Xerostomia, also known as dry mouth,
is dryness in the
mouth, which may be associated with a change in the composition of
saliva
Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be ...
, or reduced salivary flow, or
have no identifiable cause.
This symptom is very common and is often seen as a
side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
of many types of medication. It is more common in older people (mostly because this group tend to take several medications) and in persons who
breathe through their mouths.
Dehydration
In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
,
radiotherapy involving the
salivary gland
The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary ...
s,
chemotherapy
Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemotherap ...
and several diseases can cause reduced salivation (hyposalivation), or a change in saliva consistency and hence a complaint of xerostomia. Sometimes there is no identifiable cause, and there may sometimes be a
psychogenic
A psychogenic effect is one that originates from the brain instead of other physical organs (i.e. the cause is psychological rather than physiological) and may refer to:
* Psychogenic pain
*Psychogenic disease
* Psychogenic amnesia
*Psychogenic co ...
reason for the complaint.
Definition
Xerostomia is the subjective sensation of dry mouth, which is often (but not always) associated with hypofunction of the salivary glands.
The term is derived from the Greek words ξηρός (''xeros'') meaning "dry" and στόμα (''stoma'') meaning "mouth". A drug or substance that increases the rate of salivary flow is termed a
sialogogue __NOTOC__
A sialogogue (also spelled sialagogue, ptysmagogue or ptyalagogue) is a drug or substance that increases the flow rate of saliva.
Sialogogues can be used in the treatment of xerostomia (the subjective feeling of having a dry mouth), to st ...
.
Hyposalivation is a clinical diagnosis that is made based on the history and examination,
but reduced salivary flow rates have been given objective definitions. Salivary gland hypofunction has been defined as any objectively demonstrable reduction in whole and/or individual gland flow rates.
An unstimulated whole saliva flow rate in a normal person is 0.3–0.4 ml per minute,
and below 0.1 ml per minute is significantly abnormal. A stimulated saliva flow rate less than 0.5 ml per gland in 5 minutes or less than 1 ml per gland in 10 minutes is decreased.
The term subjective xerostomia is sometimes used to describe the symptom in the absence of any clinical evidence of dryness.
Xerostomia may also result from a change in composition of saliva (from serous to mucous).
Salivary gland dysfunction
Salivary gland diseases (SGDs) are multiple and varied in cause. There are three paired major salivary glands in humans – the parotid glands, the submandibular glands, and the sublingual glands. In addition there are about 800-1000 minor salivar ...
is an
umbrella term
In linguistics, semantics, general semantics, and ontologies, hyponymy () is a semantic relation between a hyponym denoting a subtype and a hypernym or hyperonym (sometimes called umbrella term or blanket term) denoting a supertype. In other wor ...
for the presence of xerostomia, salivary gland hyposalivation,
and
hypersalivation
Hypersalivation, or ptyalism, also known as sialorrhea or hypersialosis is the excessive production of saliva. It has also been defined as increased amount of saliva in the mouth, which may also be caused by decreased clearance of saliva.Medscape ...
.
Signs and symptoms
Hyposalivation may give the following signs and symptoms:
*
Dental caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
(xerostomia related caries) – Without the buffering effects of saliva, tooth decay becomes a common feature and may progress much more aggressively than it would otherwise ("rampant caries"). It may affect tooth surfaces that are normally spared, e.g., cervical caries and root surface caries. This is often seen in patients who have had radiotherapy involving the major salivary glands, termed radiation-induced caries.
Therefore, it is important that any products used in managing dry mouth symptoms are sugar-free, as the presence of sugars in the mouth support the growth of oral bacteria, resulting in acid production and development of dental caries.
*
Acid erosion
Acid erosion is a type of tooth wear. It is defined as the irreversible loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Dental erosion is the most common chronic condition of children ages 5–17, altho ...
. Saliva acts as a buffer and helps to prevent demineralization of teeth.
*
Oral candidiasis
Oral candidiasis, also known as oral thrush among other names, is candidiasis that occurs in the mouth. That is, oral candidiasis is a mycosis (yeast/fungal infection) of ''Candida'' species on the mucous membranes of the mouth.
''Candida albic ...
– A loss of the antimicrobial actions of saliva may also lead to
opportunistic infection
An opportunistic infection is an infection caused by pathogens (bacteria, fungi, parasites or viruses) that take advantage of an opportunity not normally available. These opportunities can stem from a variety of sources, such as a weakened immune ...
with ''
Candida'' species.
* Ascending (suppurative)
sialadenitis
Sialadenitis (sialoadenitis) is inflammation of salivary glands, usually the major ones, the most common being the parotid gland, followed by submandibular and sublingual glands. It should not be confused with sialadenosis (sialosis) which is a non ...
– an infection of the major salivary glands (usually the
parotid gland
The parotid gland is a major salivary gland in many animals. In humans, the two parotid glands are present on either side of the mouth and in front of both ears. They are the largest of the salivary glands. Each parotid is wrapped around the ma ...
) that may be recurrent.
It is associated with hyposalivation, as bacteria are able to enter the ductal system against the diminished flow of saliva.
There may be swollen salivary glands even without acute infection, possibly caused by
autoimmune
In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". ...
involvement.
*
Dysgeusia
Dysgeusia, also known as parageusia, is a distortion of the sense of taste. Dysgeusia is also often associated with ageusia, which is the complete lack of taste, and hypogeusia, which is a decrease in taste sensitivity. An alteration in taste or ...
– altered taste sensation (e.g., a metallic taste)
and
dysosmia
Dysosmia is a disorder described as any qualitative alteration or distortion of the perception of smell. Qualitative alterations differ from quantitative alterations, which include anosmia and hyposmia. Dysosmia can be classified as either paros ...
, altered sense of smell.
* Intraoral
halitosis
Bad breath, also known as halitosis, is a symptom in which a noticeably unpleasant breath odour is present. It can result in anxiety among those affected. It is also associated with depression and symptoms of obsessive compulsive disorder. ...
– possibly due to increased activity of halitogenic biofilm on the posterior dorsal tongue (although dysgeusia may cause a complaint of nongenuine halitosis in the absence of hyposalivation).
*
Burning mouth syndrome
Burning mouth syndrome (BMS) is a burning, tingling or scalding sensation in the mouth, lasting for at least four to six months, with no underlying known dental or medical cause. No related signs of disease are found in the mouth. People with ...
– a burning or tingling sensation in the mouth.
* Saliva that appears thick or ropey.
* Mucosa that appears dry.
* A lack of saliva pooling in the floor of the mouth during examination.
*
Dysphagia
Dysphagia is difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right.
It may be a sensation that suggests difficulty in the passage of solids or liq ...
– difficulty swallowing and chewing, especially when eating dry foods. Food may stick to the tissues during eating.
* The tongue may stick to the palate,
causing a clicking noise during speech, or the lips may stick together.
* Gloves or a
dental mirror
A mouth mirror or dentist's mirror is an instrument used in dentistry. The head of the mirror is usually round, and the most common sizes used are No. 4 (⌀ 18 mm) and No. 5 (⌀ 20 mm). A No. 2 is sometimes used when a smaller mirr ...
may stick to the tissues.
*
Fissured tongue
Fissured tongue is a benign condition characterized by deep grooves (fissures) in the dorsum of the tongue. Although these grooves may look unsettling, the condition is usually painless. Some individuals may complain of an associated burning sen ...
with
atrophy of the
filiform papillae and a lobulated,
erythema
Erythema (from the Greek , meaning red) is redness of the skin or mucous membranes, caused by hyperemia (increased blood flow) in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not asso ...
tous appearance of the tongue.
* Saliva cannot be "milked" (expressed) from the
parotid duct
The parotid duct, or Stensen duct, is a salivary duct. It is the route that saliva takes from the major salivary gland, the parotid gland, into the mouth.
Structure
The parotid duct is formed when several interlobular ducts, the largest ducts in ...
.
* Difficulty wearing
denture
Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable ( removable partial denture or ...
s, e.g., when swallowing or speaking.
There may be generalized mucosal soreness and ulceration of the areas covered by the denture.
* Mouth soreness and oral mucositis.
* Lipstick or food may stick to the teeth.
* A need to sip drinks frequently while talking or eating.
* Dry, sore, and cracked lips and angles of mouth.
*
Thirst
Thirst is the craving for potable fluids, resulting in the basic instinct of animals to drink. It is an essential mechanism involved in fluid balance. It arises from a lack of fluids or an increase in the concentration of certain osmolites, suc ...
.
However, sometimes the clinical findings do not correlate with the symptoms experienced.
For example, a person with signs of hyposalivation may not complain of xerostomia. Conversely a person who reports experiencing xerostomia may not show signs of reduced salivary secretions (subjective xerostomia).
In the latter scenario, there are often other oral symptoms suggestive of
oral dysesthesia ("burning mouth syndrome").
Some symptoms outside the mouth may occur together with xerostomia.
These include:
*
Xerophthalmia
Xerophthalmia (from Ancient Greek "xērós" (ξηρός) meaning "dry" and "ophthalmos" (οφθαλμός) meaning "eye") is a medical condition in which the eye fails to produce tears. It may be caused by vitamin A deficiency, which is someti ...
(dry eyes).
* Inability to cry.
* Blurred vision.
*
Photophobia
Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of ...
(light intolerance).
* Dryness of other mucosae, e.g., nasal, laryngeal, and/or genital.
* Burning sensation.
* Itching or grittiness.
*
Dysphonia
A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice, can be associated with a feeling of unease or scratchiness in the ...
(voice changes).
There may also be other systemic signs and symptoms if there is an underlying cause such as
Sjögren's syndrome,
for example, joint pain due to associated
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
.
Cause
The differential of hyposalivation significantly overlaps with that of xerostomia. A reduction in saliva production to about 50% of the normal unstimulated level will usually result in the sensation of dry mouth.
Altered saliva composition may also be responsible for xerostomia.
Physiologic
Salivary flow rate is decreased during sleep, which may lead to a transient sensation of dry mouth upon waking. This disappears with eating or drinking or with oral hygiene. When associated with halitosis, this is sometimes termed "morning breath". Dry mouth is also a common sensation during periods of anxiety, probably owing to enhanced
sympathetic drive.
During periods of stress, our body responds in a ‘fight or flight’ state that will interfere with the saliva flow in the mouth. Dehydration is known to cause hyposalivation,
the result of the body trying to conserve fluid. Physiologic age-related changes in salivary gland tissues may lead to a modest reduction in salivary output and partially explain the increased prevalence of xerostomia in older people.
However,
polypharmacy
Polypharmacy (polypragmasia) is the simultaneous use of multiple medicines by a patient for their conditions. Most commonly it is defined as regularly taking five or more medicines but definitions vary in where they draw the line for the minimum ...
is thought to be the major cause in this group, with no significant decreases in salivary flow rate being likely to occur through aging alone.
Drug induced
Aside from physiologic causes of xerostomia,
iatrogenic
Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence. "Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 27 ...
effects of medications are the most common cause.
A medication which is known to cause xerostomia may be termed ''xerogenic''.
Over 400 medications are associated with xerostomia.
Although drug induced xerostomia is commonly reversible, the conditions for which these medications are prescribed are frequently chronic.
The likelihood of xerostomia increases in relation to the total number of medications taken, whether the individual medications are xerogenic or not.
The sensation of dryness usually starts shortly after starting the offending medication or after increasing the dose.
Anticholinergic
Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system.
These agents inhibit the parasympathetic nervous sys ...
,
sympathomimetic, or
diuretic
A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics in ...
drugs are usually responsible.
Sjögren's syndrome
Xerostomia may be caused by autoimmune conditions which damage saliva-producing cells.
Sjögren's syndrome is one such disease, and it is associated with symptoms including fatigue,
myalgia and
arthralgia
Arthralgia (from Greek ''arthro-'', joint + ''-algos'', pain) literally means ''joint pain''. Specifically, arthralgia is a symptom of injury, infection, illness (in particular arthritis), or an allergic reaction to medication.
According to MeSH, ...
.
The disease is characterised by inflammatory changes in the moisture-producing glands throughout the body, leading to reduced secretions from glands that produce saliva, tears and other secretions throughout the body.
Primary Sjögren's syndrome is the combination of dry eyes and xerostomia. Secondary Sjögren's syndrome is identical to primary form but with the addition of a combination of other connective tissue disorders such as
systemic lupus erythematosus
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Comm ...
or
rheumatoid arthritis
Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...
.
Celiac disease
Xerostomia may be the only symptom of celiac disease, especially in adults, who often have no obvious digestive symptoms.
Radiation therapy
Radiation therapy for cancers of the head and neck (including
brachytherapy
Brachytherapy is a form of radiation therapy where a sealed radiation source is placed inside or next to the area requiring treatment. ''Brachy'' is Greek for short. Brachytherapy is commonly used as an effective treatment for cervical, prost ...
for thyroid cancers) where the salivary glands are close to or within the field irradiated is another major cause of xerostomia.
A radiation dose of 52 Gy is sufficient to cause severe salivary dysfunction. Radiotherapy for oral cancers usually involves up to 70 Gy of radiation, often given along with chemotherapy which may also have a damaging effect on saliva production.
This side effect is a result of radiation damage of the parasympathetic nerves. Formation of salivary gland ducts depends on the secretion of a
neuropeptide
Neuropeptides are chemical messengers made up of small chains of amino acids that are synthesized and released by neurons. Neuropeptides typically bind to G protein-coupled receptors (GPCRs) to modulate neural activity and other tissues like the ...
from the parasympathetic nerves, while development of the end buds of the salivary gland depends on
acetylcholine
Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Part ...
from the parasympathetic nerves.
Sicca syndrome
"Sicca" simply means dryness. Sicca syndrome is not a specific condition, and there are varying definitions, but the term can describe oral and eye dryness that is not caused by autoimmune diseases (e.g., Sjögren syndrome).
Other causes
Oral dryness may also be caused by mouth breathing,
usually caused by partial obstruction of the
upper respiratory tract
The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa.
Air is breathed in through the nose to t ...
. Examples include
hemorrhage
Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, v ...
,
vomiting
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteri ...
,
diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
, and
fever
Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...
.
Alcohol may be involved in the cause of salivary gland disease, liver disease, or dehydration.
Smoking is another possible cause.
Other recreational drugs such as
methamphetamine,
cannabis
''Cannabis'' () is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: ''Cannabis sativa'', '' C. indica'', and '' C. ruderalis''. Alternatively ...
,
hallucinogen
Hallucinogens are a large, diverse class of psychoactive drugs that can produce altered states of consciousness characterized by major alterations in thought, mood, and perception as well as other changes. Most hallucinogens can be categorize ...
s,
or
heroin
Heroin, also known as diacetylmorphine and diamorphine among other names, is a potent opioid mainly used as a recreational drug for its euphoric effects. Medical grade diamorphine is used as a pure hydrochloride salt. Various white and brow ...
, may be implicated.
Hormonal disorders, such as poorly controlled diabetes, chronic graft versus host disease or low fluid intake in people undergoing
hemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinin ...
for renal impairment may also result in xerostomia, due to dehydration.
Nerve damage can be a cause of oral dryness. An injury to the face or surgery can cause nerve damage to your head and neck area which can effect the nerves that are associated with the salivary flow.
Xerostomia may be a consequence of infection with hepatitis C virus (HCV) and a rare cause of salivary gland dysfunction may be
sarcoidosis
Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly a ...
.
Infection with Human Immunodeficiency Virus/Acquired immunodeficiency Syndrome (AIDS) can cause a related salivary gland disease known as Diffuse Infiltrative Lymphocytosis Syndrome (DILS).
Similar to taste dysfunction, xerostomia is one of the most prevalent and persistent oral symptoms associated with COVID-19. Despite a close association with COVID-19, xerostomia, dry mouth and hyposalivation tend to be overlooked in COVID-19 patients and survivors, unlike ageusia, dysgeusia and hypogeusia.
Diagnostic approach
A diagnosis of hyposalivation is based predominantly on the clinical signs and symptoms.
The
Challacombe scale maybe used to classify the extent of dryness.
The rate of the salivary flow in an individual's mouth can also be measured. There is little correlation between symptoms and objective tests of salivary flow,
such as
sialometry. This test is simple and noninvasive, and involves measurement of all the saliva a patient can produce during a certain time, achieved by dribbling into a container. Sialometery can yield measures of stimulated salivary flow or unstimulated salivary flow. Stimulated salivary flow rate is calculated using a stimulant such as 10%
citric acid
Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in ...
dropped onto the tongue, and collection of all the saliva that flows from one of the
parotid papilla
The parotid duct, or Stensen duct, is a salivary duct. It is the route that saliva takes from the major salivary gland, the parotid gland, into the mouth.
Structure
The parotid duct is formed when several interlobular ducts, the largest ducts in ...
e over five or ten minutes. Unstimulated whole saliva flow rate more closely correlates with symptoms of xerostomia than stimulated salivary flow rate.
Sialography
Sialography (also termed radiosialography) is the radiographic examination of the salivary glands. It usually involves the injection of a small amount of contrast medium into the salivary duct of a single gland, followed by routine X-ray projection ...
involves introduction of
radio-opaque
Radiodensity (or radiopacity) is opacity to the radio wave and X-ray portion of the electromagnetic spectrum: that is, the relative inability of those kinds of electromagnetic radiation to pass through a particular material. Radiolucency or hypod ...
dye such as
iodine
Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...
into the duct of a salivary gland.
It may show blockage of a duct due to a calculus. Salivary
scintiscanning using
technetium
Technetium is a chemical element with the symbol Tc and atomic number 43. It is the lightest element whose isotopes are all radioactive. All available technetium is produced as a synthetic element. Naturally occurring technetium is a spontaneous ...
is rarely used. Other medical imaging that may be involved in the investigation include
chest x-ray
A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in med ...
(to exclude sarcoidosis),
ultrasonography
Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...
and
magnetic resonance imaging (to exclude Sjögren's syndrome or neoplasia).
A minor salivary gland
biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...
, usually taken from the lip,
may be carried out if there is a suspicion of
organic disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that ar ...
of the salivary glands.
Blood tests and
urinalysis
Urinalysis, a portmanteau of the words ''urine'' and ''analysis'', is a panel of medical tests that includes physical (macroscopic) examination of the urine, chemical evaluation using urine test strips, and microscopic examination. Macroscopic ...
may be involved to exclude a number of possible causes.
To investigate xerophthalmia, the Schirmer test of lacrimal flow may be indicated.
Slit-lamp examination may also be carried out.
Treatment
The successful treatment of xerostomia is difficult to achieve and often unsatisfactory.
This involves finding any correctable cause and removing it if possible, but in many cases it is not possible to correct the xerostomia itself, and treatment is
symptomatic
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
, and also focuses on preventing tooth decay through improving
oral hygiene
Oral hygiene is the practice of keeping one's mouth clean and free of disease and other problems (e.g. bad breath) by regular brushing of the teeth (dental hygiene) and cleaning between the teeth. It is important that oral hygiene be carried out ...
. Where the symptom is caused by hyposalivation secondary to underlying chronic disease, xerostomia can be considered permanent or even progressive.
The management of salivary gland dysfunction may involve the use of saliva substitutes and/or saliva stimulants:
* Saliva substitutes – These are viscous products which are applied to the oral mucosa, which can be found in the form of sprays, gels, oils, mouthwashes, mouth rinses, pastilles or viscous liquids.
This includes water, artificial salivas (
mucin
Mucins () are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most ...
-based,
carboxymethylcellulose
Carboxymethyl cellulose (CMC) or cellulose gum is a cellulose derivative with carboxymethyl groups (-CH2-COOH) bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone. It is often used as its sodiu ...
-based), and other substances (milk,
vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...
):
**
Mucin
Mucins () are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most ...
Spray: 4 Trials have been completed on the effects of Mucin Spray on Xerostomia, overall there is no strong evidence showing that Mucin Spray is more effective than a placebo in reducing the symptoms of dry mouth.
**
Mucin
Mucins () are a family of high molecular weight, heavily glycosylated proteins (glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most ...
Lozenge: Only 1 trial (Gravenmade 1993) has been completed regarding the effectiveness of Mucin Lozenges. Whilst it was assessed as being at high risk of bias, it showed that Mucin Lozenges were ineffective when compared to a placebo.
** Mucoadhesive Disk: These disks are stuck to the palate and they contain lubricating agents, flavouring agents and some antimicrobial agents. One trial (Kerr 2010) assessed their effectiveness against a placebo disk. Strangely, patients from both groups (placebo and the real disk) reported an increase in subjective oral moistness. No adverse effects were reported. More research is needed in this area before conclusions are drawn.
* Biotene oral Balance Gel & toothpaste: One trial has been completed (Epstein 1999) regarding the effectiveness of Biotene Oral Balance gel & toothpaste. The results showed that Biotene products were "more effective than control and reduced dry mouth on waking".
* Saliva stimulants – organic acids (
ascorbic acid
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
,
malic acid
Malic acid is an organic compound with the molecular formula . It is a dicarboxylic acid that is made by all living organisms, contributes to the sour taste of fruits, and is used as a food additive. Malic acid has two stereoisomeric forms ( ...
), chewing gum,
parasympathomimetic
A parasympathomimetic drug, sometimes called a cholinomimetic drug or cholinergic receptor stimulating agent, is a substance that stimulates the parasympathetic nervous system (PSNS). These chemicals are also called cholinergic drugs because ace ...
drugs (choline esters, e.g.
pilocarpine hydrochloride
Pilocarpine is a medication used to reduce pressure inside the eye and treat dry mouth. As eye drops it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to bring abo ...
,
cholinesterase inhibitor
Cholinesterase inhibitors (ChEIs), also known as anti-cholinesterase, are chemicals that prevent the breakdown of the neurotransmitter acetylcholine or butyrylcholine. This increases the amount of the acetylcholine or butyrylcholine in the syn ...
s), and other substances (sugar-free mints,
nicotinamide
Niacinamide or Nicotinamide (NAM) is a form of vitamin B3 found in food and used as a dietary supplement and medication. As a supplement, it is used by mouth to prevent and treat pellagra (niacin deficiency). While nicotinic acid (niacin) may ...
). Medications which stimulate saliva production traditionally have been administered through oral tablets, which the patient goes on to swallow,
although some saliva stimulants can also be found in the form of toothpastes.
Lozenges, which are retained in the mouth and then swallowed are becoming more and more popular. Lozenges are soft and gentle on the mouth and there is a belief that prolonged contact with the oral mucosa mechanically stimulates saliva production.
**
Pilocarpine
Pilocarpine is a medication used to reduce pressure inside the eye and treat dry mouth. As eye drops it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to bring abo ...
: A study by Taweechaisupapong in 2006 showed no 'statistical significant improvement in oral dryness and saliva production compared to placebo' when administering pilocarpine lozenges.
**
Physostigmine
Physostigmine (also known as eserine from ''éséré'', the West African name for the Calabar bean) is a highly toxic parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean and ...
Gel: A study by Knosravini in 2009 showed a reduction in the oral dryness and a 5 times increase in saliva following physostigmine treatment.
** Chewing gum increases saliva production but there is no strong evidence that it improves dry mouth symptoms.
** The Cochrane oral health group concluded 'there is insufficient evidence to determine whether
pilocarpine
Pilocarpine is a medication used to reduce pressure inside the eye and treat dry mouth. As eye drops it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to bring abo ...
or physostigmine' are effective treatments for Xerostomia. More research is needed.
** Dentirol chewing gum (xylitol): A study by Risheim in 1993 showed that when subjects had 2 sticks of gum up to 5 x daily, the gum gave subjective dry mouth symptom relief in approximately 1/3 of participants but no change in SWS (stimulated whole saliva).
**Profylin lozenge (xylitol/sorbitol):A study by Risheim in 1993 showed that when subjects had 1 lozenge 4 to 8 x daily, Profylin lozenges gave subjective dry mouth symptom relief in approximately 1/3 of participants but no change in SWS (stimulated whole saliva).
Saliva substitutes can improve xerostomia, but tend not to improve the other problems associated with salivary gland dysfunction. Parasympathomimetic drugs (saliva stimulants) such as pilocarpine may improve xerostomia symptoms and other problems associated with salivary gland dysfunction, but the evidence for treatment of radiation-induced xerostomia is limited. Both stimulants and substitutes relieve symptoms to some extent. Salivary stimulants are probably only useful in people with some remaining detectable salivary function.
A systematic review compromising of 36
randomised controlled trials
A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical t ...
for the treatment of dry mouth found that there was no strong evidence to suggest that a specific
topical
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ...
therapy is effective.
This review also states that topical therapies can be expected to provide only short-term effects, which are reversible.
The review reported limited evidence that oxygenated glycerol triester spray was more effective than electrolyte sprays.
Sugar free
chewing gum
Chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of gum base, sweeteners, softeners/ plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. Its t ...
increases saliva production but there is no strong evidence that it improves symptoms.
Plus, there is no clear evidence to suggest whether chewing gum is more or less effective as a treatment.
There is a suggestion that intraoral devices and integrated mouthcare systems may be effective in reducing symptoms, but there was a lack of strong evidence.
A systematic review of the management of radiotherapy-induced xerostomia with parasympathomimetic drugs found that there was limited evidence to support the use of pilocarpine in the treatment of radiation-induced salivary gland dysfunction.
It was suggested that, barring any
contraindication
In medicine, a contraindication is a condition that serves as a reason not to take a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a reason to use a certain tre ...
s, a trial of the drug be offered in the above group (at a dose of five mg three times per day to minimize side effects).
Improvements can take up to twelve weeks.
However, pilocarpine is not always successful in improving xerostomia symptoms.
The review also concluded that there was little evidence to support the use of other parasympathomimetics in this group.
Another systematic review showed, that there is some low-quality evidence to suggest that amifostine prevents the feeling of dry mouth or reduce the risk of moderate to severe xerostomia in people receiving radiotherapy to the head and neck (with or without chemotherapy) in the short- (end of radiotherapy) to medium-term (three months postradiotherapy). But, it is less clear whether or not this effect is sustained to 12 months postradiotherapy.
A 2013 review looking at non-pharmacological interventions reported a lack of evidence to support the effects of electrostimulation devices, or acupuncture, on symptoms of dry mouth.
Epidemiology
Xerostomia is a very common symptom. A conservative estimate of prevalence is about 20% in the general population, with increased prevalences in females (up to 30%) and the elderly (up to 50%).
Estimates of the prevalence of persistent dry mouth vary between 10 and 50%.
History
Xerostomia has been used as a test to detect lies, which relied on emotional inhibition of salivary secretions to indicate possible incrimination.
See also
*
Xerosis
Xeroderma, xerosis or xerosis cutis, or simply dry skin, is a skin condition characterized by excessively dry skin.
The medical term ''xeroderma'', meaning "dry skin", derives from modern Latin, ''xero-'' 'dry' + Greek ''derma'' 'skin'.
In most ...
(dry skin)
References
External links
University of Illinois at ChicagoDrymouth Drymouth Drug Database
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Dermatologic terminology
Saliva
Symptoms and signs
Symptoms and signs: Digestive system and abdomen