Hyperglycaemia in diabetes mellitus could damage the function of the salivary glands leading to a reduction in the salivary flow. It depends on neuropathy that affects nerve vague and the other autonomic nerves.
The parotids commonly increased in volume in diabetic patients but it is generally asymptomatic.
Sialosis is a disease of the salivary glands, characterized by a painless bilateral growth, mainly but not only, of the parotids. This growth is generally followed by a loss of salivary production leading to xerostomia. It is a degenerative disease due to a desmyelinization of the nerve cells, that impair the secretion mechanism of salivary glands. In diabetic sialosis, the increased volume of the glands is due to the adipose infiltration of the parenchyma. When salivary flow decreases, many oral alterations can occur such as:
• increased concentration of mucin and glucose;
• impaired production and/or action of many antimicrobial factors;
• absence of a metalloprotein called gustin, that contains zinc and is responsible for the constant maturation of taste papillae;
• bad taste;
• oral candidiasis;
• increased cells exfoliation after contact, because of poor lubrication;
• increased proliferation of pathogenic microorganisms;
• coated tongue;