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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: 10.61872/sdj-2018-09-442 -
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 -
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 -
Journal of Oral Rehabilitation Aug 2018The impression of increased muscle hardness in painful muscles is commonly reported in the clinical practice but may be difficult to assess. Therefore, the aim of this... (Review)
Review
The impression of increased muscle hardness in painful muscles is commonly reported in the clinical practice but may be difficult to assess. Therefore, the aim of this review was to present and discuss relevant aspects regarding the assessment of muscle hardness and its association with myofascial temporomandibular disorder (TMD) pain. A non-systematic search for studies of muscle hardness assessment in patients with pain-related TMDs was carried out in PubMed, Cochrane Library, Embase and Google Scholar. Mechanical devices and ultrasound imaging (strain and shear wave elastography) have been consistently used to measure masticatory muscle hardness, although an undisputable reference standard is yet to be determined. Strain elastography has identified greater masseter hardness of the symptomatic side in patients with unilateral myofascial TMD pain when compared to the contralateral side and healthy controls (HC). Likewise, shear wave elastography has shown greater masseter elasticity modulus in patients with myofascial TMD pain when compared to HC, which may be an indication of muscle hardness. Although assessment bias could partly explain these preliminary findings, future randomised controlled trials are encouraged to investigate this relationship. This qualitative review indicates that the muscle hardness of masticatory muscles is still a rather unexplored field of investigation with a good potential to improve the assessment and potentially also the management of myofascial TMD pain. Nonetheless, the current evidence in favour of increased hardness in masticatory muscles in patients with myofascial TMD pain is weak, and the pathophysiological importance and clinical usefulness of such information remain unclear.
Topics: Elasticity Imaging Techniques; Hardness; Humans; Masticatory Muscles; Muscle Contraction; Myalgia; Myofascial Pain Syndromes; Reference Standards; Temporomandibular Joint Disorders
PubMed: 29745983
DOI: 10.1111/joor.12644 -
Journal of Molecular Neuroscience : MN May 2020Cytokines are proteins secreted by diverse types of immune and non-immune cells and play a role in the communication between the immune and nervous systems. Cytokines... (Review)
Review
Cytokines are proteins secreted by diverse types of immune and non-immune cells and play a role in the communication between the immune and nervous systems. Cytokines include lymphokines, monokines, chemokines, interleukins, interferons, colony stimulating factors, and growth factors. They can be both pro- and anti-inflammatory and have autocrine, paracrine, and endocrine activities. These proteins are involved in initiation and persistence of pain, and the progress of hyperalgesia and allodynia, upon stimulating nociceptive sensory neurons, and inducing central sensitization. The objective of this review is to discuss several types of pro- and anti-inflammatory mediators and their relation with inflammatory pain in masticatory muscles.
Topics: Animals; Craniomandibular Disorders; Facial Pain; Humans; Inflammation Mediators; Interleukins; Masticatory Muscles
PubMed: 32008162
DOI: 10.1007/s12031-020-01491-1 -
Sleep Nov 2022The aim of the present study was to investigate orofacial pain in individuals with Down syndrome (DS) and determine possible associations with masticatory muscle...
The aim of the present study was to investigate orofacial pain in individuals with Down syndrome (DS) and determine possible associations with masticatory muscle hypotonia (MMH), maximum mouth opening (MMO), and sleep disorders. Twenty-three individuals with DS underwent a standardized clinical examination using Axis I of the Diagnostic Criteria for Temporomandibular Disorders, for the diagnosis of pain in the masseter and temporal muscles and temporomandibular joint (TMJ). MMH was investigated using electromyography of the temporal and masseter muscles and the measurement of maximum bite force (MBF). MMO was measured using an analog caliper. Sleep disorders (obstructive sleep apnea [OSA], snoring index [SI], and sleep bruxism index [SBI]) were investigated using type II polysomnography. Statistical analysis was performed. Nonsignificant differences were found in muscle and TMJ pain between the sexes. However, myalgia and referred myofascial pain in the left masseter muscle were more frequent in males (69%) than females (40%). Electrical activity of the temporal (left: p = .002; right: p = .004) and masseter (left: p = .008) muscles was significantly lower in males than in females. MBF range was lower in males than females, indicating the highest MMH among males. OSA, SI, and SBI were identified in both sexes, but with no statistically significant differences. We concluded that myalgia and referred myofascial pain were found in some individuals with DS, especially in males. Arthralgia was found mainly in females. Temporal and masseter myalgia may have exerted an influence on the severity of MMH in males, particularly on the left side.
Topics: Male; Female; Humans; Masseter Muscle; Myalgia; Down Syndrome; Muscle Hypotonia; Masticatory Muscles; Facial Pain; Sleep Bruxism; Electromyography; Sleep Wake Disorders; Sleep Apnea, Obstructive
PubMed: 35907210
DOI: 10.1093/sleep/zsac181 -
Clinical and Experimental Dental... Jun 2023The purpose of this study was to elucidate how masticatory muscles are involved in the generation of occlusal force.
OBJECTIVES
The purpose of this study was to elucidate how masticatory muscles are involved in the generation of occlusal force.
MATERIALS AND METHODS
The experiment was conducted by fabricating an experimental apparatus for a unilateral occlusion model with the masticatory muscles imparted. The experimental apparatus was fabricated by enlarging the lateral photograph of a dried adult skull specimen 3.5 times larger than that of a standard adult and drawing the outlines of the maxilla and mandible, canines and molars of the upper and lower jaws, and temporomandibular joint on a wooden board. The masticatory muscles used in the experiment were the masseter muscle, the temporalis muscle (anterior and posterior muscle bundles), and the lateral pterygoid muscle. For the measurement of the contractile force of the masticatory muscle, we used the spring scale. For the food, we used cut plastic cylinders.
RESULTS
The results of the experiment revealed the following: First, the occlusal force was generated under the condition that the contraction forces of all the masticatory muscles were balanced. Second, when the occlusal force was applied to food, the occlusal planes of the upper and lower jaws were parallel. Third, the occlusal force occurred perpendicular to the occlusal plane. Fourth, the occlusal force was generated with a force greater than the contraction force of the individual masticatory muscles. And finally, even if occlusal force was applied to the food, the occlusal force did not load the temporomandibular joint.
CONCLUSION
Occlusal force is not generated by the action of a single masticatory muscle but under the balanced contractile force of all masticatory muscles. The occlusal force then emerges with a force greater than the contraction force of all the masticatory muscles, and its direction occurs perpendicular to the occlusal plane.
Topics: Masseter Muscle; Bite Force; Masticatory Muscles; Pterygoid Muscles; Maxilla
PubMed: 36924025
DOI: 10.1002/cre2.725 -
Journal of Oral Rehabilitation Mar 2022Muscle-related temporomandibular disorders (TMD) may affect the masticatory function. Chewing function can be assessed objectively using bolus-kneading tests, such as... (Observational Study)
Observational Study
BACKGROUND
Muscle-related temporomandibular disorders (TMD) may affect the masticatory function. Chewing function can be assessed objectively using bolus-kneading tests, such as two-colour chewing-gum mixing ability test.
OBJECTIVE
The aim was to compare the masticatory function with a two-colour chewing-gum test before and after treatment of the masticatory muscle-related temporomandibular disorder.
METHODS
Twenty-one patients with masticatory muscle disorder according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were recruited as an experimental group, and further twenty-one participants without any TMD were included as controls. Pain intensity (scored on a visual-analogue scale) and maximum mouth opening (MMO) were recorded. Jaw Functional Limitation Scale-8 (JFLS-8) was conducted on all patients. Before and after treatment, masticatory function was evaluated with a validated bolus-kneading test, using two-colour chewing gum.
RESULTS
There was no statistically significant difference in chewing function before and after treatment in the experimental group (p = .715). When these values were compared with the control group, there were no statistically significant differences (p = .489, p = .890). There was no correlation between masticatory function and VAS, MMO, JFLS-8 before and after treatment in the experimental group.
CONCLUSION
The two-colour chewing-gum test is not sensitive when the masticatory performance is not severely impaired.
Topics: Chewing Gum; Humans; Jaw; Masseter Muscle; Mastication; Masticatory Muscles; Temporomandibular Joint Disorders
PubMed: 34817873
DOI: 10.1111/joor.13286