X-Ray Crystallographic Examination of Calculi from Salivary Glands

Abstract
26 surgically-removed calculi were examined by a high-dispersion X-ray powder method. 21 calculi contained only colloidal apatite, 2 only colloidal whitlockite, 12 mixtures of apatite and whitlockite; 2 calculi also contained traces of calcite. Whitlockite is extremely rare in Ca phosphates deposited in the body. Hence it is concluded that the saliva often, perhaps always, contains a factor which impedes the normal crystallization of apatite.