Dry mouth (or xerostomia) is a common complaint in dental patients, with many possible physiological and pathological conditions being the cause.
Dry mouth associated with reduced functioning of the salivary glands can be a major nuisance in a patient’s day-to-day life. Also, the reduced saliva levels can be associated with disease of the hard and soft tissues of the oral cavity.
Possible causes of dry mouth
Hundreds of medications have been shown to cause dry mouth. The most frequently implicated drugs are antidepressants, anticholinergics and antihistamines. These particular drugs are believed to work by blocking certain functions of the body that help promote watery secretions from the salivary glands in the mouth.
Dry mouth can be associated with Sjogrens syndrome, a disease that is commonly seen in postmenopausal women. This syndrome affects both the salivary glands and the tear-producing glands of the eyes, which is why dry eyes are commonly present in addition to the dry mouth symptoms. In many people, Sjogrens syndrome is a stand-alone condition, but in some cases it can be associated with other autoimmune conditions like rheumatoid arthritis.
Dry mouth can follow direct head and neck radiation therapy as salivary glands are incidentally damaged in the process of trying to destroy cancer cells. The degree to which the saliva glands are compromised is in direct proportion to the dose and region of the radiation. Generally dry mouth symptoms last for around six months after the treatment but they can persist for longer.
Chemotherapy treatment also causes dry mouth symptoms – by making salivary secretions thicker. Generally, though, the effects of chemotherapy are far more short-lived than those of radiation therapy.
As the main component of saliva is water, reduction in water within the body, or periods of dehydration, will reduce the production of saliva. Someone who is adequately hydrated will more easily produce salivary secretions throughout the day.
Can dry mouth affect my teeth?
Prolonged dry mouth can certainly have detrimental effects on the oral environment and teeth. This is because saliva has the ability to neutralise the acids that can demineralise the tooth surface and when saliva is lacking our teeth are more prone to decay and wear. (Conversely, saliva can remineralise the tooth surface after demineralisation as it contains calcium, phosphate and fluoride ions, which make up the backbone of tooth structure.)
As well as protecting teeth from harmful acid exposure, saliva plays a role in decreasing plaque accumulation and can clear foodstuffs from the teeth due to its natural cleansing properties. (This is one reason to chew sugarless gum after eating.) Saliva has also been shown to have antibacterial properties, containing enzymes that can effectively work to destroy harmful bacteria within the oral cavity.
Topical fluoride applications in the dental surgery and at home can be used to help prevent demineralisation of the teeth while also helping to remineralise. Tooth mousse (CCP-ACP) products can also be used to the same effect as fluoride treatments. Artificial saliva substitutes (like Biotene or GC dry mouth preparations) can help relieve dryness and help aid in disease prevention and in speaking and chewing function.
In addition to the above, you can stimulate saliva production by drinking tap water to ensure that you are adequately hydrated throughout the day and by eating foods that are chewy. Avoiding caffeine can also have a positive effect.