Marginal tissue reactions at osseointegrated titanium fixtures. (II) A cross-sectional retrospective study.

Abstract 20 totally edentulous patients, provided with 24 facultatively removable fixed bridges (13 upper and 11 lower jaws) were recalled. The material consisted of 125 osseointegrated titanium fixtures with a mean observation time of 7.6 years (range 6 months to 15 years). The marginal tissues were examined by conventional periodontal clinical methods and standardised radiography. Microbiological samples and biopsies of the soft marginal barrier tissues were retrieved for dark-field and histological analysis, respectively. The percental ratios of abutment surfaces devoid of plaque and without signs of gingivitis, were 46% and 20%, respectively. In contrast to earlier studies, the presence of plaque and gingivitis was significantly correlated. This relationship was probably due to more plaque being present. The mean probing depth was 3.8 mm. In 40% of the measurements, the probing depths were 3 mm or less, and in 45% between 4 and 5 mm, whereas they only in 15% were 6 mm or more. They were greater in upper than in lower jaws and were found to be significantly correlated with gingivitis. Attached gingiva surrounded about 51% of the buccal and lingual abutment surfaces. The marginal bone height changes were very small during the follow-up period (0.07 mm annually). Coccoid cells and non-motile rods dominated the microflora to 94% in the 48 samples taken. Out of the 19 biopsies, 58% showed healthy mucosa and a further 37% had the lowest inflammation score. The indications of gingivitis and deep pockets at the clinical examination were not found accompanied by an accelerated marginal bone loss, nor by a microflora or histological changes indicative of periodontitis. Radio-graphical, microbiological and histological examinations appeared to give a better comprehension of the status at osseointegrated fixtures and their abutments than clinical examinations. With regard to the results of these latter parameters, the prognosis for the examined fixtures seemed to be very good.