Hyposalivation Treatment With Non-crosslinked Hyaluronic Acid and Amino Acids Solution

Dry mouth is one of the most common complaints among patients, in both dental and general medicine practices, especially among the older population. Xerostomia (or dry mouth) is a medical term used to describe the subjective sensation of dry mouth that commonly occurs because of decreased salivary flow (hyposalivation). Although the two terms do not correspond to the same conditions and should not be used interchangeably, many physicians do so, since most patients with xerostomia also have hyposalivation.

Approximately 30% of the population complains on some degree of dry mouth. When it happens occasionally, during dehydration or stress, it is not a cause for concern. The situation is more serious if it happens more often, such as every day. It could also point to an underlying health condition. In untreated patients, hyposalivation increase their vulnerability to tooth decay, gingivitis and oral mucosa sensation. Dry mouth is related to pain, sometimes insomnia and psychological problems and results in deterioration of life well-being.

Saliva is produced by major salivary glands (MaSGs), the parotid, submandibular and sublingual glands and by circa 600 to 1,000 minor salivary glands (MiSGs) located in the submucosa layer in the oral cavity. MaSG contributed to 90% of total saliva secretions, whereas MiSG contributed to the remaining 10%. MiSGs are important for preventing the subjective sensation of dry mouth, since the saliva produced by these glands creates a lubricating micron-thick film that protects the oral mucosae. Furthermore, MiSGs play a key role in saliva production during sleep; therefore, reduced MiSG flow appears to be a cause of nocturnal dry mouth.

Saliva is a hypotonic solution composed of 98.5% water with 1% organic and 0.5% inorganic components. The organic and inorganic components of saliva are present in low concentrations, with some proteins synthetized in the gland (such as α-amylase) present in relatively high concentrations. Other organic components detected in saliva are vitamin C, maltase, urea, uric acid, lactase, hormones (testosterone, cortisol), albumin, creatinine, amino acids, mucin and immunoglobulins (IgA, IgG, IgM). Saliva α-amylase and lipase play a role in starch digestion and triglyceride decomposition. Salivary mucins lubricate intraoral structures and help to form a barrier against microbial invasion. Salivary immunoglobulins, especially secretory IgA (SIgA), play a key role in neutralizing toxins, agglutinating bacteria, and preventing their adhesion to mucosal surfaces.

By moistening the oral mucosa, saliva facilitates chewing, swallowing, and speech. Furthermore, a constant flow of saliva facilitates the mechanical removal of food debris and microorganisms and regulates the oral pH, protecting against acidic byproducts of bacterial metabolism. This buffering capacity is essential for maintaining a healthy oral microbiome and preventing demineralization of tooth enamel. Saliva also serves as a protective factor against infections because of its numerous organic components. People with dry mouth not only have trouble chewing and swallowing food but also have difficulty with tasting, speaking, and a reduced tolerance for dentures. Furthermore, xerostomia increases the risk of caries, periodontal disease, candidiasis, oral ulcers, and dysphagia, which can negatively impact nutritional status and quality of life.