Impact of obesity on the structures and functions of the stomatognathic system: A morphofunctional approach.

OBJECTIVE: The prevalence of obesity is increasing significantly worldwide, raising great concern among health professionals. This observational study evaluated the electromyographic activity and thickness of the masseter and temporalis muscles, in addition to the maximum molar bite force, in obese and eutrophic subjects. METHODS: Sixty subjects were divided into three groups: I (7-12 years), II (13-20 years), III (21-40 years) and sex: with 10 men and 10 women for each group. Electromyographic recordings of the masticatory muscles were obtained during mandibular tasks. The masticatory muscles thicknesses were obtained at rest and during dental clenching. The maximum molar bite forces were measured on the right and left sides. The difference in outcome measures between the groups and sex was analyzed using Mann-Whitney U test (p < 0.05) and analysis of covariance (ANCOVA). RESULTS: Electromyographic activity in the masseter and temporal muscles consistently displayed lower levels in obese subjects of both sexes across all three age groups during mandibular tasks. Additionally, greater thickness of the masticatory muscles was observed in obese subjects of both sexes across all three age groups. Obese women in Group II displayed higher values of molar bite force, both on the right and left sides, compared to eutrophic women. On the other hand, women in Group III exhibited higher values of molar bite force on the right side in comparison to eutrophic women. CONCLUSIONS: This study underscores the potential impact of obesity on the morphofunctional aspects of the stomatognathic system in subjects aged 7 to 40 years.

Lycopene enhances bone neoformation in calvaria bone defects of ovariectomized rats.

Osteoporosis can affect a significant part of the population and fractures are the most common complications associated with this disease, leading to high public health costs. Thus, the prevention of fractures is relevant to individuals with signs and symptoms as well as to the health system. Postmenopausal osteoporosis has been associated with oxidative stress, emphasizing the importance of an efficient defense system to maintain bone health. Lycopene is a carotenoid with antioxidant properties that may stimulate osteoblastogenesis and inhibit osteoclastogenesis. The purpose of this investigation was to analyze the influence of lycopene in the bone neoformation of calvaria defects in ovariectomized rats utilizing the concentration of 45 mg/kg. Wistar Hannover female rats were divided into ovariectomized and sham groups. The ovariectomized animals received 45 mg/kg lycopene (OvxL) or water (Ovx) by daily gavage the day after ovariectomy/sham surgery for 16 weeks. Twelve weeks after ovariectomy, there were performed 5-mm calvaria defects followed by euthanasia after 4 weeks. Samples of bone tissue were collected to perform morphological and morphometrical analysis of the neoformed bone area, and percentage with Software Image J. Morphological evaluation showed mature bone with more osteocytes in the group OVxL when compared to the other groups. The morphometrical analysis demonstrated a significant increase of bone neoformation in the group OvxL (p<0.05). The data obtained suggest that lycopene benefits bone repair in the absence of estrogenic hormones.

Lycopene enhances bone neoformation in calvaria bone defects of ovariectomized rats

Abstract Osteoporosis can affect a significant part of the population and fractures are the most common complications associated with this disease, leading to high public health costs. Thus, the prevention of fractures is relevant to individuals with signs and symptoms as well as to the health system. Postmenopausal osteoporosis has been associated with oxidative stress, emphasizing the importance of an efficient defense system to maintain bone health. Lycopene is a carotenoid with antioxidant properties that may stimulate osteoblastogenesis and inhibit osteoclastogenesis. The purpose of this investigation was to analyze the influence of lycopene in the bone neoformation of calvaria defects in ovariectomized rats utilizing the concentration of 45 mg/kg. Wistar Hannover female rats were divided into ovariectomized and sham groups. The ovariectomized animals received 45 mg/kg lycopene (OvxL) or water (Ovx) by daily gavage the day after ovariectomy/sham surgery for 16 weeks. Twelve weeks after ovariectomy, there were performed 5-mm calvaria defects followed by euthanasia after 4 weeks. Samples of bone tissue were collected to perform morphological and morphometrical analysis of the neoformed bone area, and percentage with Software Image J. Morphological evaluation showed mature bone with more osteocytes in the group OVxL when compared to the other groups. The morphometrical analysis demonstrated a significant increase of bone neoformation in the group OvxL (p<0.05). The data obtained suggest that lycopene benefits bone repair in the absence of estrogenic hormones.

Resumo A osteoporose afeta grande parte da população e as fraturas são as complicações mais importantes relacionadas a essa doença, gerando altos gastos para o poder público. Dessa forma, a prevenção de fraturas decorrentes da osteoporose torna-se relevante tendo em vista que gera benefícios tanto para o indivíduo acometido pela doença quanto para o sistema de saúde. A osteoporose pós menoupasa tem sido associada ao estresse oxidativo, portanto, um eficiente sistema de defesa antioxidante é primordial para a manutenção da saúde óssea. O licopeno é um carotenoide antioxidante que aparentemente estimula a osteoblastogênese e inibe a osteoclastogênese. O objetivo deste estudo foi analisar a influência do licopeno na neoformação óssea em defeitos de calvária em ratas ovariectomizadas utilizando a concentração de 45 mg/kg. Foram utilizados 15 ratas Wistar Hannover pesando aproximadamente 200g, sendo que 10 animais foram submetidos à ovariectomia bilateral e 5 (Grupo Sham) foram submetidos à simulação da cirurgia de ovariectomia bilateral. Os animais ovariectomizados foram divididos aleatoriamente em 2 grupos: Ovariectomizado (Ovx) e Ovariectomizado Licopeno (OvxL) que receberam água e licopeno respectivamente, por sonda gástrica, diariamente. As administrações iniciaram-se no dia seguinte à cirurgia de ovariectomia e/ou da exposição dos ovários e foram mantidas por 120 dias, data de realização da eutanásia. O grupo Sham recebeu água diariamente. Noventa dias após a ovariectomia bilateral foram confecionados defeitos ósseos nas calvárias de todos os animais e após trinta dias as ratas foram eutanasiadas. As amostras de tecido ósseo foram coletadas e foi realizado o processamento para a obtenção das lâminas histológicas. Foram realizadas as análises morfológicas e morfométrica, onde foi estimada a área (mm2) e porcentagem (%) relativa de osso neoformado utilizando o Software Image J. A avaliação morfológica evidenciou a ação benéfica do licopeno pois os animais que receberam esse antioxidante apresentaram um tecido ósseo mais maduro, com maior presença de osteócitos quando comparados aos demais grupos. Por meio das análises morfométricas verificou-se maior neoformação óssea para os animais que receberam o licopeno (p<0,05). Diante dos resultados obtidos, concluiu-se que o licopeno na concentração de 45 mg/Kg teve efeito benéfico no processo de reparação, promovendo significante formação óssea frente à ausência de hormônios estrogênicos.

Effect of dry needling and instrumental myofascial release on masticatory, facial, and cervical muscles of patients with temporomandibular disorders of muscular origin.

Background: To evaluate the effectiveness of dry needling (DN) and instrumental myofascial release (IMR) therapies in the cervico-cranio-mandibular system through pain, bite force, and distribution of occlusal contacts in patients with muscular temporomandibular disorders. Material and Methods: Thirty patients were divided into treatment groups: DN (n=15) and IMR (n=15). Therapeutic efficacy regarding pain perception and tolerance of masticatory, facial, and cervical muscles, bite force, and distribution of occlusal contacts were analyzed in this observational longitudinal clinical study pre/post-intervention and pre/post one month of therapeutic intervention. The data were tabulated and statistically analyzed (repeated measures and Bonferroni post-hoc test, p<0.05). Results: There was a statistically significant difference in pain between the groups in the comparison of pre- and post-intervention with effect on time versus intervention in the head and neck. Pain perception and tolerance showed a statistical effect of time on the temporal, suboccipital, sternocleidomastoid, mental (right and left), right masseter, and left trapezius muscles. There was a statistically significant effect of the intervention on the mentalis, supraorbital, and infraorbital (right and left) muscles. There was a statistically significant effect of the interaction on the upper masseter (right and left), anterior temporal (left), suboccipital, sternocleidomastoid, and mentalis (left) muscles. There was an increase in post-intervention molar bite force in the groups, with a statistical effect on time versus intervention in the right and left regions. Contact of occlusal forces at the maxilla/mandible interface showed a difference between the mean times on teeth 26-36 after versus 1 month after the intervention. Conclusions: The two therapeutic techniques are viable for the treatment of muscular temporomandibular disorders; however, IMR proved to be more effective immediately after the intervention and after one month. Key words:Temporomandibular disorders, pain, masticatory muscles, facial muscles, cervical muscles, dry needling, instrumental myofascial release.

Orthodontic treatment of children with anterior open bite and posterior crossbite: An analysis of the stomatognathic system.

Dental malocclusions are deviations from normalities due to the inadequate growth and development of the dental arch which provides functional changes to the stomatognathic system. The aim of this longitudinal study was to evaluate the electromyographic activity (EMG) the masseter and temporalis muscles, strength of the orofacial tissues and occlusal force of children with anterior open bite (n = 15) and posterior crossbite (n = 20), 7 days after the removal of the orthodontic apparatus. A fixed horizontal palatal crib was used in the treatment of anterior open bite and the fixed appliances Hyrax or MacNamara was used in the treatment of posterior crossbite. EMG of the masticatory muscles was recorded using an electromyograph with wireless sensors during mandibular tasks. Habitual chewing was assessed using the integral of the linear envelope of the electromyographic signal in the masticatory cycles. The strength of the tongue and facial muscles was measured using the Iowa Oral Pressure Instrument. T-Scan was used to analyze the force of occlusal contact. Molar bite force was measured by digital dynamometer. Significant differences (p < 0.05) were found in the EMG data of the masseter and temporalis muscles in the static and dynamic mandibular tasks. There were no significant difference in strength of orofacial tissues, occlusal contact force and molar bite force 7 days after the removal of the orthodontic apparatus. The results of this study suggest that the orthodontic treatment of anterior open bite and posterior crossbite in children promoted functional alteration in the electromyographic activity of masseter and temporalis muscles.

Stroke: An electromyographic approach to the masseter and temporal muscles, orofacial soft tissue pressure, and occlusal force.

Stroke is a cerebrovascular disease that triggers changes in the central and peripheral nervous systems, and can compromise human body function. This cross-sectional observational study aimed to analyze the electromyographic (EMG) activity of the masseter and temporal muscles, orofacial soft tissue pressure, and strength of occlusal contacts in patients who had suffered a stroke. Twenty-four patients were divided into two groups: stroke (n = 12) and control (n = 12). The EMG of the masseter and temporal muscles was evaluated during mandibular rest, protrusion, right laterality, left laterality, and maximal voluntary contraction. The Iowa Oral Pressure Instrument (IOPI) was used to measure pressure from the tongue, lips, and buccinator muscles. A computerized system for occlusal analysis (T-Scan III) was used to measure the occlusal contact points of the right and left hemiarches (upper and lower) and the upper and lower first molars. Data were subjected to Student's t-test (p < 0.05). The stroke group had lower normalized electromyographic activity, with a significant difference in the left temporal muscle during rest (p = 0.03) when compared to the control group. There was a significant difference between the groups in tongue pressure (p = 0.004) with a lower mean value in the stroke group. There was a significant difference between the groups in the evaluation of the occlusal contact points of the first permanent molars, with a lower mean percentage in the stroke group. The results indicate that stroke negatively affects functional performance of the stomatognathic system.

Amyotrophic Lateral Sclerosis: An Analysis of the Electromyographic Fatigue of the Masticatory Muscles.

Amyotrophic lateral sclerosis is a chronic degenerative disease that affects motor neurons, thereby promoting functional changes in the human body. The study evaluated the electromyographic fatigue threshold of the masseter and temporal muscles of subjects with amyotrophic lateral sclerosis. A total of eighteen subjects were divided into two groups: amyotrophic lateral sclerosis (n=9) and disease-free control (n=9). The groups were equally divided according to gender (7 males, 2 females). The fatigue threshold was analysed using median frequencies obtained during the 5-second window (initial [IP], mid [MP], and final [FP] periods) of electromyographic signalling of the masseter and temporal muscles bilaterally, with reduction in muscle force during maximal voluntary dental clenching. Significant difference (p<0.05) in the left temporal muscle: IP (p=0.05) and MP (p=0.05) periods was demonstrated. The amyotrophic lateral sclerosis group showed a decrease in median frequency of the electromyographic signal of the masseter and temporal muscles compared to the control group. Amyotrophic lateral sclerosis promotes functional impairment of the stomatognathic system, especially at the electromyographic fatigue threshold of the masticatory muscles.

Effect of intervertebral disc degeneration on the stomatognathic system function in adults.

OBJECTIVE: To analyze the electromyographic activity (EMG) and thermographic patterns of the masseter and temporalis muscles and pressure of the orofacial tissues in individuals with intervertebral disc degeneration (IDD). METHODS: This study had two distinct groups: with IDD (n = 16) and controls (n = 16). EMG at rest, protrusion, right and left laterality, and maximum voluntary contraction were evaluated. Tongue, orbicularis oris, and buccinator muscles pressures were measured by Iowa Oral Performance Instrument. The thermographic patterns were analyzed using infrared thermography. RESULTS: Comparisons between groups showed significant differences regarding at rest [right (p = 0.05) and left (p = 0.05) masseter and right temporal (p = 0.05)], orofacial tissue pressure [tongue (p = 0.001), orbicularis oris (p = 0.01), and buccinator (p = 0.0001)], but no significant differences for the thermographic patterns. CONCLUSION: IDD modifies the functionality of the craniomandibular complex, influencing the performance of the stomatognathic system.

Impact of Hemorrhagic Stroke on Molar Bite Force: A Prospective Study.

Stroke is a neurological deficit of cerebrovascular origin that promotes physical impairments of adult individuals. The present study is aimed to demonstrate whether hemorrhagic stroke affects the maximum molar bite force. The prospective study carried in Centro Universitario Claretiano de Batatais, Brazil, determined the distribution of the sample into two groups: hemorrhagic stroke group (n=18, median age, 62.5 years) and disease-free group (n=18, median age, 62.0 years), with 10 men and 8 women in each group. Subjects were paired one-to-one (age and body mass index). The dynamometer was used to measure the maximum molar bite force (right and left). All analyses were performed with a significance level of 5% (Student's t-test). Differences were found on the right (p=0.048) and left (p=0.042) molar bite force, with lower bite force (both sides) in hemorrhagic stroke group. The study suggests that hemorrhagic stroke negatively affects the maximum molar bite force and necessitates changes in food intake to nutritious and softer consistency foods.

Intervertebral Disc Degeneration: Functional Analysis of Bite Force and Masseter and Temporal Muscles Thickness.

Intervertebral disc degeneration is a pathological condition associated with the intervertebral disc and is related to functional alterations in the human body. This study aimed to evaluate the maximum molar bite force and masseter and temporal muscles thickness in individuals with intervertebral disc degeneration. Thirty-two individuals were divided into two groups: those with degeneration of intervertebral discs (n=16) and those without degeneration (n=16). The maximum molar bite force (on the right and left sides) was measured using a dynamometer. Masseter and temporal muscle thickness during mandibular task rest and dental clenching in maximum voluntary contraction were analysed using ultrasound. Significant differences in the left molar bite force (p=0.04) were observed between the groups (Student's t-test, p<0.05). The intervertebral disc degeneration group had a lower maximum molar bite force. No significant differences in muscle thickness were observed between the masseter and temporal muscles in either group. However, based on clinical observations, the group with intervertebral disc degeneration presented less masseter muscle thickness and greater temporal muscle thickness in both mandibular tasks. Degenerative disease of the intervertebral discs promoted morphofunctional changes in the stomatognathic system, especially in maximum molar bite force and masticatory muscle thickness. This study provides insight into the interaction between spinal pathology and the stomatognathic system, which is important for healthcare professionals who treat patients with functional degeneration.

Texturized P(VDF-TrFE)/BT membrane enhances bone neoformation in calvaria defects regardless of the association with photobiomodulation therapy in ovariectomized rats.

OBJECTIVES: The purpose of this investigation was to evaluate in vivo the response of bone tissue to photobiomodulation when associated with texturized P(VDF-TrFE)/BT in calvaria defects of ovariectomized rats. MATERIALS AND METHODS: Wistar Hannover rats were submitted to ovariectomy/control surgery. Calvaria bone defects of 5-mm diameter were performed after 90 days of ovariectomy. The animals were divided into OVX (without laser (L) and membrane), OVX + P(VDF-TrFE)/BT, OVX + P(VDF-TrFE)/BT + L, and OVX + PTFE + L. It was utilized a low-intensity gallium-aluminum-arsenide laser (GaAlAs) with 780-nm wavelength and 30-J/cm2 energy density in 12 sessions (120 s). Thirty days after the bone defect the animals were euthanized for histological, microtomographic, and molecular evaluation. Quantitative analysis was analyzed by statistical software for p < 0.05. RESULTS: Histological parameters showed bone tissue formation at the borders of all group defects. The association of photobiomodulation and texturized P(VDF-TrFE)/BT was not synergistic and did not show significant changes in morphometric analysis and biomarkers gene expression. Nevertheless, texturized P(VDF-TrFE)/BT membrane enhanced bone repair regardless of the association with photobiomodulation therapy, with an increase of connectivity density when compared to the OVX + PTFE + L group. The association of photobiomodulation therapy and PTFE was synergistic, increasing the expression of Runx2, Alp, Bsp, Bglap, Sp7, and Rankl, even though not enough to reflect significance in the morphometric parameters. CONCLUSIONS: The utilization of texturized P (VDF-TrFE)/BT, regardless of the association with photobiomodulation therapy, enhanced bone repair in an experimental model of osteoporosis.

Stomathognatic system function in indigenous people from Brazilian Xingu villages: An electromyographic analysis.

The maintenance of postural balance can be influenced by the lifestyle of a population. This study aimed to determine the electromyographic activity of the masseter and temporalis muscles during mandibular tasks and habitual and non-habitual chewing in indigenous individuals to reveal the differences among white Brazilian individuals. Sixty Brazilians (18 and 28 years) were divided into two groups: 30 Xingu indigenous individuals and 30 white Brazilian individuals, with 20 men and 10 women in each group. The individuals were assessed using the normalized electromyographic activity of mandibular tasks (rest, protrusion, right and left laterality) and electromyographic activity of masticatory cycles in habitual (peanuts and raisins) and non-habitual (Parafilm M) chewing. Data were analyzed using Student's t-test (p < .05). Comparisons between the groups demonstrated significant differences. Indigenous individuals group presented a decrease in the normalized electromyographic activity of the masticatory muscles during mandibular rest [right masseter (p = .002) and left masseter (p = .004) muscles]. There was increase in the normalized electromyographic activity during protrusion [left temporal (p = .03) muscle]. There was increase in the electromyographic activity during chewing: peanuts [right masseter (p = .001), left masseter (p = .001) and right temporal (p = .01) muscles], raisins [right masseter (p = .001), left masseter (p = .002), right temporal (p = .008), left temporal (p = .01) muscles] and Parafilm M [left masseter muscle (p = .05)]. From the findings of this study, we concluded that in the comparison between indigenous and white individuals, positive changes were observed in the electromyographic pattern of the masticatory muscles in the mandibular postural conditions, with greater masticatory efficiency in the indigenous group.

Autologous Hematopoietic Stem Cell Therapy of the Subjects with Systemic Sclerosis: Electromyographic Results of the Masticatory Muscles.

Musculoskeletal system impairment is a major cause of functional alterations in subjects with systemic sclerosis. Autologous hematopoietic stem cell therapy (AHSCT) may have an important role in the treatment functional of systemic sclerosis patients. The aim of this pilot study was to assess whether AHSCT interferes with the electromyographic activity of the masseter and temporalis muscles of subjects with systemic sclerosis. Before transplantation, seven subjects with systemic sclerosis (mean age [± SD], 40.1 ± 9.6 years) underwent electromyographic analysis of the masseter and temporalis muscles in mandibular tasks at rest, right and left laterality, protrusion and maximum voluntary contraction. Two months after AHSCT, the subjects re-evaluated using the same methods. Data were analyzed using the repeated-measure test, with p<0.05 considered to be statistically significant. Two months after AHSCT, there was reduction in normalized electromyographic activity in the dental clenching in maximal voluntary contraction, with significant differences, for the left temporal muscle (p=0.04). AHSCT in subjects with systemic sclerosis promotes alterations in stomatognathic system function, especially those related to electromyographic activity of masticatory muscles.

Osteoarthrosis: Analyze of the Molar Bite Force, Thickness and Masticatory Efficiency.

Osteoarthrosis is a disorder of synovial joints, resulting from destruction of the cartilage and subchondral bone. The present study is aimed to investigate the molar bite force, thickness and efficiency of the masseter and temporalis muscles of subjects with osteoarthrosis. A total of forty-eight subjects participated in the study. They were distributed into two groups: with osteoarthrosis (n=24) and asymptomatic controls (n=24). Subjects were analyzed on the basis of maximal molar bite force (right and left side), thickness (mandibular rest and dental clenching in maximal voluntary contraction) and electromyographic activity of masticatory cycles through the linear envelope integral in habitual (raisins and peanuts) and non-habitual (Parafilm M) chewing of the masseter and temporalis muscles. All the data were analyzed statistically using t-test with a significance level of p≤0.05. There was no difference between groups in maximal molar bite force, muscle thickness and non-habitual chewing. Differences were found on the raisins (p=0.02) and peanuts (p=0.05) chewing for right temporal muscle, with reduced masticatory muscle efficiency in osteoarthrosis subjects. This study showed that osteoarthrosis induces negative changes in habitual chewing, highlighting the efficiency of the right temporalis muscles. The greater temporal muscle activity in subjects with osteoarthrosis may compromise chewing and consequently the nutritional status of adult subjects.

Impact of chronic allergic rhinitis on bite force and electromyographic activity of masseter and temporalis muscles of adult women.

BACKGROUND: The aim of this study was to analyse the stomatognathic system of adult women with chronic allergic rhinitis by means of molar bite force and electromyographic activity of the masseter and temporalis muscles. MATERIAL AND METHODS: A total of 26 subjects were screened and divided into two distinct groups: chronic allergic rhinitis group (n = 13) and healthy control group (n = 13). Subjects were assessed by maximal molar bite force (right and left) and normalized electromyographic activity of mandibular tasks (rest, right and left laterality, protrusion and maximal voluntary contraction). Data were submitted to Student's t test (p< .05). RESULTS: There was significant difference in right (p = .03) and left (p = .04) maximal molar bite force with force reduction in the chronic allergic rhinitis group. There was significant difference in normalized electromyographic activity in maximal voluntary contraction in the right (p =.01) and left (p = .01) temporalis muscles, with increased electromyographic activity in the masticatory muscles for the chronic allergic rhinitis group. CONCLUSIONS: The results suggest that chronic allergic rhinitis in adult women promoted negative changes in the electromyographic activity of temporalis muscles in maximal voluntary contraction and maximal molar bite force. Key words:Rhinitis, occlusal force, electromyography, masticatory muscles.

Analysis of the sleep period and the amount of habitual snoring in individuals with sleep bruxism

BACKGROUND: The literature does not report any association between habitual snoring and sleep bruxism, but these situations can be a reason for frequent complaints of individuals, impairing the quality of life. This study was per-formed to investigate the sleep period and amount of habitual snoring in individuals with sleep bruxism observing expiratory, inspiratory, and mixed snoring. MATERIAL AND METHODS: A total of 90 individuals were screened and divided into the following groups: with sleep bruxism (n = 45) and those without sleep bruxism (n = 45). Single night sleep polysomnography was performed to diagnose sleep bruxism, quantify habitual snoring and sleep period. The results were tabulated and submitted to a Multivariate analysis of variance (MANOVA) to compare the means of the two independent groups, considering the affected diagnosis of sleep bruxism, snoring (independent variables) and age as covariate. For the post hoc, was used correcting for multiple comparisons (Bonferroni test, P < .05). RESULTS: There was statistically significant difference among the groups (p = .001) in the sleep period, in that individuals with sleep bruxism slept for a longer duration (with sleep bruxism group: 460 minutes and without sleep bruxism group: 401 minutes). There were no statistically significant differences among the groups for the number of inspiratory, expiratory and mixed snores, but was observed greater amount of snoring in the with sleep bruxism group. CONCLUSIONS: The main finding of this study is that individuals with sleep bruxism slept longer than the control group. It may also be suggested that individuals with sleep bruxism tended to increase the amount of habitual snoring dur-ing sleep

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Alterations in masticatory cycle efficiency and bite force in individuals with periodontitis.

OBJECTIVES: The objective of this research was to evaluate the effect of periodontitis on masticatory cycle efficiency and maximum molar bite force. METHODS: Twenty-four individuals were divided into two groups: With periodontitis (Group I; mean age ± standard deviation (SD), 51.3 ± 2.8 years; n = 12) and without periodontitis (Group II; mean age ± SD, 48.9 ± 2.4 years; n = 12). Masticatory cycle efficiency was obtained from the value of the ensemble-averaged integrated linear envelope electromyographic signal of the masseter and temporalis muscles. Maximum bite force was recorded for the right and left molar regions. The data were tabulated and submitted to statistical analysis (P ≤ 0.05). RESULTS: There was a significant difference between the groups for the left masseter muscle when chewing raisins (P = 0.04), peanuts (P = 0.02), and biocapsules (P = 0.01). Multiple regression analysis demonstrated the influence of dental mobility on masticatory cycle efficiency for peanuts (P = 0.03) and biocapsules (P = 0.01). The maximum bite force for the left molar region was significantly different between the groups (P = 0.02). Dental mobility was a variable that had a greater effect on masticatory cycle efficiency. The periodontitis group had a reduced bite force. CONCLUSION: The present study findings indicate that the loss of periodontal supporting structures had a negative impact on masticatory cycle efficiency and molar bite force. This finding suggested that dental mobility should be considered when determining clinical treatments aimed at improving masticatory efficiency and bite force in individuals with the periodontal disease.

Spinocerebellar ataxia: Functional analysis of the stomatognathic system

Background: Neurodegenerative diseases that affect the cerebellum, especially in elderly individuals, cause impairment of motor coordination and quality of life. The presente study evaluated the electromyographic activity and thickness of the right and left masseter and temporal muscles, and the maximum molar bite force of individuals with spinocerebellar ataxia. Material and Methods: Twenty-eight individuals were divided into two groups: those with (n=14) and without (n=14) spinocerebellar ataxia. Data on the masticatory muscles obtained from the electromyographic activity (resting, right and left laterality and protrusion), muscle thickness (maximal voluntary contraction and tensile strength) and maximum bite force (right and left) were tabulated and descriptive analysis using Student’s t-test (P ≤ 0.05). Results: In the comparison between groups, greater electromyographic activity was demonstrated for individuals with spinocerebellar ataxia, with a statistically significant difference in protrusion and laterality for the temporal muscles (P = 0.05). T here was no statistically significant d ifference b etween t he g roups for m asticatory muscles thickness in the conditions evaluated. For maximum molar bite force, the group with spinocerebellar ataxia showed lower bite force (P ≤ 0.05). Conclusions: The data obtained suggest that spinocerebellar ataxia promotes functional reduction in the stomatognathic system, mainly affecting the electromyographic activity and bite force, hindering chewing, with a resultant alteration of nutritional intake and a decrease of quality of life

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Alterations in the stomatognathic system due to amyotrophic lateral sclerosis.

OBJECTIVES: To compare the molar bite force, electromyographic activity, chewing efficiency and thickness of the masseter and temporalis muscles in individuals with amyotrophic lateral sclerosis (ALS) and healthy individuals. MATERIAL AND METHODS: Thirty individuals enrolled in the study were divided into the study group (with ALS, n=15) and control group (healthy individuals, n=15). Data regarding molar bite force (right and left), electromyographic activity (mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction), chewing efficiency (habitual and non-habitual), and masticatory muscle thickness (rest and maximum voluntary contraction) were tabulated and subjected to statistical analysis (Student's t-test, p≤0.05). RESULTS: Comparisons between the groups demonstrated a statistically significant increase in the electromyographic activity of the right masseter (p=0.03) and left masseter (p=0.03) muscles during mandibular rest; left masseter (p=0.00), right temporalis (p=0.00), and left temporalis (p=0.03) muscles during protrusion; and right masseter (p=0.00), left masseter (p=0.00), and left temporalis (p=0.00) muscles during left laterality, in individuals with ALS as compared with healthy individuals. A statistically significant decrease was observed in the habitual chewing efficiency of the right masseter (p=0.00) and right temporalis (p=0.04) muscles in individuals with ALS. No statistically significant difference between the groups was found the masticatory muscle thickness and maximal molar bite force. CONCLUSIONS: ALS may lead to modifications in the activities of the stomatognathic system, including muscular hyperactivity and reduction in chewing efficiency; however, no change has been observed in the masticatory muscle thickness and molar bite force.

Functional analysis of lower limbs in individuals infected with the human immunodeficiency virus.

OBJECTIVES: The objective of this research was to analyze the functional changes of lower limbs by means of surface electromyography in patients with acquired immunodeficiency syndrome. METHODS: A total of 60 men and women (age mean of 36.77 ± 9.33 years) were divided into two groups: 30 individuals with human immunodeficiency virus group (HIVG) Subtype 1 and 30 healthy individuals control group. Muscle activity was evaluated using surface electromyography (sEMG). sEMG measurements were made while the subjects assumed the static positions: Rest in orthostatism (RS), squat "normalization factor," right and left single leg support (RSLS, LSLS) and during functional activities: Right and left single leg step rise (RSLSR, LSLSR), right and left single leg step down (RSLSD, LSLSD), rising and seating on a chair (RC, SC). RESULTS: To sEMG results revealed statistically significant values in the conditions of RSLS to left semitendinosus muscle, for LSLS to right and left semitendinosus, right rectus femoris and right gluteus medius muscles, for LSLSR to right rectus femoris and right tensor fasciae latae muscles, for RSLSD to right and left semitendinosus and right rectus femoris muscles, for RC to right rectus femoris and left gluteus medius muscles and for SC to right semitendinosus, right rectus femoris and right and left gluteus medius muscles. CONCLUSION: It can be concluded that individuals with acquired immunodeficiency syndrome presented changes in lower limb muscle activity.