J
Oral Mwllofac
Surg
48:27-32.1990
Reconstruction of the Severely Resorbed Maxilla With Bone Grafting and Osseoin tegra ted impian ts: A Preliminary
Report
J. JENSEN, DDS, E. KRANTZ SIMONSEN, DDS, MD, AND S. SINDET-PEDERSEN, DDS This article describes a surgical procedure for rehabilitation of the severely atrophic maxillary alveolar ridge by bone grafting to the maxillary sinus and nasal floor followed by installation of implants in the grafted regions at a second operation. Five treated cases are presented. Further data are considered necessary to evaluate the procedure before it can be recommended for routine use.
Since the introduction of osseointegrated implants for treatment of edentulous jaws, it has been possible to reconstruct patients with a sufficient amount of bone without the need for additional procedures. ‘.* However, patients with severe atrophy of the maxillary alveolar process and/or excessively pneumatized maxillary sinuses are difficult to treat by conventional implant techniques due to the lack of a sufficient amount of alveolar bone into which implants can be anchored.3 Clinical and experimental studies using bone grafts in combination with titanium osseointegrated implants for patients with advanced bone resorption were first reported by Breine and Brhnemark.3 Two reconstructive procedures involving bone grafting were studied. The first procedure involved simultaneous reconstruction with autologous chips of tibia1 cancellous bone and marrow in combination with titanium fixtures. Implants were apically tapped into the residual maxillary alveolar ridge, and particulate tibia1 bone was packed around the remaining part of the implants. Only 25% of the implants
supported by immediate bone grafts remained integrated, and most of the bone grafts were resorbed during the first postoperative year in the 14 maxillas investigated. The second procedure included the use of preformed autogenous bone grafts with implants incorporated in a two-stage procedure. In the first operation. the implants were placed in the proximal tibial metaphysis and surrounded by a titanium mold. After a healing period of 3 to 6 months the second stage was performed. Bone grafts with implants incorporated were placed on the resorbed residual maxilla and fixed with additional long implants. Sixty percent of the implants remained integrated when preformed autogenous onlay bone grafts were used, but only 50% of the volume of the grafts was preserved after a year in the eight maxillas investigated. Another surgical technique used by Branemark and colleagues.4 and later also reported by Keller et al5 is the so-called immediate-placement graft technique. By this procedure a bone graft from the iliac crest is adapted to the recipient site and fixed on the residual maxillary alveolar ridge with implants. Four of 28 implants in five patients did not integrate and were removed 3 weeks or 8 months after installation.s Keller et al5 also reported results from a delayedplacement graft technique. inter-positional iliac bone grafts were placed after a Le Fort I osteotomy of the residual maxilla. Six to 18 months later, im-
Received from the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark. Address correspondence and reprint requests to Dr Jensen: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Nfirrebrogade, DK-8000 Aarhus, Denmark. 0 1990 American
Association
of Oral
and Maxillofacial
Sur-
geons 0278-2391190/4801-0005$3.00/O
27
28
RECONSTRUCTION OF THE ATROPHIC MAXILLA
plants were installed in the reconstructed alveolar ridge. Five of 21 implants in four patients were nonintegrated in the healing phase and had to be removed. In 1980 Boyne and James6 reported a method by which bone was grafted into the floor of the maxillary sinus to increase the amount of alveolar ridge. This method was used primarily for treatment of patients in whom increased pneumatization of the maxillary sinus and reduction of the interarch space interfered with conventional prosthetic treatment. Three months after bone grafting, the posterior tuberosity and alveolar process were reduced to provide sufficient interarch space. Fourteen patients were treated by this procedure, of whom three later received blade implants in the grafted regions to anchor bridges. The combined bone grafting and implant technique for functional rehabilitation of the severely atrophic maxillary alveolar ridge has been further developed to include bone grafting to the maxillary sinus and nasal floor followed by installation of osseointegrated implants at a second operation. The aim of this report is to describe the course of five patients treated by this method.
horizontal incision was made above the mucogingival junction extending from the second molar to the canine region, with a relieving incision at the canine. The mucosa was elevated to expose the anterior and lateral walls of the maxillary sinus and the piriform aperature (Fig 1A). Parts of the anterior and lateral walls of the sinus were resected with a large round bur (Fig lB), and the mucosa of the maxillary sinus was carefully reflected with blunt currettes and a periosteal elevator (Fig 1C). Cancellous bone was packed into the floor of the sinus to increase the height of the alveolar ridge sufficiently to allow installation of implants in a later operation (Fig 1D). Patients with a minimal height of the alveolar process in the premaxilla also received a bone graft in the anterior part of the nasal floor after careful elevation of the nasal mucosa (Fig 1E). Antibiotic treatment was initiated at surgery and continued together with use of nose drops postoperatively. Biotes (Nobelpfarma, Kahskoga, Sweden) osseointegrated titanium implants were installed 4 to 5 months later.
Methods
The patient was a 44-year-old woman with a fixed bridge in the maxilla supported by natural teeth with advanced periodontitis on the right side and ceramic and blade-vent implants with severe infection on the other side (Fig 2A). The teeth and implants were removed, and 2 months later bone grafting to the maxillary sinus was performed due to the severe atrophy of the alveolar process (Fig 2B). Four months later, eight implants were installed in the maxillary bone; five of them in the grafted
All five patients were treated under general anesthesia. A cancellous bone graft was obtained from the posterior part of the iliac crest. Local anesthesia with a vasoconstrictor was injected into the labiobuccal vestibule to improve hemostasis, and a
Report of Cases Case 1
FIGURE 1. A, The antral wall and lateral part of the piriform aperature is exposed. B, Parts of the antral wall have been resected. C, The mucosa of the maxillary sinus is carefully reflected with blunt currettes and a periosteal elevator. D, Cancellous bone is packed into the floor of the maxillary sinus. E. Cancellous bone is packed in the anterior part of the nasal floor after careful elevation of the nasal mucosa.
JENSEN,
SIMONSEN,
29
AND SINDET-PEDERSEN
regions varied in length from 7 to 10 mm. A provisional denture was placed after 1 week. Six months after the first operation a provisional bridge was constructed. At that time two of the implants in the anterior region in a nongrafted area had to be removed because they had not integrated. This was probably due to early loading from the provisional denture. Two additional implants were installed, one in the midline and the other in the right tuberosity. Three months later, and 13 months after the bone grafting, a permanent bridge was constructed which also included the last installed implant in the anterior region (Fig 2, C and D). After 33 months of follow-up the patient returned because of pain. The bridge had loosened and was therefore removed together with all six implants supporting the bridge (Fig 2E). Case 2 This patient was an edentulous man, 59 years of age, suffering from diabetes. He had an abnormal gag reflex and was unable to use an upper denture. The radiologic examination showed excessively pneumatized maxillary sinuses and an insufficient amount of bone for implants (Fig 3A). Bone grafting of the sinus and the nasal floor was performed (Fig 3B), and 5 months later nine implants of lengths from 10 to 15 mm were installed in the grafted bone. Five months later, and 10 months after the bone grafting, a permanent bridge was fixed to the implants (Fig 3C). Radiographs taken 17 months after the primary operation showed radiolucencies in the apical part of one implant on each side of the maxillary sinus. There were no subjective symptoms. Under local anesthesia a sinusoscopy was performed, which showed that both implants were exposed in the maxillary sinus but surrounded with healthy peri-implant mucosa (Fig 3D). Reexamination 9 months later showed healthy mucosa covering the previously exposed implants. After 34 months all implants and the bridge were functioning well (Fig 3E). Case 3
FIGURE 2. A, Patient with a fixed bridge in the maxilla supported by natural teeth with advanced periodontitis on the right side and ceramic and blade-vent implants with severe infection on the left side. II, Two months after removal of teeth and implants, bone grafting to the maxillary sinus was performed. C,
Six implants installed in the grafted regions, four of which are loaded by a fixed bridge; the other two implants in the maxillary tuberosities have not yet been connected to the bridge. D, Clinical appearance of the bridge. E, Radiographic appearance at the time the bridge had loosened. Radiolucencies are seen around the implants (arrows).
A 52-year-old man could not use his upper denture due to lack of retention. Preprosthetic surgery had previously been performed with an unsatisfactory result. Clinically and radiologically the patient demonstrated severe resorption of the maxillary alveolar ridge. A grafting procedure to the maxillary sinus and nasal floor was performed, and 4 months later seven implants with lengths from 10 to 13 mm were installed in the grafted regions. Eleven months after the initial operation a fixed bridge supported by six implants was constructed. At that time an implant in the right maxillary region had to be removed because it had not integrated. Two additional implants were installed in grafted areas. Twenty months after the primary operation the bridge is well functioning, and radiographs indicate normal healing (Fig 4). The last two implants are now ready for connection to the bridge. Case 4 An edentulous 45-year-old spastic woman could not use dentures. Sixteen months earlier a fixed bridge supported by implants had been constructed in the mandible. Clinical and radiologic examination showed severe resorption of the maxillary alveolar ridge, and therefore bone grafting to both the maxillary sinus and nasal floor was performed. Four months later eight implants were
RECONSTRUCTION
OF THE ATROPHIC MAXILLA
FIGURE 3. A, Maxillary alveolar atrophy and antral pneumatization exclude placement of implants. B, Radiographic appearance 2 weeks after bone grafting. C, The bridge supported by six implants. D, Sinuscopy shows that one implant on each side is exposed to the maxillary sinus (arrows). E, Radiographic appearance 34 months after bone grafting.
installed, six of those in grafted bone were of lengths from 7 to 10 mm (Fig SA). Twelve months after bone grafting a bridge was constructed supported by only five implants, because one 7-mm fixture in the right side of the maxillary was not integrated and because it was impossible to connect abutments on the most distal implants. Two months later the patient returned complaining of pain and a loosened bridge, which required its removal (Fig 5B).
Case 5 This patient was a 44-year-old man who had an abnormal gag - - reflex and could not use an upper denture. An unsuccessful attempt was made to install conventional
implants in the maxilla. The bone quality was poor, and consequently only four of the six installed fixtures integrated. At the time of the abutment placement, bone was grafted to the maxillary sinus. A provisional bridge was constructed supported by three of the original implants. Five months later six implants with lengths from 13 to 20 mm were installed in the grafted bone, and one was placed in the anterior region of the maxilla. Twelve months after the bone grafting, abutments were connected to the fixtures. At that time the implant in the right canine region was not integrated and therefore was removed. Two additional implants, 20 mm in length, were installed mesial and distal to the site of the removed implant. Sixteen months after the bone grafting, nine implants are ready for construction of a permanent bridge (Fig 6).
Discussion
FIGURE 4. Radiographs indicate normal healing of the two additionally installed implants.
Onlay bone grafts have been recommended for augmentation of atrophic alveolar ridges; however, it is now generally recognized that these grafts are prone to extensive resorption when exposed to external loading. ‘,’ Similar findings have also been reported by Breine and Br&nemark who found extensive resorption of grafted bone after simultaneous installation of implants and grafting of particulate
31
FIGURE 5.
A, Radiographic
appearance before bridge construction.
cancellous bone.3 The reported resorption rate of the grafted bone may have been influenced by the insertion of a provisional denture as early as 3 weeks after the operatiom3 therefore, Listrom and Symington have recommended a healing time from 6 to 9 months without dentures.’ Without implants, there may even be a greater risk that the grafted bone will be gradually resorbed with time.’ We have therefore chosen to do the implant insertion after 4 months. In the cases presented, radiographs indicated consolidation of the grafted bone when implants were installed after 4 months, probably due to functional stimulation of bone by the implants.‘.” The preparation time for the bone graft used with the present technique is short compared with that for the onlay graft techniques, and the reduced preparation time may have influenced the healing of the grafted bone.3 Difficulty has been reported in obtaining adequate soft tissue coverage over both immediate and preformed grafts and implants using the onlay technique. This can increase the risk for contamination, and may also be a decisive factor for graft and implant survival.3*5.9 There are no technical difftculties in obtaining adequate soft tissue coverage of the graft and implants when using the technique presented. The Le Fort I down-fracture inter-positional bone
FIGURE 6. Radiographic appearance 16 months after bone grafting and before construction of a permanent bridge.
B, Bridge and implants removed together,
graft in combination with osseointegrated implants has been described by Keller et al.5 This procedure was advocated in selected patients with retroposition of the maxilla as well as with severe alveolar bone loss,’ whereas Sailer” advocates this technique in all patients with extreme maxillary atrophy. The surgical technique is quite extensive$‘t* therefore, we have chosen to evaluate a less extensive surgical procedure than the one advocated by Keller et al and Sailer because many patients are relatively old. The current report demonstrates the use of a modified technique for reconstruction of the severely resorbed maxillary alveolar ridge by bone grafting to the maxillary sinus and anterior nasal cavity followed by installation of implants. The follow-up period in this material is thus far limited (range, 10 to 29 months; median 16 months after installation of fixtures), as is the number of patients. A total of 51 implants were installed in the five patients. Nine of the 36 implants placed in grafted bone and 7 of the 15 implants in nongrafted bone have so far been lost. In one of the patients (case 4) muscular hyperactivity probably contributed to the failure of the reconstruction, whereas several short implants (7 to 10 mm) were used in patient No. 1. These cases indicate what can happen following an implant reconstruction when the load exceeds the bearing capacity of the reconstruction. The bearing capacity is dependent on the quantity (determining the length of fixtures) and the quality of the bone. The fact that the bearing capacity of cancellous bone is less than that of cortical bone probably was the most important factor influencing the prognosis of the osseointegrated implants in the maxilla. Although the results so far are comparable with those obtained by Breine and Brinemark using onlay bone graft techniques3 we are reluctant to recommend the procedure due to the sudden loss of two reconstructions 2 and 23 months after loading the implants. Further data are therefore necessary before the procedure can be recommended for routine use.
32
RECONSTRUCTION
References 7. 1. Laney WR, Tolman DE, Keller EE, et al: Dental implants: Tissue-integrated prosthesis utilizing the osseointegration concept. Mayo Clin Proc 61:91, 1986 2. Albrektsson T: A multicenter report on osseointegrated oral implants. J Prosthet Dent 60:75, 1988 3. Breine U, B&remark PI: Reconstruction of alveolar jaw bone. Stand J Plast Reconstr Surg 14:23, 1980 4. B&remark PI, Zarb GA, Albrektsson T (eds): TissueIntegrated Prostheses. Osseointegration in Clinical Dentistry. Chicago, IL, Quintessence, 1985 5. Keller EE, Van Roekel NB, Desjardins RP, et al: Prostheticsurgical reconstruction of severely resorbed maxilla with iliac bone grafting and tissue-integrated prostheses. Int J Oral Maxillofac Implants 2: 155, 1987 6. Boyne PJ, James RA: Grafting of the maxillary sinus floor
8.
9.
10.
11.
OF THE ATROPHIC MAXILLA
with autogenous marrow and bone. J Oral Surg 38:613, 1980 Shelton DW: Critical review of preprosthetic surgery, in Irby WB (ed): Current Advances in Oral Surgery, ~012. St Louis, MO, Mosby, 1977, p 375 Swart JGN, Allard RHB: Subperiosteal onlay augmentation of the mandible: A clinical and radiographic survey. J Oral Maxillofac Surg 43:183, 1985 Listrom RD, Symington JM: Osseointegrated dental implants in conjunction with bone grafts. Int J Oral Maxillofac Surg 17:116, 1988 Brlnemark PI, Adell R, Albrektsson T, et al: An experimental and clinical study of osseointegrated implants penetrating the nasal cavity and maxillary sinus. J Oral Maxillofac Surg 42~497, 1984 Sailer HF: A new method setting enosseous implants in cases of totally atrophied maxillae. Ninth Congress of the European Association for Cranio-Maxillo-Facial Surgery, Athens, September 1988 (abstr)
Oral Mwllofac
Surg
48:27-32.1990
Reconstruction of the Severely Resorbed Maxilla With Bone Grafting and Osseoin tegra ted impian ts: A Preliminary
Report
J. JENSEN, DDS, E. KRANTZ SIMONSEN, DDS, MD, AND S. SINDET-PEDERSEN, DDS This article describes a surgical procedure for rehabilitation of the severely atrophic maxillary alveolar ridge by bone grafting to the maxillary sinus and nasal floor followed by installation of implants in the grafted regions at a second operation. Five treated cases are presented. Further data are considered necessary to evaluate the procedure before it can be recommended for routine use.
Since the introduction of osseointegrated implants for treatment of edentulous jaws, it has been possible to reconstruct patients with a sufficient amount of bone without the need for additional procedures. ‘.* However, patients with severe atrophy of the maxillary alveolar process and/or excessively pneumatized maxillary sinuses are difficult to treat by conventional implant techniques due to the lack of a sufficient amount of alveolar bone into which implants can be anchored.3 Clinical and experimental studies using bone grafts in combination with titanium osseointegrated implants for patients with advanced bone resorption were first reported by Breine and Brhnemark.3 Two reconstructive procedures involving bone grafting were studied. The first procedure involved simultaneous reconstruction with autologous chips of tibia1 cancellous bone and marrow in combination with titanium fixtures. Implants were apically tapped into the residual maxillary alveolar ridge, and particulate tibia1 bone was packed around the remaining part of the implants. Only 25% of the implants
supported by immediate bone grafts remained integrated, and most of the bone grafts were resorbed during the first postoperative year in the 14 maxillas investigated. The second procedure included the use of preformed autogenous bone grafts with implants incorporated in a two-stage procedure. In the first operation. the implants were placed in the proximal tibial metaphysis and surrounded by a titanium mold. After a healing period of 3 to 6 months the second stage was performed. Bone grafts with implants incorporated were placed on the resorbed residual maxilla and fixed with additional long implants. Sixty percent of the implants remained integrated when preformed autogenous onlay bone grafts were used, but only 50% of the volume of the grafts was preserved after a year in the eight maxillas investigated. Another surgical technique used by Branemark and colleagues.4 and later also reported by Keller et al5 is the so-called immediate-placement graft technique. By this procedure a bone graft from the iliac crest is adapted to the recipient site and fixed on the residual maxillary alveolar ridge with implants. Four of 28 implants in five patients did not integrate and were removed 3 weeks or 8 months after installation.s Keller et al5 also reported results from a delayedplacement graft technique. inter-positional iliac bone grafts were placed after a Le Fort I osteotomy of the residual maxilla. Six to 18 months later, im-
Received from the Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark. Address correspondence and reprint requests to Dr Jensen: Department of Oral and Maxillofacial Surgery, Aarhus University Hospital, Nfirrebrogade, DK-8000 Aarhus, Denmark. 0 1990 American
Association
of Oral
and Maxillofacial
Sur-
geons 0278-2391190/4801-0005$3.00/O
27
28
RECONSTRUCTION OF THE ATROPHIC MAXILLA
plants were installed in the reconstructed alveolar ridge. Five of 21 implants in four patients were nonintegrated in the healing phase and had to be removed. In 1980 Boyne and James6 reported a method by which bone was grafted into the floor of the maxillary sinus to increase the amount of alveolar ridge. This method was used primarily for treatment of patients in whom increased pneumatization of the maxillary sinus and reduction of the interarch space interfered with conventional prosthetic treatment. Three months after bone grafting, the posterior tuberosity and alveolar process were reduced to provide sufficient interarch space. Fourteen patients were treated by this procedure, of whom three later received blade implants in the grafted regions to anchor bridges. The combined bone grafting and implant technique for functional rehabilitation of the severely atrophic maxillary alveolar ridge has been further developed to include bone grafting to the maxillary sinus and nasal floor followed by installation of osseointegrated implants at a second operation. The aim of this report is to describe the course of five patients treated by this method.
horizontal incision was made above the mucogingival junction extending from the second molar to the canine region, with a relieving incision at the canine. The mucosa was elevated to expose the anterior and lateral walls of the maxillary sinus and the piriform aperature (Fig 1A). Parts of the anterior and lateral walls of the sinus were resected with a large round bur (Fig lB), and the mucosa of the maxillary sinus was carefully reflected with blunt currettes and a periosteal elevator (Fig 1C). Cancellous bone was packed into the floor of the sinus to increase the height of the alveolar ridge sufficiently to allow installation of implants in a later operation (Fig 1D). Patients with a minimal height of the alveolar process in the premaxilla also received a bone graft in the anterior part of the nasal floor after careful elevation of the nasal mucosa (Fig 1E). Antibiotic treatment was initiated at surgery and continued together with use of nose drops postoperatively. Biotes (Nobelpfarma, Kahskoga, Sweden) osseointegrated titanium implants were installed 4 to 5 months later.
Methods
The patient was a 44-year-old woman with a fixed bridge in the maxilla supported by natural teeth with advanced periodontitis on the right side and ceramic and blade-vent implants with severe infection on the other side (Fig 2A). The teeth and implants were removed, and 2 months later bone grafting to the maxillary sinus was performed due to the severe atrophy of the alveolar process (Fig 2B). Four months later, eight implants were installed in the maxillary bone; five of them in the grafted
All five patients were treated under general anesthesia. A cancellous bone graft was obtained from the posterior part of the iliac crest. Local anesthesia with a vasoconstrictor was injected into the labiobuccal vestibule to improve hemostasis, and a
Report of Cases Case 1
FIGURE 1. A, The antral wall and lateral part of the piriform aperature is exposed. B, Parts of the antral wall have been resected. C, The mucosa of the maxillary sinus is carefully reflected with blunt currettes and a periosteal elevator. D, Cancellous bone is packed into the floor of the maxillary sinus. E. Cancellous bone is packed in the anterior part of the nasal floor after careful elevation of the nasal mucosa.
JENSEN,
SIMONSEN,
29
AND SINDET-PEDERSEN
regions varied in length from 7 to 10 mm. A provisional denture was placed after 1 week. Six months after the first operation a provisional bridge was constructed. At that time two of the implants in the anterior region in a nongrafted area had to be removed because they had not integrated. This was probably due to early loading from the provisional denture. Two additional implants were installed, one in the midline and the other in the right tuberosity. Three months later, and 13 months after the bone grafting, a permanent bridge was constructed which also included the last installed implant in the anterior region (Fig 2, C and D). After 33 months of follow-up the patient returned because of pain. The bridge had loosened and was therefore removed together with all six implants supporting the bridge (Fig 2E). Case 2 This patient was an edentulous man, 59 years of age, suffering from diabetes. He had an abnormal gag reflex and was unable to use an upper denture. The radiologic examination showed excessively pneumatized maxillary sinuses and an insufficient amount of bone for implants (Fig 3A). Bone grafting of the sinus and the nasal floor was performed (Fig 3B), and 5 months later nine implants of lengths from 10 to 15 mm were installed in the grafted bone. Five months later, and 10 months after the bone grafting, a permanent bridge was fixed to the implants (Fig 3C). Radiographs taken 17 months after the primary operation showed radiolucencies in the apical part of one implant on each side of the maxillary sinus. There were no subjective symptoms. Under local anesthesia a sinusoscopy was performed, which showed that both implants were exposed in the maxillary sinus but surrounded with healthy peri-implant mucosa (Fig 3D). Reexamination 9 months later showed healthy mucosa covering the previously exposed implants. After 34 months all implants and the bridge were functioning well (Fig 3E). Case 3
FIGURE 2. A, Patient with a fixed bridge in the maxilla supported by natural teeth with advanced periodontitis on the right side and ceramic and blade-vent implants with severe infection on the left side. II, Two months after removal of teeth and implants, bone grafting to the maxillary sinus was performed. C,
Six implants installed in the grafted regions, four of which are loaded by a fixed bridge; the other two implants in the maxillary tuberosities have not yet been connected to the bridge. D, Clinical appearance of the bridge. E, Radiographic appearance at the time the bridge had loosened. Radiolucencies are seen around the implants (arrows).
A 52-year-old man could not use his upper denture due to lack of retention. Preprosthetic surgery had previously been performed with an unsatisfactory result. Clinically and radiologically the patient demonstrated severe resorption of the maxillary alveolar ridge. A grafting procedure to the maxillary sinus and nasal floor was performed, and 4 months later seven implants with lengths from 10 to 13 mm were installed in the grafted regions. Eleven months after the initial operation a fixed bridge supported by six implants was constructed. At that time an implant in the right maxillary region had to be removed because it had not integrated. Two additional implants were installed in grafted areas. Twenty months after the primary operation the bridge is well functioning, and radiographs indicate normal healing (Fig 4). The last two implants are now ready for connection to the bridge. Case 4 An edentulous 45-year-old spastic woman could not use dentures. Sixteen months earlier a fixed bridge supported by implants had been constructed in the mandible. Clinical and radiologic examination showed severe resorption of the maxillary alveolar ridge, and therefore bone grafting to both the maxillary sinus and nasal floor was performed. Four months later eight implants were
RECONSTRUCTION
OF THE ATROPHIC MAXILLA
FIGURE 3. A, Maxillary alveolar atrophy and antral pneumatization exclude placement of implants. B, Radiographic appearance 2 weeks after bone grafting. C, The bridge supported by six implants. D, Sinuscopy shows that one implant on each side is exposed to the maxillary sinus (arrows). E, Radiographic appearance 34 months after bone grafting.
installed, six of those in grafted bone were of lengths from 7 to 10 mm (Fig SA). Twelve months after bone grafting a bridge was constructed supported by only five implants, because one 7-mm fixture in the right side of the maxillary was not integrated and because it was impossible to connect abutments on the most distal implants. Two months later the patient returned complaining of pain and a loosened bridge, which required its removal (Fig 5B).
Case 5 This patient was a 44-year-old man who had an abnormal gag - - reflex and could not use an upper denture. An unsuccessful attempt was made to install conventional
implants in the maxilla. The bone quality was poor, and consequently only four of the six installed fixtures integrated. At the time of the abutment placement, bone was grafted to the maxillary sinus. A provisional bridge was constructed supported by three of the original implants. Five months later six implants with lengths from 13 to 20 mm were installed in the grafted bone, and one was placed in the anterior region of the maxilla. Twelve months after the bone grafting, abutments were connected to the fixtures. At that time the implant in the right canine region was not integrated and therefore was removed. Two additional implants, 20 mm in length, were installed mesial and distal to the site of the removed implant. Sixteen months after the bone grafting, nine implants are ready for construction of a permanent bridge (Fig 6).
Discussion
FIGURE 4. Radiographs indicate normal healing of the two additionally installed implants.
Onlay bone grafts have been recommended for augmentation of atrophic alveolar ridges; however, it is now generally recognized that these grafts are prone to extensive resorption when exposed to external loading. ‘,’ Similar findings have also been reported by Breine and Br&nemark who found extensive resorption of grafted bone after simultaneous installation of implants and grafting of particulate
31
FIGURE 5.
A, Radiographic
appearance before bridge construction.
cancellous bone.3 The reported resorption rate of the grafted bone may have been influenced by the insertion of a provisional denture as early as 3 weeks after the operatiom3 therefore, Listrom and Symington have recommended a healing time from 6 to 9 months without dentures.’ Without implants, there may even be a greater risk that the grafted bone will be gradually resorbed with time.’ We have therefore chosen to do the implant insertion after 4 months. In the cases presented, radiographs indicated consolidation of the grafted bone when implants were installed after 4 months, probably due to functional stimulation of bone by the implants.‘.” The preparation time for the bone graft used with the present technique is short compared with that for the onlay graft techniques, and the reduced preparation time may have influenced the healing of the grafted bone.3 Difficulty has been reported in obtaining adequate soft tissue coverage over both immediate and preformed grafts and implants using the onlay technique. This can increase the risk for contamination, and may also be a decisive factor for graft and implant survival.3*5.9 There are no technical difftculties in obtaining adequate soft tissue coverage of the graft and implants when using the technique presented. The Le Fort I down-fracture inter-positional bone
FIGURE 6. Radiographic appearance 16 months after bone grafting and before construction of a permanent bridge.
B, Bridge and implants removed together,
graft in combination with osseointegrated implants has been described by Keller et al.5 This procedure was advocated in selected patients with retroposition of the maxilla as well as with severe alveolar bone loss,’ whereas Sailer” advocates this technique in all patients with extreme maxillary atrophy. The surgical technique is quite extensive$‘t* therefore, we have chosen to evaluate a less extensive surgical procedure than the one advocated by Keller et al and Sailer because many patients are relatively old. The current report demonstrates the use of a modified technique for reconstruction of the severely resorbed maxillary alveolar ridge by bone grafting to the maxillary sinus and anterior nasal cavity followed by installation of implants. The follow-up period in this material is thus far limited (range, 10 to 29 months; median 16 months after installation of fixtures), as is the number of patients. A total of 51 implants were installed in the five patients. Nine of the 36 implants placed in grafted bone and 7 of the 15 implants in nongrafted bone have so far been lost. In one of the patients (case 4) muscular hyperactivity probably contributed to the failure of the reconstruction, whereas several short implants (7 to 10 mm) were used in patient No. 1. These cases indicate what can happen following an implant reconstruction when the load exceeds the bearing capacity of the reconstruction. The bearing capacity is dependent on the quantity (determining the length of fixtures) and the quality of the bone. The fact that the bearing capacity of cancellous bone is less than that of cortical bone probably was the most important factor influencing the prognosis of the osseointegrated implants in the maxilla. Although the results so far are comparable with those obtained by Breine and Brinemark using onlay bone graft techniques3 we are reluctant to recommend the procedure due to the sudden loss of two reconstructions 2 and 23 months after loading the implants. Further data are therefore necessary before the procedure can be recommended for routine use.
32
RECONSTRUCTION
References 7. 1. Laney WR, Tolman DE, Keller EE, et al: Dental implants: Tissue-integrated prosthesis utilizing the osseointegration concept. Mayo Clin Proc 61:91, 1986 2. Albrektsson T: A multicenter report on osseointegrated oral implants. J Prosthet Dent 60:75, 1988 3. Breine U, B&remark PI: Reconstruction of alveolar jaw bone. Stand J Plast Reconstr Surg 14:23, 1980 4. B&remark PI, Zarb GA, Albrektsson T (eds): TissueIntegrated Prostheses. Osseointegration in Clinical Dentistry. Chicago, IL, Quintessence, 1985 5. Keller EE, Van Roekel NB, Desjardins RP, et al: Prostheticsurgical reconstruction of severely resorbed maxilla with iliac bone grafting and tissue-integrated prostheses. Int J Oral Maxillofac Implants 2: 155, 1987 6. Boyne PJ, James RA: Grafting of the maxillary sinus floor
8.
9.
10.
11.
OF THE ATROPHIC MAXILLA
with autogenous marrow and bone. J Oral Surg 38:613, 1980 Shelton DW: Critical review of preprosthetic surgery, in Irby WB (ed): Current Advances in Oral Surgery, ~012. St Louis, MO, Mosby, 1977, p 375 Swart JGN, Allard RHB: Subperiosteal onlay augmentation of the mandible: A clinical and radiographic survey. J Oral Maxillofac Surg 43:183, 1985 Listrom RD, Symington JM: Osseointegrated dental implants in conjunction with bone grafts. Int J Oral Maxillofac Surg 17:116, 1988 Brlnemark PI, Adell R, Albrektsson T, et al: An experimental and clinical study of osseointegrated implants penetrating the nasal cavity and maxillary sinus. J Oral Maxillofac Surg 42~497, 1984 Sailer HF: A new method setting enosseous implants in cases of totally atrophied maxillae. Ninth Congress of the European Association for Cranio-Maxillo-Facial Surgery, Athens, September 1988 (abstr)
