- Email: [email protected]
Prosthetic management of an existing transmandibular implant: A clinical report
CLINICAL REPORT
Prosthetic management of an existing transmandibular implant: A clinical report Ramtin Sadid-Zadeh, DDS, MS,a Antigoni Stylianou, DDS, MS,b and Ruth Aponte Wesson, DDS, MSc Transmandibular implants ABSTRACT (TMIs) were developed in the This report describes the prosthetic management of a fractured Dolder bar on a transmandibular Netherlands by Dr Hans implant system. The patient declined surgical removal of the implants. Therefore, to repair the Bosker during the mid-1970s. superstructure, a cast Dolder bar was fabricated and luted onto the existing transmandibular imTMIs were designed to overplants. An implant-retained bar overdenture was then fabricated to rehabilitate the mandibular come the difficulties associated arch. (J Prosthet Dent 2017;-:---) with the reconstruction of majority of reports.4,6,8,9 A few studies have directly extensively atrophied mandibles (with bone heights less compared the TMI system with other implant systems. than 12 mm) without bone-grafting surgical procedFor example, results from a clinical trial of implantures.1-4 The TMI reconstruction system allows implant retained mandibular overdentures in patients with placement in the anterior interforamina region using an severely atrophied mandibles showed no statistically extraoral and submental approach.5 Reconstruction with significant differences between the TMI, IMZ, and BråTMIs is primarily indicated in patients with severe nemark implant systems after 1 year.10 In contrast, 6-year mandibular atrophy; Type IV bone quality of the results from a multicenter clinical trial revealed that a mandible; a history of fracture or resection of the higher survival rate and clinical implant performance mandible; previously irradiated mandibular bone; or were associated with the IMZ and Brånemark implant previous failure and removal of other implant types, such systems compared with the TMI system.11 Similarly, as endosseous or subperiosteal implants.6 short endosseous implants have been shown to perform TMIs are generally supported by a box-frame structure comprising a superstructure, baseplate, transosseous posts, and cortical screws. Specifically, the baseplate is secured to the inferior border of the mandible using 5 cortical screws with 4 transosseous struts that pass through the alveolar crest and oral mucosa (Fig. 1).3,4 An intraoral Dolder bar with 2 distal cantilevers is used to connect the 4 transosseous posts. The overdenture is secured to the Dolder bar segments of the superstructure with retentive sleeves.3,7 TMI components are fabricated from a corrosion-resistant alloy consisting of 70% gold, 5% platinum, 12.8% silver, and 12.2% copper (Implator; Cendres et Métaux).4 Overall success rates of the TMI system have been reported to range between 95.8% and 97.8% in the Figure 1. Transmandibular implant system. a
Assistant Professor, Department of Restorative Dentistry, University at Buffalo School of Dental Medicine, Buffalo, NY. Private practice, Paphos, Cyprus. c Associate Professor, Department of Head and Neck Surgery, Section of Oral Oncology and Maxillofacial Prosthetics, The University of Texas MD Anderson Cancer Center, Houston, Texas. b
THE JOURNAL OF PROSTHETIC DENTISTRY
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Figure 2. Presentation before treatment. A, Intraoral. B, Panoramic radiograph.
better than TMIs in patients with severely resorbed mandibles.12 The incidence of reversible complications associated with the TMI system has been reported to vary between 7.8% and 22.2%, and the number of complications has been reported to be correlated with the level of experience of the surgeon or restorative dentist. Complications reported included soft tissue hyperplasia around the transosseous posts, loss of osseointegration, infrabony pockets, postoperative infection related to skin grafts, fenestration of implant threads, partial loss of integration due to premature loading, and fracture of the posts.4,6,8,13 As a result of recent advances in implant systems and bone grafting procedures, TMIs are rarely used. Thus, management of complications associated with these implant systems has not been adequately reported. However, because of the high survival rate of this system, failures and complications are likely to present a challenge to clinicians in the future. This clinical report illustrates a step-by-step prosthetic approach for managing a failed TMI superstructure through retreatment of the superstructure and the implant-retained prosthesis. CLINICAL REPORT An 80-year-old white woman presented to the Maxillofacial Prosthetic Clinic at the University of Alabama at Birmingham (UAB) School of Dentistry with a removable implant-retained prosthesis. The patient had a fractured bar on a TMI system (TMI Bosker) (Fig. 2) supporting an ill-fitting mandibular overdenture and opposing a conventional complete denture. Clinical and radiographic evaluations revealed that the locknut and superstructure thread were worn for 2 TMI implants, that the locknut and sleeve were lost for the rest of the implants, and that the superstructure of the TMI Bosker was fractured. However, the fastener remained intact for all of the implants, and the surrounding hard and soft tissues were healthy. The implants had been placed in early
THE JOURNAL OF PROSTHETIC DENTISTRY
1994 in the Oral and Maxillofacial Surgery Department at UAB. The patient was informed that the TMI Bosker parts were no longer available. She was then given the option of either having the existing implants removed with or without placement of endosseous implants or of maintaining the current implants with a newly customized cast framework. The patient declined any surgical intervention and consented to the fabrication of cast metal housings connected by 3 Dolder bars. Therefore, the definitive treatment plan included a maxillary conventional complete denture and a new mandibular baroverdenture. The assembly was designed to be luted onto the superstructure thread of the transosseous posts and then onto the fasteners. Preliminary impressions were recorded using irreversible hydrocolloid (Jeltrate; Dentsply Sirona) for the fabrication of study casts in Type IV stone (Microstone; Whip Mix Corp). The study casts were then used to fabricate a custom open tray from light-polymerizing acrylic resin (Triad; Dentsply Sirona) to facilitate definitive impression procedures. Before the definitive impression, a polyvinyl siloxane (PVS) putty impression was used to record the superstructure thread of the transosseous posts and fasteners. Dowel pins and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) were used to fabricate replicas of each transosseous post superstructure. A passive fit custom impression cap was fabricated for each transosseous post using autopolymerizing acrylic resin (SR Ivolen; Ivoclar Vivadent AG) to serve as an impression tray (Fig. 3). A circumferential retentive groove was engraved on the superior portion of each cap to ensure retention of the housings in the impression material. Separate interconnecting bars were also fabricated to connect the housings intraorally. The open custom tray was used for border molding with modeling plastic impression compound (GC America Inc). The acrylic resin customized impression caps were then connected intraorally with interconnecting
Sadid-Zadeh et al
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Figure 3. Custom impression cap for transosseous post.
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Figure 4. Recording impression from transosseous posts.
Figure 5. A, Resin pattern on transosseous post linked with Dolder bar pattern. B, Cast bar on definitive cast.
bars using autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc). During this step, it was critical to ensure passive fit of the assembly to control for possible bending of the post during the recording of the impression. A recording impression of the transosseous posts was made using the assembled housing caps, and PVS impression material (Monophase Aquasil; Dentsply Sirona) was used according to the manufacturer’s recommended instructions. PVS impression material (XLV Aquasil; Dentsply Sirona) was then injected below the assembled housing cap (Fig. 4), and the definitive impression was recorded (LV Aquasil; Dentsply Sirona). The dowel pins and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) were used to mold the transosseous post on the definitive impression. The definitive cast was then fabricated using Type IV dental stone (Microstone; Whip Mix Corp), while the dowel pin and resin were in the definitive impression. In order to fabricate a cast bar on the posts, a separating agent was applied to each post, and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) was applied to form a Sadid-Zadeh et al
cap for each post. Dolder bar patterns (Attachments Intl) were then used to connect the housings. The resulting pattern was cast using a noble alloy (Lodestar; Ivoclar Vivadent AG) (Fig. 5). A well-adapted closed impression tray was fabricated on the definitive cast using an autopolymerizing acrylic resin (SR Ivolen; Ivoclar Vivadent AG) to enable the pickup impression of the interconnected bar assembly. In order to optimize the fit, the bar framework was evaluated intraorally, sectioned, and laser welded (Compact Laser Welding Machine; LaserStar Technologies Corp) in the dental laboratory. Three Dolder bar clips (Attachments Intl) were placed on the bar. The bar was then luted onto the transosseous posts with an interim luting agent (Temp-Bond; Kerr Dental). The undercut below each post was blocked with a light-polymerizing material (Kool Dam; Pulpdent Corp), and the pickup impression was recorded (LV Aquasil; Dentsply Sirona), as shown in Figure 6. The impression material below the Dolder bar was removed in the laboratory, and a second definitive cast was fabricated using Type IV gypsum (Silky-Rock; Whip Mix Corp) with the bar and clips on
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Figure 6. A, Bar luted with interim cement and ready for pickup impression. B, Pickup impression.
Figure 7. A, Bar luted intraorally. B, Processed base with Dolder riders.
the cast. A laboratory-processed base (Lucitone Clear; Dentsply Sirona) was fabricated, and the clips were picked up in the base during the processing. The next clinical step required intraoral luting of the bar. First, the transosseous posts were isolated with a rubber dam, and both the posts and the intaglio surface of the housings were airborne-particle abraded chairside with 50 mm Al2O3. Next, an alloy primer (Panavia F2; Kuraray Noritake Dental Inc) was applied to the abraded surface, and the bar was luted to the post (Panavia F2; Kuraray Noritake Dental Inc) according to the manufacturer’s instructions. Subsequently, the processed base was fitted intraorally and adjusted as needed for proper fit and border extension (Fig. 7). The maxillary complete denture and mandibular implant-retained overdenture were fabricated using conventional methods, and the teeth were set in bilateral balanced occlusion. At the completion of treatment, oral hygiene instructions were provided. The patient was recalled at 48 hours and after 1 week with no further adjustments needed at that point. The patient was then scheduled for recall visits every 6 months.
THE JOURNAL OF PROSTHETIC DENTISTRY
DISCUSSION As a result of the relatively high success and survival rates of the TMI system, clinicians are likely to encounter failures and complications of these systems in the years ahead, likely involving prosthetic parts and superstructures. As a result of surgical and technical advances and the subsequent successes of contemporary endosseous implants, manufacturers may no longer produce parts for older implant systems, such as TMIs. As a result, for this patient, we were faced with an interesting predicament. Considering the potential trauma and detrimental effects associated with surgical removal of these implants, the patient instead consented to an individualized prosthodontic plan to repair the failing prosthetic parts. CONCLUSIONS This clinical report presents a description of a customized approach for repairing the superstructure of a TMI. No complications were observed after 1 year of follow-up. Sadid-Zadeh et al
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2017
REFERENCES 1. Bosker H, Van Dijk L. The transmandibular implant. Ned Tijdschr Tandheelkd 1983;90:381-9. 2. Bosker H, Jordan DJ, Powers MP, Van Pelt AWJ. Bone induction and bone loss by use of the TMI. Oral Surg Diagn 1991;2:18-26. 3. Maxson BB, Powers M, Scott RF. Prosthodontic considerations for the transmandibular implant. J Prosthet Dent 1990;63:554-8. 4. Bosker H, Dijk van L. The transmandibular implant: a 12-year follow-up study. J Oral Maxillofac Surg 1989;47:442-50. 5. Powers MP, Bosker H, van Pelt H, Dunbar N. The transmandibular implant: from progressive bone loss to controlled bone growth. J Oral Maxillofac Surg 1994;52:904-10. 6. Fonseca RJ, Davis WH. Reconstructive preprosthetic oral and maxillofacial surgery. In: The transmandibular reconstruction system. 2nd ed. Philadelphia: Saunders; 1995:565-668. 7. MacFarlane NR. Case report: prosthodontic treatment for the transmandibular implant. Eur J Prosthodont Restor Dent 1996;4:123-7. 8. Bosker H, Jordan RD, Sindet-Pedersen S, Koole R. The transmandibular implant: a 13-year survey of its use. J Oral Maxillofac Surg 1991;49:482-92. 9. Maxson BB, Sindet-Pedersen S, Tideman H, Fonseca RJ, Zijlstra G. Multicenter follow-up study of the transmandibular implant. J Oral Maxillofac Surg 1989;47:785-9.
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10. Geertman ME, Boerrigter EM, Van Waas MAJ, van Oort RP. Clinical aspects of a multicenter clinical trial of implant-retained mandibular overdentures in patients with severely resorbed mandibles. J Prosthet Dent 1996;75:194-204. 11. Meijer HJ, Geertman ME, Raghoebar GM, Kwakman JM. Implantretained mandibular overdentures: 6-year results of a multicenter clinical trial on 3 different implant systems. J Oral Maxillofac Surg 2001;59: 1260-8. 12. Stellingsma C, Raghoebar GM, Meijer HJA, Stegenga B. The extremely resorbed mandible: a comparative prospective study of 2-year results with 3 treatment strategies. Int J Oral Maxillofac Implants 2004;19: 563-77. 13. Waas MAJ, Bosker H. Evaluation of satisfaction of denture wearers with the transmandibular implant. Int J Oral Maxillofac Surg 1989;18:145-7. Corresponding author: Dr Ramtin Sadid-Zadeh University at Buffalo School of Dental Medicine 3435 Main St, 215K Squire Hall Buffalo, NY 14214 Email: [email protected] Copyright © 2017 by the Editorial Council for The Journal of Prosthetic Dentistry.
THE JOURNAL OF PROSTHETIC DENTISTRY
Prosthetic management of an existing transmandibular implant: A clinical report Ramtin Sadid-Zadeh, DDS, MS,a Antigoni Stylianou, DDS, MS,b and Ruth Aponte Wesson, DDS, MSc Transmandibular implants ABSTRACT (TMIs) were developed in the This report describes the prosthetic management of a fractured Dolder bar on a transmandibular Netherlands by Dr Hans implant system. The patient declined surgical removal of the implants. Therefore, to repair the Bosker during the mid-1970s. superstructure, a cast Dolder bar was fabricated and luted onto the existing transmandibular imTMIs were designed to overplants. An implant-retained bar overdenture was then fabricated to rehabilitate the mandibular come the difficulties associated arch. (J Prosthet Dent 2017;-:---) with the reconstruction of majority of reports.4,6,8,9 A few studies have directly extensively atrophied mandibles (with bone heights less compared the TMI system with other implant systems. than 12 mm) without bone-grafting surgical procedFor example, results from a clinical trial of implantures.1-4 The TMI reconstruction system allows implant retained mandibular overdentures in patients with placement in the anterior interforamina region using an severely atrophied mandibles showed no statistically extraoral and submental approach.5 Reconstruction with significant differences between the TMI, IMZ, and BråTMIs is primarily indicated in patients with severe nemark implant systems after 1 year.10 In contrast, 6-year mandibular atrophy; Type IV bone quality of the results from a multicenter clinical trial revealed that a mandible; a history of fracture or resection of the higher survival rate and clinical implant performance mandible; previously irradiated mandibular bone; or were associated with the IMZ and Brånemark implant previous failure and removal of other implant types, such systems compared with the TMI system.11 Similarly, as endosseous or subperiosteal implants.6 short endosseous implants have been shown to perform TMIs are generally supported by a box-frame structure comprising a superstructure, baseplate, transosseous posts, and cortical screws. Specifically, the baseplate is secured to the inferior border of the mandible using 5 cortical screws with 4 transosseous struts that pass through the alveolar crest and oral mucosa (Fig. 1).3,4 An intraoral Dolder bar with 2 distal cantilevers is used to connect the 4 transosseous posts. The overdenture is secured to the Dolder bar segments of the superstructure with retentive sleeves.3,7 TMI components are fabricated from a corrosion-resistant alloy consisting of 70% gold, 5% platinum, 12.8% silver, and 12.2% copper (Implator; Cendres et Métaux).4 Overall success rates of the TMI system have been reported to range between 95.8% and 97.8% in the Figure 1. Transmandibular implant system. a
Assistant Professor, Department of Restorative Dentistry, University at Buffalo School of Dental Medicine, Buffalo, NY. Private practice, Paphos, Cyprus. c Associate Professor, Department of Head and Neck Surgery, Section of Oral Oncology and Maxillofacial Prosthetics, The University of Texas MD Anderson Cancer Center, Houston, Texas. b
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Figure 2. Presentation before treatment. A, Intraoral. B, Panoramic radiograph.
better than TMIs in patients with severely resorbed mandibles.12 The incidence of reversible complications associated with the TMI system has been reported to vary between 7.8% and 22.2%, and the number of complications has been reported to be correlated with the level of experience of the surgeon or restorative dentist. Complications reported included soft tissue hyperplasia around the transosseous posts, loss of osseointegration, infrabony pockets, postoperative infection related to skin grafts, fenestration of implant threads, partial loss of integration due to premature loading, and fracture of the posts.4,6,8,13 As a result of recent advances in implant systems and bone grafting procedures, TMIs are rarely used. Thus, management of complications associated with these implant systems has not been adequately reported. However, because of the high survival rate of this system, failures and complications are likely to present a challenge to clinicians in the future. This clinical report illustrates a step-by-step prosthetic approach for managing a failed TMI superstructure through retreatment of the superstructure and the implant-retained prosthesis. CLINICAL REPORT An 80-year-old white woman presented to the Maxillofacial Prosthetic Clinic at the University of Alabama at Birmingham (UAB) School of Dentistry with a removable implant-retained prosthesis. The patient had a fractured bar on a TMI system (TMI Bosker) (Fig. 2) supporting an ill-fitting mandibular overdenture and opposing a conventional complete denture. Clinical and radiographic evaluations revealed that the locknut and superstructure thread were worn for 2 TMI implants, that the locknut and sleeve were lost for the rest of the implants, and that the superstructure of the TMI Bosker was fractured. However, the fastener remained intact for all of the implants, and the surrounding hard and soft tissues were healthy. The implants had been placed in early
THE JOURNAL OF PROSTHETIC DENTISTRY
1994 in the Oral and Maxillofacial Surgery Department at UAB. The patient was informed that the TMI Bosker parts were no longer available. She was then given the option of either having the existing implants removed with or without placement of endosseous implants or of maintaining the current implants with a newly customized cast framework. The patient declined any surgical intervention and consented to the fabrication of cast metal housings connected by 3 Dolder bars. Therefore, the definitive treatment plan included a maxillary conventional complete denture and a new mandibular baroverdenture. The assembly was designed to be luted onto the superstructure thread of the transosseous posts and then onto the fasteners. Preliminary impressions were recorded using irreversible hydrocolloid (Jeltrate; Dentsply Sirona) for the fabrication of study casts in Type IV stone (Microstone; Whip Mix Corp). The study casts were then used to fabricate a custom open tray from light-polymerizing acrylic resin (Triad; Dentsply Sirona) to facilitate definitive impression procedures. Before the definitive impression, a polyvinyl siloxane (PVS) putty impression was used to record the superstructure thread of the transosseous posts and fasteners. Dowel pins and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) were used to fabricate replicas of each transosseous post superstructure. A passive fit custom impression cap was fabricated for each transosseous post using autopolymerizing acrylic resin (SR Ivolen; Ivoclar Vivadent AG) to serve as an impression tray (Fig. 3). A circumferential retentive groove was engraved on the superior portion of each cap to ensure retention of the housings in the impression material. Separate interconnecting bars were also fabricated to connect the housings intraorally. The open custom tray was used for border molding with modeling plastic impression compound (GC America Inc). The acrylic resin customized impression caps were then connected intraorally with interconnecting
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2017
Figure 3. Custom impression cap for transosseous post.
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Figure 4. Recording impression from transosseous posts.
Figure 5. A, Resin pattern on transosseous post linked with Dolder bar pattern. B, Cast bar on definitive cast.
bars using autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc). During this step, it was critical to ensure passive fit of the assembly to control for possible bending of the post during the recording of the impression. A recording impression of the transosseous posts was made using the assembled housing caps, and PVS impression material (Monophase Aquasil; Dentsply Sirona) was used according to the manufacturer’s recommended instructions. PVS impression material (XLV Aquasil; Dentsply Sirona) was then injected below the assembled housing cap (Fig. 4), and the definitive impression was recorded (LV Aquasil; Dentsply Sirona). The dowel pins and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) were used to mold the transosseous post on the definitive impression. The definitive cast was then fabricated using Type IV dental stone (Microstone; Whip Mix Corp), while the dowel pin and resin were in the definitive impression. In order to fabricate a cast bar on the posts, a separating agent was applied to each post, and autopolymerizing acrylic resin (Pattern Resin LS; GC America Inc) was applied to form a Sadid-Zadeh et al
cap for each post. Dolder bar patterns (Attachments Intl) were then used to connect the housings. The resulting pattern was cast using a noble alloy (Lodestar; Ivoclar Vivadent AG) (Fig. 5). A well-adapted closed impression tray was fabricated on the definitive cast using an autopolymerizing acrylic resin (SR Ivolen; Ivoclar Vivadent AG) to enable the pickup impression of the interconnected bar assembly. In order to optimize the fit, the bar framework was evaluated intraorally, sectioned, and laser welded (Compact Laser Welding Machine; LaserStar Technologies Corp) in the dental laboratory. Three Dolder bar clips (Attachments Intl) were placed on the bar. The bar was then luted onto the transosseous posts with an interim luting agent (Temp-Bond; Kerr Dental). The undercut below each post was blocked with a light-polymerizing material (Kool Dam; Pulpdent Corp), and the pickup impression was recorded (LV Aquasil; Dentsply Sirona), as shown in Figure 6. The impression material below the Dolder bar was removed in the laboratory, and a second definitive cast was fabricated using Type IV gypsum (Silky-Rock; Whip Mix Corp) with the bar and clips on
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Figure 6. A, Bar luted with interim cement and ready for pickup impression. B, Pickup impression.
Figure 7. A, Bar luted intraorally. B, Processed base with Dolder riders.
the cast. A laboratory-processed base (Lucitone Clear; Dentsply Sirona) was fabricated, and the clips were picked up in the base during the processing. The next clinical step required intraoral luting of the bar. First, the transosseous posts were isolated with a rubber dam, and both the posts and the intaglio surface of the housings were airborne-particle abraded chairside with 50 mm Al2O3. Next, an alloy primer (Panavia F2; Kuraray Noritake Dental Inc) was applied to the abraded surface, and the bar was luted to the post (Panavia F2; Kuraray Noritake Dental Inc) according to the manufacturer’s instructions. Subsequently, the processed base was fitted intraorally and adjusted as needed for proper fit and border extension (Fig. 7). The maxillary complete denture and mandibular implant-retained overdenture were fabricated using conventional methods, and the teeth were set in bilateral balanced occlusion. At the completion of treatment, oral hygiene instructions were provided. The patient was recalled at 48 hours and after 1 week with no further adjustments needed at that point. The patient was then scheduled for recall visits every 6 months.
THE JOURNAL OF PROSTHETIC DENTISTRY
DISCUSSION As a result of the relatively high success and survival rates of the TMI system, clinicians are likely to encounter failures and complications of these systems in the years ahead, likely involving prosthetic parts and superstructures. As a result of surgical and technical advances and the subsequent successes of contemporary endosseous implants, manufacturers may no longer produce parts for older implant systems, such as TMIs. As a result, for this patient, we were faced with an interesting predicament. Considering the potential trauma and detrimental effects associated with surgical removal of these implants, the patient instead consented to an individualized prosthodontic plan to repair the failing prosthetic parts. CONCLUSIONS This clinical report presents a description of a customized approach for repairing the superstructure of a TMI. No complications were observed after 1 year of follow-up. Sadid-Zadeh et al
-
2017
REFERENCES 1. Bosker H, Van Dijk L. The transmandibular implant. Ned Tijdschr Tandheelkd 1983;90:381-9. 2. Bosker H, Jordan DJ, Powers MP, Van Pelt AWJ. Bone induction and bone loss by use of the TMI. Oral Surg Diagn 1991;2:18-26. 3. Maxson BB, Powers M, Scott RF. Prosthodontic considerations for the transmandibular implant. J Prosthet Dent 1990;63:554-8. 4. Bosker H, Dijk van L. The transmandibular implant: a 12-year follow-up study. J Oral Maxillofac Surg 1989;47:442-50. 5. Powers MP, Bosker H, van Pelt H, Dunbar N. The transmandibular implant: from progressive bone loss to controlled bone growth. J Oral Maxillofac Surg 1994;52:904-10. 6. Fonseca RJ, Davis WH. Reconstructive preprosthetic oral and maxillofacial surgery. In: The transmandibular reconstruction system. 2nd ed. Philadelphia: Saunders; 1995:565-668. 7. MacFarlane NR. Case report: prosthodontic treatment for the transmandibular implant. Eur J Prosthodont Restor Dent 1996;4:123-7. 8. Bosker H, Jordan RD, Sindet-Pedersen S, Koole R. The transmandibular implant: a 13-year survey of its use. J Oral Maxillofac Surg 1991;49:482-92. 9. Maxson BB, Sindet-Pedersen S, Tideman H, Fonseca RJ, Zijlstra G. Multicenter follow-up study of the transmandibular implant. J Oral Maxillofac Surg 1989;47:785-9.
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10. Geertman ME, Boerrigter EM, Van Waas MAJ, van Oort RP. Clinical aspects of a multicenter clinical trial of implant-retained mandibular overdentures in patients with severely resorbed mandibles. J Prosthet Dent 1996;75:194-204. 11. Meijer HJ, Geertman ME, Raghoebar GM, Kwakman JM. Implantretained mandibular overdentures: 6-year results of a multicenter clinical trial on 3 different implant systems. J Oral Maxillofac Surg 2001;59: 1260-8. 12. Stellingsma C, Raghoebar GM, Meijer HJA, Stegenga B. The extremely resorbed mandible: a comparative prospective study of 2-year results with 3 treatment strategies. Int J Oral Maxillofac Implants 2004;19: 563-77. 13. Waas MAJ, Bosker H. Evaluation of satisfaction of denture wearers with the transmandibular implant. Int J Oral Maxillofac Surg 1989;18:145-7. Corresponding author: Dr Ramtin Sadid-Zadeh University at Buffalo School of Dental Medicine 3435 Main St, 215K Squire Hall Buffalo, NY 14214 Email: [email protected] Copyright © 2017 by the Editorial Council for The Journal of Prosthetic Dentistry.
THE JOURNAL OF PROSTHETIC DENTISTRY