Marginal tissue reactions at osseointegrated titanium fixtures

A longitudinal prospective and a cross-sectional retrospective study were undertaken in order to investigate the marginal tissue reactions at osseointegrated titanium fixtures and their abutments, supporting fixed bridges. Conventional clinical periodontal examination methods were combined with a serial-identical radiography. At the termination of the studies samples were taken for microbiological and histological analyses. Altogether the reactions at 220 fixtures in 40 jaws were explored. The clinical parameters were not found correlated with the other examination methods. Only 0.9 mm marginal bone was lost as a mean during the first year and then not more than 0.05-0.07 mm as a mean annually for the follow-up years. A stress-related remodelling of the perifixtural bone was observed radiographically. The microbiotia in the gingival pockets was dominated by cocci and non-motile rods (94%), indicating a favourable composition if similar findings had been observed at teeth. Half the number of the biopsies had no inflammatory infiltrates and a further third had the lowest inflammatory score in a 3-grade scale. The results indicate that the soft tissue surrounding the gingival part of osseointegrated fixtures remains remarkably healthy, which, in combination with the annual minor loss of marginal bone, is an indication of good long-term clinical prognosis.