Identifying sialoliths through SEM technology.

OBJECTIVE: To define SEM characteristics that may aid identification of sialoliths. MATERIALS: Two sialoliths from modern patients affected by sialadenitis. METHODS: Samples were coated with silver and subjected to scanning electron microscopy using an energy-dispersive X-ray spectroscopy detector. Samples were then sectioned to permit study of the internal structure. RESULTS: Sialoliths show an external smooth surface with no distinctive features. Internal structures consist of a distinctive aggregate of coarse granules of different sizes surrounded by a lamellar coat. Elemental composition consists of carbon, phosphate, calcium and oxygen, with traces of magnesium. The proportion of these elements differs between the core and the surface. CONCLUSION: Although elemental composition is not specific, SEM analyses of sialoliths greatly differ from those of sesamoid bones, gallstones and nephroliths. Therefore, SEM analysis constitutes a useful tool for the precise identification of small calcified structures recovered during archaeological excavations. SIGNIFICANCE: Precise identification of calcified structures may provide information about nutritional and/or pathological aspects of past individuals. LIMITATIONS: Sialoliths are less common than other types of calcifications, and only two cases were analyzed in this study. FUTURE PROSPECTS: SEM technology should be applied to identify the etiology of all minute calcified remains recovered during archaeological excavations of burial sites.