Titanium and glass-ionomer cement as ossicular replacement materials: biocompatibility results after implantation in the rabbit.

The middle ear poses unique challenges when finding suitable materials for ossicular reconstruction, primarily because of its link to the external environment via the eustachian tube, which leads to a greater potential for exposure to infectious agents. In this animal study, the biocompatibilities of titanium and glass-ionomer cement were assessed in the middle ear of the rabbit after being implanted as total ossicular replacement prostheses (TORPs) or as free pins. Animals were sacrificed after 28, 84, 168, 336, or 504 days or 2 years, and a cutting saw technique was used to prepare slides for light microscopy. Slides were examined for mucosal coverage and any sign of foreign body reaction. Both materials showed good acceptance in the middle ear. After 28 days, the TORPs were covered by middle ear mucosa. As expected, it took a longer time (up to 504 days) to cover the free implants. An interesting finding was the growth of new bone on both the surface of the titanium implants and the glass-ionomer prostheses. The results of this animal study indicate that both titanium and glass-ionomer cement are favorable materials for ossicular replacement prostheses.