Salivary calculi: ultrastructural morphology and bacterial etiology.

Ultrastructural morphology of 16 salivary calculi was studied by means of transmission and scanning electron microscopy. The external surface was mostly globular or coarse, and on high magnifications and features could be divided into four main groups: a) amorphic calcified deposits covering extensive areas, b) other areas covered with crystals in a variety of arrangements, c) heavy accumulations of calcified rod-like and filamentouslike microorganisms, and d) platelet crystals in juxtaposition to calcified microorganisms in several areas. In most calculi the split area was found to be laminated. It is suggested that microorganisms have an important role in the formation and growth of salivary calculi.