Comparative Efficacy of Botulinum Toxin Type A Versus Antihomotoxic Therapy in the Treatment of Bruxism-Related Masticatory Muscle Hyperactivity: A Randomized Clinical Trial Using Electromyographic Measurements

BACKGROUND: Bruxism is currently defined, according to the international consensus of Lobbezoo and colleagues, as a repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or bracing or thrusting of the mandible. It is a motor behaviour-not a disorder in itself-that may act as a risk factor for orofacial pain, tooth wear, masticatory muscle hypertrophy and temporomandibular disorders in susceptible individuals. Pharmacological management is indicated only when such sequelae are present. Botulinum toxin type A (BTX-A) has emerged as a widely investigated option, while antihomotoxic bioregulatory medications (Traumeel and Spascupreel) have been proposed as a less invasive, nonparalytic alternative. OBJECTIVE: To compare the efficacy of BTX-A, antihomotoxic therapy and placebo (saline) in reducing masticatory muscle hyperactivity in patients with clinically manifest bruxism, using surface electromyography (EMG) and computerised occlusal analysis (T-Scan) as objective outcome measures. METHODS: Single-centre, 3-arm, assessor-blinded randomised clinical trial. Of 60 consecutively screened patients, 8 were excluded (5 declined participation; 3 did not meet eligibility criteria); 52 eligible adults with clinically diagnosed bruxism-related symptoms were randomised 1:1:1 to BTX-A (Bocouture, 40 U total, 20 U per side), antihomotoxic therapy (Traumeel 1.1 mL+Spascupreel 0.55 mL per side) or placebo (0.9% saline, equivalent volume), delivered by bilateral intramuscular injection into the masseter muscles. Allocation was generated by an independent biostatistician through a computer-based random number sequence in Epidat v4.2 and concealed in sequentially numbered sealed opaque envelopes. Forty-seven patients completed the 4-week follow-up and were analysed per-protocol (BTX-A n=16, antihomotoxic n=16, placebo n=15). The primary outcome was the change in surface EMG amplitude of the masseter muscles at rest and during maximum voluntary intercuspation at 2 and 4 weeks. RESULTS: BTX-A produced the largest and fastest reduction in masseter EMG amplitude, significantly greater than antihomotoxic therapy at 2 weeks ( P =0.011, Kruskal-Wallis H ; Dunn post hoc). The antihomotoxic group showed a slower but progressive reduction, approaching the BTX-A values by 4 weeks. The placebo showed no meaningful change. Patient-reported masticatory fatigue and tension-type headache decreased in the BTX-A group, paralleling the EMG findings, although the Fisher exact test did not reach significance given the sample size for categorical outcomes. CONCLUSIONS: In this short-term randomised trial, BTX-A produced the largest reduction in masticatory muscle hyperactivity as measured by EMG. Antihomotoxic therapy produced a biologically plausible, slower effect with an excellent safety profile and may represent a reasonable alternative for selected patients. Objective EMG monitoring supports an individualised therapeutic approach. Longer follow-up (3-6 mo) and larger multicentre trials are required.