Dry Mouth Dry mouth is a subjective complaint and can also be a complain from a patient that has a normal salivary flow rate. Dry mouth becomes apparent when there is at least a 50% decrease in saliva production.

Anatomy Of The Salivary GlandsSaliva FunctionSaliva ComponentsDry Mouth SymptomsDry Mouth SignsAetiology Of Dry MouthRisk FactorsInvestigationsTreatment Of Dry Mouth

Salivary glands can be placed into 2 categories:

  1. Major – Parotid glands, submandibular glands, sublingual glands (see below)
  2. Minor – Buccal, labial, palatal (soft palate and lateral portions of hard palate), palatoglossal (fauces), lingual, von ebner’s (circumvallate papillae)

Parotid gland:

  • Innervated by glossopharyngeal nerve via the otic ganglion 
  • Serous saliva is secreted  
  • Parotid/stensens duct transports the saliva 
  • Secreted opposite upper 7 

Submandibular gland:

  • Innervated by facial nerve via submandibular ganglion 
  • Mixed saliva is secreted 
  • Submandibular duct transports the saliva 
  • Secreted at the sublingual caruncles 
  • Consist of a superficial and deep part  

Sublingual gland:

  • Innervated by facial nerve via submandibular ganglion 
  • Majority mucous saliva is secreted 
  • 10-12 ducts that open into the sublingual folds

SDCEP guidelines on treating Dry Mouth

Saliva has many key roles which is why a dry mouth can lead to so many problems. Below are some of the key roles of saliva:

  • Swallowing
  • Chewing
  • Speaking
  • Remineralisation
  • Antimicrobial properties
  • Water
  • Electrolytes
  • Mucous
  • Antimicrobial compounds
  • Epidermal growth factor
  • Enzymes
  • Antimicrobial enzymes
  • Difficulty chewing
  • Difficulty swallowing
  • Difficulty speaking
  • Difficulty wearing denture
  • Mucosal surfaces stick to each other
  • Sore mouth
  • Halitosis
  • Salivary gland enlargement
  • Mucosa sticks to dental mirror
  • Thick frothy saliva
  • Little saliva in floor of mouth
  • Lobulated tongue
  • Shiny mucosa
  • Plaque accumulation
  • Halitosis
  • Smooth surface caries
  • Traumatic ulceration
  • Poor denture retention
  • Evidence of candidiasis
  • Angular cheilitis
  • Thrush
  • Erythematous mucosa
  • Denture stomatitis

Note:

  • Symptom = subjective evidence of a disease 
  • Sign = An objective clinical finding 

Xerostomia Via @all_things_oral_medicine

Developmental Causes:

1. Salivary gland aplasia 

  • Congenital absence of salivary glands
  • May be some or all the glands
  • May be unilateral or bilateral

2. Salivary gland atresia

  • Congenital absence or narrowing of a duct
  • Causes distension (enlargement) of the gland followed by atrophy (waste away due to degeneration of cells)

Iatrogenic Causes:

  • Drug induced
  • Radiotherapy
  • Graft vs host disease

Systemic causes:

1. Endocrine

  • Diabetes mellitus (especially if poorly controlled causing high blood glucose)
  • Thyroid disease

2. Viral infections

  • HIV
  • Hepatitis C
  • EBV
  • CMV
  • Mumps

3. Autoimmune conditions

  • Rheumatoid arthritis
  • SLE (Lupus)
  • Progressive systemic sclerosis
  • Primary biliary cirrhosis
  • Mixed connective tissue disorder
  • Sjogren’s syndrome

Other causes:

  • Dehydration
  • Anxiety
  • Stress
  • Burning mouth syndrome 
  • Mouth breathing
  • Female
  • Age
  • Smoker
  • Alcohol
  • High stress life
  • Diabetes
  • Autoimmune conditions
  • Large quantity of medications

Sialometry:

Objective evidence of a reduced unstimulated salivary flow rate:

  • Measure for 15 minutes
  • Normal = 0.3 to 0.4 ml/min
  • Significantly reduced rate = <0.1 ml/min

Stimulated salivary flow rate can also be measured, it is of no diagnostic significance, but it is of therapeutic significance:

  • Measure for 15 min
  • Sugar free gum or SST (salivary stimulating tablets) can be used
  • No normal values to compare against but should be approximately 10x unstimulated salivary flow rate

Sialography:

Radiopaque dye can be used to assess salivary glands ducts for any obstruction or dilated ducts:

  • Introduce radiopaque (iodine-based dye) into duct system
  • Requires catheter insertion
  • Radiographs are taken before and after catheter is inserted
  • Radiographs are taken to determine the flow of the dye through the ducts
  • This enables the view of constricted or dilated duct and any obstructions

Scintigraphy:

Salivary scintigraphy can be used to assess salivary gland function:

  • The isotope 99m-Technetium is intravenously injected and is taken up by the salivary glands and then secreted in saliva.
  • Gamma rays are then detected by a camera which can be sued to determine the rate, uptake and the time of excretion in the mouth.
  • This test is especially useful for diagnosis of Sjogren’s syndrome

Schirmer Test:

Measurement of lacrimal flow to determine whether lacrimal glands produce enough tears to keep eyes moist:

  • Insertion of paper strip into lower eyelid
  • Measure for 5 min
  • Results over 5 minutes
  • Normal ≥ 15 mm
  • Mild 14 – 9 mm
  • Moderate 8 – 4 mm
  • Severe < 4 mm

Treatment can be in the form of stimulation or substitution

Stimulation 

  • Sugar free chewing gum
  • SST (salivary stimulating tablets)
  • Pilocarpine 
  • Systemic therapy

Substitution

  • Carboxymethyl cellulose based – Glandosane
  • Biotene oral balance (gel)
  • Bioxtra (gel)
  • Saliva orthana (contains pork)
  • Xerotin (no animal ingredients)

Prevention 

  • Dietary advice
  • Fluoride
  • Mouthwash
  • Prescribe 2800 ppm fluoride toothpaste
  • Fluoride varnish
  • Improve/maintain OH

Other Important Conditions

Pleomorphic AdenomaSialosisSalivary Calculi (sialoliths)SialadenitisSjogren SyndromeReferences
  • This is a benign salivary gland tumour
  • It is most commonly found in the parotid gland (75% of cases) but can occur in other intramural salivary glands
  • Mainly occur in superficial lobe of parotid
  • It is slowly growing and painless with the cause being unknown.

Symptoms include:

  • Dysphagia
  • Hoarseness
  • Difficulty chewing

Diagnosed commonly through biopsy and the treatment is complete excision.

Complication of surgery include:

  • Facial nerve damage
  • Frey’s syndrome
  • Salivary fistula

Non-inflammatory, non-neoplastic swelling of the salivary glands, mainly affecting the parotid glands.

It appears as painless, bilateral enlargement of the parotid glands.

Causes:

  • Alcohol abuse
  • Cirrhosis
  • Diabetes
  • Anorexia/bulimia

Diagnosis is done through assessment of patient history and clinical findings.

Treatment focuses on treating the underlying cause (such as those mentioned above)

  • Salivary stones are formed through deposition of calcium salts around an organic nidus
  • Successive deposition of organic and inorganic material would produce calculus
  • Commonly affects the submandibular gland
  • Symptoms include pain, sudden enlargement (especially at mealtimes).

Sialadentis is an inflammation of the salivary glands and have numerous causes.

Viral Siladenitis

  • Mumps is an acute contagious infection caused by a paramyxovirus.
  • Spread is by direct contact with infected saliva. Highly infectious.
  • There is a 2-3-week incubation period
  • Symptoms include fever, malaise, and sudden, painful swelling of one or both parotid glands
  • Conservative management is advised, and the virus remains in saliva for approximately 6 weeks

Acute Bacterial Sialadenitis

  • Usually affects the parotid gland and is caused by bacteria entering the ductal system against the salivary flow
  • Streptococcus pyogenes amongst other oral bacteria may be detected in mucopurulent discharge from the duct opening, an important clinical sign
  • A reduced salivary flow increases the risk
  • Symptoms include swelling, pain, fever, and erythema of the overlying skin.

Chronic Bacterial Sialadenitis

  • Related to bacterial invasion through the ductal system and often follows chronic obstructive disease
  • The submandibular salivary gland is most commonly affected.
  • The duct orifice appears inflamed and mucopurulent discharge may be seen on examination.
  • Symptoms include painful swelling associated with eating or drinking, salty or foul taste in the mouth

Radiation Sialadenitis

  • Radiotherapy can lead to fibrous replacement of the damaged acinar cells, serous being more sensitive than mucous and can lead to post irradiation enlargement.

This is classified as an autoimmune condition where the body attacks it’s own cells commonly leading to dry eyes and dry mouth. It is often accompanied with other immune disorders such as rheumatoid arthritis, SLE, scleraderma, polymyositis.

Classification


Primary Sjogren’s syndrome: If Sjogren’s Syndrome occurs on its own without an autoimmune disease: then its classed as Primary Sjogren’s syndrome.

Secondary Sjogren’s syndrome If you already have an existing autoimmune disease and then you are diagnosed with Sjogren’s syndrome its classed as Secondary Sjogren’s syndrome

Both secondary and primary Sjogren’s syndrome lead to dry eyes and dry mouth.

Diagnosis

Histo-pathology

  • Labial gland biopsy – biopsy is taken to determine whether the gland is inflamed.

Oral investigations

  • Sialometry 
  • Sialography
  • Scintigraphy 

Ocular investigations

  • Schirmer test 
  • Rose Bengal dye

Auto-antibodies

  • Antibodies against ENA (extractable nuclear antigen)
  • Anti-SSA antibodies and/or anti-SSB antibodies

Treatment

Treatment focuses on the treatment of the dry mouth as opposed to the condition itself.

Dental Updates: Oral Medicine: 4. Dry Mouth and Disorders of Salivation –https://www.dental-update.co.uk/issuesSingleIssueArticle.asp?aKey=1091

Scully, C. (1999). Handbook of oral disease. London: Martin Dunitz.

Jordan, R. and Lewis, M. (2004). A color handbook of oral medicine. New York: Thieme.

See our Fungal Infections.