Oral health considerations in muscular dystrophies

Muscular dystrophies (MD) are a heterogeneous group of inherited neuromuscular disorders characterized by muscle necrosis and progressive muscle weakness. It is important for oral healthcare providers to be familiar with MD as special considerations are necessary to provide appropriate and safe dental care for these medically complex patients. This article briefly reviews the more common types of MD, namely, Duchenne MD, Becker MD, Emery‐Dreifuss MD, facioscapulo–humeral MD, limb‐girdle MD, oculopharyngeal MD, and myotonic dystrophy. Aspects of their epidemiology, pathophysiology, clinical presentation, diagnosis, and medical management as well as oral health considerations are discussed.     

Masseter thickness,endurance and exercise-induced pain in subjects with different vertical craniofacial morphology

The aim of the study was to compare neuromuscular features of the masseter muscle in subjects with different vertical craniofacial morphology. Fifteen short-faced (mandibular plane-Frankfurt plane angle < 15 degrees) and 15 normal- to long-faced (mandibular plane-Frankfurt plane angle > or = 23 degrees) male students participated. The thickness of the masseter was assessed by ultrasonography. Onset and endurance of exercise pain were recorded during sustained biting at a level of 15% of maximum voluntary contraction and 30 micro V electromyographic activity. Pain and fatigue was measured on visual analog scales before and after the biting, as well as before and after 10 min chewing. Statistical comparison showed that the masseter muscle was significantly thicker (+15%) in the short-faced than the normal- to long-faced subjects. The pain onset time and endurance time were also consistently shorter in short-faced subjects, whereas the intensity of pain and fatigue did not differ significantly between the two groups. Multiple stepwise regression showed positive influence from the mandibular plane inclination and the masseter thickness on the pain onset time and endurance time. The present findings support the concept that subjects with different craniofacial morphology show neuromuscular differences.     

顺式阿曲库铵部分肌松对全麻术中面神经监测的可行性评价

目的: 探讨在需要监测面神经的颅颌面手术中,使用非去极化肌松药顺式阿曲库铵部分肌松状态下进行面神经监测的可行性,并确定其合适的肌松程度。方法: 选择107例术前面神经功能正常、需行颅颌面择期手术及面神经监测的患者,术中使用异丙酚、咪唑安定、瑞芬太尼、顺式阿曲库铵实施全凭静脉麻醉（TIVA）维持全麻,术中由外科医师分别在TOF%（T4/T1）及T1%（T1/T0） 处于不同肌松区间时刺激面神经,记录不同肌松程度下面神经肌电图（EMG）的反应及数值,同时记录术中患者体动评分及是否存在呼吸机对抗。采用SPSS 26.0软件包,绘制受试者工作特征曲线（ROC）,确定面神经监测最佳肌松临床界值; χ²检验分析体动评分及麻醉机对抗与不同肌松程度的关系。结果: 面神经监测有效的最佳肌松临床界值TOF%为15%,T1%为35%,T1%优于TOF%;TOF%>50%、T1%>60%时,患者在术中可能出现体动,呼吸机对抗增加。结论: 全麻使用顺式阿曲库铵部分肌松状态下可有效进行面神经监测,适合的肌松范围推荐TOF%为15%~50%,T1%为35%~60%。     

Compartment syndrome following oral and maxillofacial surgery

Compartment syndrome must be included in the differential diagnosis in any patient who complains of pain or neuromuscular deficit in an extremity. The etiology, differential diagnosis, clinical features, and treatment of compartment syndrome are reviewed to assist in proper diagnosis and management. Although the exact etiology in this case will never be ascertained, delay in diagnosis and treatment resulted in a neuromuscular deficit. It is therefore imperative that proper patient positioning during the perioperative period be closely monitored to avoid this complication.     

Static spinal muscular atrophy causing temporomandibular joint dysfunction

A case of static spinal muscular atrophy is described. The patient presented with temporomandibular joint dysfunction. This case is unusual, not only from the perspective of clinical disease progression, but also that markedly elevated creatine kinase levels were demonstrated. Despite an obvious association of neuromuscular disorders and TMJ disease, reports of primary disorders of muscle and nerve which may predispose to this condition are rare. This case emphasizes the need for careful neuromuscular evaluation in all patients with TMJ dysfunction of nonarticular origin.     

Biologic laws governing functions of muscles that move the mandible. Part II. Condylar position.

A model to quantify muscle response to occlusal contacts is useful in developing an understanding of the mechanism by which the occlusion programs muscle function. A knowledge of how the occlusion programs muscle function enables the dentist to develop manipulative skills of the mandible which are necessary for diagnosis and effective occlusal treatment. This article presents complicated neuromuscular responses (reflexes) to occlusal contacts in an oversimplified way and with analogies so that the clinical significance of these neuromuscular reflexes in diagnosis and treatment can be more easily understood.     

Myocentric. A clinical appraisal

A clinical assessment of neuromuscular occlusal positioning with the Myo-monitor in 63 orthodontic patients.     

Correction of neurological deformity in the foot and ankle

Deformities of the foot and ankle in neuromuscular conditions are often complex and occur at multiple levels. Careful examination of the patient is key to identifying the deformity, and whether it is flexible or fixed. This will help to guide management options. This paper outlines treatment options for the common deformity patterns seen in clinical practice.     

Neuromuscular orthotics in the treatment of craniomandibular dysfunction and the effects on patients with multiple sclerosis: a pilot study

The purpose of this pilot study was to identify, measure and document an effect on the subjective multiple sclerosis symptoms and compare it to any objective data changes in the neuromuscular system of the head and neck, following the correction of the jaw position using a neuromuscular orthotic. The hope is to provide clinical evidence of improvement in the disease long-term without relying on the subjective evidence of remissions and exacerbations reported by the patient. The evidence found in the current pilot study measured improvement of head position, jaw position, jaw function, and airway in the neuromuscular bite position, which correlated with the improvement of subjective symptoms of craniomandibular dysfunction and multiple sclerosis. Studies show that the bite affects blood flow in the brain, which may explain the improvement of the patients in the current study.     

Factors influencing the pantographic tracings of mandibular border movements

Three studies were performed to evaluate the influence of anatomic and neuromuscular factors on pantographic tracings of mandibular border movements. In the first study, the tracings of 50 patients with TMJ and/or muscular dysfunction were made, and the data correlated with the clinical and radiologic findings. In the second study, the tracings of 20 patients were compared before and after therapy. In the third study, the tracings of 20 patients were evaluated before and after a relaxation session with biofeedback. The data showed that both articular and neuromuscular factors influence the tracing pattern. Internal derangements of the TMJ, as well as muscle spasm, lead to typical tracings. The neuromuscular factor can be dramatically improved by relaxation with biofeedback. Repeated pantographic tracings before and during treatment may help in diagnosis and in the evaluation of treatment.     

过渡性治疗义齿在疑难全口义齿修复前的临床应用初探

目的 探讨治疗义齿在疑难全口义齿修复前的临床应用价值。方法 选择36例疑难全口病例修复困难或失败的患者,针对修复困难或失败的原因,应用治疗义齿改善不利于义齿修复的多种因素,通过治疗义齿复制,完成最终义齿修复。采用颌位关系指数、固位力及稳定性评分、口腔健康影响程度-EDENT量表评价治疗过程的有效性。结果 36例患者中,33例患者获得有效治疗,顺利完成最终义齿修复,且修复效果良好。结论 治疗义齿是一种行之有效的治疗方法,能纠正咬合和黏膜面问题并作为口颌系统神经及肌肉康复训练的工具,有助于最终义齿修复,值得临床推广和应用。     

The gait cycle and its variations with disease and injury

Assessment of gait forms an integral part of the clinical examination of the lower limbs. Normal gait requires stability and adequate clearance and positioning of the limb throughout the gait cycle. Gait disturbances arise secondary to either musculoskeletal disorders or neuromuscular disorders. Disease processes and injuries cause characteristic changes in gait that are clinically observed dependent on the affected area (i.e. hip, knee, foot or ankle), aetiology and any resulting deformities. In this article we review the normal gait cycle and how it varies with certain disease processes and injuries.     

The use of transcranial stimulation in the fabrication of an occlusal splint.

An alternative method for fabricating occlusal splints by means of electric transcortical stimulation is presented. Ensuing results in one patient suggest neuromuscular benefits. However, the centric occlusal position determined by this method is a painful procedure because of electric stimulation on the scalp. Further and extensive investigations must be carried out to assess the clinical benefits and limits of this method.     

Duchenne muscular dystrophy — a dental healthcare program

Duchenne muscular dystrophy (DMD) is a genetically determined disease. The chief characteristic of this clinical syndrome is a progressive degeneration of particular groups of muscles. Initially there is physical impairment, contractures, and muscular atrophy. Subsequently, the disease immobilizes the patient (ages 9 to 14 years) and severe respiratory failure occurs due to chest and vertebral column deformity. We present principies for the dental care of patients with DMD. It is important to introduce dental and prophylactic treatment at a very early age for children with DMD.     

Oromandibular dystonia

Oromandibular dystonia (OMD) is a rare neuromuscular disorder characterized by involuntary repetitive muscular contraction affecting different parts of the oromandibular region. Its various physical manifestations can be extremely debilitating and socially disabling to affected patients. To date, there is no commonly accepted set of diagnostic criteria nor well-defined management pathways. This paper aims to discuss some aspects of clinical manifestations, diagnostic criteria, neurological mechanisms, and treatment options for OMD, with illustrations from 6 clinical cases.     

Functional Processes when Wearing a SII Appliance during the Day

In 20 subjects the neuromuscular activity during the day was divided into six different activities and recorded. In the case of typical application of the SII appliance for 4 hours in the afternoon and the free organization of this time by the patient himself, most of the time fell into the area "intellectual activity" followed by the area "manual activity". Since the term "functional orthodontics" naturally describes the function, this should be realized most impressively when wearing such an appliance during the day. During the day there are mouth opening and closing movements of varying frequency with quite different amplitudes. Conversation as well as reading a text aloud can be considered favorable in terms of neuromuscular adaptation. Obviously, the relatively short habituation period soon results in the patient not needing the bars as guiding bars any more (this is in contrast to investigations during nocturnal sleep). In other words, the patient needs them only for a brief time to influence the muscles in such a way that the neuromuscular masticatory pattern is virtually independent of the bars. Only during intellectual and practical activity does the patient rest on the inclined plane with the help of the bars and execute small movements. Consequently, wearing the SII appliance during the day can be regarded as extremely important to the success of treatment. Important neuromuscular influences occur while doing homework as well as during intellectual activity. Wearing the appliance during the day corresponds to neuromuscular programming, so that the term "functional orthodontic appliance" is completely correct. Since there are only about 600 biting actions during the night, a functional orthodontic appliance should definitely be worn for a certain time during the day too, in order not to jeopardize the neuromuscular adaptation.     

Implant-retained overdentures: a review

Implant-retained overdentures represent a treatment option for many patients unable to tolerate conventional dentures. They may be specifically indicated in patients with altered anatomy, neuromuscular disorders, a pronounced gag reflex or severe residual ridge resorption. This article discusses the different ways in which implant overdentures can be retained, outlines some of the clinical stages involved in planning and providing these prostheses, and highlights long-term maintenance requirements associated with implant-retained overdentures. Clinical Relevance: Patients with implant-retained overdentures are likely to present in general dental practice. Practitioners should be aware of issues associated with the design, treatment planning and maintenance of these prostheses.     

Jaw motor inputs originating from osseointegrated oral implants

Jaw motor inputs from endosseous oral implants have been investigated to a limited extent. Observations of jaw muscle reflexes in edentulous patients rehabilitated by means of implants do not prove that they originate from the implants unless the stimuli are properly defined. Few studies have isolated inputs, such as electrical of mechanical stimuli, to make sure that they are conveyed through the implants. Even under these conditions one should be aware that such stimuli can trigger distant receptors. The most striking difference is that tapping an upper jaw implant in a fully edentulous patient does not give lead to a silent period in the jaw closing muscles. At the clinical level the changes in neuromuscular reflexes do not lead to significant problems.     

Improvement and long-term stability of neuromuscular adaptation in implant-supported overdentures

Objectives: In edentulous patients, implant-supported overdentures can improve chewing efficiency and patient satisfaction, and even a positive impact on bone tissue preservation has been observed. The objective of this long-term study was to investigate whether kinesiographic and electromyographic (EMG) parameters would also benefit from implant placement and whether the status achieved would remain consistent over time.
Material and methods: The functional adaptability of the neuromuscular system in edentulous patients has been recorded in four different states of restoration: (1) insufficient old dentures, (2) new complete dentures, (3) implant-supported overdentures, and (4) implant-supported overdentures 10 years in use. In each state of restoration, the neuromuscular adaptation was assessed during masticatory activity on the basis of myodynamic parameters such as vertical opening, frontal extension and closing velocity. EMG parameters, i.e. Musculus masseter and Musculus temporalis activities were recorded simultaneously.
Results: The results revealed a general increase in the myodynamic and EMG-parameters. All of them clearly approached the values for normal dentate subjects and maintained this level over a period of 10 years. The significant changes between states 2 and 3 indicate that implant stabilization of dentures is accompanied by an immediate increase of the neuromuscular parameters.
Conclusions: In elderly edentulous patients, the treatment with two interforaminal implants provides evidence of neuromuscular adaptation towards values of healthy dentate. Thus, the known benefits of implant placement such as tissue perseverance and improved function are complemented by improved neuromuscular adaptation.     

The Influence of the Herpes Simplex Virus on Jaw Muscle Function

This article reports on electromyographic and electronic mandibular motion analysis examinations given to 25 patients with clinical symptoms of the temporomandibular joint. Twenty-three of the 25 had clear clinical histories of herpetic viral infections (HSV-I). In those 23 subjects, the electromyograph (EMG) showed dysfunction of the masticatory muscles typical of permanent motor neuron damage.

Several other studies reported in the medical literature have suggested that herpetic virus infection is associated with the neuromuscular dysfunction typically seen in the temporomandibular syndrome. The results of this preliminary study support those findings and indicate that the herpetic virus may well be involved in TMJ muscle dysfunction.