An Electromyographic Study on the Unloading Reflex of Masticatory Muscles.

BACKGROUND Masticatory system is a complex functional unit, primarily engaged in chewing, swallowing and breathing functions, and some parts are involved in taste recognition and determination of food consistency. Sophisticated functional performances of speech and emotional expressions are specifically human qualities. Irregularities in occlusion appears to be the precipitating factor in the pathogenesis of myofascial pain dysfunction syndrome. Tek- Scan III records the bite length, number, distribution, timing, duration and the relative force of each tooth contact. It also records the sequence of occlusal contacts in terms of time and the associated force with each occlusal contact. The aim of this study was to treat masticatory muscle disorders with occlusal equilibration, and compare the efficacy of treatment outcomes between selective grinding and stabilization splints using Tek-Scan III. OBJECTIVE Objective of this study was to compare the efficacy of occlusal equilibration achieved through selective griding and stabilization splints using Tek-Scan III. METHODS In this in vivo study, 40 patients with masticatory muscle disorders were selected based on the inclusion and exclusion criteria. The occlusal discrepancies were analyzed using Tek-Scan III. The selected 40 subjects were then randomly divided into 2 groups based on the treatment they recieved; Group I – Selective grinding group (20) and Group II – Stabilization splint group (20). Comparison of pre-treatment and post treatment results were evaluated in terms of pain, mouth opening, left and right side force percentage as recorded through Tek-Scan III and reduction of disclusion time. Statistical analysis was carried out with Kolmogorov Smirnov test, Wilcoxon matched pair test and Mann-Whitney U test. RESULTS Wilcoxon matched pairs test demonstrated that there was statistically significant results ( p = 0.0007) in both the groups for reduction of disclusion time, elimination of pain and improved mouth opening. Patients in Group I showed better results as compared to Group II in terms of disclusion time, pain and mouth opening. CONCLUSIONS Occlusal equilibration brought about by reducing the disclusion time using the Tek- Scan III reduced the symptoms of pain in masticatory muscles. Patients in group I (Selective grinding) however showed better results when compared to patients in group II (Stabilization splints).

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Temporomandibular Disorders and Bruxism Prevalence in a Portuguese Sample

Medical Sciences Forum ◽

10.3390/msf2021005037 ◽

2021 ◽

Vol 5 (1) ◽

pp. 37

Author(s):

João Belo ◽

André Almeida ◽

Paula Moleirinho-Alves ◽

Catarina Godinho

Keyword(s):

Temporomandibular Joint ◽

Temporomandibular Disorders ◽

Temporomandibular Disorder ◽

Masticatory Muscles ◽

Diagnostic Aspects ◽

Relevant Role

Temporomandibular disorder (TMD) encompasses a set of disorders involving the masticatory muscles, the temporomandibular joint and associated structures. It is a complex biopsychosocial disorder with several triggering, predisposing and perpetuating factors. In the etiology of TMD, oral parafunctions, namely bruxism, play a relevant role. The study of bruxism is complicated by some taxonomic and diagnostic aspects that have prevented achieving an acceptable standardization of diagnosis. The aim of this study was to analyze the prevalence of temporomandibular disorders and bruxism in a Portuguese sample.

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Smartphone addiction and the relationship with head and neck pain and electromiographic activity of masticatory muscles

Work ◽

10.3233/wor-203398 ◽

2021 ◽

pp. 1-8

Author(s):

Fabiana Foltran Mescollotto ◽

Érica Brito Gonçalves ◽

Ester Moreira de Castro Carletti ◽

Ana Beatriz Oliveira ◽

Elisa Bizetti Pelai ◽

...

Keyword(s):

College Students ◽

Neck Pain ◽

Head And Neck ◽

Muscle Activity ◽

Neck Region ◽

Masticatory Muscles ◽

Smartphone Addiction ◽

Before And After ◽

Smartphone Use ◽

The Right

Background: Excessive use of smartphones may be associated with behavioral and physical health changes and might cause musculoskeletal alterations in the head and neck region. Objective: To evaluate the prevalence of smartphone addiction in college students and its correlation with symptoms of head and neck pain and masticatory and trapezius muscle activity while resting, before and after smartphone use. Methods: Twenty university students participated in the study. They answered the Smartphone Addiction Scale and the Fonseca Anamnestic Index. Next, the participants were seated and prepared for electromyography through the placement of surface electrodes on the masseter, temporal, and trapezius muscles. Rest condition data were collected for 10 seconds before and after 30 minutes of smartphone use. Results: The results showed that 35% of the evaluated individuals were classified as smartphone addicted and 35% reported no head or neck pain in the previous 30 days. There was no association between smartphone use and head and neck pain. In the electromyography, there was an increase in RMS values after smartphone use in the right and left masseter muscles and the left trapezius. Conclusion: College students presented a high prevalence of smartphone addiction and head and neck pain, but these were not statistically associated. There was a change in muscle activity only in the right trapezius muscles before and after 30 minutes of smartphone use. These findings are contrary to the current belief that the use of smartphones correlates with pain in the neck region and changes in the electrical muscle activity, leading to fatigue in the cervical muscles.

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Short-Term Effect of Orthodontic Treatment with Clear Aligners on Pain and sEMG Activity of Masticatory Muscles

Medicina ◽

10.3390/medicina57020178 ◽

2021 ◽

Vol 57 (2) ◽

pp. 178

Author(s):

Alessandro Nota ◽

Silvia Caruso ◽

Shideh Ehsani ◽

Gianmaria Fabrizio Ferrazzano ◽

Roberto Gatto ◽

...

Keyword(s):

Surface Electromyography ◽

Orthodontic Treatment ◽

Masticatory Muscles ◽

Rank Test ◽

Nominal Data ◽

Chi Square ◽

Initial Reduction ◽

Signed Rank Test ◽

Chi Square Test ◽

Semg Activity

Background and objectives: The aim of this study is to evaluate mandibular elevator muscles activity and pain on palpation in the early stages of orthodontic treatment with clear aligners using surface electromyography (sEMG). Materials and methods: Surface electromyography (sEMG) activity and pain level on muscle palpation of masseter and anterior temporalis muscles were recorded in a sample of 16 adult subjects (aged 18–32 years; mean 22.5 +/− 3.5 SD) undergoing orthodontic treatment with clear aligners before the treatment (T0), after 1 month of treatment (two clear aligners) (T1), and after 3 months of treatment (T2) (six clear aligners). A chi-square test for nominal data, a Friedman test, and a Wilcoxon-signed rank test as post hoc analysis were applied. Results: No statistically significant differences in muscular pain were observed. At T1, the sEMG activity of masseter muscles at mandibular rest position showed a statistically significant reduction, but after 3 months (T2), the data appeared similar to T0 (p = 0.03 and p = 0.02). Conclusions: During the treatment with clear aligners, subjects could experience an initial reduction in the masseter basal activity after 1 month of treatment. This effect tends to decrease to baseline levels after 3 months of therapy.

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The reciprocal jaw-muscle reflexes elicited by anterior- and back-tooth-contacts—a perspective to explain the control of the masticatory muscles

BDJ Open ◽

10.1038/s41405-020-00056-z ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Lauri Vaahtoniemi

Keyword(s):

Masticatory Muscles ◽

Food Bolus ◽

Dental Patients ◽

Adductor Muscles ◽

Jaw Muscle ◽

Class 1 ◽

Reflex Control ◽

Control Hypothesis ◽

Muscle Reflexes ◽

Inhibitory Reflex

Abstract Aims Tooth-contact sensations are considered essential to boost jaw adductor muscles during mastication. However, no previous studies have explained the importance of the inhibitory reflex of human anterior-tooth (ANT)-contacts in mastication. Here I present the “reciprocal reflex-control-hypothesis” of mammalian mastication. Subjects and setting of the study I demonstrate the hypothesis with the live kinematics of free jaw-closures as inferred from T-Scan recordings of dental patients. Results The jaw-closures started with negligible force, predominantly with ANT-contacts (the AF-bites). The first ANT-contact inhibited the first kinematic tilt of the mandible, whereas the bites starting from a back-tooth (BAT)-contact (the BF-bites) accelerated the first tilt. The second tilt established a low-force static tripod of the ANT- and bilateral BAT-contacts for a fixed mandible-maxilla relation. Thereafter, semi-static bite force increased rapidly, relatively more in the BAT-area. Discussion and Conclusions In the vertical-closure phase of chewing, the primate joint-fulcrum (class 3 lever) conflicts with the food-bolus-fulcrum in the BAT-area (class 1 lever). The resilient class 3 and 1 lever systems are superseded by an almost static mechanically more advantageous class 2 lever with a more rigid fulcrum at the most anterior ANT-contact. For humans, the class 2 levered delivery of force also enables forceful horizontal food grinding to be extended widely to the BAT-area.

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Tratamento de disfunções temporomandibulares com toxina botulínica tipo A

Revista da Faculdade de Odontologia - UPF ◽

10.5335/rfo.v23i2.8139 ◽

2018 ◽

Vol 23 (2) ◽

Author(s):

Geovana De Oliveira Polette Petrolli ◽

Pamella Monteiro Mendes ◽

Fernanda Angeloni De Souza ◽

Matheus Coelho Blois

Keyword(s):

Botulinum Toxin ◽

Myofascial Pain ◽

Masticatory Muscles

Introdução: a disfunção temporomandibular (DTM) abrange muitos problemas clínicos nas articulações, na musculatura e em outras regiões da oroface. A origem multifatorial e sua etiologia envolvem fatores psicocomportamentais, oclusais e neuromusculares, seu diagnóstico é realizado pela anamnese detalhada, com a identificação dos fatores predisponentes, iniciadores e perpetuantes, e pelo exame físico, que consiste em palpação da musculatura, mensuração da movimentação ativa e verificação dos ruídos articulares. Objetivo: sistematizar as evidências científicas e verificar a eficácia do tratamento de disfunções temporomandibulares de origem muscular com a toxina botulínica do tipo A (TBX-A). Materiais e método: a busca bibliográfica foi realizada nas bases de dados PubMed e SciELO, com os descritores: “myofascial pain”, “botulinum toxin” e “masticatory muscles”. Foram analisados ensaios clínicos randomizados, que apresentaram tratamento para DTM com a utilização da TBX-A em pacientes de ambos os sexos. A qualidade metodológica dos artigos selecionados foi verificada de acordo com a escala de Jadad. Considerações finais: observou-se que o tratamento para a DTM por meio da TBX-A auxilia no tratamento de dores orofaciais permanentes como coadjuvante, aliado a tratamentos conservadores. Os estudos que demonstraram resultados clínicos significativos utilizaram uma dose total de 100 U de TBX-A, sendo 30 U nos músculos masseteres e 20 U nos músculos temporais, bilateralmente.

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Characteristics of masticatory muscles in children with unilateral posterior crossbite

Brazilian Oral Research ◽

10.1590/s1806-83242010000200013 ◽

2010 ◽

Vol 24 (2) ◽

pp. 204-210 ◽

Cited By ~ 12

Author(s):

Annicele da Silva Andrade ◽

Maria Beatriz Duarte Gavião ◽

Gustavo Hauber Gameiro ◽

Moara De Rossi

Keyword(s):

Masticatory Muscles ◽

Posterior Crossbite

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