RESUMO
An X-ray diffraction analysis was carried out on 10 healthy mallei and incudes which were taken from cadavers and on 50 diseased mallei and incudes taken peroperatively from patients with atticoantral otitis. X-ray powder diagrams of normal ossicles were shown as a granular hydroxyapatite. In diseased ossicles, changes were found in the crystallinity of hydroxyapatite which can be divided into four groups: (i) with characteristics of a diagram of normal bones giving peaks of maximum intensity of a granular hydroxyapatite; (ii) with less hydroxyapatite crystallinity; (iii) characterized by the occurrence of an amorphous phase of bone; (iv) characterized by the absence of all types of crystallization. The occurrence of different phases of crystalline hydroxyapatite in various forms of atticoantral otitis does not depend on the type of pathological process, i.e., with or without cholesteatoma.