Sialoliths were extracted from patients and imaged under light and scanning electron microscopy. Specimens for light microscopy were prepared using a diamond saw. Specimens for electron microscopy were freeze-fractured, thus providing an undisturbed view of the core of the sialolith.
We were able to identify clear evidence of biofilm caves at the core of each sialolith. These biofilm caves were complex with the presence of bacteria and dehydrated extrapolysaccharide matrix, host cells (immune cells, platelets and erythrocytes), and calcium nanoparticles.
The etiology of sialolith formation is likely multifactorial. We propose that biofilm formation within a single salivary gland or duct leads to local ductal injury, which results in the influx of host immune cells that interact with the biofilm and calcium nanoparticles, creating a scaffold upon which further calcium deposition can occur.
NA Laryngoscope, 130:69-74, 2020.