Evaluation of the Efficacy of Low-Dose Botulinum Toxin Injection Into the Masseter Muscle for the Treatment of Nocturnal Bruxism: A Randomized Controlled Clinical Trial

Nocturnal bruxism (NB) is a disorder of maxillomandibular activity characterized by nonfunctional grinding and clenching of teeth while sleeping.

NB can cause teeth attrition, dental prostheses/implant failure, tooth sensitivity, pain in the teeth, jaw, masticatory muscle, and temporomandibular joint (TMJ), neck pains and headache, periodontal disease, oral or facial pain, and perhaps tooth loss. The diagnosis of nocturnal bruxism is based on complaints of tooth grinding or clenching, as well as one or more of the following signs: nonfunctional teeth attrition, sounds consistent with bruxism, and jaw muscle discomfort. Teeth wear and TMJ dysfunction can both be caused by bruxism. In some circumstances, delaying therapy might lead to luxation and degenerative arthritis of the temporomandibular joint.

For the treatment of bruxism, many treatment approaches such as occlusal splints and pharmacologic medications such as psychobehavioral therapy or L-dopa, and psychobehavioral therapy have been examined but is not enough evidence to define a standard of reference approach for SB treatment.

Botulinum toxin (Botox®) is an exotoxin generated by the bacteria Clostridium botulinum that causes muscle inactivity by blocking acetylcholine release from cholinergic nerve terminals into the neuromuscular junction. In the last two decades, several studies have been conducted to investigate the efficacy of botulinum toxin type A (BTXA) in reducing nocturnal bruxism, and the results have been promising. These studies have used different doses of botulinum toxin ranging from 20 mouse units (MU) and 25 MU to 30 MU in the masseter. Most of these studies did not take into account the relationship between the amount of botulinum toxin dose and alteration of the masseter muscle's size and the shape of the lower third of the face, where injection of more than 20 MU into the masseter muscle affects its size and is an effective treatment for masseter muscle hypertrophy for at least 9 months. To avoid the unwanted side effects of doses greater than 20 MU, the trial aimed to evaluate the effectiveness of injecting 10 MU of the Botulinum toxin into the masseter muscle in reducing the nocturnal bruxism.

The idea of the research will explain to all patients, and the information sheets will distribute to them, then their consent will obtain.