 Astra Tech
BioManagement Complex
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 Surgical techniques
A wide range of different surgical techniques are applied when placing implants under different preconditions. The summaries below show that one- and two-stage surgery, immediate placement in extraction sockets, bone augmentation and sinus lift can be successfully and predictably performed using the Astra Tech Implant System'".
 Maxillary osteotomy with an interpositional bone graft and implants for reconstruction of the severely resorbed maxilla: a clinical report
Purpose: Different surgical techniques in combination with implant therapy have been employed in order to rehabณtate athrophic maxillae. Applying the Le Fort I osteotomy technique allows for the adjustment of the maxilla in both horizontal and vertical directions. The aim of this study was to report on the prospective 5-year data when interpositional bone graft and implants were used for the reconstruction of the extremely resorbed maxilla.
Materials and methods: A 2-stage implant rehabilitation procedure was applied. The included patients (15 women and 7 men; mean age 65.7 years) had extreme resorption of the maxilla. Radiographic examination was thoroughly carried out prior to surgery, immediately after the bone grafting procedure, after implant placement, at abutment connection, 1-year postoperatively and then annually for 5 years. Classification of the alveolar anatomy was performed according to modified Cawood and Howell classes. Possible pathological changes of the maxillary sinuses, the borders of the bone grafting area, and marginal bone height with reference to a reference point, were evaluated.
Surgical procedure: All patients were treated with an orthognathic surgical procedure using a maxillary osteotomy technique under general anaesthesia. The maxillary bone was cut with an oscillating saw and separated from the nasal bones before down fracture. Meanwhile, both cortical and cancellous bone grafts were taken from the iliac crest to restore the sinus cavities, nasal floor and cavities between the cortical grafts. The grafts were immobilized with osteosutures (stainless steel wires) before repositioning (anteriorly and inferiorly when necessary) with contoured plates to the midface.
Additional analgesics, cortical steroids and antibi-otics were given postoperatively. Healing of the bone graft took 4 to 5 months. At the second surgery the bone plates, screws and osteosutures were removed and 8 implants (TiOblast'" ST) with cover screws were inserted.
A relined denture was allowed during healing phases, but chewing was not recommended. The patients were restored with a temporary prosthetics solution for the first 6 months. Thereafter fixed permanent gold/acrylic resin restorations were fabricated.
Result: All 22 patients attended the 1-year control, 18 patients visited the 2-year follow-up and 50% of the patients were followed for 5-years. Healing after surgery was complication free in most instances.
Three patients developed symptoms of sinusitis.
Loose graft material (which was removed at exploratory surgery) was discovered in two of these patients, obliterated drainage from the sinus in one patient. All patients recovered fully after antibiotic admission.
The mean available bone height before therapy was about 3 mm. Corrections in the sagittal plane were in mean 5.6 mm and in vertical direction 4.7 mm. Evaluations revealed a postoperative bone height of about 14 mm, which was maintained until implant surgery. Between abutment connection and the 5-year examination approximately 1 mm was further resorbed resulting in a general bone height of 12 mm (anterior and posterior regions).
6 implants of 176 failed, all before permanent prosthetic rehabilitation (CSR 97%). In the patients followed for three years (14) or more, no further marginal bone level changes was seen.
Discussion: This patient series, many of them previously considered as hopeless cases, clearly show that a cumulative implant survival of 97% is achievable using an orthognathic surgical technique with inlay grafting. These results are similarly good compared to conventional implant treatment in the maxilla. Further, by using moderately rough implant surfaces it was possible to increase the survival and success rates from 85% to 97%, as compared with the use of machined surface implants in similar surgical situations. Small remodelling in the graft material and maintained marginal bone levels were noted throughout the study period. |
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