Ultrastructural analysis of the submandibular sialoliths: Raman spectroscopy and electron back-scatter studies

ABSTRACT

The aim of work was the epidemiological analysis of the occurrence of sialolithiasis of the submandibular gland in adults and the evaluation of the ultrastructure of salivary stones. The study sample consisted of 44 sialoliths. Analysis of the structure and chemical composition of sialoliths was performed using a Scanning Electron Microscope and Raman Spectroscopy. Comparing our results with the literature we can say that the epidemiology of sialolithiasis has not changed significantly over the past 50 years. A wide variety of sialoliths structure was observed. In 75% (33) cases a layered structure of salivary stones was observed, while in 25% (11) – homogeneous structure. The various distribution of organic and inorganic components was observed among all the analyzed sialoliths. Raman spectroscopy allows for preliminary analysis of the sialoliths structure with only a qualitative assessment of their composition, which significantly reduces the research value of this method. The presence of organic and inorganic compounds in the core and inner layers of the salivary glands stones confirms 2 basic theories of the formation of sialoliths: inflammation and deposition of the inorganic component as a result of disruption of saliva flow in the salivary glands.

KEYWORDS:

• salivary diagnostics
• scanning electron microscopy
• saliva
• infrared spectroscopy
• calculus
• inflammation

Author Contributions

D. Tretiakow: obtaining material samples, contributed to the study concept, design, data analysis, and interpretation, drafted the manuscript, gave final approval. A. Skorek: obtaining material samples, contributed to the study concept and design, critically revised the manuscript, gave final approval. J. Ryl: contributed to design, data acquisition (SEM), analysis and interpretation, design, drafting the manuscript, gave final approval. J. Wysocka: data acquisition (Raman spectroscopy), analysis and interpretation, drafted manuscript, gave final approval. K. Darowicki: contributed to the conception, critically revised the manuscript, gave final approval.

Conflicts of interest

The authors declare no potential conflicts of interest concerning the authorship and/or publication of this article.

All authors gave final approval and agree to be accountable for all aspects of the work.

Additional information

Funding

This work was supported by departmental funding of the Faculty of Medicine (Medical University of Gdansk) and Faculty of Chemistry (Gdansk University of Technology). The study protocol was approved by the Regional Bioethics Committee of Gdansk Medical University, Poland (approval nr. NKBBN/452/2019).