Accumulation of a black material around some titanium coupling posts

Purpose: To report 5 patients with a black material accumulating in the conjunctiva around the titanium peg and sleeve systems. Methods: Retrospective small case series. The clinical features of 5 patients were reviewed. Histopathologic analysis was performed on specimens from 3 patients. Neutron activation analysis was performed on 1 sample. Results: Five asymptomatic patients with black material accumulating in the conjunctiva at the conjunctival-titanium peg interface were evaluated. All patients had a hydroxyapatite-coated titanium sleeve with a titanium peg in position. Histopathologic analysis performed on specimens from 3 patients revealed a mixed inflammatory cell infiltrate with focal areas of a black, foreign-appearing material showing birefringence under polarized light that was predominantly intracytoplasmic. This black material did not respond to bleaching, and in 2 patients, it showed positive staining for iron (Perls method). The material from one patient was evaluated by neutron activation analysis and was found to contain titanium, aluminum, and vanadium. In 18 to 48 months of follow-up, the presence of the material did not appear to be associated with any problems. Conclusions: The presence of a black substance accumulating in the conjunctiva around some titanium coupling posts is uncommon and appears to be without any consequence in 18 to 48 months of follow-up. Our analysis revealed this substance to be consistent with titanium alloy (Ti-6Al-4V).