Detection of platelet-activating factor in gingival tissue surrounding failed dental implants

Background: Dental implant therapy has entered routine clinical practice. H owever, the failure rate of implants at 5 years, due to biological factors, is still around 7%. The pathogenesis of implant loss involves a complex ne twork of cells and inflammatory mediators. This study evaluated platelet-ac tivating factor (PAF), a potent phospholipid mediator of inflammation, in s oft tissue surrounding failed dental implants Versus healthy implants. Methods: PAF was estimated on extracted lipids by bioassay on washed rabbit platelets; inflammatory cell populations were assessed semiquantitatively after staining, and microvessel density was evaluated after immunohistochem ical staining. Results: Biologically active PAF was detected in the lipid extracts of samp les excised from gingival tissue of patients with failed implants, but not in samples from patients with osseointegrated implants or from healthy eden tulous subjects. The amount of PAF detected in failed implants was signific antly higher than in healthy implants, suggesting a local production of thi s mediator. Conclusions: The presence of PAF was associated with histopathological find ings of local inflammation and increased blood vessel density.