Hans Nilson

Clinical results with titanium crowns fabricated with machine duplication and spark erosion

A new method for fabrication of metal crowns has been developed by one of the authors (M.A.). There are two principles involved: machine duplication of models and electric discharge machining. The metal used is pure unalloyed titanium, which is processed as a coping and later covered by a composite resin. In 1986, 205 separate titanium crowns were made on 149 patients. One year later 192 crowns on 137 patients could be examined. Five crowns had been replaced by new ones owing to fracture of the composite resin. In accordance with the CDA quality evaluation system the following results were obtained for the remaining 187 crowns: margin integrity, 186 excellent or satisfactory (99.5%); anatomic form, 185 excellent or satisfactory (98.9%); and surface and color, 181 excellent or satisfactory results (96.8%). The 1-year results are promising, and further follow-up studies will be made.

Bone grafting to the maxillary sinuses, nasal floor and anterior maxilla in the atrophic edentulous maxilla. A two-stage technique.

This study presents the results from 20 consecutive patients treated with an autogenous bone graft from the iliac crest. In ten patients the graft was placed in the maxillary sinuses and the floor of the nose (inlay group). Ten patients, in addition to the inlay graft, had a corticocancellous bone block secured with mini-screws to the anterior maxillary ridge (inlay/onlay group). Endosteal implants (Brånemark) were placed six months after surgery. A total of 136 implants were placed, of which eight failed to integrate during the six-month healing period. A further 15 implants were lost during the follow-up period. For the inlay group the average follow-up period was 22 months and for the inlay/onlay group 19 months. Donor site morbidity was significantly less when iliac bone was harvested with a trephine (inlay group) than in patients treated with our routine procedure for bone harvesting (inlay/onlay group). Surgical technique, donor site morbidity, implant survival and patient acceptance are presented.

Implant Treatment of Patients with Edentulous Jaws: A 20-Year Follow-Up

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.

A 2-year follow-up study of titanium crowns

In 1986, 149 patients were provided with titanium crowns. The method used for fabrication of the titanium copings involved two principles: machine duplication of models and electric discharge machining. For the veneering of the copings, Isosit was used for the first 90% of the crowns in the series, and the Dentacolor-Silicoater technique for the last 10%. Of 205 individual crowns cemented in 1986, 167 could be examined after 2 years. The crowns were rated by four independent examiners using the CDA quality evaluation system. Bleeding Index and Margin Index were also used. The Margin Integrity score was recorded as satisfactory for all crowns examined over the period studied. A vast majority of the margins were rated as excellent. Isosit (n = 145) disclosed shortcomings including fractures and substantial deteriorations of Surface and Color and of Anatomic Form. With Dentacolor as veneering material (n = 18) the results with the factors Surface and Color and Anatomic Form were still rated satisfactory after 2 years, and no fractures of the veneering material were registered. Bleeding Index and Margin Index showed comparatively small changes after 2 years.

Interpositional bone grafting and Le Fort I osteotomy for reconstruction of the atrophic edentulous maxilla: A two-stage technique

This study presents the results from ten consecutive patients who, because of insufficient bone volume for conventional implant placement in the maxilla, were treated with an interpositional bone graft and Le Fort I osteotomy. The endosteal implants were placed six months after the osteotomy. A total of 60 screw-shaped titanium implants (Brånemark) were placed, of which three failed to integrate during the six-month healing period. No further implants were lost during the follow-up period, ranging from 15 to 39 months after placement of the implants. All patients received fixed bridges and all have continued to function efficiently.

A 9-14 year follow-up of onlay bone grafting in the atrophic maxilla.

Treatment of the atrophic edentulous maxilla is challenging especially when bone graft procedures are necessary. In this study an onlay bone graft, a saddle or veneer, with or without maxillary sinus floor inlay graft, harvested from the anterior iliac crest, in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. The aim was to investigate treatment outcome, and the impact of gender and smoking, in 44 patients in a prospective, long-term, follow-up study concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. Mean follow-up time was 11 years. Of 334 inserted Brånemark implants, with machined surface, 27 failed. Estimated implant survival rate was 90%. Marginal bone loss was 1.8 mm 1 year after implant surgery; 2.3 mm after 5 years; and 2.4 mm after 10 years. There was a significant difference between genders in implant survival. Marginal bone loss differed significantly between smokers and non-smokers up to the 5-year examination and between genders after the 4-year examination. The onlay bone graft, with or without a maxillary inlay graft, results in high implant survival rate, good oral function and stabilised marginal bone. All patients are still wearing their original fixed bridges.

Digitally Planned, Immediately Loaded Dental Implants with Prefabricated Prostheses in the Reconstruction of Edentulous Maxillae: A 1-Year Prospective, Multicenter Study

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 (Brånemark System, TiUnite RP, Nobel Biocare, Göteborg, Sweden) in 52 patients from eight Scandinavian clinics were digitally planned, surgically as well as prosthetically, by using the NobelGuide (Nobel Biocare AB, Göteborg, 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 (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.

Reconstruction of the atrophic maxilla with interpositional bone grafting/Le Fort I osteotomy and endosteal implants: a 11-16 year follow-up.

A Le Fort I osteotomy and interpositional bone graft in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. Surgery was performed in a two-stage procedure. The patients in this study had conditions with reversed intermaxillary relationships with or without increased vertical intermaxillary distance. The aim of the study was to investigate treatment outcome for patients in a prospective, long-term, follow-up with a mean of 13 years (range 11-16 years), concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant. The impact of gender and smoking was also investigated. Twenty-six patients were included in the study. Of 167 implants, 24 failed. The implant estimated survival rate was 85% at the end of the follow-up. There was no significant difference between smokers and non-smokers or genders concerning implant survival. Marginal bone loss was 2.5, 2.9, 3.0 and 3.1mm from the implant-abutment junction, after 1, 2, 5 and 10 years, respectively. The bone level stabilised after 2 years. This technique results in good facial morphology, good oral function and aesthetics. All patients are still wearing their original fixed bridges.