Find a Registered Dental Hygienist


Knowledge Network

FACT SHEET: Amyotrophic Lateral Sclerosis (also known as “ALS”, “Lou Gehrig’s disease”, “motor neuron disease”, and “upper and lower motor neuron disease)

Date of Publication: March 5, 2019

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • No.

Is medical consult advised?  

  • No, assuming patient/client is already under medical care for ALS and such management has been optimized for the stage of the disease.  
  • Yes, if motor neuron disease is newly suspected. 
  • Yes, if medical management is suspected to be suboptimal for the stage of the disease.
  • Yes, if the patient/client is receiving assisted ventilation (to determine if/how oral access can be safely obtained for procedures).

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • No, not typically, unless the patient/client displays signs/symptoms that may affect the appropriateness or safety of procedures, including potential exacerbation by procedures. For the patient/client whose condition is well controlled, there is no contraindication to procedures. As muscle weakness and control deteriorate, dental hygiene procedures and management techniques will need to be adapted.

Is medical consult advised? 

  • See above.

Is medical clearance required? 

  • No, unless the patient/client displays signs/symptoms that may affect the appropriateness or safety of procedures, including potential exacerbation by procedures. In particular, problems with swallowing, choking, and breathing should be assessed.

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • No, assuming the dental hygiene office can appropriately accommodate special needs of the patient/client with ALS
    (e.g., wheelchair in clinic room).
  • Yes, if patient/client displays sign/symptoms that may affect safety of procedures for which appropriate mitigation cannot be made.

Oral management implications

  • Although some persons with ALS develop mild forms of cognitive impairment, many others seen by the dental hygienist will have intact thinking and mental reasoning. Sensory (as opposed to muscular) abilities will also be intact.
  • As ALS progresses, activities of daily living for persons with the disease eventually require either additional time and/or help by others.
  • Changes in hand and arm function may make it difficult to hold a toothbrush and brush with it, hold floss and move it between teeth, and put dentures in and/or take them out. 
  • Changes in function of the mouth, lips, cheeks, and tongue may make it difficult to spit after brushing one’s teeth, swish or hold water/mouthwash in the mouth, and keep the inside of the mouth moistened.
  • Changes in mobility may make it difficult to perform oral care while sitting upright and to receive care in a regular dental clinic chair. Wheelchairs that recline or tilt may be more appropriate for dental hygiene examinations and cleanings instead of having to transfer the patient/client to the dental chair. 
  • Shorter appointment time and/or frequent breaks during a dental hygiene appointment are often indicated due to muscle weakness and spasticity.
  • When the patient/client has severe dysarthria (speech disorder), communication in the dental hygiene office can be aided by writing (if hand function is good), an alphabet board, or computerized communication aids. Eye movement is usually preserved, which can be useful in communication. Depending on the degree of difficulty in speaking, it may be appropriate to have a family member or caregiver come to the appointment to facilitate communication.
  • Because many patients/clients with ALS develop orthopnea (i.e., breathlessness when lying flat) as well as experience pooling of saliva in the oral cavity, the dental chair may have to be adjusted to a more upright position1
  • The dental hygienist should ensure appropriate adaptation for swallowing impairment in order to avoid choking or coughing by the patient/client. High volume evacuation (HVE) may be required to keep saliva from pooling and interfering with dental/dental hygiene work. 
  • A bite block and/or assistance with holding the mouth open may be required when bulbar (i.e., head, neck, and face) involvement is pronounced. 
  • While the soft palate may be weak, the gag reflex is usually preserved and may brisk. Gagging can be triggered during dental hygiene procedures, intraoral radiograph exposure, and medicament applications.
  • If not already in progress, the patient/client with ALS should be connected with an interdisciplinary ALS specialty clinic2. 
  • Dental hygiene education should involve and support the role of the family caregiver. 
  • Regular and conscientious oral hygiene is important for all patients/clients with ALS (including those receiving all nutrition and fluids via feeding tubes) to reduce harmful intra-oral bacteria production. Daily nighttime oral care is particularly important to reduce bacteria entering the upper airway during sleep, because persons with ALS are prone to respiratory tract infections. 
  • Tools that may help the patient/client with ALS include: toothpaste dispenser (e.g., pump or hands-free); oral irrigator; electric toothbrush; floss holder; tongue scraper; moisturizing oral rinse; moistening mouth swabs; portable suction device; and suction toothbrush. The patient/client may also benefit from evaluation by an occupational therapist, because assistive equipment plays a major role in the lives of persons with ALS. 
  • A portable suction device may be useful for some patients/clients to address drooling. In some ALS specialty centres, botulinum toxin injections into the parotid and submandibular glands or irradiation of the salivary glands may be offered to patients/clients with medically refractory sialorrhea. 
  • Thickened secretions may be addressed with expectorants (e.g., guaifenesin) or beta-adrenergic blocker3 medications. 
  • Xerostomia resulting from mouth breathing during sleep can be mitigated by adequate hydration and the use of a room humidifier.
  • Oral feeding may become a high-risk activity due to increased risk of aspiration, airway obstruction, and malnutrition. Therefore, the patient/client may require a percutaneous endoscopic gastrotomy (PEG) for tube feeding4.

Oral manifestations

  • In bulbar (i.e., brainstem involvement) ALS, which accounts for 30% of all cases (sporadic or familial types), the muscles of the head, face, and neck become paralyzed before muscles elsewhere in the body5.
  • Dysphagia and drooling are signs of upper motor neuron degeneration. They contribute to choking and aspiration of food and fluids. 
  • Dysphagia and chewing problems are caused by weakness of the lips, tongue, masseter muscles, soft palate, and esophagus. Oral, pharyngeal, and esophageal phases of swallowing may be individually or collectively affected. First signs/symptoms often include coughing on thin liquids and dry, crumbly foods. Dysphagia can lead to muscle spasms, dehydration, and malnutrition, as well as drooling. 
  • Drooling results from impaired control of the tongue and lips, as well impaired swallowing muscle function. Anterior pooling of secretions results in reduced triggering of swallowing to clear saliva. Poor lip seal results in leakage, producing the mistaken perception that there is excessive saliva production. Build-up of saliva and thick mucus can disrupt sleep and increase choking risk. 
  • Dysarthria is another manifestation of upper motor neuron degeneration. It is usually of the mixed flaccid-spastic type. Weakness, slowness, and ultimately paralysis of the muscles of the lips, tongue, soft palate, jaw, and larynx may occur. Hoarseness, slurring of speech (especially with fatigue), and a breathy voice are clinical features. Voice changes can also result from breathing changes. In severe cases, complete loss of intelligible speech occurs. 
  • Spasms of the jaw muscles cause pain. 
  • Xerostomia can result from mouth breathing, as well as from anticholinergic medications used to manage drooling6. It may also be caused by antidepressants7 sometimes used to manage emotional lability.

Related signs and symptoms

  • ALS is a progressive and almost universally fatal neuromuscular disease caused by degeneration and loss of upper and lower motor neurons in the brain and spinal cord9. This results in loss of motor function and paralysis of voluntary muscles. Over time, the patient/client living with ALS will lose the ability to walk, talk, eat, swallow, and, eventually, breathe. There is no known cure, and there is no definitive treatment10
  • Some ALS results from genetic predisposition, possibly in combination with environmental factors11. The most common type of the disease is classical sporadic ALS, which can affect anyone regardless of age, gender, or ethnicity, although persons between ages 40 and 70 years are affected most often, with a slight predilection for men. (Average age of diagnosis is 55 years.) The other type of ALS is familial ALS, which is inheritable (usually in an autosomal dominant fashion) and accounts for 5% to 10% of cases. 
  • About 3,000 Canadians currently live with ALS, with 2 to 3 persons dying daily. Lifetime risk is 1 in 1,000.
  • Signs/symptoms are usually first noticed focally in a limb, often involving muscle weakness. Less frequently, some patients/clients report numbness in an area of muscle weakness. Occasionally, some patients/clients may present with respiratory signs/symptoms, although these are not usually seen until later stages of disease progression. 
  • Signs of lower motor neuron degeneration occur in all patient/clients with ALS as the disease progresses. These include muscle weakness and atrophy (including the diaphragm), fasciculations (involuntary muscle contractions/twitching), muscle cramps, hyporeflexia, and flaccidity.
  • Signs of upper motor neuron degeneration occur in 85% of persons with ALS, principally hyperreflexia, spasticity, and a Babinski sign12. Other signs and symptoms are contractures, dyspnea, emotional lability (uncontrollable, often inappropriately timed crying or laughing)13, excessive fatigue, and weight loss. 
  • Lower or upper motor neuron signs may predominate in an individual patient/client and may even vary between regions in the same patient/client. For example, one limb may be flaccid and atrophied with hyporeflexia while the other is spastic with hyperreflexia. 
  • Gait disturbance is common with lower limb muscle involvement.
  • Rarely, a patient/client with ALS stops progressing and regains significant motor function, albeit usually only for a limited period of time. 
  • Dyspnea is a common symptom over the course of ALS, with respiratory muscle weakness usually occurring late in the disease14. Classical signs/symptoms include breathlessness on exertion (sometimes with just exertion of eating or speaking) and orthopnea. However, shortness of breath may also be experienced as anxiety, fatigue, claustrophobia and insomnia. Hypoventilation is worse during sleep, and it may be exacerbated by partial obstruction of the upper airway due to bulbar and laryngeal muscle weakness. Elevated levels of CO2 in the blood may cause headaches, nausea, sleepiness, and altered mental state, especially upon wakening15
  • Pain and discomfort arise as complications of stiffness, immobility, and muscle weakness and spasms. This includes neuropathic pain from entrapment or abnormal positioning (e.g., foot drop); some patients/clients experience burning, or pins and needles sensation, in their hands and feet. 
  • Mild forms of cognitive impairment (affecting executive function, insight, reasoning, social interaction, etc.) and behavioural changes (e.g., compulsive ritual-like behaviour) may occur in up to 50% of patients/clients with ALS. While frontotemporal dementia17 is sometimes a comorbid condition with ALS, advanced dementia is uncommon. 
  • Nutritional status is adversely affected by dysphagia, fatigue, and pulmonary involvement. Muscle wasting results in weight loss.
  • Hyperorality occurs in some patients with ALS, which includes cravings for carbohydrates, eating beyond the point of satiety, gaining weight (which may even be life threatening), and coughing and choking episodes during drinking and eating.
  • Constipation is common due to immobility, anticholinergic side effects of medications, and dietary challenges. 
  • Anxiety, depression, and gastroesophageal reflux disease (GERD) are common sequelae/co-morbidities with ALS.
  • Aspiration pneumonia can result from dysphagia. 
  • 80% of persons with ALS die within 2 to 5 years of diagnosis, with respiratory failure being the most common cause of death. 10% of patients/clients live more than 10 years. Palliation is part of the continuum of care from diagnosis onward.

References and sources of more detailed information

Date: July 12, 2018
Revised: March 25, 2023


1 Most patients/clients with ALS find a semi-recumbent (i.e., semi-supine) position to be most comfortable. This position allows the intercostal muscles and the diaphragm to work to their greatest mechanical advantage, and it is also more comfortable for swallowing.
2 There are several ALS specialty clinics in Ontario; namely, in Toronto (ALS Clinic, Sunnybrook Health Sciences Centre), Hamilton (ALS Clinic, McMaster University Medical Centre, Hamilton Health Sciences), London (Motor Neuron Disease Clinic, Dept. of Clinical Neurological Sciences, London Health Sciences Centre), Kingston (Neuromuscular Clinic, Providence Care, St. Mary’s of the Lake Hospital), Ottawa (The Ottawa Hospital’s Neuromuscular Clinic and OH’s Rehabilitation Centre), Mississauga (Trillium Health Partners, Credit Valley Hospital) and Thunder Bay (Outpatient Neurology Rehabilitation, St. Joseph’s Care Group). In addition to the family physician, the ALS healthcare team may comprise some or all of the following roles: neurologist, nurse (neuromuscular specialty), occupational therapist, physiotherapist, physiatrist, dietitian, gastroenterologist, speech-language pathologist, social worker, and palliative care physician.
3 Beta-blockers used in patients/clients with ALS include propranolol and metoprolol.
4 In some ALS centres, the feeding tube is inserted into the jejunum rather than the stomach – hence the term “J-tube”. Having a feeding tube does not preclude oral feeding additionally, as appropriate.
5 In bulbar ALS, the motor neurons in the corticobulbar area of the brainstem are the first to be affected. (In the majority of persons with ALS, the region of initial onset is limb rather than bulbar.) Survival time is less with bulbar initial onset (median 1 year) than with limb initial onset (median 2.4 years).
6 Such anticholinergic medications include glycopyrrolate, atropine, and scopolamine patches.
7 Antidepressant management may include tricyclic antidepressants (e.g., amitriptyline) or selective serotonin reuptake inhibitors
(e.g., fluoxetine). Valproate (an anticonvulsant) or lithium (a mood stabilizer) may also be used.
8 Other motor neuron disorders (including progressive muscular atrophy [PMA], primary lateral sclerosis [PLS], progressive bulbar atrophy, and Kennedy’s disease share some of the signs and symptoms of ALS.
9  Definitive diagnosis is made by a neurologist — ideally in conjunction with an ALS specialty clinic — on the basis of neurological and clinical investigations. While there is no specific laboratory test for ALS, various blood and urine studies, electromyography (EMG), nerve conduction study, swallowing study, muscle and/or nerve biopsy, and magnetic resonance imaging (MRI) may be employed. ALS is the most common form of motor neuron disease.
10 Two medications approved by Health Canada for treatment of ALS are riluzole (which inhibits release of glutamate and extends survival time by about 4 months) and edaravone (an antioxidant that may slow the nerve damage associated with worsening of ALS symptoms). A third medication, sodium phenylbutyrate/ursodoxicoltaurine (AMX0035), was approved with conditions by Health Canada in 2022. AMX0035, a histone deacetylase inhibitor, is believed to reduce endoplasmic reticulum stress that may contribute to motor neuron degeneration in ALS.
11 Other potential factors in the etiology of ALS include oxidative stress and free radicals; immunological factors; neurotrophic factors; altered protein and neurofilament metabolism; and glutamate excitotoxicity.
12 A Babinski sign is the upward movement of the big toe when the sole of the foot is firmly stroked. While this is a normal reflex in infants, it is abnormal in adults (in whom the toe should be down-going).
13 Emotional lability in patients/clients with ALS is thought to occur as a result of lost inhibition of the limbic motor neurons in the brain that control muscles involved in primitive vocalization. This is known as pseudobulbar affect, which is not a mood disorder but rather abnormal affective display.
14 Assisted ventilation may be appropriate for some patients/clients, including non-invasive intermittent ventilation (e.g., non-invasive positive pressure ventilation [NIPPV] or bi-level positive airway pressure therapy [BPAP] by mask) or intermittent mandatory ventilation (IMV).
15 In the setting of carbon dioxide retention, oxygen therapy (e.g., for hypoxemia with co-existing lung disease) may lead to hypercapnia (abnormally high levels of CO2 in the blood), coma, and even death. Therefore, oxygen should be used with caution.
16 Until relatively recently, it was generally believed that ALS does not affect cognitive functioning. Evolving research is elucidating ALS’s effects on cognition.
17 ALS and frontotemporal dementia (FTD) overlap in terms of common molecular pathology and anatomy.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.