Ultrastructural findings in soft tissues adjacent to titanium plates used in jaw fracture treatment.

The present study was conducted on biopsies from soft tissues overlying titanium miniplates that were used for the treatment of jaw fractures. The aim was to investigate the morphology of liberated titanium particles and cellular or ultrastructural changes in tissues adjacent to the miniplates. Conventional transmission electron microscope (TEM) images were used for ultrastructural investigation and identification of metal-dense particles. The presence of titanium was proved by an increase in the intensity of element-specific, inelastically scattered electrons from the primary beam. The results showed that 5-8 months after insertion of the plates and screws, there was weak cellular activity within the scar tissue overlying the plates without inflammatory cells. Most of the titanium particles were located extracellularly. The ultrastructural appearance of most of these particles suggested that titanium may be shaved off the plates or screws and may undergo cellular uptake and lysosomal degradation. The partially degraded titanium particles are then left in place after the phagocytic cells have been isolated by collagenous fibers and have finally perished.