Dental Treatment Considerations

Appointment Scheduling

Oral infections and/or stress of anticipating or undergoing dental treatment may precipitate or worsen myasthenic symptoms. Short-duration morning appointments may minimize fatigue and take advantage of the typically greater muscle strength experienced by most people with MG during the morning hours. Appointments are best scheduled approximately one to two hours following oral anticholinesterase (Mestinon) medication so as to benefit from maximum therapeutic effects and decrease the risk of myasthenic weakness or crisis.

Private Office or Hospital

A stable MG patient with limited or mild neuromuscular involvement you may be safely treated in the private dental office setting in most instances. However, if the patient suffers from frequent or significant exacerbations of the pharyngeal and/or respiratory tracts or from generalized weakness, he or she is most safely treated in a hospital dental clinic or other facility with emergency intubation and respiratory support capabilities.

Dentures

A patient’s ability to manage complete dentures may be compromised by the inability of the weak muscles to assist in retaining the lower denture and to maintain a peripheral seal for the upper denture. Over extended and over contoured maxillary dentures with thick flanges that impinge upon muscle and frenal attachments can lead to muscle fatigue and altered salivation. Improperly fitting dentures may exacerbate symptoms of difficulty in closing the mouth, tongue fatigue, a tight upper lip, dry mouth, impaired phonation, dysphagia, and masticatory problems.

Respiratory Collapse

If respiratory collapse occurs, an open airway and adequate respiratory exchange must be established. Dental staff should be trained in and prepared to do basic life support (CPR) until an ambulance arrives, when needed. Dental suction devices can be used to suction secretions and debris from the oropharynx to prevent aspiration and mechanical blockage of the airway. Manual retraction of the weakened tongue may prevent obstruction of the airway.

Oral Findings

• Tongue: Atrophy of the tongue (loss of muscle, replacement with fat) may result in a furrowed and flaccid clinical appearance. In severe cases, it can result in a triple longitudinal furrowing of the tongue.
• Mouth Drop: Lack of muscle strength in the lower jaw muscle, especially following a sustained chewing effort, may cause the mouth to hang open, unless the mandible (lower jaw) is held shut by hand.
• Chewing/Swallowing: Lack of strength of the muscles of chewing strength can inhibit proper eating of food.  Eating can be further inhibited by dysphagia (difficulty swallowing), when the tongue and other muscles used for swallowing are involved; also by aberrant passage of food or liquids from the nasopharynx into the nasal cavity, when the palate and pharynx muscles are affected. The consequences of this may include poor nutrition, dehydration and hypokalemia (reduced potassium levels).

Drug Interactions

Many common drugs used in dentistry may have potential complications for MG patients by exacerbating their muscle weakness or interfering with breathing. The following table may be of help to the myasthenic patient and the treating dentist. Please remember that this list cannot cover all potentially dangerous medications and one should consult with their treating physician if there are any questions.