RESUMO
BACKGROUND: The salivary glycoprotein MUC5B plays a versatile role in maintaining oral health. It contributes to lubrication, pellicle formation, antimicrobial defense, and water retention, and its glycans are an important nutrient for oral bacteria. This review aimed to describe the role of MUC5B in oral health and examine changes in its levels and composition in cases of hyposalivation and xerostomia. HIGHLIGHT: In cases of hyposalivation, the reduction of total salivary MUC5B levels and MUC5B glycosylation patterns due to Sjögren's syndrome (SS) and medication intake appeared insignificantly limited. In patients with SS, xerostomia was related to reduced MUC5B levels at the anterior tongue. In cases of xerostomia, MUC5B glycosylation might be reduced, yet other factors such as total protein concentration, MUC7 levels and glycosylation, and salivary spinnbarkeit are involved. In contrast to SS- and medication-induced hyposalivation, radiotherapy in the head and neck region leads to a bona fide reduction in salivary MUC5B levels. CONCLUSION: Our findings suggest that MUC5B levels are clearly impaired in hyposalivation and xerostomia related to radiotherapy in the head and neck region versus those related to SS and medication intake. A reduction in glycosylation in the case of dry mouth appears associated with MUC5B and MUC7 as well as other factors.
