High-resolution electron microscopic study of salivary calculus.

: The present study was performed to examine crystals in salivary calculus by high-resolution electron microscopy (HREM) and electron diffraction analyses. Microradiography (MR) showed that the calculus had three nuclei and showed complex shapes and mineralization. Hydroxyapatite (HA), in a variety of sizes and distributions, and the intermingling of HA and whitlockite (WH) at well-calcified areas, were observed.