Cerebral palsy and bruxism: Effects of botulinum toxin injections-A randomized controlled trial

Systematic review of the histological and functional effects of botulinum toxin A on masticatory muscles: Consideration in dentofacial orthopedics and orthognathic surgery

INTRODUCTION

Botulinum toxin type A causes muscle paralysis and is widely used in the masticatory muscle for stomatognathic diseases, such as temporomandibular disorder, bruxism, or masseteric hypertrophy. Nonetheless, its muscular effect remains unclear. Better understanding could aid improved use and perhaps new indications, particularly in dentofacial orthopaedics and orthognathic surgery.

METHODS

This systematic review explored the histologic and functional effects of botulinum toxin in animal and human masticatory muscles and was conducted in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The MEDLINE, Web of Science, and Cochrane Library electronic databases were searched for relevant articles. The inclusion criteria were human or animal masticatory muscle analysis after botulinum toxin injection(s) AND histological structural/ultrastructural analysis by optical or electronic microscopy OR functional effect analysis by bite force evaluation (occlusal force analyzer) and muscle activity (electromyography).

RESULTS

Of an initial 1578 articles, 44 studies were eventually included. Botulinum toxin injection in the masticatory muscle altered its histological structure and functional properties. The human and animal studies revealed ultrastructural change, atrophy, and fiber type modifications of the masticatory muscles after one injection. Botulinum toxin decreased bite force and muscle activity, but recovery was uncertain.

CONCLUSIONS

Muscle forces applied on the skeleton is a key feature of facial growth. Masticatory muscle paralysis changes mechanical stress on bones, which rebalances the force applied on facial bones. This new balance could benefit dental deformity or surgical relapse. Therefore, botulinum toxin could limit the orthognathic effect of the masticatory muscles in such patients. Given the uncertain recovery, multiple injections should be avoided, and usage should not deviate from established consensus.

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 in the rehabilitation of painful syndromes: multiperspective literature analysis, lexical analysis and systematic review of randomized controlled trials

Pain represents a common symptom of several diseases and is often associated with a reduction in rehabilitation outcomes and recovery. The effectiveness of pain alleviation by botulinum toxin has been recently demonstrated. We searched in PubMed the papers about this topic published in the last ten years, and we selected clinical trials, guidelines, meta-analyses, reviews, and systematic reviews. We used different approaches: multiperspective presentation, lexical evaluation, and systematic review. The systematic review was only performed for the randomized controlled trials. We predominantly found reviews and trials about the rehabilitation of stroke/brain injury and epicondylitis. The most common outcome measures were pain, function, and spasticity. Among the common words, pain was the most frequent and the terms were grouped into different families, especially concerning the outcomes. Rehabilitation showed a relatively low frequency. Finally, the systematic review showed moderate-low levels of bias which confirms the effectiveness of botulinum toxin for pain treatment. The current literature about botulinum toxin is wide and globally diffuse but with some limitations in study strategies and clearness in the formal presentation. The evidence justifies the use of botulinum toxin in treating pain in different diseases.

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.

Abnormal Activity of Masticatory Muscles in Patients with Diagnosis of Cerebral Palsy. A Systematic Review and Meta-Analysis of Observational Studies

AIMS

to map and synthesize the results from studies that assessed whether individuals diagnosed with cerebral palsy (CP) have abnormal masseter and temporal muscles activation during the masticatory cycle.

METHODS

Six databases were searched for comparative observational studies assessing masticatory muscles activation in individuals with CP through electromyography analysis. Methodological quality was evaluated using the Joanna Briggs Critical Appraisal Checklist. Outcome data were combined in meta-analysis using the Review Manager software.

RESULTS

We included five cross-sectional studies with an overall low risk of bias. Meta-analyses showed no difference between CP and healthy individuals regarding maximum voluntary isometric contraction: right masseter (Standard mean difference [SMD] - 0.95; 95% CI -2.03 to 0.13); left masseter (SMD -0.92; 95% CI -1.93 to 0.09); right temporal (SMD -0.72; 95% CI -1.63 to 0.18); and left temporal (SMD -0.68; 95% CI -1.76 to 0.40). Electrical activity amplitude in the inactive period was superior in the CP group, and maximum bite pressure presented higher values in the control group (Mean difference [MD] - 17.38; CI 95% -26.62 to -10.15).

CONCLUSIONS

Based on observational studies with a lower level of evidence, individuals with CP seem to present difficulties activating masticatory muscles. Future prospective cohort studies with rigorous methodology are still necessary to support these findings. PROSPERO register CRD42020208444.

Effectiveness of Botulinum Toxin Injection on Bruxism: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

The present study compiled evidence on the efficacy of botulinum toxin A (BTX) for management of bruxism.

METHODS

A literature review that included randomized control, cohort, as well as observational studies published between January 2000 and November 2022 was conducted. All studies related to BTX injections administered into the masseters of patients with bruxism were included. Primary outcomes were measured by performing a meta-analysis of changes in maximal biting forces and pain severity and meta-regression of the effects of the BTX dose.

RESULTS

Ten studies were included for quantitative analysis. The analysis of the maximal biting force after BTX injections demonstrated a significant reduction at 1 month or less compared with both oral splints (P < 0.000001) and saline injections (P = 0.01). BTX continued to outperform oral splinting (P = 0.001) and saline placebos (P = 0.03) at 3 months. Between 3 and 6 months, a significantly higher maximal biting strength was observed in the BTX group than the oral splinting group (P < 0.00001). No significant differences in the maximal biting force were observed between the BTX and saline placebo groups (P = 0.50). A similar trend was observed in the analysis of pain reduction after botulinum treatment. Additionally, for every unit increase in the BTX dose, pain severity decreased by 0.0831 points (P = 0.0011).

CONCLUSION

BTX is effective in reducing biting strength and pain severity. BTX effects are evident at less than 4 weeks, peak between 5 and 8 weeks, and last for up to 24 weeks. Higher BTX doses result in greater improvement in pain. Although BTX benefits manifest earlier, they gradually diminish, and oral splinting exerts a more enduring effect, especially after 9-12 weeks. BTX injections into masseters are recommended as management options for bruxers, especially for those having difficulties complying with wearing oral splints or those seeking earlier symptom relief. However, future studies should determine BTX effects beyond 24 weeks and after repetitive injections and how bruxers of different ages or genders respond to treatment.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Adverse events after different forms of botulinum neurotoxin A injections in children with cerebral palsy: An 8-year retrospective study

AIM

To compare the risks of adverse events 3 months after Onabotulinumtoxin-A and Lanbotulinumtoxin-A injections in children with cerebral palsy (CP) and to identify risk factors and associations.

METHOD

A total of 1037 children (682 males, 355 females; mean age 5 years 2 months [SD 3 years]; age range 2 years-17 years 10 months) with CP underwent 1013 Onabotulinumtoxin-A injections and 418 Lanbotulinumtoxin-A injections from 2012 to 2021. Information was recorded in a purpose-built database.

RESULTS

The adverse event rates of Onabotulinumtoxin-A and Lanbotulinumtoxin-A were reported as 13.92% and 11.96% respectively. Most adverse events were mild and self-limiting. Children in Gross Motor Function Classification System (GMFCS) levels IV to V had a higher risk of adverse events than those in GMFCS levels I to III (odds ratio [OR] [95% confidence interval {CI}] = 3.65 [1.56, 5.40], p < 0.01). The history of recent illness and higher dose increased the likelihood of adverse events (OR [95% CI] = 2.00 [1.55, 3.00] and 2.20 [1.53, 3.07] respectively, p < 0.01). Sex, age, and the number of injections had no significant effect on adverse event rates (p > 0.05). The incidence of upper respiratory tract infection and lower respiratory tract infection after injections was weakly correlated with the incidence before injections (r = 0.36 and r = 0.27 respectively, p < 0.01).

INTERPRETATION

Occurrence of adverse events was similar between Onabotulinumtoxin-A and Lanbotulinumtoxin-A in children with CP. Dose, GMFCS level, and health background were risk factors.

WHAT THIS PAPER ADDS

The prevalence of adverse events was similar between Onabotulinumtoxin-A and Lanbotulinumtoxin-A in children with cerebral palsy (CP). The prevalence of adverse events increased with the severity of CP and the injected dose. Sex, age, and number of injections had no significant effect on the prevalence of adverse events.

Non-surgical interventions for the treatment of masticatory muscular spasticity in patients with cerebral palsy. Systematic review of randomized clinical trials

INTRODUCTION

Muscle disorders caused by cerebral palsy (CP) can affect oral function. The treatment for masticatory muscle spasticity is important to minimize muscle hyperactivity and preclude oral damages.

OBJECTIVES

To evaluate the efficacy and safety of non-surgical interventions for the treatment of masticatory muscle spasticity in CP patients.

METHODS

A comprehensive search was performed in the following databases: MEDLINE, Embase, Cochrane Library, LILACS, BBO, PEDro, Clinicaltrials.gov and WHO/ICTRP, without date and language restrictions. Randomized controlled trials (RCT) evaluating non-surgical interventions were considered. Primary outcomes such as masticatory function and adverse events were planned to be assessed. The risk of bias assessment was performed using the Cochrane risk of bias tool. The certainty of the evidence was assessed using the GRADE approach.

RESULTS

Three RCT assessing the effects of botulinum toxin, functional masticatory training and neuromuscular electrostimulation (NMES) were included. Evidence with a very low certainty showed: (i) no difference between botulinum toxin and placebo regarding maximum chewing strength, chewing efficiency and global oral health scale; (ii) improvement in masticatory function in favor of functional masticatory training versus conventional exercises, and (iii) in favor of strengthening exercises plus NMES versus placebo.

CONCLUSIONS

There was insufficient evidence to support the use of botulinum toxin and masticatory muscle strengthening programs alone and associated with NMES for the treatment of masticatory muscle in patients with PC. The clinical decision must be individualized, and further studies are needed to support or refute the use of different non-surgical interventions for PC. PROSPERO register number CRD42020209761.

Botulinum Toxin for Treating Temporomandibular Disorders: What is the Evidence?

AIMS

To systematically review the scientific literature for evidence concerning the clinical use of botulinum toxin (BTX) for the management of various temporomandibular disorders (TMDs).

METHODS

A comprehensive literature search was conducted in the Medline, Web of Science, and Cochrane Library databases to find randomized clinical trials (RCT) published between 2000 and the end of April 2021 investigating the use of BTX to treat TMDs. The selected articles were reviewed and tabulated according to the PICO (patients/problem/population, intervention, comparison, outcome) format.

RESULTS

A total of 24 RCTs were selected. Nine articles used BTX injections to treat myofascial pain, 4 to treat temporomandibular joint (TMJ) articular TMDs, 8 for the management of bruxism, and 3 to treat masseter hypertrophy. A total of 411 patients were treated by injection of BTX. Wide variability was found in the methods of injection and in the doses injected. Many trials concluded superiority of BTX injections over placebo for reducing TMD pain levels and improving maximum mouth opening; however, this was not universal.

CONCLUSION

There is good scientific evidence to support the use of BTX injections for treatment of masseter hypertrophy and equivocal evidence for myogenous TMDs, but very little for TMJ articular disorders. Studies with improved methodologic design are needed to gain better insight into the utility and effectiveness of BTX injections for treating both myogenous and TMJ articular TMDs and to establish suitable protocols for treating different TMDs.

Bruxism in children and adolescents with cerebral palsy

This study aims to summarize the existing evidence from primary studies in order to answer the following question: "are children and adolescents with cerebral palsy (CP) frequently affected by bruxism?". For such, databases Web of Science, Medline (via PubMed), Lilacs, SciELO, Scopus and Wiley Online Library were used, with the keywords “Cerebral Palsy” and “Bruxism” alone and in combination, without the restriction of the publication date. The search included all articles published until May 2020. A total of 229 publications were found, of which 12 were selected, after careful analysis. Retrospective data analyses, cross-sectional studies and observational case-control studies published in English and with samples composed of children and/or adolescents were included. Case reports, literature reviews and studies whose sample consisted of adults-only were excluded. In the evaluated studies, bruxism was present in all samples with cerebral palsy. However, oral signs and symptoms resulting from this parafunction were reported only in three studies, in which the presence of dental wear and pain was evaluated. Therefore, bruxism in children and adolescents with cerebral palsy is a frequent oral condition, however, knowledge about the associated and risk factors for the occurrence of this problem in these patients remains limited.

Prevalence of bruxism in adults with cerebral palsy institutionalized in Lisbon

OBJECTIVE

To determine the prevalence of bruxism in individuals with cerebral palsy (CP) and evaluating the various factors associated METHODS: One hundred and ten adults diagnosed with CP were selected from six institutions for people with special needs. Data were collected through oral examinations using the diagnostic criteria proposed by the American Academy of Sleep Medicine and the modified scale of Asworth RESULTS: Of the total sample, spastic tetraplegia was the most common type and half of the population presents severe intellectual disability. The prevalence of bruxism was 74,5%. Wear facets were observed in 67.9% of the sample, 59.1% of which were brilliant. There was a positive association between mixed bruxism (MB) and the spasticity classification. Through a logistic regression it was found that the risk of having MB and general bruxism (GB) is greater in individuals who have shiny wear facets.

CONCLUSIONS

In the present study the high prevalence of GB indicates there is an urgent need for treatment options in people with CP. More studies are needed with standardized diagnostic protocols and representative samples to evaluate the factors that influence the presence of bruxism in this population and to establish an appropriate treatment planning.

Cerebral palsy and bruxism: Effects of botulinum toxin injections-A randomized controlled trial

Objective

Cerebral palsy (CP) includes disturbances in muscular control caused by perinatal brain injury. Masticatory muscle involvement hampers functions such as chewing and talking. Bruxism and temporomandibular disorders are overrepresented. Neuromuscular blocks with botulinum toxin type A (BTX‐A) may alleviate problems due to muscular hyperactivity. The aim was to evaluate masticatory muscle BTX‐A injections in subjects with CP and bruxism.

Methods

A prospective, parallel, randomized, placebo‐controlled, and double‐blind trial in 12 patients with CP was performed. End points were alterations in objective and subjective oral capacities after two BTX‐A or corresponding placebo injections. Matched, healthy references were also evaluated.

Results

The reference group demonstrated stronger and more efficient oral functions compared with the CP group. Subjective and objective oral capacities appeared to vary considerably between CP patients and also over time in this patient group and were poorly correlated. No significant effect of BTX‐A compared with placebo on outcome variables was observed at group level, but continued treatment with BTX‐A was requested by the majority of the patients.

Conclusion

The evidence is unable to support the use of BTX‐A for the treatment of affected masticatory muscles in CP, but the findings are inconclusive in certain respects. Larger, more homogeneous groups of CP patients need to be evaluated in future trials.