The purpose of this paper is to describe the application of the botulinum toxin in diseases of the temporomandibular system of a muscular type such as masticatory hypertrophy, spasm, bruxism, and tension headaches of idiopathic etiology. The masticatory system is a complex apparatus with great adaptive capacity. Still, when that capacity is exceeded, functional disorders occur followed by a series of symptoms that depend on individual, local, and systemic etiological factors. Occlusal trauma exceeding the physiological limits of the teeth, periodontium, and TMJ leads to a series of functional disorders. Temporomandibular dysfunctions (TMD) are used to describe a large, heterogeneous group of diseases of the temporomandibular joint (TMJ) and its adjacent tissues and organs. Botulinum toxin type A, hemagglutinin complex with 500 IU (DISPORT Ipsen Biopharm, UK) was used for the therapy of muscle disorders like bruxism or night teeth clenching in female patient 26 years old. Depending on the dose that was applied to the targeted muscle, a complete or partial reduction in contraction occurs with reduced function and weakening of the muscle. Two weeks after applying the neuromodulator, the patient reported a reduction in pain and episodes of teeth grinding and clenching. Bilateral hypotrophy of left and right masseter muscles was noticeable after 2 months. We concluded that botulinum toxin could be used as an effective treatment for reducing nocturnal bruxism and myofascial pain in patients with bruxism.