[Long-term decomposition of bones. 1. Mineral phase].

Based on the alteration of microstructure and gross features caused by long term fate of bony substance a model of decomposition of bone mineral is outlined. Destruction of the corps by microorganisms leads on the whole to an acid milieu. Hence hydroxyapatite is turned into brushite, which is more soluble in acid media. As this mineral is formed in a space consuming way, the expanding brushite-masses support mechanical destruction of bony substance by cracking the lamellary systems. Both mechanical stress by formation of brushite and transformation of hydroxyapatite to this mineral compound are main features for dead bone decomposition.