Efficacy of Botulinum Toxin Type-A I in the Improvement of Mandibular Motion and Muscle Sensibility in Myofascial Pain TMD Subjects: A Randomized Controlled Trial

Ultrasound-Guided Botulinum Toxin-A Injections into the Masseter Muscle for Both Medical and Aesthetic Purposes

With the increasing use of Botulinum toxin type A (BoNT-A) injections in the masseter muscles for both medical and aesthetic purposes, there is a constant need to continually enhance the efficacy of these treatments and reduce the risk of potential adverse events. This review provides an in-depth analysis of the masseter muscle's anatomical structure and essential landmarks and emphasizes the advantages of ultrasound (US) guidance in improving the precision of BoNT-A injections compared to conventional blind methods. The review is supplemented with comprehensive figures, including graphics, clinical images, and ultrasound visuals, to support the discussion. Potential complications such as paradoxical bulging, inadvertent injections into the risorius muscle or parotid gland, facial paralysis, and the risk of bone resorption are examined. Future research should aim at refining injection techniques and assessing the long-term effects of repeated treatments to ensure optimal patient care and safety.

Versatility of OnabotulinumtoxinA in Aesthetic Medicine

BACKGROUND

OnabotulinumtoxinA is an injectable product that was introduced into medicine in the 1970s and has been the subject of thousands of clinical and nonclinical publications.

OBJECTIVE

To review the data related to the versatility of onabotulinumtoxinA in medical aesthetics.

METHODS

PubMed was searched to identify literature evaluating the effects of onabotulinumtoxinA, with preference given to randomized, placebo-controlled trials and safety meta-analyses.

RESULTS

OnabotulinumtoxinA is effective and safe across multiple facial indications, racial and ethnic groups, age groups, genders, and facial line severities. Patient-reported outcomes have been prioritized in aesthetic clinical trials and indicate high patient satisfaction and appearance-related psychological outcomes. Integrated safety meta-analysis and immunogenicity analyses have documented acceptable adverse event rates and low immunogenicity of onabotulinumtoxinA.

CONCLUSION

OnabotulinumtoxinA is a versatile aesthetic product supported by a strong literature base and positive physician and patient-reported outcomes that reflect a meaningful impact on patient's quality of life.

Effects of botulinum toxin type A in patients with painful temporomandibular joint disorders: a systematic review and meta-analysis

Objective

To assess the therapeutic efficacy of botulinum toxin type A (BTX-A) for managing myofascial pain related to temporomandibular disorders (TMDs).

Methods

This study was conducted according to the PRISMA 2020 statement guidelines. The PubMed, Embase, and Cochrane Library databases were searched. Only randomized controlled trials were included. The primary outcome was a pain score on the visual analog scale, and the secondary outcomes were maximum mouth opening and adverse effects. The Cochrane risk of bias tool was used to assess risk bias. A meta-analysis of studies with the same interventions, controls, assessment methods, and follow-up durations was performed.

Results

A total of 519 studies were retrieved, of which 20 randomized controlled trials were included in the qualitative analysis and six were included in the meta-analysis. The results showed that, compared with placebo, BTX-A injection was more effective at relieving myofascial pain, and its effect was similar to that of conventional methods. However, there was no difference in maximum mouth opening between the two groups. After the study assessment with the RoB 2.0 tool, six studies showed a low risk of bias, 13 studies showed some concerns regarding the reported results, and only one study showed a high risk of bias. Adverse effects of BTX-A injection were observed in four studies.

Conclusions

In conclusion, BTX-A is effective at relieving pain in TMD patients but does not improve mouth opening. To minimize adverse effects, we recommend a low dose of BTX-A for TMD patients who do not experience complete pain relief from conservative treatments.

Analysis of the Use of Sample Size and Effect Size Calculations in a Temporomandibular Disorders Randomised Controlled Trial-Short Narrative Review

BACKGROUND/OBJECTIVES

Temporomandibular disorder (TMD) is the term used to describe a pathology (dysfunction and pain) in the masticatory muscles and temporomandibular joint (TMJ). There is an apparent upward trend in the publication of dental research and a need to continually improve the quality of research. Therefore, this study was conducted to analyse the use of sample size and effect size calculations in a TMD randomised controlled trial.

METHODS

The period was restricted to the full 5 years, i.e., papers published in 2019, 2020, 2021, 2022, and 2023. The filter article type-"Randomized Controlled Trial" was used. The studies were graded on a two-level scale: 0-1. In the case of 1, sample size (SS) and effect size (ES) were calculated.

RESULTS

In the entire study sample, SS was used in 58% of studies, while ES was used in 15% of studies.

CONCLUSIONS

Quality should improve as research increases. One factor that influences quality is the level of statistics. SS and ES calculations provide a basis for understanding the results obtained by the authors. Access to formulas, online calculators and software facilitates these analyses. High-quality trials provide a solid foundation for medical progress, fostering the development of personalized therapies that provide more precise and effective treatment and increase patients' chances of recovery. Improving the quality of TMD research, and medical research in general, helps to increase public confidence in medical advances and raises the standard of patient care.

Botulinum Toxin Type A and Hyaluronic Acid Dermal Fillers in Dentistry: A Systematic Review of Clinical Application and Indications

Background

Botulinum toxin type A (BoNT-A) and hyaluronic acid (HA) dermal fillers are increasingly utilized in dentistry for therapeutic and aesthetic purposes. However, a comprehensive synthesis of their clinical applications and indications in dentistry is lacking. This systematic review aimed to analyze the clinical application and indications of BoNT-A and HA dermal fillers in dentistry, providing insights into their efficacy, safety profiles, and limitations.

Methods

A systematic search was conducted in PubMed/MEDLINE databases to identify relevant studies published between 2018 and 2024. Medical Subject Headings (MeSH) terms and keywords related to BoNT-A, HA dermal fillers, dentistry, clinical applications, and indications were used. Study selection criteria included randomized controlled trials (RCTs) and non-RCTs involving human participants of any age group. Data extraction and synthesis followed established guidelines, focusing on study characteristics, participant demographics, intervention details, outcome measures, and key findings related to BoNT-A and HA dermal fillers' clinical application in dentistry.

Results

Systematic searches across electronic databases and grey literature identified 857 records, with an additional 73 from hand searches. After screening titles and abstracts, 542 records were excluded, leaving 374 full-text publications for evaluation. Ultimately, 12 RCTs and 13 non-RCTs were included. The systematic review encompassed diverse geographic locations: Brazil, Italy, Spain, Syria, India, Egypt, Korea, and the Netherlands, involving samples sizes ranging from 14 to 143 participants. The review synthesized findings on HA's efficacy in various areas, including bone repair, gingivitis management, temporomandibular joint disorders, postoperative swelling reduction, periodontal defect treatment, chin and check projection and lips augmentation. BoNT-A exhibited promising efficacy in managing orofacial pain conditions, gummy smile treatment and neuromodulation of the lower third muscles. Safety profiles varied among studies, with some reporting minimal adverse effects while others noted dose-related concerns.

Conclusion

BoNT-A and HA dermal fillers offer a wide array of clinical applications in dentistry, ranging from therapeutic interventions to aesthetic enhancements. Despite promising efficacy, careful consideration and monitoring of safety outcomes are essential when integrating these interventions into clinical practice. Further research addressing methodological limitations and safety concerns is warranted to optimize their utilization and improve patient care in dentistry.

Effect of botulinum toxin type A on muscular temporomandibular disorder: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Botulinum toxin type A (BTX-A) is increasingly used to manage painful temporomandibular disorders (TMD). However, the effect of BTX-A on muscular TMD remains unclear.

OBJECTIVE

To assess the efficacy, safety and optimal dose of BTX-A for treating TMD.

METHODS

We conducted systematic literature searches in MEDLINE, Embase, Web of Science, ClinicalTrials.gov and Cochrane Library until March 2023. We extracted data from randomized controlled trials (RCTs) that evaluated the efficacy and safety of BTX-A in treating muscular TMD. We performed a meta-analysis using a random-effects model.

RESULTS

Fifteen RCTs involving 504 participants met the inclusion criteria. BTX-A was significantly more effective than placebo in reducing pain intensity, as measured on a 0-10 scale, at 1 month (MD [95% CI] = -1.92 [-2.87, -0.98], p < .0001) and 6 months (MD [95% CI] -2.08, [-3.19 to -0.98]; p = .0002). A higher dosage of BTX-A (60-100 U bilaterally) was associated with a greater reduction in pain at 6 months (MD [95% CI] = -2.98 [-3.52, -2.44]; p < .001). BTX-A also resulted in decreased masseter muscle intensity (μV) (MD [95% CI] = -44.43 [-71.33, -17.53]; p = .001) at 1 month and occlusal force (kg) at 3 months (MD [95% CI] = -30.29 [-48.22 to -12.37]; p = .0009). There was no significant difference in adverse events between BTX-A and placebo.

CONCLUSIONS

BTX-A is a safe and effective treatment for reducing pain and improving temporomandibular muscle and joint function in muscular TMD patients. A bilateral dose of 60-100 U might be an optimal choice for treating muscular TMD pain.

Influence of botulinum toxin A in pain perception and condyle-fossa relationship after the management of temporomandibular dysfunction: a randomized controlled clinical trial

OBJECTIVES

To investigate the pain perception (PP) and condyle-fossa relationship (CFR) after botulinum toxin A (BoNTA) injection in the masseter muscles of painful muscular temporomandibular dysfunction (TMD) patients.

MATERIALS AND METHODS

Fourteen women (aged 29.7 ± 5.4 years) diagnosed with myogenic TMD were randomized in the BoNTA-treated group (TG) and control group (CG). TG masseter muscles (n = 7) were bilaterally injected with 30 U. The CG (n = 7) were injected with saline injections. Condyle-fossa relationship (CFR) spaces were measured in sagittal (SP) and frontal planes (FP) of images of cone-beam computed tomography (CBCT) done before (T0) and after 30 days' interventions (T1). Visual analogue scale (VAS) measured the patients' TMD pain perception (PP). Data were compared by generalized linear models considering the results over time (α = .05).

RESULTS

There were no statistical differences in CFR in the SP or FP for TG and CG over time (p ˃ .05), except for frontal lateral space CFR (p < .05). In both groups, the condyle was positioned medially after interventions. Frontal lateral space increased in TG for both, left and right sides, over time (p < .05), as well as PP decreased over time (p < .05) for TG and CG.

CONCLUSIONS

The results depicted that there was no significant association with BoNTA injection in TMD masseter muscles in PP and CFR, except considering the frontal lateral space of CFR.

CLINICAL RELEVANCE

BoNTA injection in the masseter muscles may not promote clinically significant shifts in the condyle-fossa relationships of muscular TMD patients.

Anatomical Bases of the Temporal Muscle Trigger Points

Method

Temporal muscles of 14 adult cadavers were studied. The muscle bellies were divided into six areas, three superior (1.2 and 3) and three inferior areas (4, 5, and 6) lower, according to a Cartesian plane to analyze and describe the entry points of the branches of the deep temporal nerves into the muscle. The branching distribution was analyzed using Poisson log-linear tests with Bonferroni post hoc tests for comparison between groups (sextants) (p < 0.05).

Results

Deep temporal nerve entry points were found in the temporal muscle in all areas. Most of the branches were observed in areas 2 and 5, which coincide with the muscle fibers responsible for mandible elevation and related to the previously described MTPs. Fewer branches were found in areas 1 and 6, where contraction produces mandible retraction.

Conclusion

There is an anatomical correlation between the branching pattern of the deep temporal nerve and temporal muscle trigger points. Adequate knowledge of the innervation of the temporal muscle may help elucidate the pathophysiology of myofascial syndromes and provide a rational basis for interventional or conservative approaches and help surgeons avoid iatrogenic lesions to the deep temporal nerve lesion.

Pharmacological Treatments of Temporomandibular Disorders: A Systematic Review Including a Network Meta-Analysis

OBJECTIVE

Temporomandibular disorders (TMD) comprise a cluster of conditions with a wide range of etiological factors that causes pain and discomfort in the masticatory muscles (TMD-M) and temporomandibular joints (TMD-J). More than 50% of the patients with TMD report regular usage of drugs. However, there is still no consensus, nor is there any evidence-based support for clinicians when choosing between different drugs. Therefore, this systematic review, including a network meta-analysis (NMA), aimed to evaluate the scientific evidence and discuss the pharmacological treatment options available to treat painful TMD.

METHOD

An electronic search was undertaken to identify randomized controlled trials (RCTs) investigating pharmacological treatments for TMD-M and/or TMD-J, published until 6 April 2023. Since only 11 articles could be used for an NMA regarding TMD-M, a narrative synthesis was also performed for all 40 included RCTs. The quality of evidence was rated according to Cochrane's tool for assessing risk of bias, while the certainty of evidence was rated according to Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

When it comes to TMD-M, evidence arises for wet needling therapies with BTX-A, granisetron, and PRP as well as muscle relaxants. For TMD-J, evidence points toward pharmacological treatment approaches including non-steroidal antiinflammatory drugs (NSAIDs) and glucocorticosteriods (for inflammatory conditions) as well as hyaluronic acid and dextrose.

CONCLUSIONS

The evidence clearly indicates that the pharmacological treatment approaches differ between TMD-M and TMD-J. Therefore, it is of great importance to first try to uncover each patient's individual and multifactorial etiology and then employ a multifaceted treatment strategy, including pharmacological treatment approaches.

Effect of Botulinum Toxin on Masticatory Muscle Pain in Patients with Temporomandibular Disorders: A Randomized, Double-Blind, Placebo-Controlled Pilot Study

This study aimed to evaluate the efficacy of botulinum toxin type A (BoNT/A) in patients with temporomandibular disorders (TMDs) associated with masticatory muscle pain (MMP) and headaches. This randomized, double-blind, placebo-controlled pilot study is the first clinical trial to evaluate both disorders simultaneously. Twenty-one patients with myogenous TMD were randomly assigned to two groups. The experimental and control groups received injections of either BoNT/A or saline into the sites showing tenderness after palpation of a total of 16 muscle areas, including each masseter, a temporalis, splenius capitis, sternocleidomastoid, and trapezius muscle. During each visit, the clinical effects, based on the intensity of orofacial pain (OVAS), headache (HVAS), number of tender points (TPs), maximum mouth opening (MMO), and headache frequency (HF), were evaluated at four time points, namely, pre-injection and 4, 8, and 12 weeks after the injection, in both groups. Friedman and Mann-Whitney tests were used for the analyses. In the experimental group, the reductions in OVAS, TP, HVAS, and HF showed significant differences over time, excluding MMO, whereas there was no significant difference in any of the variables in the control group. In addition, the decline in TPs was significantly different between the experimental and control groups at all time points, especially after 4 and 12 weeks, compared to that during pre-injection. In conclusion, treatment with BoNT/A was relatively effective for masticatory muscle pain caused by TMDs and headache compared to the saline placebo.

Unilateral Hypofunction of the Masseter Leads to Molecular and 3D Morphometric Signs of Atrophy in Ipsilateral Agonist Masticatory Muscles in Adult Mice

Mice are commonly used to study mandibular dynamics due to their similarity in chewing cycle patterns with humans. Adult mice treated unilaterally with botulinum toxin type A (BoNTA) in the masseter exhibit atrophy of this muscle characterized by an increase in the gene expression of atrophy-related molecular markers, and a reduction in both muscle fiber diameter and muscle mass at 14d. However, the impact of this muscle imbalance on the non-treated masticatory muscles remains unexplored. Here, we hypothesize that the unilateral masseter hypofunction leads to molecular and 3D morphometric signs of atrophy of the masseter and its agonist masticatory muscles in adult mice. Twenty-three 8-week-old male BALB/c mice received a single injection of BoNTA in the right masseter, whereas the left masseter received the same volume of saline solution (control side). Animals were euthanized at 2d, 7d, and 14d, and the masticatory muscles were analyzed for mRNA expression. Five heads were harvested at 14d, fixed, stained with a contrast-enhanced agent, and scanned using X-ray microtomography. The three-dimensional morphometric parameters (the volume and thickness) from muscles in situ were obtained. Atrogin-1/MAFbx, MuRF-1, and Myogenin mRNA gene expression were significantly increased at 2 and 7d for both the masseter and temporalis from the BoNTA side. For medial pterygoid, increased mRNA gene expression was found at 7d for Atrogin-1/MAFbx and at 2d-7d for Myogenin. Both the volume and thickness of the masseter, temporalis, and medial pterygoid muscles from the BoNTA side were significantly reduced at 14d. In contrast, the lateral pterygoid from the BoNTA side showed a significant increase in volume at 14d. Therefore, the unilateral hypofunction of the masseter leads to molecular and morphological signs of atrophy in both the BoNTA-injected muscle and its agonistic non-injected masticatory muscles. The generalized effect on the mouse masticatory apparatus when one of its components is intervened suggests the need for more clinical studies to determine the safety of BoNTA usage in clinical dentistry.

Outcomes of IncobotulinumtoxinA Injection on Myalgia and Arthralgia in Patients Undergoing Temporomandibular Joint Arthroscopy: A Randomized Controlled Trial

BACKGROUND

Several studies have considered Botulinum Neurotoxin Type A injections effective in treating temporomandibular joint disorder (TMD) symptoms. A double-blind, randomized, controlled clinical trial investigated the benefit of complementary incobotulinumtoxinA (inco-BoNT/A) injections in the masticatory muscles of patients submitted to bilateral temporomandibular joint (TMJ) arthroscopy.

METHODS

Fifteen patients with TMD and an indication for bilateral TMJ arthroscopy were randomized into inco-BoNT/A (Xeomin, 100 U) or placebo groups (saline solution). Injections were carried out five days before TMJ arthroscopy. The primary outcome variable was a Visual Analogue Scale for TMJ arthralgia, and secondary outcomes were the myalgia degree, maximum mouth opening, and joint clicks. All outcome variables were assessed preoperatively (T0) and postoperatively (T1-week 5; T2-6-month follow-up).

RESULTS

At T1, the outcomes in the inco-BoNT/A group were improved, but not significantly more than in the placebo group. At T2, significant improvements in the TMJ arthralgia and myalgia scores were observed in the inco-BoNT/A group compared to the placebo. A higher number of postoperative reinterventions with further TMJ treatments were observed in the placebo group compared to inco-BoNT/A (63% vs. 14%).

CONCLUSIONS

In patients submitted to TMJ arthroscopy, statistically significant long-term differences were observed between the placebo and inco-BoNT/A groups.

Botulinum Toxin and Percutaneous Needle Electrolysis for the Treatment of Chronic Masticatory Myalgia

Botulinum toxin type A (BTA) is applied in muscle hyperactivity disorders and injected into affected muscles, producing deep and persistent muscle relaxation. Several multidisciplinary groups investigated the treatment of temporomandibular disorders for several years, and there is currently some data on the beneficial effects of BTA in specific cases of chronic masticatory myalgia. Percutaneous needle electrolysis (PNE), which applies a low-intensity galvanic current to promote tissue regeneration, has been shown to be effective in reducing pain and improving masticatory function. The purpose of this study was to investigate the efficacy and safety of BTA and to assess whether its application in patients with localized masticatory myalgia can significantly reduce pain and improve function compared to a group treated with PNE. Fifty-two patients with long-term refractory masticatory myalgia were randomly assigned to two groups. The BTA group (n = 26) received a bilateral botulinum toxin injection and the PNE group (n = 26) received percutaneous electrolysis. The dose of BTA injected was 100 units distributed among the main primary masticatory muscles, and PNE was administered at 0.5 mA/3 s/3 consecutive times in a single session. Patient assessments were performed prior to treatment and one, two, and three months after treatment. The results revealed good therapeutic response in both groups. In the long term, both BTA and PNE showed high efficacy and safety in reducing pain and improving muscle function for the treatment of chronic masticatory myalgia. This improvement was sustained over a three-month period in both groups. Therefore, the use of BTA and PNE could be considered a valid and safe therapeutic alternative among the available options to treat refractory and localized masticatory myalgia when a better therapeutic response is expected as it demonstrated high efficacy.

Diagnosis and Treatment of Myogenous Temporomandibular Disorders: A Clinical Update

Myogenous temporomandibular disorders (M-TMDs) are the most common chronic orofacial pain, affecting the masticatory muscles and, thus, jaw movement. While a concise diagnosis is crucial to formulate a rational treatment plan, the similarities in clinical presentations that M-TMDs share with other neuromuscular disorders affecting the temporomandibular joint (TMJ) could easily confuse physicians. In addition to the basics, such as thorough history taking and meticulous clinical examinations, different imaging techniques are useful adjuncts to facilitate the diagnostic process. This review presents an overview of the current understanding on a variety of diagnostic and treatment modalities for M-TMD patients. It is essential to highlight that there is not a single treatment for all, and the benefits of multidisciplinary strategies have been noted for the effective management of myogenous TMD pain. Treatment modalities ranging from conservative to minimally invasive options are discussed in this review.

Long-Term Effects of a Single Application of Botulinum Toxin Type A in Temporomandibular Myofascial Pain Patients: A Controlled Clinical Trial

This study assessed the long-term effects of botulinum toxin type A (BoNT-A) in subjective pain, pain sensibility, and muscle thickness in persistent myofascial temporomandibular-disorder pain (MFP-TMD) patients. Fourteen female subjects with persistent MFP received BoNT-A treatment with different doses (10U-25U for temporalis muscle and 30U-75U for masseter muscle). The treatment was injected bilaterally in the masseter and anterior temporalis muscles in a single session. Clinical measurements included: self-perceived pain (VAS), pain sensibility (PPT), and muscles thickness (ultrasonography). Follow-up occurred 1, 3, 6, and 72 months after treatment for VAS and PPT and 1, 3, and 72 months for ultrasonography. For statistical analysis, the Friedman test with the Bonferroni test for multiple comparisons as a post hoc test was used for non-parametric repeated measures comparisons among the evaluation times. A 5% probability level was considered significant in all tests. VAS values presented a significant decrease throughout the study (p < 0.05). Regarding PPT values, a significant increase was found when comparing baseline data with post-treatment follow-ups (p < 0.05), and even though a significant decrease was found in muscle thickness when baseline values were compared with the 1- and 3-months assessments, no differences were found when compared with the 72 months follow-up (p > 0.05). A single injection of BoNT-A presents long-term effects in reducing pain in persistent MFP-TMD patients, and a reversibility of adverse effects on masticatory-muscle thickness.

Effects of Botulinum Toxin Therapy on Health-Related Quality of Life Evaluated by the Oromandibular Dystonia Rating Scale

Oromandibular dystonia (OMD) refers to a focal dystonia in the stomatognathic system. Health-related quality of life (HRQoL) in isolated dystonia is associated with non-motor symptoms such as depression, anxiety, and pain, as well as motor symptoms. To evaluate HRQoL in patients with OMD, the therapeutic effects of botulinum neurotoxin (BoNT) therapy were assessed using a recently developed and validated comprehensive measurement tool called the Oromandibular Dystonia Rating Scale (OMDRS). Altogether, 408 patients (jaw closing dystonia, n = 223; tongue (lingual) dystonia, n = 86; jaw opening dystonia, n = 50; jaw deviation dystonia, n = 23; jaw protrusion dystonia, n = 13; and lip (labial) dystonia, n = 13) were evaluated at baseline and after the end of BoNT therapy or in a stable status. The total OMDRS score reduced significantly from 149.1 to 57.6 (p < 0.001). Mean improvement was 63.1%. All examiner-rated subscales (severity, disability, and pain) and patient-rated questionnaire scores (general, eating, speech, cosmetic, social/family life, sleep, annoyance, mood, and psychosocial function) were significantly lower at the endpoint than at baseline (p < 0.001). The BoNT injection had a highly positive impact on patient HRQoL, and the OMDRS could evaluate both motor phenomena and non-motor symptoms.