Implants for single-tooth replacement. A clinical and experimental study on the Brånemark CeraOne System.

The general aim of the thesis was to study single-tooth replacements with implants using a recently developed prosthodontic concept, CeraOne. More specifically, the aims were to present prosthodontic procedures and early clinical experiences of CeraOne, and to study the following: the acceptance and the rejection of referred patients, the mechanical strength of the complete implant post and of superstructures on the CeraOne abutment, the treatment outcome from an on-going prospective clinical investigation, the effect of guided tissue regeneration when using e-PTFE membranes in narrow alveolar ridges, and finally, the outcome from treatments by general practitioners (GPs) who had performed the complete care of the single-tooth patient. The acceptance and the rejection of patients were studied on 184 patients, and the conclusions were based on data from referral, case history, clinical examination, and therapy planning. External trauma, root fractures, and congenitally missing teeth were the main reasons for lost or missing teeth in referred patients, while anatomical limitations were the most frequent reasons for the rejections. The mechanical strength was determined after testing in an Instron universal testing machine. The abutment screw was shown to be the weakest link, while a satisfactory safety margin against fractures was observed for the metal-ceramic and the all-ceramic crowns. It was also shown that the all-ceramic ¿ crown could resist bending moments up to a level that was more than three times as high as the one at which the porcelain crown fractured. In the clinical prospective study, the results from treatments of 57 patients (65 implants) were reported after two years and from 34 patients (37 implants) after three years. Favourable survival rates were shown for the implants (97.3% at 3-4 years) and, as a mean, only a small bone loss around the implants and the adjacent teeth was observed. The conical implants, however, showed a higher degree of bone los in comparison to the other implants. The CeraOne prosthodontic concept was simple to sue because of prefabricated components, and favourable aesthetic and clinical short-term results were achieved. Problems of screw loosening and fistulas were avoided and the cementation of the crown and the subgingival placement of the abutment shoulder did not cause any soft tissue recession. Fifteen patients (20 implants) with a suspected need of guided tissue regeneration were selected for the study using e-PTFE membranes. After treatment and at the second stage surgery, it was shown that most of the primarily exposed implant surfaces at this time were covered by a newly formed tissue with signs of osteoid activity.(ABSTRACT TRUNCATED AT 400 WORDS)