RT Journal Article T1 Evolutionary conformation model of salivary gland lithiasis A1 Sánchez Barrueco, Álvaro A1 López-Acevedo Cornejo, María Victoria A1 López De Andrés, María Sol A1 Díaz Tapia, Gonzalo A1 Alcalá Rueda, Ignacio A1 Santillán Coello, Jessica M A1 Cenjor Español, Carlos A1 Villacampa Aubá, José Miguel AB Introduction: Salivary stones, or sialoliths, are calcified concretions forming within salivary glands and their ducts through a two-stage process: an initial formation of a central core via precipitation of inorganic material mediated by organic substances, followed by layering of additional organic and inorganic material. Substrates for sialolith formation include mucoid agglomerates, organic vesicles, foreign bodies, and bacterial biofilms. Understanding the detailed structure of sialoliths may aid in developing specific preventive or therapeutic strategies.Materials and methods: This study analyzed 137 sialoliths from 102 patients treated across three university hospitals. Stones were extracted via sialendoscopy, direct extraction, or spontaneous extrusion. Structural and compositional analyses were conducted using scanning electron microscopy (SEM-EDX) and x-ray diffraction (XRD).Results: Most sialoliths were from the submandibular gland (82%), with the remainder from the parotid gland (18%). Parotid stones predominantly exhibited irregular shapes, while submandibular stones were generally ellipsoidal. All stones demonstrated an oolitic structure characterized by a central core surrounded by concentric layers and frequently associated with bacteria. Mineral composition predominantly included octacalcium phosphate (OCP), hydroxyapatite, and whitlockite. Larger sialoliths exhibited a higher proportion of hydroxyapatite, indicating increased crystallinity compared to OCP.Discussion: Despite diverse origins and locations, sialoliths share common morphological and compositional traits. Their formation begins with heterogeneous nucleation of calcium phosphates around organic spherules, likely induced by bacterial biofilms. These initial nuclei aggregate into a central core upon which additional layers of organic and inorganic materials deposit progressively. This layering increases the size and crystallinity of the sialoliths over time. The coexistence of amorphous phases and structural heterogeneity within layers explains the variability among stones. Detailed SEM-EDX analysis supports a unified conformational model for sialoliths that integrates the interplay of organic substrates, inorganic minerals, bacterial biofilms, and temporal factors.Conclusions: Sialoliths are oolitic aggregates featuring a central core surrounded by concentric layers composed of organic and inorganic materials. Their formation process involves initial heterogeneous nucleation, bacterial influence, and progressive crystallization. This universal conformational model effectively describes sialolith formation irrespective of patient-specific or anatomical variations. PB Frontiers Media YR 2025 FD 2025-06-05 LK https://hdl.handle.net/20.500.14352/122336 UL https://hdl.handle.net/20.500.14352/122336 LA eng NO Sánchez Barrueco, Á., López-Acevedo Cornejo, M. V., Aragonés Sanzen-Baker, W., López-Andrés, S., Díaz Tapia, G., Alcalá Rueda, I., Santillán Coello, J. M., Cenjor Español, C., & Villacampa Aubá, J. M. (2025). Evolutionary conformation model of salivary gland lithiasis. Frontiers in Oral Health, 6, 1610977. https://doi.org/10.3389/froh.2025.1610977 DS Docta Complutense RD 10 jul 2025