Objectives:To compare the electromyographic (EMG) activity of the masseter and anterior portion of temporal muscles in different vertical facial types. Materials and Methods: Clinical examination, cephalometric analysis, and electromyographic examination were performed in 44 volunteers ranging from 18 to 35 years old. The volunteers were classified on the basis of their vertical facial characteristics into three groups-brachyfacial, mesofacial, and dolicofacial-by the grouping analysis. The EMG records were obtained with three repetitions during mandibular rest, maximum voluntary contraction in intercuspidation, and simultaneous bilateral isotonic contraction. The Kolmogorov-Smirnov and Levene tests were applied to verify the normality and homogeneity of variance. Analysis of variance and the Kruskal-Wallis test identified statistical differences among groups that did not present normality and homogeneity of distribution, respectively. Significance for all statistical tests was set at P Ͻ .05. Results: At rest, only the right temporal and masseter muscles presented statistically significant differences among the groups. The differences were observed between groups 1 and 2 (P ϭ .02) and 1 and 3 (P ϭ .038) for the right temporal muscle, and between groups 1 and 2 (P ϭ .029) for the right masseter muscle. Generally, group 1 presented the lowest EMG values for the four muscles evaluated during rest. For isotonic evaluation, none of the groups of muscles presented statistically significant differences. Conclusion: Different vertical facial types do not determine distinct patterns of EMG activity for the masseter and anterior portion of temporal muscles during rest and bilateral mastication. (Angle Orthod. 2009;79:515-520.)

Different vertical facial types do not determine distinct patterns of EMG activity for the masseter and anterior portion of temporal muscles during rest and bilateral mastication.

No abstract

The aim of the present study was to verify the relationship between the angle of the coronoid process of the mandible in the latero-lateral direction and electromyographic activity of the anterior part of the temporal muscle in skeletal Class I and III individuals. Forty-five volunteers were assessed subdivided into two groups, according to angle ANB, in Class I and III. Two radiographic examinations were performed, one lateral cephalogram to measure angle ANB and one frontal cephalogram to measure the angle of the coronoid process. The electromyographic examination of the volunteers' temporal muscles was performed. Statistical analysis of the data showed that the relationship between the angle of the coronoid process and the skeletal class was negative for both classes analysed. The relationship between electromyographic activity of the temporal muscle and angle of the coronoid process was negative for Class I individuals. In the Class III group, smaller angles of the coronoid process were related to higher values of electromyographic activity of the temporal muscle. There was no statistically significant difference between the electromyographic activity of the temporal muscle in skeletal Class I and III individuals. Based on the results obtained, it was concluded that there was no influence of the skeletal classes analysed on the angle of the coronoid; the angle of the coronoid process may be influenced by the electromyographic activity of the temporal muscle in the Class III group; the electromyographic activity of the temporal muscle is not influenced by the skeletal class in Class III individuals.

RESUMOObjetivo: avaliar através da eletromiogra a de superfície o comportamento dos músculos esternocleidomastóideo e paraespinhais cervicais bilateralmente em pacientes que se comunicam por meio da fala esofágica e laringe arti cial, para determinar se o tipo de voz utilizada altera o comportamento dos músculos cervicais. Métodos: foram avaliados dez voluntários (duas mulheres e oito homens), idade média de 49,7 anos, com laringectomia total, tempo de pós-operatório médio de 2,6 anos, com limitação dos movimentos do pescoço, divididos em dois grupos: grupo 1: cinco voluntários (laringe arti cial); grupo 2: cinco voluntários (voz esofágica); grupo 3 controle (sete voluntários). Resultados: na fonação não houve alteração no padrão de ativação muscular dos indivíduos que utilizam a voz esofágica e a laringe arti cial, com relação ao grupo controle. No entanto, na condição de repouso houve diferença signi cativa, comparando-se os valores médios de Root Mean Square dos grupos 1 e 2 com o grupo 3, para o músculo esternocleidomastóideo direito e para os músculos paraespinhais cervicais direito. Conclusão: o tipo de opção vocal não interferiu no padrão de ativação muscular durante a fonação, bem como não existiu diferença no padrão de ativação muscular na fonação dos voluntários quando comparados a indivíduos sem intercorrências no aparelho fonador. cie mostrou ser um método favorável na avaliação terapêutica dos pacientes, porém são necessários novos estudos para se ter o per l mais completo destes aspectos. AGRADECIMENTOSAgradecemos à CNPQ pelo apoio nanceiro concedido para a realização dessa pesquisa.ABSTRACT Purpose: to evaluate by the surface electromyography the behavior of the sternocleidomastoid and cervical paraspinalis muscles, bilaterally in patients who use esofagic and arti cial larynx as alternative to talk and to determine if these conditions modify the cervical muscles behavior. Methods: ten volunteers were evaluated (two women, eight men), with average age: 49. 7 years, with total laryngectomy, average time of postoperative: 2.6 years, with neck movements limitation, divided in two groups: group 1 with ve volunteers (arti cial larynx); group 2 with ve volunteers (esofagic voice); and group 3 control (seven volunteers). Results: there was no signi cant difference in the muscular activation pattern during phonation in individuals with esofagic voice and the arti cial larynx compared to the control group, however, in the rest condition, there was a signi cant difference comparing the average values of Root Mean Square (RMS) of groups 1 and 2 with group 3, for the right sternocleidomastoid muscle and the right cervical paraspinalis muscles. Conclusion: the vocal option did not interfere on the muscular activation pattern during the phonation, as well as there was no difference in the muscular activation pattern comparing the experimental groups with the control group.