Structure and composition of sialoliths.

Salivary calculi consist of a concentrically arranged, heterogeneous mixture of different phosphates of calcium, together with an inorganic matrix. The different crystalline phases are: hydroxyl- and carbonate-apatite, whitlockite and calcium octaphosphate. Investigation of 50 cases of sialothiasis (salivary gland disease) revealed characteristic sex-dependent differences in the uptake of toxic heavy metals by salivary calculi. The contents of fluorine and lead were positively correlated, which may be due to the fact that lead substitutes for calcium in the apatite structure of the inorganic matrix.