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1.
J Oral Rehabil ; 48(1): 10-17, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32979854

RESUMO

BACKGROUND: The diagnosis of temporomandibular disorders (TMD) is based on patient history and physical examination, and may require medical imaging. Masticatory muscle palpation is essential to make a diagnosis of TMD. However, the response of masticatory muscles to mechanical pressure stimuli depends on many physical and psychological factors. OBJECTIVE: This study aimed at determining the impact of somatosensory amplification (SSA)-an estimate of somatic awareness and bodily hypervigilance-on pressure pain thresholds (PPTs) measured at both trigeminal and extra-trigeminal locations in healthy individuals. METHODS: PPTs were measured at the right anterior temporalis and superficial masseter, and the thenar eminence of the right hand in one hundred healhty individuals (69F, 31M), divided in three groups based on their SSA scores: low (N = 32), intermediate (N = 34) and high (N = 34). General linear models were used to test between-group differences in PPTs including sex as a covariate. The level of significance was set at P < .05. RESULTS: Individuals with high SSA had lower PPTs at the anterior temporalis than individuals with low (P = .006) and intermediate (P = .001) SSA. No significant between-group differences were found in PPTs measured at the masseter (P = .372). PPTs measured at the thenar eminence were significantly lower in the high than the low SSA group (P = .009). Females had lower PPTs at the masseter than males (P = .021) but not at other muscle locations (all P > .05). CONCLUSION: Increased somatosensory amplification is associated with decreased pressure pain thresholds at both trigeminal and extra-trigeminal locations in healthy individuals. SSA could be a potential confounder while diagnosing TMD and evaluating treatment outcomes.


Assuntos
Limiar da Dor , Transtornos da Articulação Temporomandibular , Feminino , Humanos , Masculino , Músculo Masseter , Músculos da Mastigação , Músculo Temporal
2.
J Oral Rehabil ; 48(1): 35-44, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33031568

RESUMO

BACKGROUND: In skeletal muscle, free nerve endings are mostly located within the connective tissue. However, the distribution of sensory afferent fibres in healthy human masseter muscle tissues has not been studied. OBJECTIVES: Primarily to investigate human masseter muscle nerve fibre densities as well as expression of NR2B receptors, substance P (SP) and nerve growth factor (NGF), and secondarily to compare this between a) nerve fibres associated with myocytes and within connective tissue; b) sexes; and c) ages. METHODS: Microbiopsies of the masseter muscle were obtained from 60 sex- and age-matched healthy participants. Biopsy sections were analysed using immunohistochemistry and were visualised with a Leica TCS SPE confocal microscope. The Mann-Whitney U test was used for statistical analyses. RESULTS: The density of nerve fibres within connective tissue was significantly greater than in nerve fibres associated with myocytes (P < .001). Nerve fibres within connective tissue expressed SP alone or together with NR2B significantly more often than those associated with myocytes (P < .001). The frequency of nerve fibres, which expressed SP alone or in combination with NR2B or NGF, was significantly greater in women than in men (P < .050). Moreover, the co-expression of the three markers together was inversely correlated with age in women (P < .002). CONCLUSIONS: There is a higher density and greater expression of sensory nerve fibres within the connective tissue than associated with myocytes in healthy human masseter muscle. This suggests that nerve fibres within connective tissue are more involved in nociception than nerve fibres associated with myocytes.


Assuntos
Músculo Masseter , Substância P , Feminino , Humanos , Masculino , Músculo Esquelético , Fibras Nervosas , Fator de Crescimento Neural
3.
J Oral Maxillofac Surg ; 79(1): 88.e1-88.e9, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33045182

RESUMO

PURPOSE: Masticatory myofascial trigger points (TrP) are one of the major causes of nondental pain in the orofacial region. Intramuscular injections are considered the first-line treatment for myofascial TrPs. The objectives of this study were to evaluate and compare the effectiveness of local anesthesia (LA), botulinum toxin (BTX), and platelet-rich plasma (PRP) injections for the treatment of myofascial TrPs in the masseter muscle. METHODS: In this retrospective study, the sample was composed of patients with myofascial TrPs in masseter muscle who were treated between 2016 and 2019. Patients were divided into 3 groups according to treatment methods: group I (LA injection), group II (BTX injection), and group III (PRP injection). Primary outcome variable was the average pain level at rest and while chewing, and pressure pain intensity (PPI), Jaw Functional Limitation Scale (JFLS) value, and quality-of-life (measured using Oral Health Impact Profile-14 (OHIP-14)) were secondary outcomes. The outcome variables were assessed at diagnosis, and 1, 3, and 6 months post-treatment. RESULTS: The study consisted of 82 patients (group I, 27; group II, 26; group III, 29). At 1 and 3 months, improvement in all parameters was recorded in all groups. Groups I and II showed superior improvement in all parameters compared with group III at 3 months. Improvements in VAS pain, JFLS, and OHIP-14 values were significantly better in group II than group I at 3 months (P = .009; P = .004; P = .002). At 6 months, significant improvement in VAS pain, JFLS, and OHIP-14 (P = .008; P < .001; P < .01) values was recorded only in group II. CONCLUSIONS: All procedures successfully improved the symptoms of TrPs in the masseter muscle at 1 and 3 months. However, BTX injection seemed superior at the 3-month follow-up and remained effective up to 6 months.


Assuntos
Toxinas Botulínicas Tipo A , Síndromes da Dor Miofascial , Fármacos Neuromusculares , Plasma Rico em Plaquetas , Anestesia Local , Toxinas Botulínicas Tipo A/uso terapêutico , Humanos , Injeções Intramusculares , Músculo Masseter , Síndromes da Dor Miofascial/tratamento farmacológico , Fármacos Neuromusculares/uso terapêutico , Estudos Retrospectivos , Resultado do Tratamento , Pontos-Gatilho
4.
Am J Orthod Dentofacial Orthop ; 159(1): e25-e33, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33234460

RESUMO

INTRODUCTION: Patients undergoing clear aligner therapy (CAT) report muscle tenderness and produce wear facets on their aligner trays. However, little is known about the masticatory muscle response to clear aligners. Here, we measured the activity of the masseter during CAT using ambulatory electromyography. We also explored whether psychological traits modulate the masticatory muscle response to CAT. METHODS: Using portable data loggers, we recorded the electromyographic (EMG) activity in the right masseter muscle of 17 healthy adults without temporomandibular disorder (16 females, 1 male; mean age ± standard deviation, 35.3 ± 17.6 years) commencing treatment with CAT over 4 weeks, under the following conditions: week 1 without aligners (baseline), week 2 with a passive aligner (dummy), week 3 with their first active aligner (active1), and week 4 with their second active aligner (active2). We used a mixed-effect model to test differences in EMG activity over the 4-weeks and a general linear model to test the effect of psychological traits on EMG activity. RESULTS: The EMG activity of the masseter increased significantly with aligners compared with baseline. The largest relative increase in EMG activity was seen during the dummy (152%; P <0.001) and active1 (155%; P <0.001) stages. During active2, the activity of the masseter decreased significantly toward baseline levels. Participants' trait anxiety was positively associated with increases in EMG activity (P = 0.027). CONCLUSIONS: CAT is associated with a transient increase in masticatory muscle activity, possibly because of an increase in wake-time parafunctional tooth clenching. Temporomandibular disorder-free patients adapt well to CAT as the masticatory muscle activity decreases toward baseline levels after 2 weeks.


Assuntos
Músculo Masseter , Aparelhos Ortodônticos Removíveis , Adulto , Eletromiografia , Feminino , Humanos , Masculino , Músculos da Mastigação , Músculo Temporal
5.
J Oral Sci ; 63(1): 37-40, 2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33298638

RESUMO

PURPOSE: This study assessed the effectiveness of incobotulinum toxin type A (IBTx) for chronic myofascial pain affecting the masseter and temporal muscles. METHODS: Twenty two patients who received a diagnosis of chronic masseter and temporalis myofascial pain were evaluated by using a visual analog pain scale (VAS), digital pressure algometry, and the SF-36 Health Survey at baseline (T0), before IBTx injection. Patients were again evaluated at 2 months (T1) and 7 months (T2) after IBTx injection. RESULTS: VAS scores for pain significantly differed (P = 0.029, Friedman test). Post-hoc tests showed a significant reduction in pain at 2 months (T0-T1) and 7 months (T0-T2) (P = 0.011 and P = 0.028, respectively; Wilcoxon test) but not between 2 and 7 months (P = 0.676; Wilcoxon test). There was no significant difference in pressure algometry values (P = 0.385, Friedman test). Quality of life (QOL) assessment showed a significant difference (P = 0.002, Friedman test). Post-hoc tests showed a significant improvement in QOLat 2 months, but no significant difference at 7 months (P = 0.004 and P = 0.260, Wilcoxon test). CONCLUSION: IBTx injection resulted in safe, effective short-term pain relief for patients with chronic facial pain affecting the masseter and temporalis muscles.


Assuntos
Síndromes da Dor Miofascial , Qualidade de Vida , Humanos , Músculo Masseter , Síndromes da Dor Miofascial/tratamento farmacológico , Músculo Temporal , Resultado do Tratamento
6.
J Surg Oncol ; 122(8): 1747-1754, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32869304

RESUMO

BACKGROUND: This study investigated the morbidity of the marginal mandibular nerve (MMN) post vascularized submental lymph node (VSLN) harvest. METHODS: The VSLN with sacrifying or preserving the medial platysma was retrospectively classified as group I or II. Midline deviation and horizontal tilt were subjectively evaluated. Horizontal, vertical, and "area distribution" of the lower lip excursions of the surgical site were objectively compared with the nonsurgical site. RESULTS: Seventeen patients in group I and 12 patients in group II were included. At a median follow-up of 48.6 ± 16.8 months in group I and 14.8 ± 7.5 months in group II, no MMN palsy was found in both groups. Median midline deviation and horizontal tilt were 4.53 ± 0.52 and 5 ± 0 in group I and 4.67 ± 0.65 and 5 ± 0 in group II, respectively (P = .419 and 1.000). Median horizontal, vertical and area of distribution of lower lip excursions were 97.5 ± 12.3%, 98.8 ± 14.4% and 87.2 ± 14.7% in group I, and 99.3 ± 15.1%, 95.8 ± 8.2% and 84.2 ± 14.2% in group II, respectively (P = .679, .948 and .711). CONCLUSION: The VSLN flap was a safe procedure with minimal MMN morbidity.


Assuntos
Linfonodos/transplante , Linfedema/cirurgia , Mandíbula/fisiopatologia , Músculo Masseter/fisiopatologia , Retalhos Cirúrgicos/transplante , Adulto , Idoso , Feminino , Seguimentos , Humanos , Linfonodos/irrigação sanguínea , Linfedema/epidemiologia , Linfedema/patologia , Masculino , Pessoa de Meia-Idade , Morbidade , Prognóstico , Estudos Retrospectivos , Retalhos Cirúrgicos/irrigação sanguínea , Taiwan/epidemiologia
7.
Clin Ter ; 171(5): e414-e420, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32901785

RESUMO

OBJECTIVE: Surface Electromyography of masticatory muscles (sEMG) is used as a tool to support diagnosis and treatment of Temporomandibular disorders (TMDs). The study aimed at examining jaw muscles pattern in individuals with temporomandibular joint disc displacement with reduction (TMJ/DDR). This sort of subjects was supposed to have a different muscular pattern compared to the control group. MATERIALS AND METHODS: Sixty-four women with unilateral TMJ/DDR and forty TMD-free women underwent a sEMG assessment of masticatory muscles. Descriptive statistics were performed. Student T-Test assessed differences between the two groups. Statistical significance was set at ρ < 0.05. RESULT: The t-test showed statistically significant results only in BAR and SMI scores (ρ value < 0,0001). The other measurements did not differ between the two groups. BAR index values of all healthy subjects were within the reference range. Almost the entire TMJ/DDR group had BAR index out of reference range and anteriorly placed. CONCLUSION: Women with TMJ/DDR showed an altered recruitment of the jaw muscles, with significant difference between the activity of the couple of temporalis and the one of masseters, compared to the control group. A lower chewing efficiency was found in the DDR group compared to the control one.


Assuntos
Eletromiografia , Disco da Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/fisiopatologia , Adulto , Eletromiografia/métodos , Feminino , Humanos , Músculo Masseter/fisiopatologia , Mastigação , Músculos da Mastigação/fisiopatologia , Pessoa de Meia-Idade , Músculo Temporal/fisiopatologia , Transtornos da Articulação Temporomandibular/diagnóstico
8.
J Oral Rehabil ; 47(12): 1521-1529, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32898936

RESUMO

BACKGROUND: Clinical findings suggest that orthodontic treatment with clear aligners (clear aligner therapy/CAT) may cause masticatory muscle soreness in some patients. OBJECTIVE: This multi-site prospective study investigated tooth pain and masticatory muscle soreness and tenderness in patients undergoing CAT and explored whether psychological traits affected these outcomes. METHODS: Twenty-seven adults (22F, 5M; mean age ± SD=35.3 ± 17.6 years) about to start CAT were recruited at three clinics. During CAT, they reported on 100-mm visual analogue scales their tooth pain, masticatory muscle soreness and stress three times per day over 4 weeks (week 1 = baseline; week 2 = dummy aligner; week 3 = first active aligner; week 4 = second active aligner). Pressure pain thresholds (PPTs) were measured at the masseter and temporalis at baseline and after week 4. Mixed models were used to evaluate the outcome measures over time. RESULTS: Clear aligner therapy caused mild tooth pain, which was greater with the passive than the first and second active aligners (both P < .001). Mild and clinically not relevant masticatory muscle soreness was produced by all aligners (all P < .05), with the first active aligner producing less soreness than the dummy aligner (P < .001). PPTs did not change significantly after 4 weeks. Both tooth pain and masticatory muscle soreness were affected by stress and trait anxiety, whilst muscle soreness was affected also by oral behaviours. CONCLUSIONS: In the short term, CAT produces tooth pain and masticatory muscle soreness of limited significance. Frequent oral behaviours are related to increased masticatory muscle soreness during CAT. The medium- and long-term effects of CAT should be further explored.


Assuntos
Mialgia , Aparelhos Ortodônticos Removíveis , Adulto , Humanos , Músculo Masseter , Músculos da Mastigação , Mialgia/etiologia , Limiar da Dor , Estudos Prospectivos
9.
J Oral Facial Pain Headache ; 34(3): 281-290, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870957

RESUMO

AIMS: To investigate pain sensitivity in the masseter muscle and index finger in response to acute psychologic stress in healthy participants. METHODS: Fifteen healthy women (23.7 ± 2.3 years) participated in two randomized sessions: in the experimental stress session, the Paced Auditory Serial Addition Task (PASAT) was used to induce acute stress, and in the control session, a control task was performed. Salivary cortisol, perceived stress levels, electrical and pressure pain thresholds (PTs), and pain tolerance levels (PTLs) were measured at baseline and after each task. Mixed-model analysis was used to test for significant interaction effects between time and session. RESULTS: An interaction effect between time and session occurred for perceived stress levels (P < .001); perceived stress was significantly higher after the experimental task than after the control task (P < .01). No interaction effects occurred for salivary cortisol levels, electrical PTs, or pressure PTLs. Although significant interactions did occur for electrical PTL (P < .05) and pressure PT (P < .001), the simple effects test could not identify significant differences between sessions at any time point. CONCLUSION: The PASAT evoked significant levels of perceived stress; however, pain sensitivity to mechanical or electrical stimuli was not significantly altered in response to the stress task, and the salivary cortisol levels were not altered in response to the PASAT. These results must be interpreted with caution, and more studies with larger study samples are needed to increase the clinical relevant understanding of the pain mechanisms and psychologic stress.


Assuntos
Hidrocortisona , Limiar da Dor , Estudos Cross-Over , Feminino , Humanos , Músculo Masseter , Projetos Piloto , Saliva , Estresse Psicológico
10.
Sci Rep ; 10(1): 15458, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963266

RESUMO

The aim of this investigation was to evaluate the effects of local anaesthesia on nerve growth factor (NGF) induced masseter hyperalgesia. Healthy participants randomly received an injection into the right masseter muscle of either isotonic saline (IS) given as a single injection (n = 15) or an injection of NGF (n = 30) followed by a second injection of lidocaine (NGF + lidocaine; n = 15) or IS (NGF + IS; n = 15) in the same muscle 48 h later. Mechanical sensitivity scores of the right and left masseter, referred sensations and jaw pain intensity and jaw function were assessed at baseline, 48 h after the first injection, 5 min after the second injection and 72 h after the first injection. NGF caused significant jaw pain evoked by chewing at 48 and 72 h after the first injection when compared to the IS group, but without significant differences between the NGF + lidocaine and NGF + IS groups. However, the mechanical sensitivity of the right masseter 5 min after the second injection in the NGF + lidocaine group was significantly lower than the second injection in the NGF + IS and was similar to the IS group. There were no significant differences for the referred sensations. Local anaesthetics may provide relevant information regarding the contribution of peripheral mechanisms in the maintenance of persistent musculoskeletal pain.


Assuntos
Anestésicos Locais/administração & dosagem , Dor Facial/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Lidocaína/administração & dosagem , Músculo Masseter/efeitos dos fármacos , Fator de Crescimento Neural/efeitos adversos , Adulto , Estudos de Casos e Controles , Método Duplo-Cego , Dor Facial/etiologia , Dor Facial/patologia , Feminino , Humanos , Hiperalgesia/etiologia , Hiperalgesia/patologia , Injeções Intramusculares , Masculino , Músculo Masseter/fisiopatologia , Limiar da Dor
11.
Arch Oral Biol ; 118: 104854, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32763472

RESUMO

OBJECTIVE: The aim of this study was to assess the correlation of inflammatory and pain genes polymorphisms with the presence of temporomandibular disorder (TMD) patients and with pressure pain sensitivity. DESIGN: Data was collected from 268 consecutive subjects at Bauru School of Dentistry. Subjects aged younger than 20 years, with dental and neuropathic pain, sinusitis, cognitive and neurologic disorder were excluded. Included subjects were evaluated using the Research Diagnostic Criteria for Temporomandibular disorders and divided into two groups: TMD cases and healthy controls. Groups were submitted to pressure pain threshold (PPT) test for the temporomandibular joint, anterior temporalis and masseter muscles and genotyped for Val158Met, IL6-174, IL-1ß-3954 and TNFA-308. Student's t-test and Pearson chi-square test were used to comparisons between groups. A linear multiple regression was used to evaluate the influence of genetics variables on the PPT and a bivariate analysis was used to assesses the influence of genetics variables on pain sensitivity below the PPT cut off of the structures in TMD group. RESULTS: TMD group showed significantly lower PPT values for all structures when compared with control group (p < 0.001). SNP IL6-174 predicted higher pain sensitivity in the temporomandibular joint (p < 0.005) and in anterior temporalis muscle (p < 0.044) and SNP Val158Met in the masseter muscle (p < 0.038); when TMD group was divided according to PPT cut-off values the SNP Val158Met influenced increase pain sensibility in the masseter muscle. CONCLUSION: TNFA-308 was associated with TMD and SNP IL6-174 and SNP Val158Met influenced pain sensitivity of patients with TMD.


Assuntos
Inflamação/genética , Limiar da Dor , Transtornos da Articulação Temporomandibular , Adulto , Genótipo , Humanos , Interleucina-6/genética , Músculo Masseter , Polimorfismo de Nucleotídeo Único , Pressão , Músculo Temporal , Articulação Temporomandibular/fisiopatologia , Transtornos da Articulação Temporomandibular/genética , Adulto Jovem
12.
Arch Oral Biol ; 118: 104861, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32835988

RESUMO

OBJECTIVE: To show the possible occurrence of exosomal transport of neprilysin from masseter muscle to hippocampus via trigeminal nerve in the living mouse. DESIGN: Mouse C2C12 myotube-derived exosomes were labeled with near-infrared (NIR) dye and injected into the masseter muscle to track their fluorescence from masseter muscle to hippocampus via trigeminal nerve. A plasmid vector encoding green fluorescent protein (GFP)-tagged neprilysin (GFP-neprilysin) was transfected into masseter muscle of C57BL/6 J mice. Expression of mRNA and encoded protein of the transgene was identified in masseter muscle, trigeminal nerve and hippocampus by RT-PCR and Western blot, respectively. RESULTS: Peak of exosomal NIR in masseter muscle at time 0 rapidly reduced at 3 h and 6 h along with the subsequent increases in trigeminal nerve and hippocampus. Expression of GFP-neprilysin mRNA was detected in masseter muscle, but not trigeminal nerve and hippocampus. On the other hand, the corresponding protein of GFP-neprilysin was identified in the three tissues on day 3 after transfection into masseter muscle as a single band on Western blots with anti-GFP and anti-neprilysin antibodies. CONCLUSION: The appearance of GFP-neprilysin protein in trigeminal nerve and hippocampus without a corresponding mRNA expression indicated the protein's origin from the masseter muscle. Concomitant migration of NIR-exosomes from masseter muscle to hippocampus via trigeminal nerve suggested the possible occurrence of exosomal transport of neprilysin.


Assuntos
Hipocampo/metabolismo , Músculo Masseter/metabolismo , Neprilisina/metabolismo , Nervo Trigêmeo/metabolismo , Animais , Exossomos , Genes Reporter , Vetores Genéticos , Proteínas de Fluorescência Verde , Camundongos , Camundongos Endogâmicos C57BL , Neprilisina/genética , Transporte Proteico
13.
Niger J Clin Pract ; 23(8): 1095-1102, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788487

RESUMO

Aims: The purpose of this study is to compare the thickness and elasticity of the masseter muscle before and after orthognathic surgery in patients with class III skeletal deformity and to investigate the relationship between the sonographic changes in the masseter muscle and the amount of mandibular setback. Subjects and Methods: The study group consisted of 14 patients with skeletal class III malocclusions who had orthognathic surgery. The control group consisted of 14 patients who had dental and skeletal class I occlusion. Muscle thickness measurements were performed with B-mode and high-frequency linear scanning probe of the ultrasound device. Elastography feature and muscle hardness ratio were obtained by applying compression and decompression on muscles at rest and during maximum contraction in the transverse plane. Patients were categorized into two groups according to the mandibular setback as <5 mm and ≥5 mm. Results: The masseter muscle thickness after surgery was found statistically increased bilaterally in both at rest and during contraction for the study group (P < 0.05). No difference was found between preoperative orthognathic measurements and postoperative measurements for elasticity index ratio measurements (P > 0.05). Conclusion: We believe that in the present study important findings have been emphasized for further research aiming to investigate the possible relationship between masticatory alterations and surgical outcomes after orthognathic surgery.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Má Oclusão de Angle Classe III/cirurgia , Mandíbula/diagnóstico por imagem , Músculo Masseter/diagnóstico por imagem , Procedimentos Cirúrgicos Ortognáticos/efeitos adversos , Adulto , Cefalometria , Feminino , Humanos , Masculino , Músculo Masseter/fisiologia , Resultado do Tratamento , Ultrassonografia
14.
Georgian Med News ; (303): 55-58, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32841181

RESUMO

Type of breathing (nasal, oral, oronasal) can turn out to be a causative factor for (or result of) orthodontic anomalies alongside the respiratory-metabolic disorders. Consequently, assessment of functional characteristics of the masticatory apparatus, which differ in oral and nasal breathing modes, could be of interest for the evaluation of the degree of orthodontic dysfunction and formation of an effective individualized treatment plan. Aim of the study was to assess electrophysiologic characteristics of the masticatory muscles bilaterally in nasal and oral breathing modes. The study was conducted on the group of 22 women-volunteers aged 18-30 years. All subjects enrolled in the study had permanent dentition with all second molars present; minimum 28 natural teeth in total. None of them had clinical manifestations of somatic, neurological or endocrine disorders or those of nasal cavity, paranasal sinus or tonsillar disorders.Written informed consent was obtained from all subjects. To narrow the selection of patients eligible for the study, we applied a protocol of normalized electromyographic recording during maximal voluntary contraction of clenching on a cotton roll. Indicators of the degree of mean muscle contractility recorded as a result of standardized maximal voluntary contraction show that in nasal breathing muscle activity is homogenous and symmetric in the right and left masseter and temporalis muscles. Conversely, the indicators are dissociated in oral breathing. Electrophysiological activity and, consequently, contractility of the muscles are reduced, which must be caused by recruitment of decreasing number of less excitable motor units. The results yielded by the study suggest that the data on the state of neuromuscular balance of the masticatory apparatus could be utilized for the assessment of the degree of orthodontic dysfunction and for development of individualized treatment plan.


Assuntos
Músculos da Mastigação , Músculo Temporal , Adolescente , Adulto , Eletromiografia , Feminino , Humanos , Músculo Masseter , Contração Muscular , Adulto Jovem
15.
Anesth Prog ; 67(2): 103-106, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32633773

RESUMO

The twin block, introduced in 2014, has proven to be more advantageous for the management of myogenous orofacial pain than the masseteric nerve block, which was introduced in 2009. The twin block is an extraoral nerve block injection which passes through the temporal fossa to anesthetize both the masseteric and the deep temporal nerves as they exit the infratemporal fossa at the infratemporal crest. Similar to the masseteric nerve block, the twin block has demonstrated efficacy with expeditious and sustained relief of myogenous face pain originating from the masseter muscle. Furthermore, in a 6-month prospective treatment study, that has been accepted for publication, the twin block has been demonstrated as comparable to trigger point injections in the management of chronic myofascial pain of masseteric origin. The twin block's ability to mitigate myogenous pain from both the masseter and temporalis muscles and its ease of administration are the key advantages over the masseteric nerve block. Since its inception, we have refined the technique for administering the twin block and our clinical experience corroborates its safety and efficacy. This review describes the refined technique and its safety in the context of the region's applied anatomy.


Assuntos
Dor Facial , Músculo Masseter , Humanos , Estudos Prospectivos , Segurança , Gêmeos
16.
Artigo em Inglês | MEDLINE | ID: mdl-32646041

RESUMO

This study is aimed at investigating the effects of synchronized neuromuscular electrical stimulation (NMES) and chewing exercises on bite force and the masseter muscle thickness in community-dwelling older adults. Material and methods: Forty older adults were enrolled in South Korea and randomly assigned to either an experimental or control group. The experimental group performed chewing exercises using the No-Sick Exerciser equipment synchronized with NMES applied to the bilateral masseter muscles, while the control group performed only chewing exercises. Both groups received interventions for 20 min/day, 5 days/week, for 6 weeks. Bite force was measured using the OCCLUZER device, and masseter muscle thickness was measured using a portable ultrasound. Results: Both groups showed a significant increase in bite force and masseter muscle thickness compared to baseline measurements (p < 0.05). The experimental group showed a significantly higher increase in bite force and masseter muscle thickness than the control group after combined intervention (p < 0.05). Conclusion: This study demonstrates that NMES synchronized with chewing exercises is more efficient in increasing bite force and masseter muscle thickness than chewing exercises alone in community-dwelling older adults.


Assuntos
Força de Mordida , Estimulação Elétrica , Músculo Masseter , Mastigação/fisiologia , Músculos da Mastigação/fisiopatologia , Idoso , Eletromiografia , Feminino , Humanos , Vida Independente , Masculino , Músculo Masseter/anatomia & histologia , Músculo Masseter/diagnóstico por imagem , República da Coreia , Ultrassonografia
17.
J Oral Maxillofac Surg ; 78(12): 2281.e1-2281.e8, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32652049

RESUMO

PURPOSE: The effect of botulinum toxin type A (BTX-A) on fracture healing of the long bones is controversial, and no controlled clinical or experimental study has investigated the effect of BTX-A on mandibular fractures. The purpose of this study was to investigate whether BTX-A injection into the masseter muscles affects bone healing by reducing the displacing forces in an unfavorable mandibular fracture model. MATERIALS AND METHODS: Forty-eight male New Zealand white rabbits were used. Ten units of BTX-A was injected into each masseter muscle in the animals in the BTX-A group, whereas saline solution was injected in the animals in the control group. A unilateral osteotomy and fixation with a microplate were performed. Bone healing was evaluated by radiodensitometric, biomechanical, histologic, and histomorphometric methods after 21 days. RESULTS: The mean bone mineral density in the fracture area was significantly higher in the BTX-A group (P = .038). The mean failure load and bending modulus values were significantly higher in the BTX-A group than in the control group (P = .032 and P = .005, respectively). The mean histologic bone healing scores, bone volume-total volume values, and trabecular diameter values were significantly higher in the BTX-A group than in the control group (P = .001, P = .001, and P = .026, respectively). CONCLUSIONS: BTX-A application into the masseter muscles improves bone healing of a unilateral mandibular fracture in rabbits.


Assuntos
Toxinas Botulínicas Tipo A , Fraturas Mandibulares , Animais , Consolidação da Fratura , Masculino , Mandíbula/cirurgia , Fraturas Mandibulares/tratamento farmacológico , Fraturas Mandibulares/cirurgia , Músculo Masseter , Coelhos
18.
Gerodontology ; 37(4): 383-388, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32662134

RESUMO

OBJECTIVE: To develop a simple method to estimate masseter muscle mass. BACKGROUND: The masseter muscle is important for optimal oral function. A decrease in the masseter muscle mass may affect the oral and physical function of the whole body; therefore, it is an important entity to measure. However, to date, no easy measurement method has been developed for the same. Herein, we devised a simple method to estimate masseter muscle mass. In addition, we compared our method with magnetic resonance imaging (MRI) and skeletal muscle mass (SMM) to verify its validity. MATERIALS AND METHODS: We recorded the age, sex, masseter muscle mass (by MRI), number of retained natural teeth, number of functional teeth, length and thickness of masseter muscle, and skeletal muscle mass in 53 community-dwelling elderly people (21 men and 32 women, average age 72.9 ± 4.5 years). The estimated masseter muscle mass was calculated by multiplying the length, width and thickness of the muscle. RESULTS: The correlation coefficient between masseter muscle mass and estimated masseter muscle mass was r = .903; thus, a strong correlation was recognised. The correlation coefficient between the estimated masseter muscle mass and SMM was r = .279, considering age and sex. CONCLUSION: We obtained substantial results using our method for estimating the masseter muscle mass and verified its validity by comparing it with masseter muscle mass measured by MRI and SMM. We believe that our proposed technique is simple and useful for estimating masseter muscle mass.


Assuntos
Músculo Masseter , Dente , Idoso , Feminino , Humanos , Vida Independente , Imagem por Ressonância Magnética , Masculino , Músculo Masseter/diagnóstico por imagem
19.
BMC Oral Health ; 20(1): 181, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32600308

RESUMO

BACKGROUND: Facial esthetics is a major concern of orthodontic patients. This study aims to evaluate orthodontic treatment-related thickness changes of the masseter muscles and surrounding soft tissues and the potential factors that would influence these changes during orthodontic treatment in female adults. METHODS: Forty-two female adult patients were included in this retrospective study and were divided into extraction (n = 22) and nonextraction (n = 20) groups. Pretreatment and posttreatment cone-beam computed tomography (CBCT) images were superimposed and reconstructed. The thickness changes of the masseter area of facial soft tissue (MAS), masseter muscles (MM) and surrounding fat tissue (FT) were measured. Pretreatment age, treatment duration, sagittal relationship (ANB), and vertical relationship (Frankfort-mandibular plane angle, FMA)-related MAS, MM and FT changes were compared between extraction and nonextraction groups. Spearman's correlation coefficient was calculated between the above variables. Regression analysis was conducted to confirm the causal relations of the variables. RESULTS: The thickness of MAS and MM significantly decreased in both groups, with larger decreases (> 1 mm) in the extraction group. There were strong correlations (r > 0.7) between the thickness decrease in MAS and MM in both groups and moderate correlations (r > 0.4) between MAS and FT in the nonextraction group. A significantly greater decrease of MAS and MM were found to be moderately correlated with a smaller FMA (r > 0.4) in the extraction group. Scatter plots and regression analysis confirmed these correlations. CONCLUSIONS: Masseter muscles and the surrounding soft tissue exhibited a significant decrease in thickness during orthodontic treatment in female adults. Low-angle patients experienced a greater decrease in soft tissue thickness in the masseter area in the extraction case. But the thickness changes were clinically very small in most patients.


Assuntos
Estética Dentária , Músculo Masseter/diagnóstico por imagem , Adulto , Cefalometria , Tomografia Computadorizada de Feixe Cônico , Face/anatomia & histologia , Feminino , Humanos , Estudos Retrospectivos
20.
Rev. esp. cir. oral maxilofac ; 42(2): 91-93, abr.-jun. 2020. ilus
Artigo em Espanhol | IBECS | ID: ibc-189947

RESUMO

Paciente de 20 años que presentó aumento de volumen facial izquierdo. Estudiado con ecografía, TAC y biopsia quirúrgica. Se establece el diagnóstico de hipertrofia maseterina unilateral idiopática. La hipertrofia maseterina es un desorden benigno que puede manifestarse de forma unilateral o bilateral, que provoca una asimetría facial, frecuentemente asintomática. Se han propuesto varios tratamientos, siendo la infiltración con toxina botulínica tipo A un tratamiento mínimamente invasivo y eficaz


A 20-year-old patient who present an increase in left facial side. Studied with ultrasound, CT scan and surgical biopsy. The diagnosis of idiopathic unilateral masseter hypertrophy was established. Masseter hypertrophy is a benign disorder that can manifest unilaterally or bilaterally, causing facial asymmetry, often asymptomatic. Several treatments have been introduced, such as infiltration with Botulinum toxin type A, a minimally invasive and effective treatment


Assuntos
Humanos , Feminino , Adulto Jovem , Músculo Masseter/patologia , Toxinas Botulínicas Tipo A/uso terapêutico , Hipertrofia/tratamento farmacológico
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