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BACKGROUND: Clinical studies on immediate loading of implants in the posterior atrophic maxilla are rare.

PURPOSE: The study aims to evaluate immediate loading of implants placed with sinus membrane elevation without additional grafting material for bone augmentation of the maxillary sinus floor.

MATERIALS AND METHODS: The study group comprised of 10 patients in whom a total of 10 maxillary sinus floor augmentations were performed. A total of 21 dental implants (1 to 4) were inserted through the residual bone to protrude into the maxillary sinus under the elevated sinus membrane. The implant site was underprepared to improve primary stability. All the implants were inserted with a torque insertion no less than 20 Ncm. Implants were loaded immediately after surgery with a screw-retained temporary acrylic restoration. Intraoral X-rays were taken at implant insertion, after 6 months loading, and after 1st and 2nd year of loading. Resonance frequency analysis (RFA) was performed at the time of initial placement and after 6 months of functional loading. RESULTS: RFA after implant insertion gave an implant stability quotient (ISQ) level with a range from 62 to 72. All implants remained clinically stable during the follow-up period of 2 years. Radiography demonstrated on average 5.7 ± 3.4 mm of intrasinus new bone formation after 6 months of implant loading. RFA measurements showed ISQ mean values of 67 (range: 62-72) and 68 (range: 62-71) at placement and after 6 months of loading, respectively.

CONCLUSION: Within the limits of this case series report, it is concluded that maxillary sinus membrane elevation with simultaneous placement and immediate loading of implants without the use of any additional grafting material shows predictable results after 2 years of functional loading. Moreover, evidence of intrasinus bone formation around the implants was found in all patients. Further studies are needed to study the influence of immediate loading on the mineralization of bone forming at dental implant sites.

BACKGROUND: Bone grafting is a surgical technique for the reconstruction of the atrophic edentulous maxilla prior to treatment with endosseous implants. The anterior iliac crest is a commonly used donor site.

PURPOSE: The aim of this study was to evaluate the donor site morbidity and complications when harvesting corticocancellous bone from the medial table of the anterior iliac crest and compare this with results when bone was harvested from the lateral and superior table of the anterior iliac crest. In addition, the outcome of the oral rehabilitation was evaluated by means of a quality-of-life questionnaire.

MATERIAL AND METHODS: The study was composed of 70 consecutively treated patients with a mean age of 56 years. The patients were retrospectively evaluated with regard to postoperative donor site morbidity and complications at the donor site.

RESULTS: For the donor site morbidity, 74% of the patients were free of pain within 3 weeks, whereas 26% of the patients had a prolonged period of pain lasting from a few weeks to several months. For 11% of the patients, there was still some pain or discomfort 2 years after the grafting surgery. For gait disturbance the figures were similar: 79% had no problems after 3 weeks. For the eight patients who still had some pain after 2 years, which was considered permanent, three also had gait disturbance. There was a total of three major complications (4%), one iliac wing fracture and two neurologic injuries.

CONCLUSION: When harvesting a large amount of unicortical corticocancellous bone blocks from the the superolateral site of the iliac crest with a "peel off" technique, morbidity and complication rates do not differ significantly compared with those of the traditional anterior medial approach. Oral rehabilitation with maxillary reconstruction with bone grafts from the iliac crest and endosseous implants significantly improved oral function, facial appearance, and recreation/social activities and resulted in an overall improvement in quality of life in formerly edentulous patients.

Background: Previous studies have pointed out that the mere elevation of the maxillary sinus membrane promotes bone formation without the use of augmentation materials.

Purpose: This experimental study aimed at evaluating if the two-stage procedure for sinus floor augmentation could benefit from the use of a space-making device in order to increase the bone volume to enable later implant installation with good primary stability.

Materials and Methods: Six male tufted capuchin primates (Cebus apella) were subjected to extraction of the three premolars and the first molar on both sides of the maxilla to create an edentulous area. The sinuses were opened using the lateral bone-wall window technique, and the membrane was elevated. One resorbable space-making device was inserted in each maxillary sinus, and the bone window was returned in place. The animals were euthanatized after 6 months, and biopsy blocks containing the whole maxillary sinus and surrounding soft tissues were prepared for ground sections.

Results: The histological examination of the specimens showed bone formation in contact with both the schneiderian membrane and the device in most cases even when the device was displaced. The process of bone formation indicates that this technique is potentially useful for two-stage sinus floor augmentation. The lack of stabilization of the device within the sinus demands further improvement of space-makers for predictable bone augmentation.

Conclusions: It is concluded that (1) the device used in this study did not trigger any important inflammatory reaction; (2) when the sinus membrane was elevated, bone formation was a constant finding; and (3) an ideal space-making device should be stable and elevate the membrane to ensure a maintained connection between the membrane and the secluded space.

BACKGROUND: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants.

PURPOSE: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants.

MATERIALS AND METHODS: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections.

RESULTS: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity.

CONCLUSIONS: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results.

Background: The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation.

Purpose: The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption.

Materials and Methods: Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n = 9) and 6 weeks (n = 9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein.

Results: The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p ≤ 0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group.

Conclusion: The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis.

BACKGROUND: Bovine hydroxyapatite (Bio-Oss, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long-term histologic fate of this material is not well understood. PURPOSE: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure. MATERIALS AND METHOD: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis. RESULTS: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 +/- 12.6% nonmineralized tissue, followed by 21.2 +/- 24.5% lamellar bone, 14.5 +/- 10.3% BH particles, and 10.2 +/- 13.4% woven bone. The nonmineralized tissue seen in bone-forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 +/- 19.0% (p < .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 +/- 22.8% (p < .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 +/- 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle-bone contact had increased from 28.8% +/- 19.9% after 6 months to 54.5 +/- 28.8% after 3 years (p < .05). CONCLUSION: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3-year specimens. Moreover, bone-integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available.

Background: In cases when the alveolar crest is too narrow to host an implant, lateral augmentation is required. The use of autogenous bone blocks harvested from the iliac crest is often demanded. One disadvantage is the associated patient morbidity.

Purpose: The purpose of this study was to clinically and histologically evaluate the use of morselized impacted bone allograft, a novel technique for reconstruction of the narrow alveolar crest.

Materials and methods: Two patients with completely edentulous maxillae and one partially edentulous, with a mean age of 77 years (range 76-79 years) were included in the study. The alveolar crest width was < 3 mm without possibility to place any implant. Bone grafts were taken from a bone bank in Gavle Hospital. Bone from the neck of femur heads was milled to produce bone chips. The milled bone was partially defatted by rinsing in 37 degrees C saline solution. After compression of the graft pieces with a size of 15 mm (height), 30 mm (length), and 6 mm (width), they were then fit to adapt to the buccal surface of the atrophied alveolar crest. One piece was placed to the right and one to the left side of the midline. On both sides fibrin glue was used (Tisseel (R), Baxter AG, Vienna, Austria) to stabilize the graft. After 6 months of graft healing, dental implants were placed, simultaneously biopsies were harvested and in one patient two oxidized microimplants were placed. At the time of abutment connection, microimplants were retrieved with surrounding bone for histology. Fixed screw-retained bridges were fabricated in mean of 7 months after implant surgery. Radiographs were taken before and after implant surgery and after 1 year of loading.

Results: Sixteen implants with an oxidized surface were placed (TiUnite (R), Nobel Biocare AB, Goteborg, Sweden). After 1 year of functional loading, all implants were clinically stable. The marginal bone loss was 1.4 mm (SD 0.3) after 1 year of loading. The histological examination showed resorption and subsequent bone formation on the allograft particles. There were no signs of inflammatory cell infiltration in conjunction with the allograft. The two microimplants showed bone formation directly on the implant surface.

Conclusions: This study shows that morselized impacted bone allograft can be used to increase the width of the atrophied narrow alveolar crest as a good alternative to autogenous bone grafts in elderly patients. The histological examination of biopsies revealed a normal incorporation process and no signs of an immunological reaction. Further studies with larger samples are of important to be able to conclude if equal results can be obtained using morselized impacted bone allograft as for autogenous bone graft.

Background: The introduction of digital planning programs has made it possible to place dental implants in preplanned positions and being immediately functionally loaded by using prefabricated prostheses.

Purpose: The aim of this multicenter study was to describe the 1-year results of digitally planned, immediately loaded edentulous maxillae.

Materials and Methods: A total of 312 implants (Branemark System (R), TiUnite RP, Nobel Biocare, Goteborg, Sweden) in 52 patients from eight Scandinavian clinics were digitally planned, surgically as well as prosthetically, by using the NobelGuide (R) (Nobel Biocare AB, Goteborg, Sweden) and received prefabricated, immediately loaded fixed prosthetic constructions in the maxillae. Individual implant stability was manually tested at 1-year follow-up.

Results: All patients received a Procera Implant Bridge (R) (Nobel Biocare AB); however, in two cases, the bridges were reconstructed due to misfit. In five patients, difficulties in getting the surgical guide completely in position, and in five patients, getting the prostheses completely seated, were noted. All but four patients fulfilled the 1-year follow-up. Two implants were lost during the study period, resulting in a cumulative survival rate of 99.4%. The mean marginal bone resorption from implant placement to the 1-year follow-up was 1.3 mm (SD 1.28). More than 2 mm of marginal resorption was noted in 19% of the implants at this instant. The most frequently reported complications during the first year were gingival hyperplasia and prosthesis-related problems (prosthesis screw loosening, occlusal fractures, and occlusal adjustments).

Conclusion: The 1-year results in this multicenter are promising regarding implant and bridge stability; however, the study is planned to be running for at least 3 years.

Background: Previous studies have shown predictable bone formation in the maxillary sinus after membrane elevation. However, how and where the bone is formed is not well understood.

Purpose: The aim of the study was to histologically and immunohistochemically study the early bone formation events in primates after membrane elevation in the maxillary sinus.

Materials and Methods: Nine adult male tufted capuchin primates (Cebus apella) were included in the study. Eight animals were subjected to bilateral maxillary sinus membrane elevation using a lateral replaceable bone window technique. One oxidized dental implant was placed into the maxillary sinus cavity on both sides. In four animals, one sinus was left without any additional treatment, whereas the contralateral sinus was filled with autologous bone grafts from the tibia. In two animals, the implants were inserted under the elevated sinus membrane on both sides. In two animals, the sinus membrane was totally removed. The animals were euthanized after 10 or 45 days. One nonoperated animal representing pristine tissue conditions served as control. The maxillary sinuses with implants were retrieved and further processed for light microscopic ground sections or decalcified sections for immune-histochemical analyses.

Results: Bone formation started from the bottom of the sinus floor, sprouting into the granulation tissue along the implant surface under the elevated membrane irrespective of time and surgical technique. Bone formation was not seen in direct conjunction with the sinus membrane. A distinct expression of osteopontin was observed in the serous glands of the lamina propria close to the implant within all groups.

Conclusion: Bone formation after sinus membrane elevation with or without additional bone grafts starts at the sinus floor and sprouts into the elevated space along the implant surface. The sinus membrane does not seem to present osteoinductive potential in sinus membrane elevation procedures in this study.

Background: Long-term clinical follow-up studies comparing different implant surfaces with regard to survival and marginal conditions are rare. Objectives: The objective of this study was to compare the clinical performance of turned and oxidized implants after more than 5 years of loading Material and Methods: One hundred three patients (43 men, 60 women; mean age 67.4 years, range 32–90) previously treated with 287 implants (Nobel Biocare AB, Gothenburg, Sweden), 133 with turned surface (MKIII, Nobel Biocare AB) and 154 with an oxidized surface (MKIII, TiUnite, Nobel Biocare AB) were examined after at least 5 years of loading (mean 82 months, range 60–93 months). The implants had been used for support of single crowns (33 patients/36 implants), partial bridges (39 patients/103 implants), or full bridges (31 patients/148 implants) following an early loading protocol (14 patients /54 implants), a one-stage protocol (32 patients/59 implants) or a two-stage protocol (57 patients/174 implants). Clinical examinations of bleeding on probing (BoP) and pocket depth (PD) were performed. Intraoral radiographs were used for assessments of marginal bone levels (MBLs). Results: Seven turned implants and one oxidized implant failed, giving overall cumulative survival rates of 94.7 and 99.4%, respectively. There were no differences for BoP scores (0.5 1 0.7 vs 0.4 1 0.6) and PD measurements (1.7 1 0.8 mm vs 1.8 1 1.0 mm) parameters when comparing turned and oxidized implants, respectively. The mean MBL was 1.8 1 0.8 mm and 2.0 1 0.9 mm for turned and oxidized implants, respectively, after more than 5 years in function (NS). Frequency distribution of MBL loss showed no statistically significant differences between the two surfaces. A total of four implants (1.4%) (three oxidized and one turned) showed a PD > 3 mm, MBL > 4 mm, and BoP. However, none of these were associated with suppuration on examination. Conclusion: The present study does not state any differences in implant failure, MBL, presence of bleeding or PD around implants when comparing turned and oxidized titanium implants after at least 5 years of function. 

Background: The technique of using bone grafts or different biomaterials for augmentation of the maxillary sinus prior to implant placement is well accepted by clinicians. However, clinical documentation of some bone substitutes is still lacking.

Purpose: This prospective study was designed to evaluate the success rate of implants placed after maxillary sinus augmentation with a novel synthetic biphasic calcium phosphate (BCP) or deproteinized bovine bone (DBB), the latter acting as control.

Material and Methods: Nine edentulous patients and two partially edentulous patients with a mean age of 67 years with a bilateral need for sinus augmentation, < 5 mm residual bone in the floor of the sinus and a crestal width 34 mm, were included in the study. After bilateral elevation of the Schneiderian membrane, all patients were randomized for augmentation with synthetic BCP in one side and DBB in the contralateral side. After 8 months of graft healing, 62 implants with an SLActive surface were placed. Implant survival, graft resorption, plaque index, bleeding on probing, sulcus bleeding index, probing pocket depth, and implant success rate were evaluated after 1 year of functional loading.

Results: After a mean of 118 days, all patients received their fixed prosthetic constructions. One implant was lost in each biomaterial, giving an overall survival rate of 96.8%. Success rates for implants placed in BCP and DBB were 91.7 and 95.7%, respectively. No significant difference in marginal bone loss was found around implants placed in BCP, DBB, or residual bone, respectively. The mean graft resorption was 0.43 mm (BCP) and 0.29 mm (DBB).

Conclusion: In this limited study, implant success rate was not dependent on the biomaterial used for maxillary sinus augmentation. Similar results were found after 1 year of functional loading for implants placed after sinus augmentation using BCP or DBB.

Background: Lateral sinus membrane elevation with simultaneous implant placement without grafting material (graft‐less LSFE) is a widely investigated method for bone augmentation of the maxillary sinus floor. Long‐term follow‐up studies are rare.

Purpose: This study aimed to investigate the long‐term effects of implants placed with graft‐less LSFE.

Materials and methods: The study group was comprised of 111 patients previously treated with graft‐less LSFE. The first follow‐up visit, which occurred after a mean of 5 years after surgery, included a clinical examination, cone beam computerized tomography, and panorama or intraoral radiography. The second follow‐up included panorama or intraoral radiography, and it was conducted after a mean of 8 years.

Results: Overall, 218 implants were placed in 127 sinuses. Nine of the 218 implants failed resulting in an overall implant survival of 95.9%. The average bone gain at the follow‐up was 4.0 ±2.0 mm.

Conclusion: The implant‐supported rehabilitation achieved using graft‐less LSFE was stable over time, and there was no or little impact on sinus health. Furthermore, it was concluded that the new bone formation and the amount of bone gain is proportional to the length of the implant protruding into the sinus cavity.

Background: Straumann (R) BoneCeramic (TM) is a synthetic biphasic calcium phosphate (BCP) aimed for sinus floor augmentation. Long-term follow-up of implants placed in BCP after sinus augmentation is still missing. Purpose: The primary aim of the study was to compare survival rates and marginal bone loss of Straumann SLActive implants placed in either BCP (test) or Bio-Oss (R) (DBB) (control) after sinus floor augmentation. The secondary aim was to calculate graft sinus height at different time points. Materials and Methods: Bilateral sinus floor augmentation was performed in a split mouth model. Eleven patients (mean age 67 years) received 100% BCP on one side and 100% DBB on the contralateral side. After 8 months of graft healing, 62 Straumann SLActive implants were placed. After 5 years of functional loading (6 years after augmentation) of implants, marginal bone levels and grafted sinus height were measured, and implant survival and success rates were calculated. Results: After 5 years of loading, all prosthetic constructions were in function although two implants were lost in each grafting material. The overall implant survival rate was 93.5% (91.7% for BCP, 91.3% for DBB, and 100% for residual bone). The success rates were 83.3% and 91.3% for BCP and DBB, respectively. There was no statistically significant difference in mean marginal bone level after 5 years between BCP (1.4 +/- 1.2 mm) and DBB (1.0 +/- 0.7 mm). Graft height reduction (GHR) after 6 years was limited to 6.6% for BCP and 5.8% for DBB. Conclusion: In this limited RCT study, the choice of biomaterial used for sinus floor augmentation did not seem to have any impact on survival rates and marginal bone level of the placed implants after 5 years of functional loading and GHR was minimal.

Purpose: Evaluate correlations between volume change for iliac crest bone grafts in maxillary reconstruction (graft volume change [GVC]) and bone mineral density (BMD), bone volume fraction (BVF), hematologic bone metabolic factors (I), and identify indicators of implant failure (II).

Material and Methods: Forty-six consecutive patients had their edentulous atrophic maxilla reconstructed with free autogenous bone grafts from anterior iliac crest. Endosteal implants were placed 6 months after graft healing. Computer tomography was performed after 3 weeks and 6 months after grafting. Bone biopsies were taken from the internal table of donor site for calculation (BVF), and blood samples were collected. Implant stability was measured at placement with resonance frequency analysis and expressed as implant stability quotient (ISQ). Implant failure was registered.

Results: GVC in onlay bone graft was 37%. The BVF in iliac crest biopsies was 32%. Serum-IGFBP3 differed with 79% of the samples over normal range. Fifteen patients had one or more implant failures prior to loading (early failures). Forty-two patients were followed for a minimum of 3 years after implant loading and, in addition, 6/42 patients had one or more implants removed during the follow-up (late failures). GVC correlated to decreased BMD of lumbar vertebrae L2-L4 (Kruskal-Wallis test, p=.017). No correlation was found between GVC and hematologic factors (Pearson correlation test) or between GVC and BVF (Kruskal-Wallis test). No correlation was found between ISQ and GVC (Pearson correlation test, p=.865). The association between implant failures and the described factors were evaluated, and no significant correlations were found (unconditional logistic regression).

Conclusion: Onlay bone grafts decrease 37% during initial healing period, which correlate to BMD of lumbar vertebrae L2-L4. No other evaluated parameters could explain GVC. The evaluated factors could not explain implant failure.

PURPOSE: The purpose of this study was to perform a longitudinal follow-up study of implant stability in grafted maxillae with the aid of clinical, radiological, and resonance frequency analysis (RFA) parameters. MATERIALS AND METHODS: The atrophic edentulous maxillae in 29 patients were reconstructed with free iliac crest grafts using onlay/inlay or interpositional grafting techniques. The endpoint of the resorption pattern in the maxilla determined the grafting technique used. Endosteal implants were placed after 6 months of bone-graft healing. Implant stability was measured four times using RFA: when the implants were placed, after 6 to 8 months of healing, after 6 months and 3 years of bridge loading. Individual checkups were performed at the two later RFA registrations after removal of the supraconstructions (Procera Implant Bridge, Nobel Biocare AB, Goteborg, Sweden). Radiological follow up of marginal bone level was performed annually. RESULTS: Twenty-five patients remained for the follow-up period. A total of 192 implants were placed and with a survival rate of 90% at the 3-year follow up. Women and an implant position with a class 6 resorption prior to reconstruction were factors with significant increased risk for implant failure (multivariate logistic regression). Twelve of the 20 failed implants were lost before loading (early failures). The change in the marginal bone level was 0.3 +/- 0.3 mm between baseline (bridge delivery) and the 3-year follow up. The implant stability quotient (ISQ) value for all implants differed significantly between abutment connection (60.2 +/- 7.3) and after 6 months of bridge loading (62.5 +/- 5.5) (Wilcoxon signed ranks test for paired data, p=.05) but were nonsignificant between 6 months of bridge loading and 3 years of bridge loading (61.8 +/- 5.5). There was a significant difference between successful and failed implants when the ISQ values were compared for individual implants at placement (Mann-Whitney U test, p=.004). All 25 patients were provided with fixed implant bridges at the time of the 3-year follow up. CONCLUSION: This clinical follow up using radiological examinations and RFA measurements indicates a predictable and stable long-term result for patients with atrophic edentulous maxillae reconstructed with autogenous bone and with delayed placement of endosteal implants. The ISQ value at the time of placement can probably serve as an indicator of level of risk for implant failure.

BACKGROUND: Implant-supported prostheses are today often used in rehabilitation of partially or totally edentulous patients. Both patients and the dental profession often regard implant treatment as successful in a life perspective. Therefore, studies with a long-term follow-up are important.

PURPOSE: The aim was to investigate the outcome of implant treatment with fixed prostheses in edentulous jaws after 20 years, with special reference to survival rate of implants and prostheses and frequency of peri-implantitis.

MATERIALS AND METHODS: The patient material was a group of patients treated in the early 1980s. The original patient group comprised the first 48 consecutive patients treated with implant-supported prostheses at Umeå University. All patients were edentulous in one or two jaws. The patients had a mean age at the implant insertion of 54.3 years (range 40-74). At the planning of this study 20 years after treatment, 19 of the 48 patients were found to be deceased. Of the 29 patients still alive, 21 patients with altogether 23 implant-supported prostheses could be examined clinically and radiographically. All patients were treated ad modum Brånemark (Nobel Biocare AB, Göteborg, Sweden) with a two-stage surgical procedure. The implants had a turned surface. Abutment connections were performed 3 to 4 months after fixture insertion in the mandible, and after a minimum of 6 months in the maxilla. The prostheses were fabricated with a framework of gold alloy and acrylic artificial teeth.

RESULTS: The 21 patients (with 23 implant prostheses) examined had at the time of treatment got 123 implants (27 in the upper jaw and 96 in the lower jaw) inserted. Only one of these implants had been lost (about 2 years after loading) giving a survival rate of 99.2%. Very small changes occurred in the marginal bone level. Between the 1 and 20-year examinations, the mean bone loss was 0.53 mm and the mean bone level at the final examination was 2.33 mm below the reference point.

CONCLUSIONS: This follow-up over two decades of implant-supported prostheses demonstrates a very good prognosis for the treatment performed. The frequencies of peri-implantitis, implant failures, or other complications were very small, and the original treatment concept with a two-stage surgery and a turned surface of the implants will obviously give very good results.

BACKGROUND: The survival rate of oral implants in soft-quality bone has been demonstrated to be inferior to that of implants inserted in good-quality bone. A possible way to increase the survival rate in soft-quality bone may be to use a tapered implant. Such an implant has been developed and manufactured by Nobel Biocare AB, Gothenburg, Sweden. So far, there have been only a few publications regarding this implant. PURPOSE: The aim of the study was to compare the outcome of using the tapered Brånemark System Mark IV fixture with the outcome of using earlier Brånemark fixtures in a controlled prospective study. MATERIALS AND METHODS: The study was performed as a multicenter study including seven specialist centers. The material consisted of 40 patients in need of implant-supported bridges in the maxilla. Twenty-five patients belonged to the test group, in which the tapered Mark IV implants were inserted, and 15 patients belonged to the control group, in which Brånemark Standard or Mark II implants were used. The patients were allocated to the test group or the control group according to randomization schedules. The implants were inserted according to the guidelines for Brånemark implants. A two-stage surgical protocol was used, and abutment connection was made 6 months after fixture insertion. The test group comprised 97 Mark IV implants, and the control group made up 92 implants. The prosthetic procedure followed the guidelines for Brånemark implants, and all patients were provided with full fixed maxillary bridges. The patients were followed up with clinical and radiographic records for 1 year after loading. RESULTS: The survival rate was 96.9% for the Mark IV implants and 98.9% for the control implants. There was no significant difference between the two groups. There was a mean marginal bone loss of 0.2 mm during the observation period, and there was no difference between test implants and control implants. CONCLUSIONS: With regard to survival rate and marginal bone level changes, no differences could be demonstrated between the Mark IV tapered implant and the Brånemark implants used earlier. However, compared with earlier results of Brånemark implants in soft-quality bone, the Mark IV implant demonstrated an improved survival rate.