Hyposalivation is the objective reduction in the flow rate of saliva, often called salivary gland hypofunction. This measurable condition means the salivary glands do not produce enough fluid to maintain oral function. It is distinct from xerostomia, which is the subjective sensation of having a dry mouth. While many people with hyposalivation feel dryness, the terms are not interchangeable, as some report dryness even with normal flow rates. Saliva is a complex fluid foundational to oral homeostasis, performing numerous protective and functional roles.
Recognizing the Signs of Reduced Saliva
The immediate impact of reduced salivary flow is the feeling of dryness that characterizes xerostomia. Patients often describe this persistent oral sensation as sticky, parched, or like having sandpaper in the mouth. Objectively, the remaining saliva frequently appears thick, frothy, or stringy, rather than clear and watery. This lack of lubrication directly impairs daily functions, leading to difficulty speaking (dysphonia) and trouble chewing or swallowing dry foods (dysphagia).
Clinical examination may reveal a dry, fissured, or lobulated tongue due to the loss of its protective coating. The oral mucosa, including the cheeks and gums, may look dry, pale, or red, and a key sign is the absence of a normal pool of saliva beneath the tongue. This chronic lack of moisture often results in cracked lips and sores at the corners of the mouth. Furthermore, patients frequently report an altered sense of taste, sometimes perceiving a metallic or bitter flavor.
Understanding the Roots of the Problem
The most common cause of reduced salivary flow is the side effect of various medications, particularly in patients undergoing polypharmacy. Hundreds of drugs interfere with the neural pathways that stimulate saliva production, primarily by blocking muscarinic receptors. Classes frequently implicated include antihistamines, tricyclic and selective serotonin reuptake inhibitor (SSRI) antidepressants, and antihypertensives such as diuretics and beta-blockers. Antipsychotics, anti-anxiety agents, and opioids also contribute to decreased output.
Beyond medications, several systemic diseases can directly impair salivary gland function. Sjögren’s syndrome is an autoimmune disorder where the immune system attacks moisture-producing glands, causing chronic inflammation and damage. Other conditions like diabetes, Parkinson’s disease, rheumatoid arthritis, and systemic lupus erythematosus are also associated with hyposalivation.
Other Causes
Local interventions, such as radiation therapy used to treat head and neck cancers, can cause irreversible damage to the salivary gland tissue. Lifestyle factors also play a role, as chronic dehydration, high consumption of caffeine and alcohol, and tobacco use can suppress salivary production.
Protecting Your Health from Lack of Saliva
Saliva’s protective role is multifaceted, and its absence leaves the mouth vulnerable to rapid deterioration. The fluid contains bicarbonate and phosphate ions, which provide a buffering capacity to neutralize the acids produced by plaque bacteria and dietary sources. When this buffering fails, the oral pH drops, creating an environment where dental enamel quickly demineralizes. This leads to accelerated or rampant dental caries, which can affect the smooth surfaces of teeth not typically prone to decay.
Saliva also contains minerals like calcium and phosphate, which are necessary for the remineralization of early enamel lesions. Without these components, the teeth cannot naturally repair themselves, increasing the risk of tooth sensitivity and widespread decay. Furthermore, saliva possesses antimicrobial agents such as lysozyme and immunoglobulins that suppress the growth of harmful pathogens. The loss of this defense increases the susceptibility to oral infections, most commonly oral candidiasis, or thrush, which presents as white patches on the tongue and oral lining.
Practical Steps for Management and Relief
Management of hyposalivation begins with non-pharmacological strategies to stimulate residual salivary function and replace lost moisture. Sipping water frequently throughout the day helps keep the oral tissues hydrated, and using a room humidifier, especially at night, can reduce moisture loss. Avoiding oral irritants like tobacco, dry or acidic foods, and caffeinated or alcoholic beverages is highly recommended, as these can exacerbate dryness. Sugar-free gum or candies containing xylitol can mechanically and gustatorily stimulate the salivary glands to produce more flow.
For direct relief and protection, patients can use over-the-counter topical agents, such as specialized rinses, gels, and sprays, which function as artificial saliva substitutes. To combat the heightened risk of decay, dentists often prescribe high-concentration fluoride products, such as 1.1% sodium fluoride toothpaste or gel, for daily home use. In cases where gland function remains, prescription medications called sialogogues, such as pilocarpine or cevimeline, can be used to systemically stimulate the salivary glands to increase fluid secretion.