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FACT SHEET: Bell’s Palsy (also known as “BP”, “acute peripheral facial palsy of unknown cause”, and “idiopathic facial nerve paralysis”)

Date of Publication: September 11, 2014
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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 Bell’s palsy; if not, then consult is advised to ensure appropriate diagnosis and management1). Also, sudden weakness on one side of the face should be checked by a physician to rule out stroke or transient ischemic attack — TIA.)

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

  • No.

Is medical consult advised? 

  • No; see above. 

Is medical clearance required? 

  • No.

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • No, not typically, unless facial palsy significantly complicates procedures. 

Oral management implications

  • The patient/client who is experiencing an episode of BP may benefit from the dental hygiene visit being broken up into multiple visits, depending on tolerance level and recommended treatment. Protective eyewear is of extra importance, because the patient/client’s eyelids may not close on the affected side of the face.
  • Dental hygienists can help by being understanding and supportive. Patients/clients with Bell’s palsy may not be able to tolerate their normal oral hygiene routines and adjuncts. For example, they may have impaired ability to clean interdentally and/or be unable to properly rinse with mouthwash.
  • Adaptations for impaired oral musculature may be required in the context of dental hygiene self-care. Options such as water-powered devices, electric toothbrushes, interdental brushes, and long-handled flossing devices may be beneficial.
  • Oral self-care instructions should include establishment of a brushing pattern to help the patient/client with altered oral muscle control and sensation from missing areas. Eating soft, smooth foods, such as yogurt, may help decrease swallowing problems, as will eating slowly and chewing food well. 
  • Xerostomia and angular cheilitis, should be managed, as applicable.
  • Facial exercises (e.g., tightening and relaxing the facial muscles) may aid in recovery. Formal physical therapy may be indicated for some patients/clients to help massage, stretch, and elongate the affected muscles. 
  • Accommodation may need to be made for wearing of oral prostheses, including dentures.

Oral manifestations

  • Signs/symptoms include twitching, weakness, or paralysis on one or rarely both sides of the face, include drooping of the corner of the mouth and flattening of the nasolabial fold. Most often these signs/symptoms begin suddenly and reach their peak within 48 to 72 hours, leading to significant facial distortion. Other oral signs/symptoms include drooling, xerostomia due to salivary gland dysfunction, and taste impairment.  
  • Patients/clients typically have difficulty puffing out their cheeks and pursing their lips.
  • Facial and dental neuralgia, temporomandibular joint pain, masticatory muscle pain, loss of taste (in the anterior two-thirds of the tongue), impaired speech, and difficulty eating or drinking occur.
  • Chewing ability is often impaired, and this may lead to oral trauma (such as cheek biting), as well as to increased debris on the affected side of the mouth.2 Glossitis and candidiasis may be present.
  • Angular cheilitis may result from drooling and loss of muscle tone.

Related signs and symptoms

  • Bell’s palsy is a form of usually temporary and unilateral facial neuropathy resulting from inflammation/ischemia/damage affecting the seventh cranial nerve (i.e., facial nerve). Diagnosis is based on exclusion; other potential specific etiologies of facial paralysis and paresis should be excluded before diagnosing BP.3 In addition to facial muscles, facial nerve innervation involves tears, saliva, taste, and a bone in the middle ear.
  • Although the specific reason(s) Bell’s palsy occurs isn’t clear, a history of a recent viral syndrome and/or upper respiratory tract infection is common. Viruses and viral conditions that have been linked to Bell’s palsy include: the common cold sore virus (Herpes simplex); chickenpox and shingles (Herpes zoster); mononucleosis (Epstein-Barr virus); cytomegalovirus; adenovirus; rubella; mumps; influenza (especially influenza B); and hand-foot-and-mouth disease (coxsackie virus). Regardless of underlying cause, the facial nerve swells and becomes inflamed, causing pressure within the Fallopian canal of the skull. Facial palsy may be associated with headaches, chronic middle ear infection, high blood pressure, diabetes, sarcoidosis, radiation exposure, Lyme disease, and certain vaccines. 
  • BP is the most common cranial mononeuropathy. About 1 in 60 persons will experience an episode during their life. Males and females are affected equally. While Bell’s palsy can occur at any age, it is less common before age 15 years or after age 60. It disproportionally afflicts persons who have diabetes or upper respiratory tract infections, or who are pregnant (especially during the third trimester and during the peripartum period). Bilateral BP is rare (o.3% to 1% of cases), and the recurrence rate of PB in general is about 7%.
  • The onset of BP is usually sudden and worsens over minutes to hours.
  • Loss of forehead wrinkling and inability to raise ipsilateral eyebrow are common.
  • Drooping of the eyelid and dryness of the eye on the affected side are frequent. There may also be excessive tearing in one eye. The corneal reflex may be reduced on the affected side. The most pathognomonic sign of BP is Bell’s phenomenon, characterized by upward rolling of the eye when attempting to close the eyelid.
  • Ringing in one or both ears, hypersensitivity to sound, post-auricular (behind the ear) pain, headache, and dizziness may occur.
  • A feeling of facial numbness on the affected side is a common complaint, but facial sensation is preserved.
  • For patients/clients with incomplete recovery, long-term complications have physiological, esthetic, and psychological implications. Complications include misdirected regrowth of nerve fibers, resulting in involuntary contraction of certain muscles while trying to move others (“synkinesis”); e.g., eye closing when smiling attempted or lacrimation with eating (“crocodile tears”).

References and sources of more detailed information


Date: August 26, 2014
Revised: September 25, 2019; June 16, 2024


FOOTNOTES

1 Most cases of Bell’s palsy improve or resolve spontaneously within 3 weeks. Even without treatment, 70% of affected persons will have complete resolution within 6 to 9 months, while about 30% will experience partial recovery. However, treatment can reduce cases of incomplete recovery. Treatment of BP may involve oral corticosteroids (such as prednisone), antiviral drugs, and lubricating eye-drops.
2 Food can become trapped in the vestibule of the cheek due to impairment of the buccinator muscle that normally promotes movement of food onto the occlusal plane.
3 For example, trauma such as skull fracture or facial injury can cause facial nerve injury, as can tumours.


* 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.