Masseter Muscles In Children Research Articles

The Influence of the Type of Breathing on the Masticatory Muscle Patterns in Children.

Background and Objectives: The aim was to compare the activity of the masseter muscles in children with different types of breathing. Materials and Methods: A cross-sectional study was conducted including patients aged 6-12 years with mixed dentition, who came for oral care at the Master's Degree in Pediatric Dentistry program at the Complutense University of Madrid (UCM), according to inclusion and exclusion criteria. The sample was divided into three groups: nasal breathers without dental alterations (control group), oral breathers with dental malocclusion, and oral breathers with previous orthodontic treatment. An electromyography was performed, and statistic methods were conducted with a 95% confidence to contrast hypothesis. Results: A total of 122 children were analyzed and distributed into three groups. The electrical muscle activity of masseters was significantly different between the study groups (p < 0.001 for all comparisons). Pairwise comparisons revealed a significantly higher electrical muscle activity in the control group (nasal breathers) during chewing compared to both groups of oral breathers (p < 0.001 for both comparisons). Orthodontic treatment decreased electrical muscle activity during isometric contraction in oral breathers compared to nasal breathers (p < 0.001), but did not significantly affect electrical muscle activity during chewing. Higher decompensation values were obtained in oral breathers without previous orthodontic treatment compared the other study groups (p < 0.001 for both comparisons), although electrical muscle activity values were similar in both groups of oral breathers (p > 0.05 for both comparisons). Conclusions: Differences in electrical muscle activity between nasal and oral breathers can be confirmed. Oral breathers with and without orthodontic treatment showed lower electrical muscle activity of masseters during chewing than nasal breathers, while at isometric contraction, only oral breathers with previous orthodontic treatment showed lower electrical activity. Higher decompensation values were found in oral breathers without previous orthodontic treatment, in comparison to the control group and oral breathers with previous orthodontic treatment.

Electromyographic Study of Masticatory Muscle Function in Children with Down Syndrome.

This study assessed the electrical activity of the masticatory muscles in both children with down syndrome (DS) and healthy children. After applying the inclusion and exclusion criteria, 30 patients aged between 7.9 and 11.8 years participated in the study. They were divided into two groups of 15: DS and non-DS. A DAB-Bluetooth device (Zebris Medical GmbH, Germany) was used to record the electromyographical (EMG) activity of the right and left temporal and of the right and left masseter muscles at rest and during maximum voluntary clenching (MVC). The asymmetry index between right and left masticatory muscle EMG activity was calculated for each position. The Mann–Whitney U test was applied to analyze the study results. There were no differences in the electrical activity of the temporal and masseter muscles at rest between the groups. During MVC, the asymmetry index for the masseter muscles was significantly higher in subjects with DS. The electrical potentials of the temporal and masseter muscles in children with DS were significantly lower compared to the corresponding parameters for healthy children when clenching.

Stiffness of the Masseter Muscle in Children-Establishing the Reference Values in the Pediatric Population Using Shear-Wave Elastography.

In children, the quality and muscle function are altered in many pathologic conditions, including temporomandibular disorders. Although several methods have been used to evaluate muscle tonus, none became a golden standard. Moreover, the masseter muscle characteristics in children have not been investigated to date. This study aimed to measure the stiffness of the masseter muscle using shear-wave elastography in healthy children. We enrolled 30 healthy children (mean age 10.87 ± 3.38 years). The stiffness of masseter muscles was measured with shear wave elastography. Stiffness for the total sample was 6.37 ± 0.77 kPa. A comparison of the measurements did not show significant differences between the right and the left masseter muscles (left—6.47 ± 0.78 kPa; right—6.24 ± 0.76 kPa; p = 0.3546). A significant difference was seen between boys and girls (boys—5.94 ± 0.50 kPa; girls—6.63 ± 0.80; p = 0.0006). Shear-wave elastography is a promising diagnostic tool. It may help to detect changes in the stiffness of the masseter muscle and draw attention to pathological processes within the jaw muscles. Directions for further research shall include determining stiffness values in pathological conditions and the impact of biological and functional factors on the stiffness of the masseter muscle.

Bite force and electromyographic activity of the masseter muscle in children with hemifacial microsomia

Hemifacial microsomia (HFM) is a malformation characterized by asymmetric facial growth with mandibular and muscular involvement. There are no reports focused on the functional status of the masticatory system of patients with HFM. The objective of this work evaluate bite force and electrical activity of masseter muscle in children with HFM, and compare them to healthy controls. A cross-sectional study was performed to compare bite force and electrical activity of masseter muscle between subjects with HFM and healthy children. Mean bite force (MBF) and surface electromyography (EMG) on maximum intercuspation (MIC) and rest position (RP) from both sides of the face were recorded. Comparative statistics between HFM patients and controls were performed using the Mann–Whitney test, Wilcoxon’s signed rank test was used to compare the microsomic and healthy hemifaces. Twenty children with HFM and 10 controls were included, average age was 7.2 years (range 3–14). MBF did not show statistical significance between both groups. Surface EMG signal at MIC was significantly diminished when compared to the healthy side (p = .003) and to the control group (p = .016), this significance was also present at RP when comparing the affected and non-affected sides of the face (p < .01) but not against the controls (p = .08). This study showed that patients with HFM had diminished EMG values of the masseter muscle on the affected side, compared to healthy individuals, but bite force did not show significant alterations.

Electromyographic Analysis of Masticatory Muscles in Cleft Lip and Palate Children with Pain-Related Temporomandibular Disorders.

Aim The aim of this study was to assess the electrical activity of temporalis and masseter muscles in children with cleft lip and palate (CLP) and pain-related temporomandibular disorders (TMD-P). Methods The sample consisted of 31 CLP patients with a TMD-P (mean age 9.5 ± 1.8 years) and 32 CLP subjects with no TMD (mean age 9.2 ± 1.7 years). The children were assessed for the presence of temporomandibular disorders (TMD) using Axis I of the Research Diagnostic Criteria for TMD (RDC/TMD). Electromyographical (EMG) recordings were performed using a DAB-Bluetooth Instrument (Zebris Medical GmbH, Germany) in the mandibular rest position and during maximum voluntary contraction (MVC). Results The rest activity of the temporalis and masseter muscles was significantly higher in TMD-P group compared with non-TMD children. A significant decrease in temporalis muscle activity during MVC was observed in TMD-P patients. There was a significant increase in the Asymmetry Index for temporalis and masseter muscle rest activity in the TMD-P group. Conclusion Cleft children diagnosed with TMD-P have altered masticatory muscle activity, and this can affect their muscle function.

Photobiomodulation effect on the masseter muscle in children with cerebral palsy: a case report

Spasticity causes stiffness in the masticatory muscles of individuals with cerebral palsy (CP), affecting the amplitude of mouth opening, making oral hygiene conditions difficult and predisposing these individuals to the risk of developing oral diseases. Objective: To evaluate the effect of a low-intensity photobiomodulation diode laser on the thick part of the masseter muscle in a child with spastic type CP. Method: The caregiver reported that the child had great difficulty in performing the oral hygiene, making avoidance movements of the head when the toothbrush touched the mucosa of the upper molar region in the mouth. The mother described the child’s discomfort as extreme. The first ultrasound evaluation was performed at the first appointment, and the second evaluation after 6 sessions of photobiostimulation. The low-intensity Infrared Laser Diode, Ga-As-Al, was employed (λ = 808 ± 3 nm, 120 mW; Twin Flex Evolution Laser MMOptics São Paulo, Brazil), using 5.0 J/cm2 dose energy/location, with 20 seconds exposure/site. The area of the masseter muscle was bilaterally irradiated towards the midpoint of its length and width. Six sessions were performed, with an interval of 7 days between them. Results: At the end of the sixth session of photobiostimulation, the mother reported that the child slept better, had reduction in involuntary movements performed by the jaw, and oral hygiene was possible now with no painful expression of the child. During palpation there was less stiffness in the bilateral masseter and an increased masseter thickness and increase in the amplitude of the mouth opening of 7 mm. Conclusion: The diode laser photobiostimulation appears to be effective in reducing spasticity in the masseter muscle of children with spastic type CP.

Photobiomodulation effect on the masseter muscle in children with cerebral palsy: a case report

A espasticidade acarreta hipertonia nos músculos mastigatórios dos indivíduos com paralisia cerebral (PC), interferindo na amplitude de abertura bucal, dificultando a realização da higiene oral predispondo estes indivíduos a condições consideradas de risco para o desenvolvimento de doenças bucais. Objetivo: Avaliar o efeito da fotobiomodulação com laser de diodo, de baixa intensidade na espessura do músculo masseter em uma criança com PC do tipo espástico. Método: O relato do cuidador era que a criança apresentava grande dificuldade na realização da higiene bucal e com movimentos de fuga da cabeça quando a escova dental tocava a região de molares superiores. Com relação ao desconforto da criança, a mãe referiu como extremo. A 1ª avaliação ultrassonográfica foi realizada na avaliação inicial, e a 2ª avaliação após 6 sessões de aplicação de fobioestimulação. Foi empregado o Laser infravermelho, de Diodo, de baixa intensidade, As-Ga-Al, (λ = 808 ± 3 nm, 120 mW; Twin Flex Evolution Laser MMOptics São Paulo, Brazil), usando 5,0 J/cm2 energia dose/local, com 20 segundos de exposição/local. A área do músculo masseter irradiado bilateralmente foi o ponto médio no sentido da sua extensão e largura. Foram realizadas seis sessões, com intervalo de 7 dias entre elas. Resultados: Ao final da sexta sessão da fotobioestimulação, a responsável relatou que a criança dormia melhor, apresentava redução no número de movimentos involuntários realizados pela mandíbula e a realização da higiene bucal era possível sem expressão dolorosa da criança. Durante a palpação observou-se menor hipertonia em masseter bilateral, ganho em espessura, e aumento na distância inter-incisal de 7 mm. Conclusão: A fotobioestimulação com laser de diodo parece ser efetiva na redução da espasticidade no músculo masseter de crianças com PC do tipo espástico.

From the journal archives: masseter muscle rigidity: a dose-related drug effect or an early manifestation of a rare potentially fatal pharmacogenetic disorder.

Plumley MH, Bevan JC, Saddler JM, Donati F, Bevan DR. Dose-related effects of succinylcholine on the adductor pollicis and masseter muscles in children. Can J Anaesth 1990; 37: 15-20.

Masseter muscle thickness and mechanical advantage in relation to vertical craniofacial morphology in children

Objective. To investigate the relationship between vertical craniofacial morphology and masseter muscle thickness and mechanical advantage in children. Material and methods. The sample comprised 72 children (36 F, 36 M), 8.5–9.5 years of age, with various malocclusions and no previous orthodontic treatment. The thickness of the masseter was measured bilaterally by means of ultrasonography, and the recordings were performed both in relaxation and under contraction. Mechanical advantage was measured on the lateral cephalograms as the ratio between the masseter moment and the bite force moment arms. Two linear ratios and three angular measurements were used to describe vertical craniofacial morphology. Results. The mean masseter thickness was greater in the male group (p<0.05) in both relaxed and contracted conditions. There were no significant sex differences for the mechanical advantage or for the measurements of vertical craniofacial morphology. In females, there is a positive association between masseter muscle thickness and its mechanical advantage. Multiple regression analysis showed a positive association between posterior to anterior facial height ratio in both genders and a negative association between masseter thickness and the intermaxillary angle in females. Conclusions. There is a significant association between posterior to anterior facial height and the masseter muscle in children. The importance of the masseter muscle is more evident in the vertical facial morphology of females.

EMG power spectrum patterns of anterior temporal and masseter muscles in children and adults.

The power spectrum of electromyograms (EMG) has been demonstrated to vary with muscles having different muscle fiber type compositions. This study investigated the variations in EMG power spectrum patterns of the masticatory muscles with age and gender by comparison of the mean power frequency (MPF) of the anterior temporal and masseter muscles in children and adults. Surface EMG signals were sampled bilaterally from the muscles when the subjects were performing maximum voluntary isometric clenches at maximal intercuspal position. The results indicated that MPF values were age-dependent (p less than 0.001), and sexual dimorphism was evident (p less than 0.001), with lower MPF values in male and adult muscles. While male adults had the lowest and female children had the highest MPF values, female adults had MPF values closer to values obtained from male children. These differences or similarities could be attributed to the degree of differentiation of the muscles during growth and development of the craniofacial morphology.

Frequency Analysis of the EMG Power Spectrum of the Anterior Temporal and Masseter Muscles in Children and Adults

Frequency Analysis of the EMG Power Spectrum of the Anterior Temporal and Masseter Muscles in Children and Adults

Posterior periodontal loading plays a key role in the suppression of a short latency excitatory reflex in the masseter muscle in children being treated with the Bionator.

Post-stimulus EMG complexes (PSECs), consisting of a series of inhibitory and excitatory reflexes, were elicited by means of standardized taps to an upper incisor in 5 children being treated with a bionator functional appliance. These stimuli were delivered while the children were clenching in three biting conditions which were randomly alternated during the experiments, namely the maximal occlusion, the incisor edge-to-edge and the Bionator biting position. Different PSEC morphologies were observed in each of these positions, but a short latency excitatory reflex was only present in the incisor edge-to-edge biting position. It could be demonstrated that periodontal loading in the maximal occlusion and in the Bionator biting position, plays a key-role in the suppression of this reflex.

Isometric endurance of masseter muscle in children.

SummaryEight children, mean age of 12 years, exercised maximal voluntary tooth clenching to determine the isometric endurance time of the masseter muscle. The endurance time seemed to depend on psychological and/or physiological determinants. The latter might have been Wedensky inhibition, changes in energy metabolism, progressive fatigue and so‐called muscle fitness.

Electromyography of the temporalis and masseter muscles in children with unilateral cross-bite.

Abstract— Unilateral cross‐bite is a morphologic trait observed in the intercuspal position. The present report deals with its influence on the activity in the muscles of mastication as studied by electromyography. In 12 children 8–11 years of age with unilateral cross‐bite the action of the temporal and masseter muscles was studied (1) with the mandible at rest, i. e. without tooth contact, and (2) during maximal bite in the intercuspal position. With the mandible at rest the activity in the anterior temporal muscle was strongest on the side of normal occlusion and in the posterior temporal muscles it tended to be strongest on the side of the cross‐bite. During maximal bite the action of the posterior temporal muscles was reduced on the side with normal occlusion as compared with the side of the cross‐bite. The activity in the masseter muscles was not modified. As a whole the pattern of activity at rest and during full effort indicated adaptation to the transverse occlusion.