Maxillary sinus-floor elevation with nanoporous biphasic bone graft material for early implant placement.

BACKGROUND: Insufficient bone height in the posterior maxilla is caused by bone atrophy after tooth extraction and continued pneumatization of the maxillary sinus. To allow for implant placement in this area, external sinus-floor elevations are performed. For this indication, the application of various bone graft materials can be a reliable alternative to autologous bone. PURPOSE: The aim of this study was to analyze a nanoporous bone graft material under the condition of early implant treatment in sinus floor elevations. MATERIALS AND METHODS: Sixty-six patients received 94 individual external sinus-floor elevations as a precondition for implant surgery. As grafting material, a synthetic, nanoporous bone graft material consisting of a mixture of nano-hydroxyapatite and nano-ß-tricalciumphosphate crystals, combined with blood from the defect side, was used. Depending on the remaining vertical bone height, implant placement was performed either simultaneously with bone augmentation or consecutively in a delayed approach. After a 4-month healing period, the patients received 218 implants and were followed up clinically, radiographically, and histologically. To quantify the bone situation at implant placement, immunohistochemical analysis using tenascin-C was performed. RESULTS: We achieved an average vertical bone increase of 8.28 mm (SD, 2.59) for the one-stage approach and 10.99 mm (SD, 1.73) for the two-stage approach after sinus-floor elevation. The augmented areas showed mean resorption rates of 10.32% (one stage) and 10.82% (two stages) of vertical graft during the observation period. Immunohistochemical analysis after 4 months of healing showed high tenascin activity, indicating bone growth. Good primary stability was achieved during implant placement. Mean peri-implant marginal bone loss was 0.45 mm (SD, 0.31). CONCLUSION: After a mean observation time of 21.45 months, the biomaterial showed good osseointegration and bone stability radiographically. Adding to this the positive histological and immunohistochemical findings, we conclude that, after a relatively short 4-month healing period, the biomaterial showed predictable results.

Reconstruction of severely atrophied alveolar ridges with calvarial onlay bone grafts and dental implants.

OBJECTIVE: Severely atrophied alveolar ridges are most commonly reconstructed with free autologous bone grafts from the iliac crest. The use of these grafts, however, is frequently associated with bone resorption as possible late complication after implant surgery and prosthetic loading. Other donor sites, especially intraoral donor sites, show limited availability. The aim of this present study was to evaluate the clinical and radiographical outcome of alveolar ridge reconstruction with bone from the calvarium and subsequent implant rehabilitation. PATIENTS AND METHODS: Reconstruction was performed by using calvarial split grafts in case of severe and complex alveolar ridge defects induced by trauma or bone atrophy. Fifteen patients were treated at 19 different intraoral recipient sites (15 sites in the maxilla, four in the mandible). Autologous block grafts were used for combined vertical and horizontal grafting. After a 3-month healing period, patients received dental implants. A total of 99 dental implants (OsseoSpeed™, Astra Tech AB, Mölndal, Sweden) were inserted and left to heal in a submerged position for 3 months before the prosthetic implant-based rehabilitation was performed. RESULTS: No donor site complications occurred during or after surgery. At the intraoral recipient sites two infections occurred, leading to partial loss of the grafts. Implant placement, however, was possible in all cases. Two of 99 implants were lost in two patients prior to prosthetic loading. Patients were followed up clinically and radiographically for an average observation period of 28 months. Implant survival rate and success rates were 97.85 and 95.7%, respectively, and a minimal marginal bone loss was documented. DISCUSSION: The low morbidity at the donor sites and the good marginal bone stability in the reconstructed regions indicate that calvarial bone grafts represent a viable treatment alternative to grafts from the iliac crest.

Use of 8-mm and 9-mm implants in atrophic alveolar ridges: 10-year results.

PURPOSE: The use of short implants can reduce the need for augmentative procedures prior to implant placement and, thus, morbidity and treatment time for patients with severely atrophied alveolar ridges. However, the inevitably less favorable crown-to-implant ratio is often associated with higher implant failure rates and greater marginal bone loss. The aim of this study was to evaluate the long-term survival and success rates of short implants in severely atrophic alveolar ridges retaining restorations on these short implants only. MATERIALS AND METHODS: In this study, 8-mm and 9-mm implants were inserted in atrophic alveolar ridges according to the manufacturer's protocol for the respective bone quality and loaded after 3 months of healing. Prosthetic restorations were supported only by short implants (not in combination with longer implants). After a mean observation period of 10.1 years (±1.9 years), all patients were re-examined clinically and radiographically. RESULTS: In this study, fifty-two 8-mm and 9-mm implants were placed in 14 patients. After 10.1 years, no implants and suprastructures had been lost. A mean marginal bone loss of 0.3 mm (±0.4 mm) was recorded. According to the Albrektsson criteria, all implants were successful; with respect to the more rigorous Karoussis et al criteria, four implants failed. CONCLUSIONS: The results of this long-term study suggest that the use of short implants results in marginal bone resorption and failure rates similar to those for longer implants. The higher crown-to-implant ratio did not seem to have any negative influence on implant success in this study.

Fixed implant-retained rehabilitation of the edentulous maxilla: 11-year results of a prospective study.

OBJECTIVES: The aim of the present study was to assess long-term survival and success rates of implants in the edentulous maxilla restored with an implant-supported fixed prosthesis. MATERIALS AND METHODS: Seventeen edentulous patients received six to eight implants and implant-supported fixed prostheses by one surgeon. Yearly recalls were conducted by two examiners over a period of 11 years. Survival and success rates (biological complications) were determined; marginal bone loss was examined radiographically. Furthermore, microbiological tests as well as test for interleukin-1 composite genotype were assessed and potential risk factors were evaluated. RESULTS: After a mean time of 11.26 years, 15 patients of 17 could be reexamined. Out of 94 implants, three were lost in one patient. Mean marginal bone loss reached 0.88 mm, two patients (at seven implants) showed bone loss of ≥3.2 mm. Survival rate of implants reached 96.8%. Success rates on implant level hit 92.6% according to the criteria of Albrektsson and colleagues and 83.0% in accordance with Karoussis and colleagues. One prosthesis had to be renewed. CONCLUSION: Within the limitation of this study, restoration of the edentulous maxilla with an implant-supported fixed prosthesis represents an effective tool for rehabilitation over a period of 11 years.

Early and immediate loading of titanium implants with fluoride-modified surfaces: results of 5-year prospective study.

OBJECTIVE: Multiple experimental and animal studies have shown that topographic, mechanical and chemical properties of implant surfaces lead to in vivo responses such as increased bone formation, increased bone anchorage and reduced healing time. A fluoride modification of the titanium implant surface also seems to positively influence bone anchorage as compared with unmodified titanium implants. Using implant survival and marginal bone loss as primary outcome parameters, the purpose of the present prospective study was to investigate whether a fluoride modification of the titanium implant surface has positive clinical effects. MATERIALS AND METHODS: The 17 patients included in this study received 49 Astra Tech OsseoSpeed implants for various indications in the maxilla and mandible. Implants were either loaded immediately or after a mean healing period of 9.56 weeks. Fifteen patients were followed up clinically including radiographic examination for 5 years. Forty-two implants were assessed for implant survival, marginal bone loss, surgical and/or prosthetic complications, presence or absence of plaque, signs of inflammation and size of the papilla. RESULTS: Of the original 17 patients, 15 patients were available for the full 60-month follow-up. One early implant failure occurred, leading to an implant survival rate of 97%. Radiographic analyses demonstrated stable bone conditions with a mean marginal bone loss of 0.1 mm (SD 0.4 mm, min -0.7 mm, max 1.7 mm) after 5 years of function. Immediately loaded implants did not show a different mean marginal bone loss as compared with implants that were not loaded immediately. Repeated soft-tissue examinations revealed healthy conditions in terms of 6.1% plaque and 4.2% of the implants with signs of inflammation at the 5-year control. DISCUSSION: Implants used in this study had high survival and success rates after 5 years. Marginal bone was well maintained, irrespective of the loading regime.

Implant-supported fixed prostheses in the edentulous maxilla: 8-year prospective results.

OBJECTIVE: The purpose of this prospective study was to evaluate the long-term survival and success rates of implants and screw-retained, full-arch prostheses placed in edentulous maxillae over 8 years of function. MATERIALS AND METHODS: A total of 106 Astra Tech implants were placed in the maxillae of 17 edentulous patients in a one-stage surgical approach. After a healing period of 6 months, the patients received fixed screw-retained bridges. Follow-up visits, including clinical and radiographic examinations, were performed after 6 months and at yearly intervals. Implant survival, implant success, and marginal bone-level changes were defined as the primary outcome variables. The secondary aims were to report periodontal pathogens at 5 years' follow-up and patients' satisfaction at the 8-year follow-up. RESULTS: The overall observation time was 8 years. One patient died during the study and one implant failed during the healing period, yielding an 8-year cumulative implant survival rate of 99%. The prosthetic survival rate was 100%. The mean crestal bone loss amounted to 0.3 ± 0.72 mm. Patients' subjective evaluations demonstrated an overall high level of satisfaction. In all cases, except for one, microbiologic probing of the peri-implant sulcus after 5 years showed no higher incidence of periodontal pathogens. CONCLUSIONS: Screw-retained, full-arch restorations on six implants in an edentulous maxilla are a predictable and highly successful treatment concept as observed throughout this study with an observation period of 8 years of function, in particular with respect to low crestal bone loss and high patient satisfaction.