Bruxism and cranial-cervical dystonia: is there a relationship?

Secondary bruxism: A valid diagnosis or just a coincidental finding of additional masticatory muscle activity? A narrative review of literature

INTRODUCTION

Bruxism is defined as a repetitive masticatory muscle activity that can manifest it upon awakening (awake bruxism-AB) or during sleep (sleep bruxism-SB). Some forms of both, AB and SB can be associated to many other coexistent factors, considered of risk for the initiation and maintenance of the bruxism. Although controversial, the term 'secondary bruxism' has frequently been used to label these cases. The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques, however, are important factors to be considered when judging the literature findings. The use (and abuse) of drugs, caffeine, nicotine, alcohol and psychoactive substances, the presence of respiratory disorders during sleep, gastroesophageal reflux disorders and movement, neurological and psychiatric disorders are among these factors. The scarcity of controlled studies and the complexity and interactions among all aforementioned factors, unfortunately, does not allow to establish any causality or temporal association with SB and AB. The supposition that variables are related depends on different parameters, not clearly demonstrated in the available studies.

OBJECTIVES

This narrative review aims at providing oral health care professionals with an update on the co-risk factors and disorders possibly associated with bruxism. In addition, the authors discuss the appropriateness of the term 'secondary bruxism' as a valid diagnostic category based on the available evidence.

CONCLUSION

The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques found in many studies preclude any solid and convincing conclusion on the existence of the 'secondary' bruxism.

The Effect of TMJ Intervention on Instant Postural Changes and Dystonic Contractions in Patients Diagnosed with Dystonia: A Pilot Study

(1) Background: The aim of the present study is to analyze the instant postural changes and changes in the dystonic contractions among patients with dystonia following the use of an intraoral device called a key integrative dynamic TMJ treatment appliance (KIDTA). (2) Methods: Twelve subjects, previously diagnosed with dystonia were enrolled. Their existing records were utilized to assess the changes in their posture and dystonic contractions. The posture analysis was conducted using a mobile application (APECS). The initial records (T0) and records acquired after the delivery of the KIDTA (T1) were utilized in the analysis. The Wilcoxon signed-rank test was performed to compare parameters between T0 and T1, with a significance level set at p < 0.05. (3) Results: Based on the Wilcoxon signed-rank test, statistically significant differences in T1 compared to T0 were observed in the severity of dystonic spasms, body alignment, head shift, head tilt, shoulder alignment, shoulder angle, axillae alignment, ribcage tilt, pelvic tilt, knee angle, and tibia angle (p < 0.05). (4) Conclusions: Within the limitations of the present pilot study, an intervention to the TMJ through a KIDTA appliance seems to mitigate the severity of dystonic contractions and improve the posture with respect to certain postural parameters.

Pathophysiological mechanisms of oromandibular dystonia

Oromandibular dystonia (OMD) is a rare form of focal idiopathic dystonia. OMD was clinically identified at the beginning of the 20th century, and the main clinical features have been progressively described over the years. However, OMD has several peculiarities that still remain unexplained, including the high rate of oral trauma, which is often related to the onset of motor symptoms. The purpose of this paper was to formulate a hypothesis regarding the pathophysiology of OMD, starting from the neuroanatomical basis of the masticatory and facial systems and highlighting the features that differentiate this condition from other forms of focal idiopathic dystonia. We provide a brief review of the clinical and etiological features of OMD as well as neurophysiological and neuroimaging findings obtained from studies in patients with OMD. We discuss possible pathophysiological mechanisms underlying OMD and suggest that abnormalities in sensory input processing may play a prominent role in OMD pathophysiology, possibly triggering a cascade of events that results in sensorimotor cortex network dysfunction. Finally, we identify open questions that future studies should address, including the effect of abnormal sensory input processing and oral trauma on the peculiar neurophysiological abnormalities observed in OMD.

Association between Temporomandibular Joint Disorder and Parkinson's Disease

This study performed two different analyses using a large set of population data from the Korean National Health Insurance Service Health Screening Cohort to evaluate the interactional association between temporomandibular disorder (TMD) and Parkinson’s disease (PD). Two nested case–control population-based studies were conducted on 514,866 participants. In Study I, 4455 participants with TMD were matched with 17,820 control participants, with a ratio of 1:4. In Study II, 6076 participants with PD were matched with 24,304 control participants, with a ratio of 1:4. Obesity, smoking, alcohol consumption, systolic, diastolic blood pressure, fasting blood glucose level, and total cholesterol were adjusted. The adjusted odds ratio (OR) for TMD was 1.43 (95% confidence interval (CI) = 1.02–2.00) in PD patients compared to non-PD patients in Study I (p < 0.001). The adjusted OR for PD was 1.56 (95% CI = 1.13–2.15) in TMD patients compared to non-TMD patients in Study II (p = 0.007). This study demonstrated that patients with TMD have a significantly higher risk of developing PD and, conversely, those with PD have a significantly higher risk of developing TMD.

The association between Parkinson's disease and temporomandibular disorder

The prevalence of temporomandibular disorder (TMD) among elderly people with Parkinson’s disease (PD) is relatively high, but a population-based study of the relationship between PD and TMD is still lacking. This study, therefore, sought to investigate the association between TMD and PD by using data for one million randomly sampled beneficiaries of Taiwan’s National Health Insurance program, including 6,185 PD patients who were matched through propensity score matching with 18,555 non-PD patients. Both the PD and non-PD cohorts were followed until death, any diagnosis of TMD, or December 31, 2013, whichever occurred first. Each diagnosis of TMD was made by a qualified physician according to the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM), using the diagnosis codes 524.60, 524.62, 524.63, and 524.69 while excluding tooth abscess, wisdom tooth eruption, herpes zoster and postherpetic neuralgia, mastoiditis, otitis externa, otitis media, parotitis, sialadenitis, and trigeminal neuralgia. We used Cox proportional hazard regression models to calculate the relative risk of TMD and found a 2.11-fold (95% CI: 1.35–3.30) increased risk of TMD overall in the PD group compared with the non-PD group. Stratified by follow-up period, there was a 4.25-fold (95% CI: 1.51–11.93) increased risk in the PD group in the first year after the initial PD diagnosis and a 3.88-fold (95% CI: 1.33–11.28) increased risk in the second year. Over the long-term (>5 years), PD was significantly associated with an increased risk of TMD. These findings suggest that it is important to closely monitor the temporomandibular joint health of PD patients.

A systematic review of botulinum toxin in the management of patients with temporomandibular disorders and bruxism

Introduction The medical and cosmetic use of botulinum toxin (BTX) is now widespread. With an increased number of clinicians adopting the use of BTX in the management of temporomandibular disorders (TMD) and/or bruxism, as either a standalone treatment or as an adjunct, affirmation is required in regards to whether it has a clinically justifiable position among the current spectrum of available treatment modalities.Objectives To establish the usefulness of BTX when treating patients with TMD and/or bruxism, and thereby determine whether there may be an appropriate purpose for the prescription of BTX in the management of these patients.Data sources and data selection A systematic review of the relevant literature was conducted. The literature search was carried out by applying key terms to appropriate data sources (Medline, Embase, Pubmed, Cochrane Central Register of Controlled Trials, and OpenSIGLE). The resultant papers were subjected to inclusion and exclusion criteria, which were then assessed for bias using a framework outlined in the Cochrane Handbook.Results A total of 11 trials met the inclusion criteria. The primary outcome measure was changes in pain experience in groups that had been treated with BTX, relative to an appropriate control group. Secondary outcomes included changes in the frequency of bruxism events, changes in maximum mouth opening, changes in occlusal force and changes in electromyography (EMG) readings of muscles of mastication.Conclusion The evidence to support the use of BTX in the management of TMD and/or bruxism is not entirely unequivocal. A number of studies that have met the inclusion criteria have shown promising results and thereby justify further investigation. Given the current evidence, BTX should certainly be considered but due to financial implications and possible side effects, it seems appropriate that conservative options, such as self-management with explanation and physical therapies, should be exhausted first.

Long-term follow-up of a patient with venlafaxine-induced diurnal bruxism treated with an occlusal splint: A case report

BACKGROUND

Bruxism is a jaw-muscle activity characterized by the clenching or grinding of teeth. It can be divided into nocturnal bruxism and diurnal bruxism (DB). DB secondary to antidepressants is rare and refractory. Reports associated with antidepressant-induced DB are mostly anecdotal without long-term follow-up. The effect of drug intervention on antidepressant-induced DB is still contested. We herein report the first case of successful treatment of venlafaxine-induced DB with an occlusal splint.

CASE SUMMARY

This case report describes detailed 7-year follow-up of a patient with venlafaxine-induced DB treated with an occlusal splint. The patient who complained about involuntary daytime tooth grinding after taking venlafaxine for a period of 4 mo and was diagnosed with venlafaxine-induced DB. Subsequently, an occlusal splint with modified bilateral buccal-pterygoid pads was used to treat his tooth grinding and to protect the dental structures from tooth wearing. The patient reported remission of symptoms after several months of treatment. His grinding activity was gradually and stably controlled after 2 years, with an almost complete recovery from DB after 6 years.

CONCLUSION

The maxillary buccal-pterygoid splint can be used as a noninvasive approach to treat venlafaxine-induced DB.

Bruxismo durante o Sono

Bruxismo durante o sono (BS) é uma parassonia caracterizada por movimentos involuntários e estereotipados com ranger dos dentes durante o sono. A prevalência do BS é igual nos dois sexos, variando de 3% a 20% na população geral, sendo mais comum nos jovens. O BS secundário é causado por transtornos neurológicos ou pode estar associado a transtornos primários do sono e antidepressivos inibidores seletivos da recaptação da serotonina. Já o BS primário apresenta fatores de predisposição genética ou psicológica, má oclusão dentária, disfunção leve dos gânglios da base e combinações desses fatores. Os principais sinais e sintomas do BS incluem o ruído característico de ranger dos dentes, desgaste dentário, dor local, hipertrofia dos músculos masseteres e temporais, cefaléias, disfunção da articulação temporomandibular, sono de má qualidade e sonolência diurna. O diagnóstico clínico de BS é feito por meio da história do paciente, do cônjuge e do exame odontológico. A polissonografia documenta a presença de episódios de ranger dos dentes, permitindo identificar alterações da arquitetura do sono, presença de microdespertares, abalos mioclônicos de membros inferiores, roncos e distúrbios respiratórios sonodependentes. O tratamento deve ser direcionado para os fatores etiológicos com base no BS secundário. Não existe tratamento-padrão para o BS primário, devendo este ser individualizado ao paciente. O tratamento odontológico do BS primário e secundário com placas de repouso tem como objetivo prevenir danos das estruturas orofaciais e aliviar dor craniofacial. O tratamento comportamental inclui técnicas de relaxamento, abstinência de cafeína e tabaco. O tratamento farmacológico do BS primário e secundário emprega drogas agonistas dopaminérgicas, benzodiazepínicos ansiolíticos, buspirona, hipnóticos não-benzodiazepínicos, como o zolpidem, relaxantes musculares, certos antidepressivos, como mirtazapina, nefazodona, trazodona, bupopriona e drogas antiepilépticas, como a gabapentina. Aplicações locais de toxina botulínica nos músculos masseteres e temporais podem ser utilizadas em casos de bruxismo intenso não-responsivo à terapêutica convencional.

An update on new and unique uses of botulinum toxin in movement disorders

The therapeutic applications of botulinum toxin (BoNT) have grown manifold since its initial approval in 1989 by the US Food and Drug Administration (FDA) for the treatment of strabismus, blepharospasm, and other facial spasms. Although it is the most potent biologic toxin known to man, long-term studies have established its safety in the treatment of a variety of neurologic and non-neurologic disorders. This review focuses on some novel and uncommon uses of BoNT in the treatment of movement disorders, such as oromandibular dystonia, including bruxism, anterocollis, camptocormia, tremor, tics, tardive and levodopa-induced dyskinesia, and restless legs syndrome. Despite a paucity of randomized controlled trials and lack of FDA approval for these movement disorders, there is growing body of evidence that BoNT provides benefit to patients with these hyperkinetic movement disorders and that BoNT is a safe treatment when used by clinicians skilled in the administration of the drug for these conditions.

Temporomandibular joint dysfunction in Parkinson's Disease: an integrative literature review

ABSTRACT Temporomandibular joint dysfunction is a set of disorders involving the masticatory muscles, temporomandibular joint and associated structures. It is known that the progression of motor symptoms in Parkinson's disease is an indication that these people are more prone to the development of this dysfunction. Thus, this study aims to investigate the signs and symptoms of temporomandibular dysfunction in people with Parkinson's disease. The search was performed in the databases: MEDLINE/ PubMed, LILACs, CINAHL, SCOPUS, Web of Science and PEDro, without timing or language restriction. Specific descriptors were used for each database and keywords, evaluated by the instruments: Critical Appraisal Skill Program and Agency for Health care and Research and Quality. A total of 4,209 articles were found but only 5 were included. After critical analysis of the methodology of the articles, one did not reach the minimum score required by the evaluation instruments, thus, it was excluded. The selected articles addressed, as signs and symptoms of temporomandibular joint dysfunction, the following: myofascial pain, bruxism, limitation of mouth opening, dislocation of the articular disc and asymmetry in the distribution of occlusal contacts. Further studies are needed in order to determine the relationship between cause and effect of the analyzed variables, so as to contribute to more specific and effective therapeutic interventions.

The Evaluation of the Clinical Effects of Botulinum Toxin on Nocturnal Bruxism

OBJECTIVES

Nocturnal bruxism can be managed by botulinum toxin (Botox®) in patients who have not responded to conservative treatment. The aim of this study was to evaluate the efficacy of botulinum toxin A (BTXA) in the treatment of nocturnal bruxism.

MATERIAL AND METHODS

The retrospective study comprised 25 female patients, aged 23-55 years (mean 35.84 ± 8.41 years). All patients received a single injection of BTXA in the right and left masseters. Evaluation was made by Visual Analogue Scale (VAS) values, complaint duration, onset of effect, and duration of effectiveness.

RESULTS

BTXA produced significant improvements in pain scores. Only 2 adverse events (8%) were recorded.

CONCLUSION

BTX-A is effective in the treatment of nocturnal bruxism.

Treatment of chronic pain associated with nocturnal bruxism with botulinum toxin. A prospective and randomized clinical study

Background

To evaluate the role of botulinum toxin type A (BTX-A) in the treatment of pain associated with nocturnal bruxism.

Material and Methods

Fifty subjects reporting nocturnal bruxism were recruited for a randomized clinical trial. Twenty five bruxers were injected with botulinum toxin in both masseters, and twenty five were treated with traditional methods of treating bruxism. Patients were evaluated at 3rd week, 2nd and 6th month and one year after injection and then used to calculate bruxism events. Bruxism symptoms were investigated using questionnaires.

Results

Mean pain score due to Bruxism events in the masseter muscle decreased significantly in the botulinum toxin injection group A (P =0.000, highly significant). However, in the conventional treatment group, mean pain score does not show improvement with time (p>0.05).

Conclusions

Our results suggest that botulinum toxin injection reduced the mean pain score and number of bruxism events, most likely by decreasing the muscle activity of masseter rather than affecting the central nervous system.

Key words:Temporomandibular pain, nocturnal bruxism, botulinum toxin.

Bruxism in craniocervical dystonia: a prospective study

AIMS

Bruxism pathophysiology remains unclear, and its occurrence has been poorly investigated in movement disorders. The aim of this study was to compare the frequency of bruxism in patients with craniocervical dystonia vs. normal controls and to determine its associated clinical features.

METHOD

This is a prospective-control study. A total of 114 dystonic subjects (45 facial dystonia, 69 cervical dystonia) and 182 controls were included. Bruxism was diagnosed using a hetero-questionnaire and a clinical examination performed by trained dentists. Occurrence of bruxism was compared between the different study populations. A binomial logistic regression analysis was used to determine which clinical features influenced bruxism occurrence in each population.

RESULTS

The frequency of bruxism was significantly higher in the dystonic group than in normal controls but there was no difference between facial and cervical dystonia. It was also higher in women than in men. Bruxism features were similar between normal controls and dystonic patients except for a higher score of temporomandibular jaw pain in the dystonic group.

DISCUSSION

The higher frequency of bruxism in dystonic patients suggests that bruxism is increased in patients with basal ganglia dysfunction but that its nature does not differ from that seen in bruxers from the normal population.

Current Treatments of Bruxism

Despite numerous case reports, the evidence for treatment of bruxism is still low. Different treatment modalities (behavioral techniques, intraoral devices, medications, and contingent electrical stimulation) have been applied. A clinical evaluation is needed to differentiate between awake bruxism and sleep bruxism and rule out any medical disorder or medication that could be behind its appearance (secondary bruxism). A polysomnography is required only in a few cases of sleep bruxism, mostly when sleep comorbidities are present. Counselling with regard to sleep hygiene, sleep habit modification, and relaxation techniques has been suggested as the first step in the therapeutic intervention, and is generally considered not harmful, despite low evidence of any efficacy. Occlusal splints are successful in the prevention of dental damage and grinding sounds associated with sleep bruxism, but their effects on reducing bruxism electromyographic (EMG) events are transient. In patients with psychiatric and sleep comorbidities, the acute use of clonazepam at night has been reported to improve sleep bruxism, but in the absence of double-blind randomized trials, its use in general clinical practice cannot be recommended. Severe secondary bruxism interfering with speaking, chewing, or swallowing has been reported in patients with neurological disorders such as in cranial dystonia; in these patients, injections of botulinum toxin in the masticatory muscles may decrease bruxism for up to 1–5 months and improve pain and mandibular functions. Long-term studies in larger and better specified samples of patients with bruxism, comparing the effects of different therapeutic modalities on bruxism EMG activity, progression of dental wear, and orofacial pain are current gaps of knowledge and preclude the development of severity-based treatment guidelines.

Early effect of Botox-A injection into the masseter muscle of rats: functional and histological evaluation

Background

The purpose of this study was to evaluate the change of food intake after different dosages of botulinum toxin A (BTX) injection in the animal model. Additionally, the dimensional and histological change at 14 days after BTX injection was also evaluated.

Methods

The comparative study was performed using the BTX injection model in rats (n = 5 for each group). Group 1 was the saline-injected group. Group 2 was the 5-unit BTX-injection group to each masseter muscle. Group 3 was the 10-unit BTX-injection group to each masseter muscle. Food intake rates and body weight were checked daily before and after BTX injection until 10 days. All animals were sacrificed at 14 days after BTX injection, and the specimens underwent hematoxylin and eosin stain and immunohistochemical staining for myosin type II (MYH2).

Results

The recovery of food intake in groups 2 and 3 decreased significantly compared with group 1 from day 2 to day 7 and day 9 after injection (p < 0.05). The BTX-treated masseter muscles were significantly smaller than those in group 1 (p = 0.015). The immunohistochemical findings demonstrated that the expression of MYH2 was significantly higher in group 3 compared to groups 1 and 2 (p < 0.001).

Conclusions

BTX injection to the masseter muscle in rats demonstrated short food-intake-rate reduction with recovery until 10 days after injection. The thickness of the masseter muscle and MYH2 expression were significantly changed according to the injected dose of BTX.

Prevalence of Bruxism in Hemifacial-Spasm Patients

PURPOSE

A previous study reported an increased prevalence of bruxism (25%) in patients with cranio-cervical dystonia (CCD) compared to normal controls (13%). CCD can affect the muscles of the head and neck. Besides the CCD affecting these muscles, hemifacial spasm (HFS) is a form of peripheral myoclonus due to a neurovascular conflict affecting the muscles of the face. The fact that they affect the same muscle regions could lead to other links in clinical manifestations such as bruxism, which is more common in patients with CCD than in the normal population. The aim was to study the prevalence of bruxism in patients with HFS.

MATERIALS AND METHODS

Patients with HFS were enrolled in the department of clinical neurophysiology (Bordeaux University Hospital) over a 6-month period. They were paired regarding age, the absence of neurological pathology or neuroleptics intake. To be included in the study, patients needed to have had unilateral involuntary facial muscle contractions affecting one hemiface. A hetero-questionnaire and a clinicial study were performed. The diagnostic criteria of bruxism included parafunction items such as grinding and clenching and at least one of the following clinical signs: abnormal tooth wear, temporomandibular joint (TMJ) pain, TMJ clicking, muscle hypertonia (masseter or temporal muscles). Additional epidemiological data were collected including age, sex, disease duration, stress, and sleep disorders. Stress symptoms inventory included symptoms like depression, strong heartbeat, dry mouth, anger, inability to concentrate, weakness, fatigability, insomnia, headache, and excessive sweating. The sleep disorder diagnosis included at least two of the symptoms described in the ICSD-3. All these criteria were recorded as either present (scored "1") or absent (scored "0").

RESULTS

The prevalence of bruxism in the two groups (normal and HFS) was not significantly different (p = 0.37). The rate was not significantly different between sleep and awake bruxism (p = 0.15) in both groups. Stress influenced the occurrence of bruxism in these two groups (p < 0.001).

CONCLUSION

The results of this study indicated that clenching behaviors were higher in the HFS group, and that factors such as stress affected this group. The prevalence of bruxism was not higher in this population than in the normal control.

A relationship between bruxism and orofacial-dystonia? A trigeminal electrophysiological approach in a case report of pineal cavernoma

Background

In some clinical cases, bruxism may be correlated to central nervous system hyperexcitability, suggesting that bruxism may represent a subclinical form of dystonia. To examine this hypothesis, we performed an electrophysiological evaluation of the excitability of the trigeminal nervous system in a patient affected by pineal cavernoma with pain symptoms in the orofacial region and pronounced bruxism.

Methods

Electrophysiological studies included bilateral electrical transcranial stimulation of the trigeminal roots, analysis of the jaw jerk reflex, recovery cycle of masseter inhibitory reflex, and a magnetic resonance imaging study of the brain.

Results

The neuromuscular responses of the left- and right-side bilateral trigeminal motor potentials showed a high degree of symmetry in latency (1.92 ms and 1.96 ms, respectively) and amplitude (11 mV and 11.4 mV, respectively), whereas the jaw jerk reflex amplitude of the right and left masseters was 5.1 mV and 8.9 mV, respectively. The test stimulus for the recovery cycle of masseter inhibitory reflex evoked both silent periods at an interstimulus interval of 150 ms. The duration of the second silent period evoked by the test stimulus was 61 ms and 54 ms on the right and left masseters, respectively, which was greater than that evoked by the conditioning stimulus (39 ms and 35 ms, respectively).

Conclusions

We found evidence of activation and peripheral sensitization of the nociceptive fibers, the primary and secondary nociceptive neurons in the central nervous system, and the endogenous pain control systems (including both the inhibitory and facilitatory processes), in the tested subject. These data suggest that bruxism and central orofacial pain can coexist, but are two independent symptoms, which may explain why numerous experimental and clinical studies fail to reach unequivocal conclusions.

Bruxism Associated with Anoxic Encephalopathy: Successful Treatment with Baclofen

Introduction. Bruxism is a movement disorder characterized by grinding and clenching of the teeth. Etiology of bruxism can be divided into three groups: psychosocial factors, peripheral factors, and pathophysiological factors. Methods. The clinical investigation was conducted at King Khaled Hospital in Hail, Saudi Arabia, in 2012. Results. A 16-year-old Saudi female was brought to the hospital in a comatose state and with generalized convulsive seizures secondary to acute anoxic encephalopathy. In the third week of hospitalization, while still in a state of akinetic mutism, she developed incessant bruxism which responded favorably to a GABA receptor agonist (baclofen). Conclusion. Our data support the hypothesis that bruxism emanates from imbalance or dysregulation of the neurotransmitter system. Larger scale studies will be needed to confirm this hypothesis.

Botulinum toxin type A combined with cervical spine manual therapy for masseteric hypertrophy in a patient with Alzheimer-type dementia: a case report

OBJECTIVE

The purpose of this case study is to present the findings of combining botulinum toxin type A (BoNT-A) and cervical spine manual therapy to address masseter muscle spasticity in a patient with Alzheimer-type dementia.

CASE REPORT

A 78-year-old woman with bilateral spasticity of the masseteric regions for 2 years was referred for physiotherapy. She had trismus and bruxism, and could neither close nor open her mouth normally; thus, she was unable to be fed orally in a normal manner.

INTERVENTION AND OUTCOME

The patient underwent combined treatment with BoNT-A and cervical spine manual therapy. A medical physician (neurologist) performed the BoNT-A injections into 2 points at the center of the lower third of the masseter muscle. A physical therapist performed manual therapy interventions targeted at the cervical spine. Manual therapy started the day after the BoNT-A injection and continued for 5 sessions per week for a total period of 2 weeks. Clinical outcomes were measured including spasticity (Modified Ashworth Scale), functionality (Barthel Index), and jaw opening. Outcomes were conducted at baseline, 2 weeks after treatment, and at 2-month follow-up session after finishing the treatment. The patient improved in all of the outcomes at the end of treatment, and these results were maintained during the follow-up. After treatment, the patient was able to feed with minimal caregiver dependency because oral feeding was possible.

CONCLUSION

The patient in this study responded positively to a combination of BoNT-A and manual therapy, resulting in decreased masseter muscles spasticity and improved trismus and bruxism.

Effectiveness of botulinum toxin type A treatment of neck pain related to nocturnal bruxism: a case report

OBJECTIVE

This case report describes a patient with nocturnal bruxism and related neck pain treated with botulinum toxin type A (BTX-A).

CLINICAL FEATURES

The patient was a 27-year-old man with nocturnal bruxism and difficulty in active mouth opening and chewing and neck pain at rest. His numeric pain score was 7 of 10. Surface electromyography of the temporalis and masseter muscles showed typical signs of hyperactivity, characterized by compound muscle action potential amplitude alterations.

INTERVENTION AND OUTCOME

After clinical evaluation, he was treated with BTX-A to reduce masseter and temporalis muscle hyperactivity. After 3 days of treatment with BTX-A, with each masseter muscle injected with a dose of about 40 mouse units with a dilution of 1 mL and with temporal muscle bilaterally injected with 25 mouse units with the same dilution, a decrease in bruxism symptoms was reported. Neck pain also decreased after the first treatment (visual analog scale of 2/10) and then resolved completely. After 4 weeks, electromyography showed the reduction of muscle hyperactivity with a decrease in the amplitude of the motor action potential. The same reduction in signs and symptoms was still present at assessment 3 months posttreatment.

CONCLUSION

These findings suggest that BTX-A may be a therapeutic option for the treatment of bruxism and related disorders.

The many faces of hemifacial spasm: differential diagnosis of unilateral facial spasms

Hemifacial spasm is defined as unilateral, involuntary, irregular clonic or tonic movement of muscles innervated by the seventh cranial nerve. Most frequently attributed to vascular loop compression at the root exit zone of the facial nerve, there are many other etiologies of unilateral facial movements that must be considered in the differential diagnosis of hemifacial spasm. The primary purpose of this review is to draw attention to the marked heterogeneity of unilateral facial spasms and to focus on clinical characteristics of mimickers of hemifacial spasm and on atypical presentations of nonvascular cases. In addition to a comprehensive review of the literature on hemifacial spasm, medical records and videos of consecutive patients referred to the Movement Disorders Clinic at Baylor College of Medicine for hemifacial spasm between 2000 and 2010 were reviewed, and videos of illustrative cases were edited. Among 215 patients referred for evaluation of hemifacial spasm, 133 (62%) were classified as primary or idiopathic hemifacial spasm (presumably caused by vascular compression of the ipsilateral facial nerve), and 4 (2%) had hereditary hemifacial spasm. Secondary causes were found in 40 patients (19%) and included Bell's palsy (n=23, 11%), facial nerve injury (n=13, 6%), demyelination (n=2), and brain vascular insults (n=2). There were an additional 38 patients (18%) with hemifacial spasm mimickers classified as psychogenic, tics, dystonia, myoclonus, and hemimasticatory spasm. We concluded that although most cases of hemifacial spasm are idiopathic and probably caused by vascular compression of the facial nerve, other etiologies should be considered in the differential diagnosis, particularly if there are atypical features.

Associated conditions and clinical significance of awake bruxism

BACKGROUND

Awake bruxism is defined as an oral parafunctional activity that includes clenching and grinding of teeth during wakefulness. Confirming the possible related anatomy and the clinical significance of awake bruxism in geriatric hospitals is the aim of this study.

METHODS

We analyzed the medical records of 503 patients who were admitted to hospital from April to June 2008. After the recognition of bruxism, the clinical, brain imaging studies and statistical parametric mapping (SPM) of brain single photon emission computed tomography were performed.

RESULTS

In each disease group, five of 125 Alzheimer's disease (AD) patients (4.0%), three of 11 frontotemporal dementia (FTD) patients (27.3%), seven of 230 stroke patients (including two patients related to citalopram, 3.0%), one of 45 Parkinson's disease patients (2.2%) and four of 17 hydrocephalus patients (23.5%) had bruxism. Even though awake bruxism occurred early after stroke onset, it occurred late after AD and FTD onset. This occurred in a far advanced stage of AD, while it occurred in a moderately advanced stage of FTD. SPM analysis in AD and FTD patients with awake bruxism revealed significant hypoperfusion in frontotemporal and other subcortical structures. Surface electromyography recordings from the masseter muscle showed rhythmic regular motor activity at a rate of 1-2/s.

CONCLUSION

This study suggests that awake bruxism is encountered not infrequently in various diseases in geriatric hospitals. It is frequently observed in FTD and normal pressure hydrocephalus, which characteristically shows frontal lobe dysfunction. These facts and SPM analysis show that awake bruxism can be regarded as a frontal neurological sign of various neurological disorders.

Effect of botulinum toxin injection on nocturnal bruxism: a randomized controlled trial

OBJECTIVE

To evaluate the effect of botulinum toxin type A on nocturnal bruxism.

DESIGN

Twelve subjects reporting nocturnal bruxism were recruited for a double-blind, randomized clinical trial. Six bruxers were injected with botulinum toxin in both masseters, and six with saline. Nocturnal electromyographic activity was recorded in the subject's natural sleeping environment from masseter and temporalis muscles before injection, and 4, 8, and 12 wks after injection and then used to calculate bruxism events. Bruxism symptoms were investigated using questionnaires.

RESULTS

Bruxism events in the masseter muscle decreased significantly in the botulinum toxin injection group (P = 0.027). In the temporalis muscle, bruxism events did not differ between groups or among times. Subjective bruxism symptoms decreased in both groups after injection (P < 0.001).

CONCLUSIONS

Our results suggest that botulinum toxin injection reduced the number of bruxism events, most likely mediated its effect through a decrease in muscle activity rather than the central nervous system. We controlled for placebo effects by randomizing the interventions between groups, obtaining subjective and objective outcome measures, using the temporalis muscle as a control, and collecting data at three postinjection times. Our controlled study supports the use of botulinum toxin injection as an effective treatment for nocturnal bruxism.

Oromandibular dystonia and hormonal factors: twelve years follow-up of a case report

Oromandibular dystonia (OMD) is a focal neurological movement disorder characterized by involuntary sustained and often painful muscle contraction, usually producing repetitive movements or abnormal positions of the mouth, jaw and/or tongue. We report on a 30-year-old woman affected with OMD with a 12-year follow-up. Focal dystonia involved an involuntary activity of the lateral pterygoid muscles causing forceful jaw displacement in the maximal protrusive position. These episodes initially occurred during jaw function and increased up to an open-lock with bilateral pre-auricular pain. Dystonic spasms were absent during sleep and were reduced temporarily by sensory tricks. Treatment with botulinum toxin type A (BTX) was performed during three different sessions over a 1-year period. Electromyographic-guided BTX injections into the lateral pterygoid muscles were given with cannula electrodes. Botox reduced the involuntary activity of the muscles. Recurrence and exacerbation of dystonic symptoms occurred during the two pregnancies and completely disappeared immediately after both deliveries with prolonged symptom-free periods. During the last 8 years, the patient had a slight relapse of symptoms during flu attacks, periods of stress and during menses. The temporal pattern of these symptoms indicates a possible relationship between OMD and hormonal factors.

Orofacial movement disorders

This article reviews three poorly recognized yet relatively common presentations of hyperactive orofacial movement disorders: oromandibular dystonia, orofacial dyskinesia, and drug-induced extrapyramidal syndrome reactions. Orofacial movement disorders are often misdiagnosed as temporomandibular disorders, hence understanding these conditions is pertinent for the practitioner treating orofacial pain. Aspects of epidemiology, etiology, pathophysiology, clinical presentation, and diagnosis are discussed along with treatment considerations for these orofacial movement disorders.

Esthetic Restorative Materials and Opposing Enamel Wear

The data obtained in this study can help practitioners with selection of the appropriate restorative materials to minimize further tooth and restoration wear, which is an important consideration during treatment planning.

Botulinum toxin in the treatment of tremors, dystonias, sialorrhea and other symptoms associated with Parkinson's disease

Botulinum toxins are an effective treatment modality for a growing number of neurologic conditions. Although there has been varied interest and success in their use, they have been studied for a variety of conditions associated with Parkinson's disease. Conditions reviewed in this paper include hand and jaw tremor, dystonia, blepharospasm and apraxia of eyelid opening, bruxism, camptocormia, freezing of gait, sialorrhea and constipation. We will make comments when applicable on our unique experience with botulinum toxin in these conditions. Other conditions associated with Parkinson's disease, which will not be reviewed here, but may benefit from botulinum toxin treatment include anterocollis (also known as dropped head syndrome), hyperhidrosis, seborrhea and overactive bladder.

Involvement of ATP and its receptors on nociception in rat model of masseter muscle pain

The exact mechanism of the masseter muscle pain recognized as a prominent symptom in temporomandibular disorders remains unclear, although it is clinically known that excessive muscular contraction causes tenderness in masseter muscles. It has been demonstrated that P2X3 receptors (P2X3Rs) in sensory neurons play a role in pain signaling from the periphery. We determined the role of P2X(3)R on pressure pain and mechanical hyperalgesia in a newly developed rat model of masseter muscle pain. The pain in the masseter muscle was assessed by the pressure pain threshold (PPT), which was defined as the amount of pressure required to induce head flinching. In naive animals, systemic treatment with morphine was associated with increase of PPTs. Changes in PPTs were examined after administration of P2XR agonists or antagonists into the masseter muscle. The masseter muscle injection of alpha,beta-meATP (P2X(1,3,2/3)R-specific agonist) induced a significantly greater behavioral response than its vehicle. This enhanced response was completely blocked by the co-application of alpha,beta-meATP with PPADS (P2X(1,2,3,5,1/5,2/3)R-specific antagonist). Excessive contraction in masseter muscle was produced by electrical stimulation. The exerted masseter muscles showed a significant reduction in PPTs indicating the induction of mechanical hyperalgesia of the muscle. Moreover, administration of PPADS to the exerted masseter muscles produced a complete recovery of reducing PPT. Immunohistochemically, the number of P2X3R-positive neurons innervating the masseter muscles increased in the excessively contracted condition in trigeminal ganglia. Our results suggested that P2X3R plays an important role in pressure pain and mechanical hyperalgesia in masseter muscle caused by excessive muscular contraction.

Severe bruxism following basal ganglia infarcts: insights into pathophysiology

Bruxism characterized by clenching and grinding of teeth can lead to toothwear, headaches and depression. While bruxism has been associated with a number of neurological diseases, it has not been highlighted following cerebral infarction. An elderly man presented with an acute onset of tooth grinding and jaw clenching associated with dysarthria. His bruxism was worse during the day and resolved during sleep. He had frequent jaw aches, headaches and swallowing difficulty. Examination demonstrated the presence of dysarthria with jaw clenching and tooth grinding, producing persistent high pitch and loud squeaky sounds. A magnetic resonance imaging and angiography examination revealed a recent infarct in the right thalamus. In addition, chronic lacunar infarcts were present in the bilateral caudate nuclei with severe basilar artery stenosis. He was successfully treated with botulinum toxin. We discuss the pathophysiologic mechanisms of bruxism associated with basal ganglia infarcts. Dysfunction of the efferent and/or afferent thalamic or striatopallidal tracts may play a role in bruxism. Early recognition of bruxism following stroke could reduce unnecessary suffering since the condition can be effectively treated.

Asymmetrical awake bruxism associated with multiple system atrophy

We describe a 51-year-old man who developed awake bruxism during the course of multiple system atrophy. Electromyographic studies revealed side-to-side amplitude asymmetry of the bursts of motor activity. The bruxism responded favourably to low-dose levodopa-carbidopa therapy. Possible mechanisms of this rare association are discussed.

Vectored upper cervical manipulation for chronic sleep bruxism, headache, and cervical spine pain in a child

OBJECTIVE

To discuss the management of chronic sleep bruxism in a 6-year old girl. Clinical features The patient had morning headaches and cervical spine pain. Due to abnormal tooth wear, bruxism had been previously diagnosed and was verified by observation during sleep. She also had abnormal postural and palpatory findings, indicating upper cervical joint dysfunction. Intervention and outcome Bilateral rotary cervical stretching/mobilization and a vectored high-velocity, low-amplitude adjustment were performed in the upper cervical spine, using the atlas transverse process as the contact point. There was complete relief of the chronic subjective symptoms concomitant with remission of the objective signs of joint dysfunction.

CONCLUSIONS

Cervical, particularly upper cervical, spine muscle-joint dysfunction should be considered as a potential etiology in chronic childhood sleep bruxism.

Severe amphethamine-induced bruxism: treatment with botulinum toxin

While chewing and grinding movements have been observed in amphetamine addicts, recognition and management of this problem have rarely been highlighted. Botulinum toxin (BTX) has previously been demonstrated to be effective for bruxism associated with movement disorders, such as cranial-cervical dystonia. However, there is little information on its use in tardive bruxism. Here we report an amphetamine addict who presented with medically intractable bruxism, and discuss its pathophysiology and successful treatment with BTX.

Treatment of temporomandibular disorders with botulinum toxin

Temporomandibular disorder (TMD) is a collective term used to characterize a heterogeneous group of conditions involving the temporomandibular joint (TMJ) and its contiguous tissues. Although the pathologies behind TMDs have not been completely explained, the symptoms associated with these disorders are similar and are most commonly manifest as pain in the orofacial region. In preliminary studies, botulinum toxin has been used successfully to treat various pain syndromes, including TMDs. Because of the complex nature of TMDs and proximity of affected muscles to facial nerves, correct injection technique and appropriate dosing guidelines are very important for successful results. This article describes common TMDs and their treatment with botulinum toxin. Dosing guidelines and illustrations of affected muscles and target injection sites are provided.

Temporomandibular disorders in 19-year-old Korean men

PURPOSE

The purpose of this study was to determine the prevalence and the nature of the relationships between 3 temporomandibular joint disease (TMD) symptoms and symptoms of associated structures.

MATERIALS AND METHODS

This study was designed to rule out the effect from the uneven composition of the samples on TMD symptoms. The samples were collected from subjects who were of the same age, gender, district, and race. Nineteen-year old men (n = 27,978) were selected and investigated by means of questionnaires and clinical examinations. The prevalence of each symptom was studied and tried to determine the effects of the TMD-associated signs on the TMD signs. The indices allocated to reflect the TMD signs and symptoms and the others were dichotomized for bivariate analysis. The predictor variables were headache, neck pain, referred pain, stress, past trauma history in the TMJ, past TMJ dislocation, bruxism, and clenching. The outcome variables were mouth opening limitation, TMJ pain on rest, and TMJ pain during function.

RESULTS

The incidence of masticatory muscle stiffness was 17.8%; TMJ sounds, 14.3%; headache, 7.2%; neck pain, 13.5%; bruxism, 8.4%; and clenching, 9.9%. Stress occurred in 12.8%, past trauma history in 11%, and previous joint dislocation in 2.5%. The experience of dislocation in the TMJ was found to be the most important risk factor in terms of mouth opening limitation (odds ratio, 4.08, P <.0001), joint pain during function (odds ratio, 5.50, P <.0001), and joint pain in the rest state (odds ratio, 4.63, P <.0001). Referred pain and the experience of trauma in TMJ were the secondary risk factors in terms of joint pain and referred pain and the stress in terms of mouth opening limitation. Considering referred pain can be induced by TMD, stress may be more related to mouth opening limitation (odds ratio, 2.18, P <.0001), and the experience of trauma in TMJ may be more related to pain in the rest state (odds ratio, 2.56, P <.0001) and during function (odds ratio, 2.47, P <.0001).

CONCLUSIONS

The prevalence of TMD signs and symptoms as determined by this examination was in accord with the findings in women or mixed samples of other workers. Prior experience of a dislocated disc was found to be the most risky factor in TMD. Stress was related to limitations of mouth opening, and the experience of trauma in the TMJ was found to be related to pain in the joint region. Bruxism may not be a direct risk factor in TMD, and the clenching habit found to be more harmful than bruxism.

Focal dystonia: the role of botulinum toxin

Botulinum toxin (BTX) has been found to be effective in a wide range of focal dystonias. Debate surrounds the selection of injection sites. In general, localization is satisfactory by clinical examination, but poor response, requiring localization of deep muscles, may necessitate use of electromyography for localization. Delineation of optimal doses of BTX is a work in progress; as studies have tended to show efficacy at lower doses than used in the past, the trend is to use lower doses. This is important, because development of antibodies to BTX, the main reason for secondary resistance to this treatment, is more frequent with larger doses and shorter inter-injection intervals. Although the mechanism of denervation of the neuromuscular injunction by BTX is relatively well understood, secondary changes at the level of the basal ganglia, thalamus, and cortex, and their role in response to BTX, need further exploration.

Treating severe bruxism with botulinum toxin

BACKGROUND

Locally administered botulinum toxin, or BTX, is an effective treatment for various movement disorders. Its usefulness in treating bruxism, however, has not been systematically evaluated.

SUBJECTS AND METHODS

The authors studied 18 subjects with severe bruxism and whose mean duration of symptoms was 14.8 +/- 10.0 years (range three-40 years). These subjects audibly ground their teeth and experienced tooth wear and difficulty speaking, swallowing or chewing. Medical or dental procedures had failed to alleviate their symptoms. The authors administered a total of 241 injections of BTX type A, or BTX A, in the subjects' masseter muscles during 123 treatment visits. The mean dose of the BTX A was 61.7 +/- 11.1 mouse units, or MU (range 25-100 MU), per side for the masseter muscles.

RESULTS

The mean total duration of response was 19.1 +/- 17.0 weeks (range six-78 weeks), and the mean peak effect on a scale of 0 to 4, in which 4 is equal to total abolishment of grinding, was 3.4 +/- 0.9. Only one subject (5.6 percent) reported having experienced dysphagia with BTX A.

CONCLUSION

The results of this study suggest that BTX administered by skilled practitioners is a safe and effective treatment for people with severe bruxism, particularly those with associated movement disorders. It should be considered only for those patients refractory to conventional therapy. Future placebo-controlled studies may be useful in further evaluating the potential of BTX in the treatment of bruxism.