A prospective clinical evaluation of different single-tooth restoration designs on osseointegrated implants. A 3-year follow-up of Brånemark implants.

Since single-tooth implant restorations were introduced 12 years ago (Jemt 1986), there has been continuous development both in the technical design and the aesthetic outcome of the treatment. In order to ensure high quality in single-tooth implant treatments a clinical follow-up study was carried out on patients treated with modifications to the original regimen. In this study 69 consecutive patients were provided with 80 single-tooth implant restorations. The patients were followed for 3 years. There was continuous development of the prosthetic design during the time of the study, allowing us to analyse possible prognostic differences for the different prosthetic treatments. This study confirms earlier reports which describe the single-tooth implant treatment as a safe method with few surgical complications and minimal marginal bone loss. Only 1 implant was lost during the follow-up period and the average marginal bone loss was 0.48 mm over the 3-year follow-up period. Crowns veneered with acrylic and with gold casted directly to the abutments, screwed onto the implants, led to recurring prosthetic complications and gave an appearance of rapid ageing. The first generation of crowns made following the Cera-One design, sometimes produced a gap between the crown and the abutment associated with significant marginal bone loss during the first year. Few surgical or prosthetic complications were noted with cemented all-ceramic constructions, although the number of these crowns in this study was limited.