Sialolithiasis: mineralogical composition, crystalline structure, calculus site, and epidemiological features

Abstract

The purpose of this paper was to describe the characteristics of salivary calculi and their relationship to epidemiological factors, through a cross-sectional study. We analysed 100 calculi obtained in 2017–2021. Patient data including age, time since onset of symptoms, gland involved, and site of location in the salivary system were studied. The calculi were studied to determine their morphological features using scanning electron microscopy and energy dispersive plain radiographic analysis. Most of the calculi had formed in the submandibular gland (SG) (82%). The mean age of patients at onset was 45.83 years; patients presenting parotid gland (PG) stones were somewhat older (p = 0.031). The mean time since the onset of symptoms was longer in PG calculi (p = 0.038). The most common lithiasis site was the main duct (74%), followed by the hilum (22%). Hilar stones were the largest (p < 0.05) and heaviest (p = 0.028). Octacalcium phosphate (OCP) was the most common crystalline phase (Cp) founded, followed by hydroxyapatite (HA) and whitlockite (WH). Specifically, OCP had a higher presence in PG calculi (p = 0.029) and WH was the most common phase in SG calculi (p = 0.017). The most prevalent site of lithiasis was the main duct, and the largest and heaviest calculi were found in the SG. PG stones were associated with a longer history of symptoms and older age. OCP was the most frequent Cp of the calculi studied, and the main Cp in PG stones. WH was the predominant Cp in SG stones. The Cp of the calculi was not influenced by location, patient age, or time of symptoms.