CLINICAL REPORT
Using the “final-on-four” concept to deliver an immediate metal-resin implant-fixed complete dental prosthesis Burak Yilmaz, DDS, PhD,a Tuncer Burak Ozcelik, DDS, PhD,b and Edwin McGlumphy, DDS, MSc Placement of 4 to 6 dental ABSTRACT implants vertical to their axes In traditional dental implant therapy, the time between implant placement and delivery of the between the mental foramena definitive prosthesis can be long and uncomfortable for a patient wearing a conventional is a viable option for the resremovable denture on an atrophied ridge. New clinical protocols, often with tilted implants, are toration of mandibular edenbeing used to immediately restore mandibular implants with interim restorations, thus shortening tulous ridges with fixed the patient’s return to function. However, these conversion type interim restorations do not decrease the time to definitive prosthetic rehabilitation. The Ohio State University (OSU) develrestorations. With this sooped an immediate load surgical and prosthetic protocol to compensate for the disadvantages of called Brånemark approach, previous techniques. With this protocol, a custom, definitive, screw-retained metal-resin fixed clinicians can deliver 1-piece, prosthesis can be delivered 2 to 4 days postoperatively and has been described using 5 implants. screw-retained, distal cantiThis clinical report presents the OSU immediate loading protocol, combined with a tilted implant lever fixed dental prostheses technique, for the fabrication of a mandibular metal-resin implant fixed complete dental prosafter 3 months of healing. This thesis (MRIFCDP) in 3 days postoperatively and with only 4 implants. Replacing the mandibular method often helps avoid dentition with an immediate load-fixed metal-resin prosthesis by means of the “final-on-four” technique resulted in a custom, definitive, and functional restorative solution immediately after the need for advanced surgical surgery. (J Prosthet Dent 2015;-:---) procedures to augment the bone in the posterior regions of the mouth.1,2 prostheses, avoiding expensive and time-consuming The “all-on-4” concept was also introduced to avoid the limitations of fixed restorations for posterior regions bone augmentation procedures. with compromised bone quality and quantity. In this The immediate loading of dental implants has also been popular in the last decade. During the osseointetechnique, 4 implants are used between the mental gration period, if the micromovement of implants can be foramina and maxillary sinuses to support fixed restoracontrolled properly, implants can be used to support tions in the edentulous arch. The distal implants are fixed dental prostheses sooner.11,12 The micromovement angled to avoid the relevant anatomic structures.3-6 of the implants during healing should not be more than Tilting the distal implants also helps place the im100 mm.13-16 plants’ platform to a more distal position, increasing anterior-posterior (A-P) distance between mesial and Minimizing movement may be accomplished through distal implant platforms, and, therefore, decreasing splinting of the implants. The “conversion technique” allows the clinician to convert a new or existing complete the length of the cantilever extending distally. It has denture to an interim fixed implant-supported complete been reported that increasing the A-P distance creates arch restoration immediately after implant placement. a better situation biomechanically.7-10 Essentially, the With the use of interim acrylic resin based fixed dental all-on-4 concept allows clinicians to deliver fixed dental
a
Associate Professor, Ohio State University, College of Dentistry, Division of Restorative and Prosthetic Dentistry, Columbus, Ohio. Associate Professor, Department of Prosthodontics, Bas¸kent University, Faculty of Dentistry, Ankara, Turkey. c Professor, Ohio State University, College of Dentistry, Division of Restorative and Prosthetic Dentistry, Columbus, Ohio. b
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Figure 1. Preoperative panoramic radiograph. Figure 2. Preoperative intraoral view.
prostheses, micromovement of the implants is minimized, and the soft/hard tissues are protected during initial healing.15 However, some in vitro studies have shown that acrylic resin frameworks are not as efficient as metal frameworks in preventing micromovement of implants under loads.16,17 Also, fracture of the acrylic resin frameworks could occur during healing.6 A Columbus Bridge Protocol (CBP) has been proposed to overcome previously mentioned complications with interim restorations used for immediate loading.18,19 The prosthodontic portion of the protocol sought to optimize adverse occlusal loading. According to this protocol, no cantilever is used with the provisional screwretained prostheses, acrylic resin is used for occlusal surfaces, and metal cast framework is used for rigidity. CBPs are delivered in 24 hours after implant placement.18,19 Still, the definitive prosthesis is fabricated after healing time.19 In all of these approaches, after osseointegration is achieved, patients should return to the clinic for the fabrication of definitive prostheses, which can be time consuming and costly. Most clinical protocols with tilted implants have been limited to immediately restoring mandibular implants with interim restorations, thus shortening the return to function but not decreasing the time to definitive prosthetic rehabilitation.6 The Ohio State University (OSU) immediate-load surgical and prosthetic protocol was developed to compensate for these previous techniques’ inadequacies. The cornerstone of this method is a prefabricated resin framework. The resin pattern is used at the time of surgery as a surgical guide to place 5 interforaminal implants and then is used prosthetically as a pattern to cast the custom metal framework. The resin pattern can be contoured and added to in order to allow placement of the implants in the A-P spread that best fits the patient’s arch. Thus the prefabricated yet modifiable framework expedites the fabrication of the definitive prosthesis while THE JOURNAL OF PROSTHETIC DENTISTRY
providing maximum adaptability to the patient’s arch form. With this protocol, custom, definitive screwretained metal-resin fixed prosthesis can be delivered 2 to 4 days postoperatively.20 This clinical report describes the use of the OSU technique combined with a tilted implant protocol on 4 implants (final-on-four) for the fabrication of mandibular metal-resin implant fixed complete dental prosthesis (MRIFCDP) 3 days postoperatively. CLINICAL REPORT A 60-year-old man with advanced periodontal disease and hopeless remaining teeth agreed to undergo maxillomandibular rehabilitation (Figs. 1, 2). Options were presented, including maxillary and mandibular complete dentures, implant supported overdentures, and MRIFCDP on 4 to 6 dental implants. The patient agreed to be treated with an immediately placed and loaded 4implant-retained MRIFCDP using a tilted implant protocol along with a maxillary immediate complete dental prosthesis. The OSU immediate loading protocol was decided to be combined with final-on-four technique for the fabrication of mandibular screw retained metal-resin fixed prosthesis 2 to 3 days after surgery. Maxillary and mandibular diagnostic impressions were made with irreversible hydrocolloid impression material (Cavex; Holland BV). Type III stone (Microstone; Whip Mix Corp) was poured and the diagnostic casts were mounted in an articulator with a facebow transfer. The remaining teeth on the gypsum casts were removed to the cervical level and acrylic resin teeth were set on acrylic resin base plates. The mandibular tooth arrangement was duplicated in clear acrylic resin (Ortho-Jet; Lang Dental Mfg Co) for the fabrication of a surgical guide. On the ground mandibular cast, an OSU frame was prepared in baseplate wax (Truwax; Dentsply Intl), conforming to the patient’s edentulous ridge. The wax frame was duplicated in Yilmaz et al
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Figure 3. Surgical guide in place to determine amount of bone reduction.
Figure 4. Bone reduction for interocclusal clearance.
Figure 5. Surgical guide, OSU acrylic resin framework and removed bone.
Figure 6. Placement of implants with surgical guide.
Figure 7. Acrylic resin framework in place before implant placement.
Figure 8. Acrylic resin framework in place to verify implant positions.
acrylic resin (Pattern Resin; GC America). Proposed implant positions were determined on the cast and holes were opened on the acrylic resin frame. The maxillary tooth setup was processed with heatpolymerizing acrylic resin (Lucitone 199; Dentsply Intl)
for the fabrication of an immediate complete fixed dental prosthesis. The patient was seen at the Department of Oral and Maxillofacial Surgery for extractions. After all extractions were completed, the surgical guide was used to evaluate
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Figure 9. Abutments screwed onto implants.
Figure 10. Acrylic resin framework with waxing sleeves.
Figure 11. Acrylic resin framework waxing sleeves gingival clearance record complex.
Figure 12. Metal framework evaluation.
interocclusal clearance (Fig. 3). The necessary amount of bone was reduced with a saw (OsteoMed) to create space for implant prosthetic components to be used for the fabrication of definitive MRIFCDP (Figs. 4, 5). Four implants (Tapered Screw-Vent; Zimmer Dental) were inserted. The anterior 2 implants were straight and the posterior implants were angled at 30 degrees medial to the mental foramen. The positions of the implants were determined and verified with the use of a surgical guide and the acrylic resin OSU frame (Figs. 6-8). Straight abutments (Tapered Abutment; Zimmer Dental) in the anterior and angled abutments (Angled Tapered Abutment; Zimmer Dental) in the posterior were tightened to 35 Ncm with a torque wrench (Fig. 9). Primary soft tissue closure was completed and the patient was transferred to the Implant Prosthodontic Clinic for the prosthetic procedures to be performed. Waxing sleeves were tightened on the abutments and passive proper seating was ensured by inspecting the abutment sleeve connection. The acrylic resin OSU frame was adjusted on the sleeves to ensure passive seating (Fig. 10). Once passive seating of the frame was achieved, a rubber dam was used to
protect the soft tissues and prevent locking of the frame on the abutments during frame luting procedures. The sleeves were bonded to the frame with autopolymerizing acrylic resin (Pattern Resin; GC America) applied with a brush-bead technique. After polymerization for 15 minutes, the sleeve/frame complex was removed from the mouth after loosening the waxing sleeve screws (Fig. 11). Polyvinyl siloxane (PVS) material (Blu-Mousse; Parkell Inc) was used to record the clearance between the soft tissue surface of the framework and gingiva, and the same complex was reinserted in the mouth. After the PVS material had polymerized, the complex was removed after loosening the waxing sleeve screws. Abutment analogs (Tapered Abutment Replica; Zimmer Dental) were tightened on the waxing sleeves and the complex was stabilized in Type III dental stone (Microstone; Whip Mix Corp). The maxillary immediate complete dental prosthesis was delivered and the patient remained edentulous in the mandible until the next day. An impression of the maxillary complete dental prosthesis was made with a hydrocolloid impression material (Cavex; Holland BV), and Type III dental stone
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Figure 13. Intraoral view of maxillary immediate complete and mandibular metal-resin implant fixed complete dental prostheses.
(Microstone; Whip Mix Corp) was poured to form the maxillary cast. A facebow transfer record was made for the maxillary and mandibular casts to be mounted on an articulator (Denar Mark II; Whip Mix Corp). The patient was dismissed to be seen the next morning for metal framework evaluation. The articulator, duplicate of the mandibular tooth arrangement, and the poured cast was sent to the dental laboratory for refinement of the wax pattern of the definitive framework and casting. The framework was cast in a Pd-Ag alloy (Super Star; Heraeus Kulzer) and returned to the clinic overnight. The framework was evaluated intraorally and passive seating was ensured using the 1-screw test (Fig. 12). Maxillomandibular records were made and teeth were arranged the same day on the mandibular framework opposed by the maxillary immediate complete dental prosthesis. The trial arrangement was evaluated and esthetics, occlusion, and phonetics were confirmed before returning to the dental laboratory for processing in heat polymerized acrylic resin (Lucitone 199; Dentsply Intl). The patient was seen the following morning and the processed prosthesis was delivered after occlusal adjusting. The prosthetic screws were tightened to 15 Ncm and access holes were sealed with cotton and light polymerizing interim composite resin (Fermit; Ivoclar Vivadent) (Figs. 13, 14). The patient was instructed to proceed with a soft diet for 8 weeks and hygiene instructions were given. The patient was reevaluated at 2 weeks, 3 months, and 1 year after restoration (Fig. 15). DISCUSSION Replacing the mandibular dentition with an immediate load MRIFCDP via the “final-on-four” technique delivered a predictable treatment option that resulted in a custom, definitive, and functional restorative solution immediately following surgery. The primary aim with multiple immediately loaded implants is to splint the Yilmaz et al
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Figure 14. Postoperative panoramic radiograph.
Figure 15. Two-year follow-up.
implants rigidly to minimize the micromovement and to distribute the occlusal loads equally. Acrylic resin based prostheses (conversion) are commonly used to splint immediately loaded implants. The use of acrylic resin for this purpose may lead to some complications such as fracture. Maló et al6 recorded mechanical complications after treatment with the all-on-four approach, including fractures of the interim acrylic resin prosthesis, abutment screw loosening, prosthetic screw loosening, and wear of prosthetic and abutment screws. They reported that these complications occurred in the first 6 months of healing. In another study by Maló et al,5 12 screw loosening situations were reported with acrylic resin implant prostheses, whereas only 2 mechanical complication situations were seen when definitive prosthesis after delivery. Tealdo et al19 evaluated immediately loaded implants for 3 years and delivered CBPs. With the CBP protocol, interim prostheses are fabricated with a rigid metal framework, no cantilevers are used, occlusal surfaces are finished in acrylic resin (which may help absorbing the occlusal loads) and potential risks are said to be THE JOURNAL OF PROSTHETIC DENTISTRY
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minimized with this technique. However, patients need to still return for the fabrication of a definitive prosthesis, which requires additional visits and cost. Holst et al18 compared polymethyl methacrylate resin restorations to metal-reinforced acrylic resin interim restorations supported by 4 implants inserted into homogenous artificial bone. In this study, the effect of vertical loads on the displacement was evaluated. They reported increased displacement of implants when “distal extension acrylic resin only” prostheses are used as interim restorations which may lead to osseointegration complications. With the use of OSU final-on-four protocol, these disadvantages and complications may be prevented. Definitive prostheses can be delivered in 2 to 4 days after implant placement with no impression necessary. The presence of a metal framework with the definitive prosthesis minimizes the risk of micromovement of the implants. In addition, potential mechanical complications seen with acrylic resin prosthesis (such as fracture or screw loosening) may also be minimized or avoided. The described technique eliminates all of the dental visits after tissue healing to deliver definitive prosthesis. Therefore, considerable time and money are saved for both the patient and the clinician. Despite its advantages, the described technique has some limitations. The prefabricated acrylic resin framework must be cast and fitted passively. There is a need for at least 2 to 3 days after implant placement to complete the definitive prosthesis. One of the potential issues after the complete healing period is the unpredictable tissue level under the MRIFCDP. The soft tissue level may potentially result in limited hygiene spaces under the prosthesis or excessive spaces and air escape between the prosthesis and tissue. SUMMARY The “OSU frame resin pattern” was used at the time of surgery as a surgical guide to place 4 interforaminal implants with a tilted implant protocol. The resin framework was used prosthetically as a pattern to cast the custom metal framework. The resin pattern was contoured and added to in order to allow placement of the implants in the A-P spread that best fit the patient’s arch. Thus, the prefabricated, yet modifiable framework expedited the fabrication of the definitive prosthesis while providing maximum adaptability to the patient’s arch form. Using the final-on-four technique avoids some of the reported problems with the immediate loading, allows compatibility with any implant system, and allows delivery of the definitive restoration in the same week as implant surgery.
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REFERENCES 1. Adell R, Lekholm U, Rockler B, Brånemark PI. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg 1981;10:387-416. 2. Adell R, Eriksson B, Lekholm U, Brånemark PI, Jemt T. Long-term follow-up study of osseointegrated implants in the treatment of totally edentulous jaws. Int J Oral Maxillofac Implants 1990;5:347-59. 3. Maló P, Rangert B, Nobre M. “All-on-four” immediate-function concept with Brånemark system implants for completely edentulous mandibles: a retrospective clinical study. Clin Implant Dent Relat Res 2003;5(1):2-9. 4. Maló P, Rangert B, Nobre M. All-on-4 immediate-function concept with Brånemark system implants for completely edentulous maxillae: a 1-year retrospective clinical study. Clin Implant Dent Relat Res 2005;7(1):S88-94. 5. Maló P, de Araújo Nobre M, Lopes A, Moss SM, Molina GJ. A longitudinal study of the survival of All-on-4 implants in the mandible with up to 10 years of follow-up. J Am Dent Assoc 2011;142:310-20. 6. Maló P, de Araújo Nobre M, Lopes A, Francischone C, Rigolizzo M. “All-on4” immediate-function concept for completely edentulous maxillae: a clinical report on the medium (3 years) and long-term (5 years) outcomes. Clin Implant Dent Relat Res 2012;14:e139-50. 7. Zampelis A, Rangert B, Heijl L. Tilting of splinted implants for improved prosthodontic support: a two-dimensional finite element analysis. J Prosthet Dent 2007;97:35-43. 8. Bevilacqua M, Tealdo T, Menini M, Pera F, Mossolov A, Drago C, Pera P. The influence of cantilever length and implant inclination on stress distribution in maxillary implant-supported fixed dentures. J Prosthet Dent 2011;105:5-13. 9. Kim KS, Kim YL, Bae JM, Cho HW. Biomechanical comparison of axial and tilted implants for mandibular full-arch fixed prostheses. Int J Oral Maxillofac Implants 2011;26:976-84. 10. Fazi G, Tellini S, Vangi D, Branchi R. Three-dimensional finite element analysis of different implant configurations for a mandibular fixed prosthesis. Int J Oral Maxillofac Implants 2011;26:752-9. 11. Vandamme K, Naert I, Geris L, Vander Sloten J, Puers R, Duyck J. The effect of micro-motion on the tissue response around immediately loaded roughened titanium implants in the rabbit. Eur J Oral Sci 2007;115:21-9. 12. Kawahara H, Kawahara D, Hayakawa M, Tamai Y, Kuremoto T, Matsuda S. Osseointegration under immediate loading: biomechanical stress-strain and bone formationeresorption. Implant Dent 2003;12:61-8. 13. Brunski JB. Influence of biomechanical factors at the bone-material interface. In: Davies EJ, editor. The boneebiomaterial interface. Toronto: University of Toronto Press; 1991. p. 391-405. 14. Pilliar RM, Lee JM, Maniatopoulos C. Observations on the effect of movement on bone ingrowth into porous surfaced implants. Clin Orthop Relat Res 1986;208:108-13. 15. Zarb G, Hobkirk JA, Eckert SE, Jacob RF. Prosthodontic treatment for edentulous patients. 13th ed. St. Louis: Elsevier Mosby; 2013. p. 387-94. 16. Holst S, Geiselhoeringer H, Wichmann M, Holst AI. The effect of provisional restoration type on micromovement of implants. J Prosthet Dent 2008;100: 173-82. 17. Degidi M, Gehrke P, Spanel A, Piattelli A. Syncrystallization: a technique for temporization of immediately loaded implants with metal-reinforced acrylic resin restorations. Clin Implant Dent Relat Res 2006;8:123-34. 18. Tealdo T, Bevilacqua M, Pera F, Menini M, Ravera G, Drago C, Pera P. Immediate function with fixed implant-supported maxillary dentures: a 12month pilot study. J Prosthet Dent 2008;99:351-60. 19. Tealdo T, Bevilacqua M, Menini M, Pera F, Ravera G, Drago C, Pera P. Immediate versus delayed loading of dental implants in edentulous maxillae: a 36-month prospective study. Int J Prosthodont 2011;24: 294-302. 20. Tames R, McGlumphy E, El-Gendy T, Wilson R. The OSU frame: a novel approach to fabricating immediate load fixed-detachable prostheses. J Oral Maxillofac Surg 2004;62:17-21.
Corresponding author: Dr Burak Yilmaz Ohio State University, College of Dentistry Division of Restorative and Prosthetic Dentistry Columbus, Ohio 43210 Email: [email protected] Acknowledgment The authors thank Drs Namrata Nayyar and Tam Issa-Abbas for their valuable contribution. Copyright © 2015 by the Editorial Council for The Journal of Prosthetic Dentistry.
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Using the “final-on-four” concept to deliver an immediate metal-resin implant-fixed complete dental prosthesis Burak Yilmaz, DDS, PhD,a Tuncer Burak Ozcelik, DDS, PhD,b and Edwin McGlumphy, DDS, MSc Placement of 4 to 6 dental ABSTRACT implants vertical to their axes In traditional dental implant therapy, the time between implant placement and delivery of the between the mental foramena definitive prosthesis can be long and uncomfortable for a patient wearing a conventional is a viable option for the resremovable denture on an atrophied ridge. New clinical protocols, often with tilted implants, are toration of mandibular edenbeing used to immediately restore mandibular implants with interim restorations, thus shortening tulous ridges with fixed the patient’s return to function. However, these conversion type interim restorations do not decrease the time to definitive prosthetic rehabilitation. The Ohio State University (OSU) develrestorations. With this sooped an immediate load surgical and prosthetic protocol to compensate for the disadvantages of called Brånemark approach, previous techniques. With this protocol, a custom, definitive, screw-retained metal-resin fixed clinicians can deliver 1-piece, prosthesis can be delivered 2 to 4 days postoperatively and has been described using 5 implants. screw-retained, distal cantiThis clinical report presents the OSU immediate loading protocol, combined with a tilted implant lever fixed dental prostheses technique, for the fabrication of a mandibular metal-resin implant fixed complete dental prosafter 3 months of healing. This thesis (MRIFCDP) in 3 days postoperatively and with only 4 implants. Replacing the mandibular method often helps avoid dentition with an immediate load-fixed metal-resin prosthesis by means of the “final-on-four” technique resulted in a custom, definitive, and functional restorative solution immediately after the need for advanced surgical surgery. (J Prosthet Dent 2015;-:---) procedures to augment the bone in the posterior regions of the mouth.1,2 prostheses, avoiding expensive and time-consuming The “all-on-4” concept was also introduced to avoid the limitations of fixed restorations for posterior regions bone augmentation procedures. with compromised bone quality and quantity. In this The immediate loading of dental implants has also been popular in the last decade. During the osseointetechnique, 4 implants are used between the mental gration period, if the micromovement of implants can be foramina and maxillary sinuses to support fixed restoracontrolled properly, implants can be used to support tions in the edentulous arch. The distal implants are fixed dental prostheses sooner.11,12 The micromovement angled to avoid the relevant anatomic structures.3-6 of the implants during healing should not be more than Tilting the distal implants also helps place the im100 mm.13-16 plants’ platform to a more distal position, increasing anterior-posterior (A-P) distance between mesial and Minimizing movement may be accomplished through distal implant platforms, and, therefore, decreasing splinting of the implants. The “conversion technique” allows the clinician to convert a new or existing complete the length of the cantilever extending distally. It has denture to an interim fixed implant-supported complete been reported that increasing the A-P distance creates arch restoration immediately after implant placement. a better situation biomechanically.7-10 Essentially, the With the use of interim acrylic resin based fixed dental all-on-4 concept allows clinicians to deliver fixed dental
a
Associate Professor, Ohio State University, College of Dentistry, Division of Restorative and Prosthetic Dentistry, Columbus, Ohio. Associate Professor, Department of Prosthodontics, Bas¸kent University, Faculty of Dentistry, Ankara, Turkey. c Professor, Ohio State University, College of Dentistry, Division of Restorative and Prosthetic Dentistry, Columbus, Ohio. b
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Figure 1. Preoperative panoramic radiograph. Figure 2. Preoperative intraoral view.
prostheses, micromovement of the implants is minimized, and the soft/hard tissues are protected during initial healing.15 However, some in vitro studies have shown that acrylic resin frameworks are not as efficient as metal frameworks in preventing micromovement of implants under loads.16,17 Also, fracture of the acrylic resin frameworks could occur during healing.6 A Columbus Bridge Protocol (CBP) has been proposed to overcome previously mentioned complications with interim restorations used for immediate loading.18,19 The prosthodontic portion of the protocol sought to optimize adverse occlusal loading. According to this protocol, no cantilever is used with the provisional screwretained prostheses, acrylic resin is used for occlusal surfaces, and metal cast framework is used for rigidity. CBPs are delivered in 24 hours after implant placement.18,19 Still, the definitive prosthesis is fabricated after healing time.19 In all of these approaches, after osseointegration is achieved, patients should return to the clinic for the fabrication of definitive prostheses, which can be time consuming and costly. Most clinical protocols with tilted implants have been limited to immediately restoring mandibular implants with interim restorations, thus shortening the return to function but not decreasing the time to definitive prosthetic rehabilitation.6 The Ohio State University (OSU) immediate-load surgical and prosthetic protocol was developed to compensate for these previous techniques’ inadequacies. The cornerstone of this method is a prefabricated resin framework. The resin pattern is used at the time of surgery as a surgical guide to place 5 interforaminal implants and then is used prosthetically as a pattern to cast the custom metal framework. The resin pattern can be contoured and added to in order to allow placement of the implants in the A-P spread that best fits the patient’s arch. Thus the prefabricated yet modifiable framework expedites the fabrication of the definitive prosthesis while THE JOURNAL OF PROSTHETIC DENTISTRY
providing maximum adaptability to the patient’s arch form. With this protocol, custom, definitive screwretained metal-resin fixed prosthesis can be delivered 2 to 4 days postoperatively.20 This clinical report describes the use of the OSU technique combined with a tilted implant protocol on 4 implants (final-on-four) for the fabrication of mandibular metal-resin implant fixed complete dental prosthesis (MRIFCDP) 3 days postoperatively. CLINICAL REPORT A 60-year-old man with advanced periodontal disease and hopeless remaining teeth agreed to undergo maxillomandibular rehabilitation (Figs. 1, 2). Options were presented, including maxillary and mandibular complete dentures, implant supported overdentures, and MRIFCDP on 4 to 6 dental implants. The patient agreed to be treated with an immediately placed and loaded 4implant-retained MRIFCDP using a tilted implant protocol along with a maxillary immediate complete dental prosthesis. The OSU immediate loading protocol was decided to be combined with final-on-four technique for the fabrication of mandibular screw retained metal-resin fixed prosthesis 2 to 3 days after surgery. Maxillary and mandibular diagnostic impressions were made with irreversible hydrocolloid impression material (Cavex; Holland BV). Type III stone (Microstone; Whip Mix Corp) was poured and the diagnostic casts were mounted in an articulator with a facebow transfer. The remaining teeth on the gypsum casts were removed to the cervical level and acrylic resin teeth were set on acrylic resin base plates. The mandibular tooth arrangement was duplicated in clear acrylic resin (Ortho-Jet; Lang Dental Mfg Co) for the fabrication of a surgical guide. On the ground mandibular cast, an OSU frame was prepared in baseplate wax (Truwax; Dentsply Intl), conforming to the patient’s edentulous ridge. The wax frame was duplicated in Yilmaz et al
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Figure 3. Surgical guide in place to determine amount of bone reduction.
Figure 4. Bone reduction for interocclusal clearance.
Figure 5. Surgical guide, OSU acrylic resin framework and removed bone.
Figure 6. Placement of implants with surgical guide.
Figure 7. Acrylic resin framework in place before implant placement.
Figure 8. Acrylic resin framework in place to verify implant positions.
acrylic resin (Pattern Resin; GC America). Proposed implant positions were determined on the cast and holes were opened on the acrylic resin frame. The maxillary tooth setup was processed with heatpolymerizing acrylic resin (Lucitone 199; Dentsply Intl)
for the fabrication of an immediate complete fixed dental prosthesis. The patient was seen at the Department of Oral and Maxillofacial Surgery for extractions. After all extractions were completed, the surgical guide was used to evaluate
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Figure 9. Abutments screwed onto implants.
Figure 10. Acrylic resin framework with waxing sleeves.
Figure 11. Acrylic resin framework waxing sleeves gingival clearance record complex.
Figure 12. Metal framework evaluation.
interocclusal clearance (Fig. 3). The necessary amount of bone was reduced with a saw (OsteoMed) to create space for implant prosthetic components to be used for the fabrication of definitive MRIFCDP (Figs. 4, 5). Four implants (Tapered Screw-Vent; Zimmer Dental) were inserted. The anterior 2 implants were straight and the posterior implants were angled at 30 degrees medial to the mental foramen. The positions of the implants were determined and verified with the use of a surgical guide and the acrylic resin OSU frame (Figs. 6-8). Straight abutments (Tapered Abutment; Zimmer Dental) in the anterior and angled abutments (Angled Tapered Abutment; Zimmer Dental) in the posterior were tightened to 35 Ncm with a torque wrench (Fig. 9). Primary soft tissue closure was completed and the patient was transferred to the Implant Prosthodontic Clinic for the prosthetic procedures to be performed. Waxing sleeves were tightened on the abutments and passive proper seating was ensured by inspecting the abutment sleeve connection. The acrylic resin OSU frame was adjusted on the sleeves to ensure passive seating (Fig. 10). Once passive seating of the frame was achieved, a rubber dam was used to
protect the soft tissues and prevent locking of the frame on the abutments during frame luting procedures. The sleeves were bonded to the frame with autopolymerizing acrylic resin (Pattern Resin; GC America) applied with a brush-bead technique. After polymerization for 15 minutes, the sleeve/frame complex was removed from the mouth after loosening the waxing sleeve screws (Fig. 11). Polyvinyl siloxane (PVS) material (Blu-Mousse; Parkell Inc) was used to record the clearance between the soft tissue surface of the framework and gingiva, and the same complex was reinserted in the mouth. After the PVS material had polymerized, the complex was removed after loosening the waxing sleeve screws. Abutment analogs (Tapered Abutment Replica; Zimmer Dental) were tightened on the waxing sleeves and the complex was stabilized in Type III dental stone (Microstone; Whip Mix Corp). The maxillary immediate complete dental prosthesis was delivered and the patient remained edentulous in the mandible until the next day. An impression of the maxillary complete dental prosthesis was made with a hydrocolloid impression material (Cavex; Holland BV), and Type III dental stone
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Figure 13. Intraoral view of maxillary immediate complete and mandibular metal-resin implant fixed complete dental prostheses.
(Microstone; Whip Mix Corp) was poured to form the maxillary cast. A facebow transfer record was made for the maxillary and mandibular casts to be mounted on an articulator (Denar Mark II; Whip Mix Corp). The patient was dismissed to be seen the next morning for metal framework evaluation. The articulator, duplicate of the mandibular tooth arrangement, and the poured cast was sent to the dental laboratory for refinement of the wax pattern of the definitive framework and casting. The framework was cast in a Pd-Ag alloy (Super Star; Heraeus Kulzer) and returned to the clinic overnight. The framework was evaluated intraorally and passive seating was ensured using the 1-screw test (Fig. 12). Maxillomandibular records were made and teeth were arranged the same day on the mandibular framework opposed by the maxillary immediate complete dental prosthesis. The trial arrangement was evaluated and esthetics, occlusion, and phonetics were confirmed before returning to the dental laboratory for processing in heat polymerized acrylic resin (Lucitone 199; Dentsply Intl). The patient was seen the following morning and the processed prosthesis was delivered after occlusal adjusting. The prosthetic screws were tightened to 15 Ncm and access holes were sealed with cotton and light polymerizing interim composite resin (Fermit; Ivoclar Vivadent) (Figs. 13, 14). The patient was instructed to proceed with a soft diet for 8 weeks and hygiene instructions were given. The patient was reevaluated at 2 weeks, 3 months, and 1 year after restoration (Fig. 15). DISCUSSION Replacing the mandibular dentition with an immediate load MRIFCDP via the “final-on-four” technique delivered a predictable treatment option that resulted in a custom, definitive, and functional restorative solution immediately following surgery. The primary aim with multiple immediately loaded implants is to splint the Yilmaz et al
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Figure 14. Postoperative panoramic radiograph.
Figure 15. Two-year follow-up.
implants rigidly to minimize the micromovement and to distribute the occlusal loads equally. Acrylic resin based prostheses (conversion) are commonly used to splint immediately loaded implants. The use of acrylic resin for this purpose may lead to some complications such as fracture. Maló et al6 recorded mechanical complications after treatment with the all-on-four approach, including fractures of the interim acrylic resin prosthesis, abutment screw loosening, prosthetic screw loosening, and wear of prosthetic and abutment screws. They reported that these complications occurred in the first 6 months of healing. In another study by Maló et al,5 12 screw loosening situations were reported with acrylic resin implant prostheses, whereas only 2 mechanical complication situations were seen when definitive prosthesis after delivery. Tealdo et al19 evaluated immediately loaded implants for 3 years and delivered CBPs. With the CBP protocol, interim prostheses are fabricated with a rigid metal framework, no cantilevers are used, occlusal surfaces are finished in acrylic resin (which may help absorbing the occlusal loads) and potential risks are said to be THE JOURNAL OF PROSTHETIC DENTISTRY
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minimized with this technique. However, patients need to still return for the fabrication of a definitive prosthesis, which requires additional visits and cost. Holst et al18 compared polymethyl methacrylate resin restorations to metal-reinforced acrylic resin interim restorations supported by 4 implants inserted into homogenous artificial bone. In this study, the effect of vertical loads on the displacement was evaluated. They reported increased displacement of implants when “distal extension acrylic resin only” prostheses are used as interim restorations which may lead to osseointegration complications. With the use of OSU final-on-four protocol, these disadvantages and complications may be prevented. Definitive prostheses can be delivered in 2 to 4 days after implant placement with no impression necessary. The presence of a metal framework with the definitive prosthesis minimizes the risk of micromovement of the implants. In addition, potential mechanical complications seen with acrylic resin prosthesis (such as fracture or screw loosening) may also be minimized or avoided. The described technique eliminates all of the dental visits after tissue healing to deliver definitive prosthesis. Therefore, considerable time and money are saved for both the patient and the clinician. Despite its advantages, the described technique has some limitations. The prefabricated acrylic resin framework must be cast and fitted passively. There is a need for at least 2 to 3 days after implant placement to complete the definitive prosthesis. One of the potential issues after the complete healing period is the unpredictable tissue level under the MRIFCDP. The soft tissue level may potentially result in limited hygiene spaces under the prosthesis or excessive spaces and air escape between the prosthesis and tissue. SUMMARY The “OSU frame resin pattern” was used at the time of surgery as a surgical guide to place 4 interforaminal implants with a tilted implant protocol. The resin framework was used prosthetically as a pattern to cast the custom metal framework. The resin pattern was contoured and added to in order to allow placement of the implants in the A-P spread that best fit the patient’s arch. Thus, the prefabricated, yet modifiable framework expedited the fabrication of the definitive prosthesis while providing maximum adaptability to the patient’s arch form. Using the final-on-four technique avoids some of the reported problems with the immediate loading, allows compatibility with any implant system, and allows delivery of the definitive restoration in the same week as implant surgery.
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Corresponding author: Dr Burak Yilmaz Ohio State University, College of Dentistry Division of Restorative and Prosthetic Dentistry Columbus, Ohio 43210 Email: [email protected] Acknowledgment The authors thank Drs Namrata Nayyar and Tam Issa-Abbas for their valuable contribution. Copyright © 2015 by the Editorial Council for The Journal of Prosthetic Dentistry.
Yilmaz et al
