The nature of the hyaline rings in chronic periostitis and other conditions: an ultrastructural study.

The hyaline rings found in chronic periostitis and a radicular cyst were investigated ultrastructurally. These rings were composed of fine fibrillar material which was probably derived from degraded collagen fibrils, all of which eventually became degraded and unrecognizable. Foreign-body material in the form of circular bodies of probable plant origin were also found and should not be confused with the hyaline rings.