OBJETIVO: Quantificar e comparar as forças produzidas pela língua de crianças respiradoras orais pré-cirúrgicas, respiradoras orais em tratamento fonoaudiológico e respiradoras nasais, além de comparar os achados da avaliação objetiva com os dados da avaliação clínica. MÉTODOS: Estudo transversal com 15 crianças, de ambos os gêneros, com idades entre oito e 12 anos, sendo cinco respiradoras orais pré-cirúrgicas (Grupo 1), cinco respiradoras orais em tratamento fonoaudiológico (Grupo 2) e cinco respiradoras nasais (Grupo 3). Foi realizada uma avaliação clínica das características linguais das crianças e, em seguida, uma avaliação objetiva da força axial da língua por meio de equipamento desenvolvido na Universidade Federal de Minas Gerais. Os resultados foram analisados de forma descritiva por meio das medidas de tendência central e dispersão. RESULTADOS: A média dos valores das forças médias encontrada nos Grupos 1, 2 e 3, respectivamente, foi de 5,6, 6,0 e 7,3N. Já a média dos valores de força máxima foi de 8,2, 9,2 e 10,4N. Obtiveram os maiores valores de força média (7,0N) e máxima (10,3N) os indivíduos que apresentaram tensão adequada de língua na avaliação clínica e os valores mais baixos (3,5N e 2,0N) aqueles cuja avaliação subjetiva indicou hipotensão lingual. A análise estatística indicou dados heterogêneos nos Grupos 1 e 2, tendendo a homogêneos no Grupo 1. CONCLUSÕES: A média das forças foi maior nos indivíduos respiradores nasais, seguidos pelos respiradores orais em tratamento fonoaudiológico e, por fim, os respiradores orais pré-cirúrgicos. Houve concordância entre os resultados das avaliações objetiva e clínica.

PURPOSE: To quantify and to compare the forces produced by the tongues of pre-surgical mouth-breathing children, oral-breathing children enrolled in therapy and nasal-breathing children, and also to compare the findings of objective and clinical evaluations. METHODS: Transversal study with 15 children of both genders with ages between eight and 12 years: five pre-surgical mouth breathers (Group 1), five mouth breathers enrolled in speech therapy (Group 2) and five nasal-breathing children (Group 3). A clinical assessment of each child's tongue characteristics was carried out, followed by the objective evaluation of the axial centre line force of the tongue using the instrument created at Federal University of Minas Gerais. The results were descriptively analyzed using measures of central tendency and dispersion. RESULTS: The average of the force values found in Groups 1, 2 and 3, respectively, were 5.6, 6.0 and 7.3N. The average values of maximum force were 8.2, 9.2 and 10.4N. The individuals with adequate tongue tension in the clinical evaluation were the ones with highest values of average (7.0N) and maximum force (10.3N). The lowest values (3.5N and 2.0N) were obtained by the subjects whose subjective evaluation showed hypotension of the tongue. Statistical analysis indicated heterogeneous data in Groups 1 and 2, tending towards homogeneous in Group 1. CONCLUSION The average of the forces was higher for nasal breathers, followed by mouth breathers undergoing speech therapy and, finally, pre-surgical oral-breathing children. There was agreement between the results of objective and clinical evaluations.

Oral forces applied to human teeth during biting and mastication are normally described in the literature only in terms of their axial components. The purpose of this study was to fully determine the spatial characteristics of the oral resultant force - its normal and tangential components - for a given individual. A load cell was especially manufactured to measure oral force and was temporarily implanted as a prosthetic device in the dental arch of a volunteer, replacing his missing upper first molar. The mastication and occlusion tests were carried out in such a way the cell should withstand the loads applied to the molar, and its state of strain was recorded by strain gauges attached to it. Based on the results of these tests and using balance equations, normal and tangential components of the resultant oral force were determined. For direct occlusion, without interposition any obstacle between cusps, a peak normal force of 135 N was recorded simultaneously to a tangential force of 44 N. For mastication of biscuits, a peak normal force of 133 N and a tangential force of 39 N were obtained.