Perspectives on tongue coating: etiology, clinical management, and associated diseases — a narrative review

Tongue coating (TC) is a biofilm comprising desquamated epithelial cells, food debris, and microorganisms. TC is commonly found across populations and may hold significant implications for both oral and systemic health. Factors such as age, diet, smoking, and systemic conditions influence its formation. TC is a primary reservoir for pathogenic bacteria and is closely linked to halitosis and periodontal disease. Beyond oral health, TC has been associated with systemic diseases, including aspiration pneumonia, cardiovascular disease, and diabetes, through mechanisms involving microbial translocation and low-grade inflammation. Literature search was performed using search engines and databases including, PubMed, Google Scholar, Web of Science and Medline, utilizing key words such as "Tongue coating," "Tongue cleaning," "Halitosis and Oral malodor". This review assesses the etiology, composition, and health implications of TC, highlighting its microbial diversity and correlation with oral and systemic conditions. Additionally, it examines interventions such as mechanical cleaning, chemical treatments, and dietary modifications to manage TC effectively. Emphasizing tongue hygiene as part of routine oral care is crucial for enhancing oral health, mitigating systemic risks, and improving quality of life.