Botulinum Toxin Injections for Reducing Bruxism or Teeth Grinding
Botulinum toxin type A injections can be used to reduce excessive tension of the masticatory muscles caused by bruxism — involuntary clenching or grinding of the teeth. The preparation is injected into specific masticatory muscles, most commonly the masseter muscle, to temporarily reduce excessive muscle activity and bite force.
Bruxism can occur both during sleep and while awake. It may be associated with jaw muscle fatigue and pain, morning headaches, discomfort in the temple area, tooth wear or sensitivity, and other signs of overloading.
Botulinum toxin does not treat the underlying cause of bruxism, but in some patients it may help reduce muscle activity and related symptoms. Recent systematic reviews indicate potential benefits in reducing muscle activity and pain; however, study methodologies vary, and the evidence is not yet sufficiently consistent to consider this method a universal treatment for all patients with bruxism.
What is bruxism?
Bruxism is repetitive activity of the masticatory muscles that may manifest as teeth clenching, grinding or jaw tightening. A distinction is made between sleep bruxism and awake bruxism.
Sometimes a person may not be aware that they grind their teeth, but possible signs include:
tension or fatigue in the jaw muscles, especially in the morning;
pain in the jaw or temple area;
recurrent headaches;
tooth wear, cracks or increased sensitivity;
visibly tense or enlarged masticatory muscles;
teeth grinding during sleep noticed by a partner.
These symptoms do not always indicate bruxism, so a consultation with a specialist is recommended before treatment.
How does botulinum toxin work in bruxism?
Botulinum toxin temporarily inhibits the transmission of nerve impulses to a specific muscle. When injected into an overactive masticatory muscle, it reduces the muscle’s contraction force.
As a result, it may help reduce:
excessive jaw tension;
the force of teeth clenching and grinding;
pain caused by overloading of the masticatory muscles;
discomfort associated with muscle tension.
Important: the aim of the procedure is not to completely paralyse the masticatory muscles. The doctor selects the dose and injection points individually in order to reduce excessive muscle activity while preserving normal chewing function as much as possible.
Studies have associated botulinum toxin type A injections with reduced bite force, muscle activity and, in some studies, pain. However, the treatment effect and its duration vary between patients.
When may botulinum toxin injections be suitable for bruxism?
The procedure may be considered when overactivity of the masticatory muscles caused by bruxism leads to significant symptoms and conservative methods have not provided sufficient improvement.
Botulinum toxin therapy may be one of the treatment options when there is:
pronounced masticatory muscle tension;
recurrent pain in the jaw or temple area;
pronounced teeth clenching or grinding;
signs of tooth overload or wear;
insufficient benefit from previously used treatment methods.
Suitability for the procedure is determined individually by the doctor, taking into account symptoms, masticatory muscle function, the condition of the teeth and jaw, general health and previous treatment.
How is the botulinum toxin injection procedure performed?
Before the procedure, the doctor asks about the patient’s symptoms, medical history and medications and assesses the activity of the masticatory muscles.
Botulinum toxin is injected with a fine needle into several precisely selected points. Injections are most commonly given into the masseter muscles, although in some cases treatment of other muscles involved in chewing may also be required after medical assessment.
The procedure is performed on an outpatient basis and usually takes approximately 20–30 minutes, depending on the treatment area and individual treatment plan.
When does the effect appear?
The effect of botulinum toxin is not immediate. A reduction in muscle activity may be noticed within the first few days, while the treatment effect continues to develop over the following weeks.
The effect of botulinum toxin on bite force and pain can be observed in the first few weeks, with a more pronounced effect around weeks 5–8. The effect may persist for several months, although its duration varies individually.
What should be observed after the procedure?
After botulinum toxin injections, patients can usually return to their daily activities shortly afterwards. Mild redness, tenderness, swelling or bruising may occur temporarily at the injection sites.
After the procedure, the doctor’s individual recommendations regarding physical activity, care of the injection area and other restrictions should be followed. If unusual or pronounced symptoms occur, the healthcare provider should be contacted.
Possible side effects
Botulinum toxin injections are generally well tolerated; however, side effects are possible.
These may include:
pain or tenderness at the injection site;
mild swelling, redness or bruising;
temporary reduction in chewing strength;
temporary muscle weakness;
changes in facial contour or smile asymmetry if neighbouring muscles are affected.
Temporary changes in the smile have also been observed in some cases. In very rare cases, the effects of botulinum toxin may spread beyond the injection area. If swallowing, speech or breathing difficulties occur after the procedure, urgent medical attention is required.
Contraindications and precautions
Before the procedure, the doctor should be informed about medical conditions, medications and previous botulinum toxin injections.
Botulinum toxin should not be administered in cases of known hypersensitivity to the ingredients of the preparation or infection at the intended injection site. Particular caution is required in patients with disorders of neuromuscular transmission and when taking certain medicines that affect neuromuscular transmission.
Botulinum toxin preparations are generally not recommended during pregnancy. During breastfeeding, suitability should also be assessed according to the information for the specific preparation.
What is important to know about botulinum toxin injections for bruxism?
Botulinum toxin reduces excessive activity of the masticatory muscles but does not eliminate all possible causes of bruxism. Therefore, treatment begins with a medical consultation and an individual assessment.
Depending on the patient’s situation, the treatment plan may also include:
consultation with a dentist or another specialist;
an individual night guard or protective splint;
assessment of sleep quality and possible sleep disorders;
reduction of stress and awake teeth-clenching habits;
other conservative treatment methods.
A night guard and botulinum toxin work in different ways. A night guard mainly helps protect the teeth and distribute bite forces, while botulinum toxin reduces excessive contraction force of the masticatory muscles. Therefore, in suitable cases these methods may be combined.
Recent reviews conclude that there is no single universally effective treatment for bruxism and that an individualised, combined treatment plan may be optimal.
