DENTAL IMPLANTS. J Oral Maxillofac Surg 64: , 2006

Transcription

1 DENTAL IMPLANTS J Oral Maxillofac Surg 64: , 2006 Using Distraction Osteogenesis for Repositioning the Multiple Dental Implants-Retained Premaxilla With Autogenous Bone Graft and Keratinized Palatal Mucosa Graft Vestibuloplasty in a Trauma Patient: Report of a Case Jenny Hwai-Jen Fong, DDS, DMSc,* Man-Tin Lui, DDS, Jen-Hsein Wu, DDS, I-Chiang Chou, DDS, Tze-Cheung Yeung, DDS, MS, and Shou-Yen Kao, DDS, DMSc We present a case with loss of teeth, gingiva, and alveolar bone in the premaxilla resulting from traumatic injury. To overcome the surgically compromised soft and hard tissue status for implant rehabilitation, surgical approaches including an autogenous bone graft from the symphysis of the mandible and a palatal mucosal graft vestibuloplasty were first performed. Implant fixtures were then placed. The esthetics of the provisional bridge *Associate professor, Division of Orthodontics, School of Dentistry, National Yang-Ming University, Taipei, Taiwan. Attending Physician, Oral and Maxillofacial Surgery, Taipei Veterans General Hospital; National Yang-Ming University, Taipei, Taiwan. Attending Physician, Oral and Maxillofacial Surgery, Taipei Veterans General Hospital; National Yang-Ming University, Taipei, Taiwan. Resident, Oral and Maxillofacial Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. Attending Physician, Prosthetic Dentistry, Taipei Veterans General Hospital, Taipei, Taiwan. Professor and Chief, Oral and Maxillofacial Surgery, Taipei Veterans General Hospital; School of Dentistry, National Yang-Ming University; Central Clinic Hospital, Taipei, Taiwan. Sponsored by grants VGH93C230, NSC B075, and CI937, Taipei Veterans General Hospital, National Science Council, Taiwan, ROC. Address correspondence and reprint requests to Dr Kao: No 201, Sec II, Shih-Pai Road, Oral and Maxillofacial Surgery, Department of Dentistry, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; sykao@vghtpe.gov.tw 2006 American Association of Oral and Maxillofacial Surgeons /06/ $32.00/0 doi: /j.joms were unsatisfactory because of insufficient vertical ridge height. A segmental osteotomy, creating a greenstick fracture of the premaxilla, was performed, followed by a novel procedure to reposition the premaxillary fragment vertically downward to an ideal position. The fragment, retained by implant fixtures, was moved 1 mm per day for a 5-day period of distraction. An esthetic prosthesis was achieved by this surgical design. After 2 years of follow-up, rehabilitation was stable. Multiple methods have been proposed to reconstruct the compromised alveolar ridge lacking bone and an appropriate vestibule. For augmenting the deficient ridge, symphyseal bone of the mandible is a good donor material. It provides sufficient compact bone volume to rebuild the severely traumatized or resorbed ridge in the premaxilla. 1-5 The morphology of the augmented ridge may be further improved by vestibuloplasty with nonkeratinized or keratinized mucosal graft (KMG) In cases of excessive tooth and bone loss, augmentation of the width and height at the deficient ridge is required for an ideal implant support. However, difficulties have been encountered with various techniques for simultaneously augmenting the width and height of the premaxilla. This patient suffered trauma resulting in the loss of multiple teeth, gingiva, and alveolar bone, with scar formation at the shallow compromised vestibule in the premaxilla. A novel comprehensive procedure to rehabilitate the compromised soft and hard tissue with dental implants was used to restore bond, soft tissue, and teeth. 794

2 FONG ET AL 795 FIGURE 1. The 17-year-old patient requested dental rehabilitation at 3 months after open reduction for maxillofacial injury. A, Intraoral front view showing scar band, deficiency of premaxilla, loss of teeth from upper right lateral incisor to upper left central incisor, and loss of lower left central incisor. B, A vestibular approach was used for access to the mandibular symphyseal bone graft estimating cm. C, The bone graft was transferred to the premaxilla to recover its normal contour. D, The labial flap covering the bone graft led to a temporary compromise in the anterior vestibule. E, The vestibuloplasty with KMG improved the esthetic and vestibular contour at the premaxilla. F, Four fixtures were implanted just at the position for replacing each missing tooth. An average of 5-mm long discrepancy of the bone level between the ridge crest of the grafted area and that of the adjacent teeth was observed. Fong et al. DO for Implants-Retained Premaxilla in a Trauma Patient. J Oral Maxillofac Surg Report of a Case A 17-year-old boy was involved in a motorcycle accident and suffered a maxillofacial injury to the midface with soft tissue laceration and Le Fort I and II fractures. There was avulsion of 3 upper teeth from the right lateral incisor to the left central incisor, 1 lower left central incisor, and severe loss of alveolar bone and gingiva in the premaxilla. He underwent open reduction surgery with titanium miniplate fixation for the fractures to correct an occlusion. Three months later, he was evaluated for dental rehabilitation. Physical and radiographic examinations revealed multiple functional and cosmetic problems. Extraorally, retrusion of the premaxillary facial profile and scarring from the previous trauma was observed. Intraorally, the patient s occlusion was correct but had deficient premaxillary alveolar ridge with scarring compromised vestibule and loss of multiple teeth in both jaws (Fig 1A). Different treatment plans including conventional denture, conventional fixed bridge, and implant prosthesis were carefully explained to the patient and his family regarding their respective esthetics, convenience, stability, and cost. They preferred the implant prosthesis and accepted a comprehensive treatment plan including the soft and hard tissue management, after informing them of the potential for failure, complications, and uncertain outcomes of either procedure. Surgical Procedures BONE GRAFT The edentulous premaxilla in need of augmentation was carefully evaluated by tomography and model study. A vestibular incision similar to the Le Fort I approach was performed to expose the premaxillary bone. A symphyseal bone graft was trimmed with a rongeur and bur to adapt to the deficient portion of the premaxilla. The symphyseal bone graft was immobilized with a 10-mm long microscrew to the premaxilla after removal of fracture hardware. The submucosal dissection with a bilateral releasing incision ensured sufficient flexibility of the flap to cover the grafted bone. After closure, an even more compro-

3 796 DO FOR IMPLANTS-RETAINED PREMAXILLA IN A TRAUMA PATIENT mised shallow vestibule remained at this stage (Figs 1B-D). SOFT TISSUE MANAGEMENT Two months after the bone graft, the second-stage vestibuloplasty was performed to improve the soft tissue condition at the premaxilla. At the mucogingival junction, a supraperiosteal dissection was used to elevate the mucosal flap. The edge of the labial flap was sutured apically to leave a 10-mm wide supraperiosteal surface extending mesio-distally to the adjacent teeth. The microscrew for immobilization of the grafted bone was removed. A band of palatal KMG was sutured to the recipient site and was covered by a surgical stent with soft lining tissue conditioner for 7 days postoperatively. The vestibular contour at the premaxilla was created after this stage (Fig 1E). A temporary removable partial denture was used during this transition stage to maintain esthetics. IMPLANT SURGERY Four months after the bone graft, implant surgery included mm endosteal dental implants inserted via the crestal approach, guided by the surgical stent to ensure correct position and axis (Fig 1F). Primary suturing of the wound was performed to ensure secure coverage of the implants. DISTRACTION OSTEOGENESIS Four months later, the top of the implant fixtures was exposed to prepare a provisional bridge. Radiographic examination showed an estimated 5 mm distance from the ridge crest to the ideal bone level of the adjacent natural teeth (Fig 1F). Clinically, the insufficient vertical ridge height of the augmented premaxilla was esthetically unsatisfactory around the cervical area of the provisional bridge, where varying degrees of metal exposure (with a maximum of 5 mm) was observed. To improve esthetics, a downward distraction of the premaxilla was planned to reposition the implant fixture 5 mm occlusally. Brackets and wires were bonded to the provisional bridge for retracting the bone fragment (Fig 2A). A 5-mm occlusal reduction and thinning from the incisal edge of the provisional bridge was prepared to permit the downward movement of the premaxilla (Fig 2B). Under general anesthesia, 2 vertical incisions were made from the ridge crest of the premaxilla directly at the osteotomy site. With minimal vertical exposure of bone, bilateral vertical osteotomy was performed from the crestal area to the basal bone with medial extension to connect the opposite cut at the midpalatal vault. The anterior nasal spine was exposed by dissection through a short vertical incision at the midline of the anterior vestibule, followed by partial separation of the nasal septum at the palatal junction with a nasal septum osteotomy. A greenstick fracture of the premaxillary fragment was achieved by a careful bending of the bone fragment. A surgical stent for receiving the polished provisional bridge was adapted to the maxilla by wire fixation to the arch bar (Fig 2C). Two weeks after surgery, the brackets on the temporary prosthesis were connected by 2 orthodontic elastic chains to the surgical stent. The whole fragment was distracted down by the elastic chain by 1 mm per day for 5 days, which was achieved by changing different sized small resin vertical stops between the provisional prosthesis and the stent each day. Five days later, the fragment was transported to the final position in the occlusal stent (Fig 2D). The fragment was further immobilized to the surgical stent with light wire for another month of consolidation of the distraction osteogenesis. Two months after the distraction, the fragment was firm and stable at the new ideal position. The presurgical provisional bridge was then transferred to the esthetic resin prosthesis with a satisfactory result (Fig 2E). After 2 years of follow-up, the rehabilitation outcome of the final prosthesis is stable and satisfactory (Fig 2F). Discussion Compromised alveolar ridges in need of soft and hard tissue management can be caused by age, prior excision of a tumor, or maxillofacial injury. 1,2 Various bone augmentation methods for surgically compromised ridges with either alloplastic material or autogenous bone have been reported. 1-5,11 One significant complication is unpredictable postoperative bone resorption, which is commonly seen in iliac bone grafts. Additionally, donor site morbidity from harvesting the iliac bone is another consideration. 12 The corticocancellous bone graft from the mandibular symphysis provides a reliable implant supporting tissue resistant to resorption and has a high content of marrow stem cells leading to the success of osseointegration of implants. 5 However, a deficit or insufficiency in the ridge height was observed even after the bone graft surgery. To overcome this problem, 1 possible method, already proposed, is to distract the bone and increase the ridge height before implant surgery It would be extremely difficult to combine increase of ridge height simultaneously with increase of ridge width. The method for splitting the alveolar ridge at the maxilla, also called palatal splitting, to create a greenstick fracture could potentially be beneficial when there is insufficient ridge width for implant surgery. 16 However, the benefit is limited for cases such as in this report, which combines insufficient

4 FONG ET AL 797 FIGURE 2. A, The provisional bridge had unsatisfactory esthetics at the cervical area of the provisional bridge with high cervical line and metal exposure. Braces were prepared for distraction of the bone fragment. B, A 5-mm occlusal reduction and thinning of the incisal edge of the provisional bridge allow the downward movement of the premaxilla. C, A minimal exposure of the premaxillary bone was designed for the surgical access to the anterior nasal spine and bilateral vertical osteotomy sites between dental implants and adjacent teeth. The surgical stent for adapting the provisional bridge during traction was fixed to other maxillary teeth by the arch bars and wires. D, After a 5-day period of controlled distraction of the fragment, the reduced incisal edge of the provisional bridge in the distracted fragment was precisely adapted to the check point of the surgical stent. E, Two months after distraction, a new provisional prosthesis showed its satisfactory esthetics and even cervical gum line supported by the KMG. F, Satisfactory esthetics and stability of the final restoration was observed at the 2-year follow-up. Fong et al. DO for Implants-Retained Premaxilla in a Trauma Patient. J Oral Maxillofac Surg ridge width and ridge height. The onlay bone graft at the ridge crest combined with palatal splitting in implant surgery could potentially make results even more unpredictable and raise the possibility of insufficient soft tissue coverage for the bone graft. Ilizarov et al 17 proposed the distraction osteogenesis theory to generate new bone by stretching the bone fragment along the force-conducted direction. This method succeeded in getting new bone to grow in the distracted bone gap. Since Ilizarov et al s experience, more and more clinical applications by various expensive commercial products have been applied in stretching the oral-maxillofacial skeleton for the treatment of hemifacial microstomia, ectodermal dysplasia, mandibular retrognathism, mid-face deficiency and severely resorbed edentulous ridge ,18,19 In contrast to slow distraction of the bone fragment, the segmental osteotomy to immediately correct a single malposed implant has also recently been used by placing a miniscrew for fixation or immobilization. 20 In this article, we propose a reliable and inexpensive method to first gain osseointegration of implant fixtures in a solid basis of grafted bone. This novel distracting approach, increasing ridge height at the multiple implants, retained premaxilla with ease and with a predictable result that does not require expensive commercial distracting devices or screw fixation of the bone fragment. This comprehensive rehabilitation with a bone graft, vestibuloplasty, implant surgery, and distraction osteogenesis (to fine tune the ultimate ridge height) resulted in a predictable cosmetic result with satisfactory stability during follow-up.

5 798 DO FOR IMPLANTS-RETAINED PREMAXILLA IN A TRAUMA PATIENT Acknowledgment The authors thank S.T. Tsai, who contributed greatly to the administrative and editorial work. References 1. Keller EE, Tolman DE, Eckert S: Surgical-prosthodontic reconstruction of advanced maxillary bone compromise with autogenous onlay block bone grafts and osseointegrated endosseous implants: A 12-year study of 32 consecutive patients. Int J Oral Maxillofac Implants 14:197, Verhoeven JW, Cune MS, Terlou M, et al: The combined use of endosteal implants and iliac crest onlay grafts in the severely atrophic mandible: A longitudinal study. J Oral Maxillofac Surg 26:351, Boyne PJ, Cole MD, Stringer D, et al: A technique for osseous restoration of deficient edentulous maxillary ridges. J Oral Maxillofac Surg 43:87, Astrand P, Nord PG, Branemark PI: Titanium implants and onlay bone graft to the atrophic edentulous maxilla: A 3-year longitudinal study. Int J Oral Maxillofac Surg 25:25, Jensen J, Sindet-Pedersen S: Autogenous mandibular bone grafts and osseointegrated implants for reconstruction of the severely atrophied maxilla: A preliminary report. J Oral Maxillofac Surg 49:1277, Froschl T, Kerscher A: The optimal vestibuloplasty in preprosthetic surgery of the mandible. J Craniomaxillofacial Surg 25:85, Hughes WG, Howard CW III: Simultaneous split-thickness skin grafting and placement of endosteal implants in the edentulous mandible: A preliminary report. J Oral Maxillofac Surg 50:448, Goldstein M, Boyan BD, Schwarts Z: The palatal advanced flap: A pedicle flap for primary coverage of immediately placed implants. Clin Oral Implant Res 13:644, Kao SY, Yeung TC, Hung KF, et al: Transpositioned flap vestibuloplasty combined with implant surgery in the severely resorbed atrophic edentulous ridge. J Oral Implantol 28:194, Kao SY, Yeung TC, Chou IC, et al: Reconstruction of the severely resorbed atrophic edentulous ridge of the maxilla and mandible for implant rehabilitation: Report of a case. J Oral Implantol 28:128, Kent JN, Quinn JH, Zide MF, et al: Alveolar ridge augmentation using nonresorbable hydroxylapatite with or without autogenous cancellous bone. J Oral Maxillofac Surg 41:629, Cocklin J: Autogenous bone grafting Complications at the donor site. J Bone Joint Surg 46:290, Rachmiel A, Srouji S, Peled M: Alveolar ridge augmentation by distraction osteogenesis. Int J Oral Maxillofac Surg 30:510, Klug CN, Millesi-School GAW, Watzinger F, et al: Preprosthetic vertical distraction osteogenesis of the mandible using an L- shaped osteotomy and titanium membranes for guided bone regeneration. J Oral Maxillofac Surg 59:1302, Nosaka Y, Kitano S, Wada K, et al: Endosseous implants in horizontal alveolar ridge distraction osteogenesis. Int J Oral Maxillofac Implants 17:846, Palti A: Ridge splitting and implant techniques for the anterior maxilla. Dental Implantol Update 14:25, Ilizarov GA, Devyatov AA, Kamerin VK: Plastic reconstruction of longitudinal bone defects by means of compression and subsequent distraction. Acta Chir Plast (Prague) 22:32, Kearns G, Sharma A, Perrott D, et al: Placement of endosseous implants in children and adolescents with hereditary ectodermal dysplasia. J Oral Maxillofac Surg 88:5, Huisinga-Fischer CE, Vaandrager JM, Prahl-Andersen B: Longitudinal results of mandibular distraction osteogenesis in hemifacial microsomia. J Craniofacial Surg 14:6, Kassolis JD, Baer ML, Reynolds MA: The segmental osteotomy in the management of malposed implants: A case report and literature review. J Periodontol 74:529, 2003