Ruíz MF, FonsFont A. Zirconia in fixed prosthesis: a literature review. J Clin Exp Dent 2014;6:66-73. Corresponding author: Dr Maria Fernanda Solá-Ruíz University of Valencia C/ Gascó Oliag, 1 46021 Valencia SPAIN Email: [email protected] Copyright © 2015 by the Editorial Council for The Journal of Prosthetic Dentistry.
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