Botulinum toxin for the treatment of bruxism

Aims: Botulinum toxin, the most potent biological toxin, has been shown to be effective for a variety of disorders in several medical conditions, when used both therapeutically and cosmetically. In recent years, there has been a rising trend in the use of this pharmacological agent to control bruxing activity, despite its reported adverse effects. The aim of this review was to provide a brief overview to clarify the underlying essential ideas for the use of botulinum toxin in bruxism based on available scientific papers.

Methodology: An electronic literature search was performed to identify publications related to botulinum toxin and its use for bruxism in PubMed. Hand searching of relevant articles was also made to identify additional studies.

Results: Of the eleven identified studies, only two were randomized controlled trials, compared with the effectiveness of botulinum toxins on the reduction in the frequency of bruxism events and myofascial pain after injection. The authors of these studies concluded that botulinum toxin could be used as an effective treatment for reducing nocturnal bruxism and myofascial pain in patients with bruxism.

Conclusion: Evidence-based research was limited on this topic. More randomized controlled studies are needed to confirm that botulinum toxin is safe and reliable for routine clinical use in bruxism.     

Clinical investigation of botulinum toxin (prabotulinumtoxin A) for bruxism related to masseter muscle hypertrophy: A prospective study

This study aims to confirm the effectiveness and safety of a prabotulinumtoxin type A (praBTX-A) injection in patients with bruxism and masseter hypertrophy.The study included patients who ground or clenched their teeth while sleeping and had computed tomography (CT) scans that showed a maximum thickness of the masseter muscle of 15 mm or more. The praBTX-A was administered bilaterally into the masseter muscles; 15 U/side for group 1, 25 U/side for group 2, and 35 U/side for group 3. CT scans and bruxism questionnaires were conducted before and eight weeks after the injection.Thirty-seven patients were enrolled, but three dropped out due to loss of follow-up. After injection, masseter thickness decreased to 15.1 ± 2.0 mm for group 1, 14.3 ± 2.9 mm for group 2, and 13.4 ± 1.8 mm for group 3 (p = 0.043). Group 3 showed a statistically significant lower masseter thickness compared to group 1 (p = 0.039). Both subjective and objective frequencies of bruxism decreased for all groups, but there were no significant differences in either subjective (p = 0.396) or objective frequencies (p = 0.87) between the groups after the injection.The results of this study suggest that praBTX-A injection is a safe and effective treatment for bruxism and masseter hypertrophy. A dosage of 35 IU/side can effectively decrease masseter thickness and relieve bruxism symptoms. Even the minimum dosage of 15 IU/side can contribute to improvements in bruxism symptoms. This investigation provides valuable information for managing bruxism that is associated with hypertrophic masseter muscles.     

Efficacy of botulinum toxins on bruxism: an evidence-based review

The objective of this study was to assess the efficacy of botulinum toxins on bruxism. Electronic databases (PubMed, Embase and Science Citation Index), websites (Cochrane Central Register of Controlled Trials and ClinicalTrials.gov) and the literature database of SIGLE (System for Information on Grey Literature in Europe) were searched from January 1990 to April 2011 for randomised controlled trials or nonrandomised studies assessing the efficacy of botulinum toxins on bruxism. There was no language restriction. Through a predefined search strategy, we retrieved 28 studies from PubMed, 94 from Embase, 60 from the Science Citation Index, two ongoing clinical trials and two from the Cochrane Central Register of Controlled Trials. Of these, only four studies met our inclusion criteria and were finally included. Of the four included studies, two were randomised controlled trials and two were controlled before-and-after studies. These studies showed that botulinum toxin injections can reduce the frequency of bruxism events, decrease bruxism-induced pain levels and satisfy patients' self-assessment with regard to the effectiveness of botulinum toxins on bruxism. In comparison with oral splint, botulinum toxins are equally effective on bruxism. Furthermore, botulinum toxin injections at a dosage of <100 U are safe for otherwise healthy patients. Botulinum toxin injections are effective on bruxism and are safe to use. Therefore, they can be used clinically for otherwise healthy patients with bruxism.     

The medical management of masseteric hypertrophy with botulinum toxin

The authors present a series of cases of masseteric hypertrophy with associated muscular facial pain treated with botulinum toxin.     

Effect of botulinum toxin A on pain,bite force,and satisfaction of patients with bruxism: A randomized single-blind clinical trial comparing two protocols

PurposeThe current study aims to evaluate bite force, perception of orofacial pain, and treatment satisfaction of patients with bruxism using two protocols of botulinum toxin A (BTX-A) injections.Material and MethodsTwo groups of patients seeking bruxism treatment and presenting bilateral orofacial pain of muscle origin were randomly created according to BTX-A injection sites: masseter muscle only, bilaterally (3 points in each muscle, 10 U per point), and masseter and temporal muscles (3 points in each masseter muscle and 2 points in each temporal muscle, 10 U per point). The patients were evaluated preoperatively and longitudinally at 15, 90, 120, and 180 days by the use of visual analog scales for pain and treatment satisfaction and a gnathodynamometer for bite force recording.ResultsThe final sample included 10 participants in each group. Both groups presented mitigation of pain at 15, 90, 120, and 180 days in comparison with baseline; however, reduction in the posterior bite force was noted only at 15, 90, and 120 days. Quite high treatment satisfaction was reported from both groups at 15, 90, 120, and 180 days. No differences were observed between the groups in all evaluations and study periods.ConclusionIn general, considering pain relief, reduction in bite force, and treatment satisfaction, both protocols of BTX-A seem to be somewhat equally effective in the short-term management (up to 120 days) of bruxism.     

Focal dystonia of the lateral pterygoid muscles treated with botulinum toxin

Oromandibular dystonia (OD) is a movement disorder characterized by involuntary activity of the craniofacial muscles. The present study deals with dystonic activity in the lateral pterygoid muscles (LP) of two women causing mandibular overbite, tiredness in the face and chewing and speech difficulties in one (HN, 61 years). In the other (BS, 37 years) OD was characterized by irregular lateral and protrusive jaw movements with and without tooth contact and frequent bilateral headache.
By intra-oral approach and without attempt to distinguish between the two heads the activity of LP was assessed by quantitative electromyography (EMG). Concentric needle electrodes were used for diagnosis and follow-up, monopolar cannula electrodes for the EMG-guided injection of botulinum toxin (Botox^®, Allergan Inc., USA). In addition, activity in the temporal, masseter and digastric muscles was recorded with bipolar surface electrodes and mandibular movements were assessed graphically. Compared with reference values of postural activity, OD in both patients was associated with a marked increase in LP. Botox injections resulted in transient reduction of spontaneous and maximal activity, but it took two to three treatments with intervals of 3–4 months to obtain distinct subjective and clinical improvement. However, in HN followed for 18 months after breakthrough of treatment, the effect of the two latest injections lasted 8–9 months or three to four times longer than typical.
Using quantitative EMG to locate the abnormal activity and to guide injections, treatment of LP dystonia with botulinum toxin is effective and safe .     

Treatment of recurrent temporomandibular joint dislocation with intramuscular botulinum toxin injection

Recurrent dislocation of the mandibular condyle poses a difficult problem for affected patients. In the course of time, dislocations often become more frequent and more difficult to avoid. Even with good patient compliance, conservative treatment is often not sufficient. Operative procedures have also been described for the treatment of temporomandibular joint dislocation. However, these interventions are invasive, involving open arthrotomy with possible complications, and cannot safely guarantee a successful outcome. On the other hand, botulinum toxin injections into the lateral pterygoid muscles offer the option of a predictable and prolonged period without renewed dislocation. We present the results of this treatment carried out in 21 patients with recurrent temporomandibular joint dislocation. Four patients were treated following unsuccessful physical therapy and the use of occlusal splints. The remaining 17 patients were treated for a number of conditions resulting in dislocation, including some with senile dementia and mental impairment in whom compliance with conservative measures was poor or completely absent. Injections were given on a 3-month basis in order to have a sustained effect. Within the study period of 6 months to 3 years, only two of the 21 patients suffered further dislocation. There were no side effects recorded as a result of treatment.     

Treatment of iatrogenic submandibular sialocele with botulinum toxin. Case report

We report the case of a 40-year-old woman with a submandibular sialocele (diagnosed by ultrasonography and magnetic resonance sialography) after sialoadenectomy for sialolithiasis. Type A botulinum toxin was injected percutaneously under colour Doppler ultrasonographic guidance into the sialocele and the residual salivary gland. Five months later the submandibular swelling had gone, and we gave a second injection of botulinum toxin to block any residual secretory activity. There were no side effects. This is, as far as we know, the first published report of the use of botulinum toxin to treat an iatrogenic submandibular sialocele.     

Treatment of severe temporomandibular joint clicking with botulinum toxin in the lateral pterygoid muscle in two cases of anterior disc displacement

A novel treatment procedure is introduced for severe clicking of the temporomandibular joint (TMJ) associated with anterior disc displacement (ADD), using injections with botulinum toxin (BTX-A) in the lateral pterygoid muscle (LP). It has been suggested that ADD may be caused, precipitated, or maintained by LP activity, but the role of the LP in the dynamics of the TMJ clicking is uncertain. The case report includes 2 women, followed with clinical examinations, TMJ imaging, and electromyography (EMG), in whom local anesthetics in the LP could abolish the clicking for several days. BTX-A block of the LP (30 U Botox, given twice under EMG guidance with 6-month interval) temporarily reduced the action of the muscle, but the clicking was permanently eliminated and did not return during the observation period of 1 year, and a small but distinctive positional improvement in the disc-condyle relationship was obtained. However, the precise mechanisms behind the favourable treatment outcome are unclear.     

Uncommon foreign body reaction caused by botulinum toxin

Botulinum toxin is composed of 7 botulinum toxin antigenic subtypes. It is produced by Clostridium botulinum bacterial fermentation. Several botulinum toxin subtypes are under investigation for clinical use, but only botulinum toxin type A (BTX-A) is currently approved for cosmetic use because of its clinical safety profile and efficacy. The use of BTX-A in cosmetic facial procedures is a reliable way to enhance aesthetics in the face and is becoming commonplace in oral and maxillofacial surgery. This article reports an uncommon complication after Botox injection in the upper lip, for cosmetic reasons, originating a mass in the anterior region of the maxilla, which leads to failure in orthodontic treatment. Knowledge of the site anatomy, pharmacology, and dose of BTX-A before its use in cosmetic surgery should be strengthened.