Bruxism Treatment with Botox Masseter Injection

Bruxism is involuntary teeth grinding and clenching, classified as awake bruxism (associated with stress, anxiety) and sleep bruxism (a sleep-related movement disorder). Bruxism causes tooth wear, fractures, fillings and crown failures, masseter and temporalis hypertrophy, headache (especially temple), jaw pain, TMJ dysfunction, and sleep disturbance for the partner. Conservative management includes occlusal splints (night guards), cognitive behavioral therapy, stress management, sleep hygiene, and pharmacotherapy.

Botulinum toxin injection into the masseter muscle reduces muscle hyperactivity and is an effective adjunctive therapy for refractory bruxism, masseter hypertrophy with bony face, and TMJ dysfunction. Onabotulinumtoxin A (Botox), abobotulinumtoxin A (Dysport), and incobotulinumtoxin A (Xeomin) are used. Doses vary: typical Botox 25-30 units per masseter (3-4 injection sites), Dysport 60-90 units per masseter, repeated every 3-6 months.

Procedure technique includes palpation of masseter during clenching to identify muscle bulk, injection in the safety zone (avoiding parotid duct, facial artery, marginal mandibular branch of facial nerve), distribution across multiple sites within the muscle, and bilateral treatment for symmetric effect. Onset of effect within 1-2 weeks, peak effect at 4-6 weeks, duration 3-6 months. Side effects include transient chewing weakness, headache (rare), bruising, asymmetric smile if facial nerve affected (avoid in superficial injections), and rare allergic reactions.