Structural analysis of phleboliths and salivary calculi.

Three phleboliths and ten salivary calculi in the submandibular duct were studied with scanning electron microscopy (SEM) and computer aided microanalyser (CMA). The surface of the phleboliths was rather even with some irregularity. According to their surface structure the salivary calculi were divided into three types: the rock-like type, the granular type, and the globular type. The phleboliths were classified into two types according to their cut surface: the calcified-core type, and the uncalcified-core type. The core structure was similar to the surface structure in the calcified-core type of phleboliths, but in the salivary calculi the core structure was different from the surface structure in that the cut surface of the core was an accumulation of circular or polygonal structures forming a honey-comb pattern which was surrounded by small projections distributed radially. On the basis of these results some etiological factors of phleboliths and salivary calculi are discussed.