Efficacy of botulinum toxin type A in bruxism management: A systematic review

Botulinum toxin type A (BTX-A) injections have emerged as a promising alternative for the management of bruxism. In this context, a systematic review of randomized controlled trials on the impact of BTX-A on patients with bruxism was conducted. A literature search of multiple online electronic databases (PubMed®, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials (CENTRAL)) was undertaken from their inception to February 1, 2024. The Medical Subject Headings (MeSH) included "Botulinum Toxins", "Botulinum Toxins, Type A", "Bruxism", and "Sleep Bruxism", which were combined with the Boolean operators "AND" and "OR". The methodological quality of each included study was assessed using the Joanna Briggs Institute (JBI) critical appraisal tool. Reducing muscle pain and activity were assessed as primary outcomes, while the quality of sleep was considered as a secondary outcome. Twelve articles met the inclusion criteria. The risk of bias was low in 10 studies and moderate in 2. Bilateral injections of BTX-A into the masseter, temporalis and medial pterygoid muscles were compared to saline injections, the use of occlusal splints and conventional treatment. Of the 12 studies, 6 reported a reduction in muscle activity recorded by rhythmic masticatory muscle activity (RMMA) and electromyography (EMG) after the administration of BTX-A. In addition, 3 studies indicated that the intensity of muscle pain, measured using the visual analogue scale (VAS), decreased significantly in individuals with bruxism who received BTX-A. Finally, 1 study highlighted improved sleep quality in patients with bruxism who were rehabilitated with a single-arch implant overdenture and received either BTX-A or occlusal appliances. Botulinum toxin type A can effectively reduce symptoms of bruxism. However, the included studies exhibited heterogeneity and methodological differences. Long-term follow-up studies with large sample sizes and the incorporation of repeated injections are necessary to further validate the findings.