SCANNING ELECTRON-MICROSCOPY AND ENERGY-DISPERSIVE X-RAY-MICROANALYSIS STUDIES OF SEVERAL HUMAN CALCULI CONTAINING CALCIUM-PHOSPHATE CRYSTALS

Human calcium phosphate calculi: two sialoliths, a urolith, a rhinolit h, and a tonsillolith were investigated by scanning electron microscop y (SEM) and energy-dispersive X-ray analysis (EDX). The sialoliths and urolith had appositional shells with thick cortices, respectively, ar ound several nuclei composed of calcospherulites and a rubber-film fra gment. The rhinolith had a thin cortex with appositional laminations a round a glomerulus-like mass of calcified cotton-like strings. The ton sillolith had a rough cortex with appositional laminations. Its porous interior was composed of numerous calcified conglomerates with microo rganisms and calcified masses with fine appositional laminations aroun d the conglomerates. The major crystals were identified as biological apatites (AP) with a sand-grain rather than a needle-like shape, and p late-shaped octacalcium phosphate (OCP). The AP deposits of the rhinol ith probably were associated with magnesium (Mg) phosphates or contain ed Mg. No OCP was found in the rhinolith. The AP deposits were mainly formed by extracellular calcification. Hexahedral crystals, identified as Mg-containing whitlockite (WH), were precipitated in the internal spaces of the AP and OCP deposits. The rhinolith nucleus consisted of WH crystal deposits only.