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Journal of Oral Rehabilitation Nov 2018In 2013, consensus was obtained on a definition of bruxism as repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or by...
In 2013, consensus was obtained on a definition of bruxism as repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible and specified as either sleep bruxism or awake bruxism. In addition, a grading system was proposed to determine the likelihood that a certain assessment of bruxism actually yields a valid outcome. This study discusses the need for an updated consensus and has the following aims: (i) to further clarify the 2013 definition and to develop separate definitions for sleep and awake bruxism; (ii) to determine whether bruxism is a disorder rather than a behaviour that can be a risk factor for certain clinical conditions; (iii) to re-examine the 2013 grading system; and (iv) to develop a research agenda. It was concluded that: (i) sleep and awake bruxism are masticatory muscle activities that occur during sleep (characterised as rhythmic or non-rhythmic) and wakefulness (characterised by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible), respectively; (ii) in otherwise healthy individuals, bruxism should not be considered as a disorder, but rather as a behaviour that can be a risk (and/or protective) factor for certain clinical consequences; (iii) both non-instrumental approaches (notably self-report) and instrumental approaches (notably electromyography) can be employed to assess bruxism; and (iv) standard cut-off points for establishing the presence or absence of bruxism should not be used in otherwise healthy individuals; rather, bruxism-related masticatory muscle activities should be assessed in the behaviour's continuum.
Topics: Bruxism; Consensus; Diagnosis, Differential; Electromyography; Humans; Masticatory Muscles; Polysomnography; Sleep; Wakefulness
PubMed: 29926505
DOI: 10.1111/joor.12663 -
The International Journal of... 2017Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international... (Review)
Review
Bruxism is a common phenomenon involving repetitive activation of the masticatory muscles. Muscle-stretching exercises are a recommended part of several international guidelines for musculoskeletal disorders and may be effective in management of the jaw muscle activity that gives rise to bruxism. However, most studies of muscle-stretching exercises have mainly focused on their influence on performance (eg, range of motion, coordination, and muscle strength) of the limb or trunk muscles of healthy individuals or individuals with sports-related injuries. Very few have investigated stretching of the human masticatory muscles and none muscle-stretching exercises in the management of (sleep) bruxism. This article reviews the literature on muscle-stretching exercises and their potential role in the management of sleep bruxism or its consequences in the musculoskeletal system.
Topics: Bruxism; Exercise Therapy; Humans; Masticatory Muscles
PubMed: 28267818
DOI: 10.11607/ijp.5082 -
Swiss Dental Journal Sep 2018The individual appearance and facial expression are based on the musculoskeletal system of the face. The bones of the face contribute to the anterior portion of the... (Review)
Review
The individual appearance and facial expression are based on the musculoskeletal system of the face. The bones of the face contribute to the anterior portion of the skull. This region is also referred to as the facial skeleton or viscerocranium. The muscles of the face include all mimetic muscles innervated by the cranial nerve VII (facial nerve). Two masticatory muscles (masseter, temporalis) that are supplied by the motoric portion of the cranial nerve V3 (mandibular nerve) also contribute to the contour of the face. The mimetic muscles (also known as facial muscles or skin muscles) generally originate from underlying bone surfaces and insert to the skin of the face or intermingle with other facial muscles. This complex musculature contributes to the functioning of the orofacial sense organs and the mediation of emotional and affective states (facial expression). Other soft tissue components of the face include the fasciae and fat compartments. The face commonly exhibits a superficial and a deep fascia, and various facial fat compartments are present.
Topics: Face; Facial Muscles; Facial Nerve; Masseter Muscle; Temporal Muscle
PubMed: 30056693
DOI: No ID Found -
Clinical Oral Investigations Mar 2022To investigate the effects of dental/skeletal malocclusion and orthodontic treatment on four main objective parameters of chewing and jaw function (maximum occlusal bite... (Review)
Review
OBJECTIVE
To investigate the effects of dental/skeletal malocclusion and orthodontic treatment on four main objective parameters of chewing and jaw function (maximum occlusal bite force [MOBF], masticatory muscle electromyography [EMG], jaw kinematics, and chewing efficiency/performance) in healthy children.
MATERIALS AND METHODS
Systematic searches were conducted in MEDLINE (OVID), Embase, and the Web of Science Core Collection. Studies that examined the four parameters in healthy children with malocclusions were included. The quality of studies and overall evidence were assessed using the Joanna Briggs Institute and GRADE tools, respectively.
RESULTS
The searches identified 8192 studies; 57 were finally included. The quality of included studies was high in nine studies, moderate in twenty-three studies, and low in twenty-five studies. During the primary dentition, children with malocclusions showed similar MOBF and lower chewing efficiency compared to control subjects. During mixed/permanent dentition, children with malocclusion showed lower MOBF and EMG activity and chewing efficiency compared to control subjects. The jaw kinematics of children with unilateral posterior crossbite showed a larger jaw opening angle and a higher frequency of reverse chewing cycles compared to crossbite-free children. There was a low to moderate level of evidence on the effects of orthodontic treatment in restoring normal jaw function.
CONCLUSIONS
Based on the limitations of the studies included, it is not entirely possible to either support or deny the influence of dental/skeletal malocclusion traits on MOBF, EMG, jaw kinematics, and masticatory performance in healthy children. Furthermore, well-designed longitudinal studies may be needed to determine whether orthodontic treatments can improve chewing function in general.
CLINICAL RELEVANCE
Comprehensive orthodontic treatment, which includes evaluation and restoration of function, may or may not mitigate the effects of malocclusion and restore normal chewing function.
Topics: Bite Force; Child; Electromyography; Humans; Malocclusion; Masseter Muscle; Mastication; Masticatory Muscles
PubMed: 34985577
DOI: 10.1007/s00784-021-04356-y -
International Journal of Environmental... Dec 2021Temporomandibular disorders (TMD) are primarily characterized by pain as well as disorders concerning the proper functioning of individual elements of the stomatognathic... (Randomized Controlled Trial)
Randomized Controlled Trial
Temporomandibular disorders (TMD) are primarily characterized by pain as well as disorders concerning the proper functioning of individual elements of the stomatognathic system (SS). The aim of the study was to compare the degree of relaxation of the anterior part of the temporal muscles and the masseter muscles, achieved through the use of post-isometric relaxation and myofascial release methods in patients requiring prosthetic treatment due to temporomandibular joint disorders with a dominant muscular component. Sixty patients who met the inclusion criteria were alternately assigned to one of the two study groups, either group I-patients received post-isometric relaxation treatment (PIR), or group II-patients received myofascial release treatment (MR). The series of ten treatments were performed in both groups. The comparative assessment was based on physiotherapeutic examination, a surface electromyography (sEMG) of the anterior temporal and masseter muscles and the intensity of spontaneous masticatory muscle pain, assessed using the Visual Analogue Scale (VAS). We observed a significant decrease in the electrical activity of examined muscles and a significant drop in the intensity of spontaneous pain in the masticatory muscles both in group I and II. There were no significant differences between groups. Both therapeutic methods may be used as successful forms of adjunctive therapy in the prosthetic treatment of TMD. The trial was registered with an international clinical trials register.
Topics: Electromyography; Humans; Masseter Muscle; Masticatory Muscles; Myofascial Release Therapy; Temporal Muscle; Temporomandibular Joint Disorders
PubMed: 34948580
DOI: 10.3390/ijerph182412970 -
Journal of Veterinary Internal Medicine 2004A retrospective study was performed on 200 randomly selected cases of inflammatory myopathy in dogs from diagnostic muscle biopsies received at the Comparative...
A retrospective study was performed on 200 randomly selected cases of inflammatory myopathy in dogs from diagnostic muscle biopsies received at the Comparative Neuromuscular Laboratory, University of California, San Diego. The most common clinical signs in dogs diagnosed with an inflammatory myopathy were generalized weakness, stilted gait, dysphagia, masticatory or generalized muscle atrophy, inability to open the jaw, megaesophagus, and dysphonia. Myalgia was rarely described. Age of onset ranged from 0.25 to 14 years. Genders were equally represented. Breed distribution approximated the 2002 American Kennel Club registration statistics (r = .85) with the notable exception of Boxers and Newfoundlands. From the results of muscle biopsies, clinical signs, and presence or absence of antibodies against type 2M fibers, dogs were classified as a generalized inflammatory myopathy (gIM)--including immune-mediated polymyositis; infectious and preneoplastic myositis; and, rarely, dermatomyositislike or overlap syndromes or unclassified myositis-or a focal inflammatory myopathy (flM)--including masticatory muscle and extraocular myositis. Average creatine kinase (CK) and aspartate aminotransferase (AST) concentrations in gIMs were significantly higher than those with fIMs (P < .05). Neoplasia developed in 12 of 200 dogs within 12 months of diagnosis of polymyositis, with lymphoma diagnosed in 6 of 32 Boxers. Inflammatory myopathy was associated with antibody titers against infectious diseases in 38 dogs. Neospora caninum and Hepatozoon americanum cysts were found in tissues of 2 dogs not serologically tested. Antibodies against an unidentified sarcolemmal antigen were found in 9 of 19 Newfoundlands with polymyositis. The spectrum of canine inflammatory myopathies can be broad, with infectious etiologies relatively common, and can include preneoplastic and uncharacterized syndromes.
Topics: Animals; Aspartate Aminotransferases; Creatine Kinase; Dermatomyositis; Dog Diseases; Dogs; Female; Male; Masticatory Muscles; Muscle Fibers, Fast-Twitch; Myositis; Polymyositis; Retrospective Studies; Serologic Tests
PubMed: 15515585
DOI: 10.1892/0891-6640(2004)18<679:cimacr>2.0.co;2 -
Anatomical Record (Hoboken, N.J. : 2007) Apr 2019The masticatory muscles, which are composed of four main muscles, are innervated by branches of only one of the cranial nerves, the mandibular nerve. This muscle group... (Review)
Review
The masticatory muscles, which are composed of four main muscles, are innervated by branches of only one of the cranial nerves, the mandibular nerve. This muscle group has a variety of very complex functions. We have investigated the origins and insertions of the masticatory muscles and the adjacent bundles of the main muscles, and closely examined the positional relationships between the muscle bundles and innervating branches. According to the findings of the nerve branching patterns, the masticatory muscles can be classified into two groups: the inner group consisting of the lateral pterygoid muscle, and the outer group consisting of the other muscles and adjacent muscle bundles. Further, the outer muscle group is sub-divided into the three other main muscles (the masseter, the temporalis, and the medial pterygoid muscle) and the adjacent various transitional muscle bundles. Anat Rec, 302:609-619, 2019. © 2018 Wiley Periodicals, Inc.
Topics: Humans; Mandibular Nerve; Masticatory Muscles
PubMed: 30312011
DOI: 10.1002/ar.23943 -
Frontiers in Endocrinology 2020The masticatory system is a complex and highly organized group of structures, including craniofacial bones (maxillae and mandible), muscles, teeth, joints, and... (Review)
Review
The masticatory system is a complex and highly organized group of structures, including craniofacial bones (maxillae and mandible), muscles, teeth, joints, and neurovascular elements. While the musculoskeletal structures of the head and neck are known to have a different embryonic origin, morphology, biomechanical demands, and biochemical characteristics than the trunk and limbs, their particular molecular basis and cell biology have been much less explored. In the last decade, the concept of muscle-bone crosstalk has emerged, comprising both the loads generated during muscle contraction and a biochemical component through soluble molecules. Bone cells embedded in the mineralized tissue respond to the biomechanical input by releasing molecular factors that impact the homeostasis of the attaching skeletal muscle. In the same way, muscle-derived factors act as soluble signals that modulate the remodeling process of the underlying bones. This concept of muscle-bone crosstalk at a molecular level is particularly interesting in the mandible, due to its tight anatomical relationship with one of the biggest and strongest masticatory muscles, the masseter. However, despite the close physical and physiological interaction of both tissues for proper functioning, this topic has been poorly addressed. Here we present one of the most detailed reviews of the literature to date regarding the biomechanical and biochemical interaction between muscles and bones of the masticatory system, both during development and in physiological or pathological remodeling processes. Evidence related to how masticatory function shapes the craniofacial bones is discussed, and a proposal presented that the masticatory muscles and craniofacial bones serve as secretory tissues. We furthermore discuss our current findings of myokines-release from masseter muscle in physiological conditions, during functional adaptation or pathology, and their putative role as bone-modulators in the craniofacial system. Finally, we address the physiological implications of the crosstalk between muscles and bones in the masticatory system, analyzing pathologies or clinical procedures in which the alteration of one of them affects the homeostasis of the other. Unveiling the mechanisms of muscle-bone crosstalk in the masticatory system opens broad possibilities for understanding and treating temporomandibular disorders, which severely impair the quality of life, with a high cost for diagnosis and management.
Topics: Animals; Biomechanical Phenomena; Bone and Bones; Humans; Mandible; Masticatory Muscles; Maxilla; Stomatognathic System
PubMed: 33732211
DOI: 10.3389/fendo.2020.606947 -
Nutrients Nov 2021Sensing subjective hedonic or emotional experiences during eating using physiological activity is practically and theoretically important. A recent psychophysiological... (Randomized Controlled Trial)
Randomized Controlled Trial
Sensing subjective hedonic or emotional experiences during eating using physiological activity is practically and theoretically important. A recent psychophysiological study has reported that facial electromyography (EMG) measured from the corrugator supercilii muscles was negatively associated with hedonic ratings, including liking, wanting, and valence, during the consumption of solid foods. However, the study protocol prevented participants from natural mastication (crushing of food between the teeth) during physiological data acquisition, which could hide associations between hedonic experiences and masticatory muscle activity during natural eating. We investigated this issue by assessing participants' subjective ratings (liking, wanting, valence, and arousal) and recording physiological measures, including EMG of the corrugator supercilii, zygomatic major, masseter, and suprahyoid muscles while they consumed gel-type solid foods (water-based gellan gum jellies) of diverse flavors. Ratings of liking, wanting, and valence were negatively correlated with corrugator supercilii EMG and positively correlated with masseter and suprahyoid EMG. These findings imply that subjective hedonic experiences during food consumption can be sensed using EMG signals from the brow and masticatory muscles.
Topics: Adult; Eating; Electromyography; Eyebrows; Facial Muscles; Female; Humans; Male; Mastication; Masticatory Muscles; Philosophy; Young Adult
PubMed: 34959773
DOI: 10.3390/nu13124216 -
Folia Medica Cracoviensia Apr 2023Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular... (Review)
Review
Temporomandibular disorder (TMD) is a disease of multifactorial etiology and a complex of symptoms, related to disorders of the masticatory muscles, temporomandibular joints and the surrounding orofacial structures. One of the main problems in the course of TMD disorders is the systematic increase in the tension of the masticatory muscles (masseter muscles, temporalis and medial and lateral pterygoid muscles), what is the cause of many damages and the development of pathological conditions in the stomatognathic system. The article discusses the differences in the structure of the masticatory and skeletal muscles, as well as the different nature and isoforms of myosin, which determines the much faster generation of contraction in the masticatory muscles and consequently easier generation of excessive, harmful tensions in the masticatory muscles. The article describes the causes of increased tension in the masticatory muscles and methods of their relaxation used in the basic and supportive treatment of temporomandibular disorders. The use of occlusal splints, physiotherapeutic procedures and TMD treatment with botulinum toxin type A were characterized. A role of psychological support and the methods used for patients with TMD were emphasized.
Topics: Humans; Temporomandibular Joint Disorders; Masticatory Muscles; Masseter Muscle; Temporomandibular Joint; Occlusal Splints
PubMed: 37406276
DOI: 10.24425/fmc.2023.145429