The fine surface structure and composition of salivary calculi

Salivary calculi were formed by a laminated mixture of inorganic and organic substances. However, there was no regular pattern for the growth of stones, as laminal thickness and the arrangement of the laminal component were not uniform. Finger‐like radial projections, longitudinal pavements or amorphous structures were seen on the fractured surface of the calculi. No inert foreign body or microorganism was found in the calculi. There were two modes of formation in calculous nucleus, one developed by maturation of a primitive core, the other formed in homogenous mineral mass. X‐ray microanalysis proved that most salivary calculi contained chemical elements such as calcium, phosphorous, potassium, sodium, magnesium, chlorine, sulfur, manganese, chromium and aluminum. As far as we have examined, these elements were distributed with almost equal density throughout the calculus.