Long-term results of glass ionomer cement, Ionocem, in the middle ear of the rat.

Long-term results of glass ionomer cement, Ionocem, in the middle ear of the rat. An ionomeric cement (Ionocem), a new bone replacement material, was used for obliteration material of the mastoid cavity in the rat. Iononcem is biocompatible, biostable and in most of the cases well tolerated by bone and soft tissues. The bone cement was implanted in the left mastoid cavity of 17 rats. After periods of 3 and 12 months, 6 animals from each time interval were sacrificed and the mastoids were studied and compared with the unimplanted right ears. Five animals died of a middle ear infection. In the middle ears of the rats sacrificed after 3 months no abnormalities were observed but after 12 months in all implanted ears a granular tissue reaction around the glass ionomer cement was found. In some of these cases the cochlea was destroyed as well. The results of this animal experiment indicate that glass ionomer cement is not the material of first choice for obliterating the mastoid cavity.