Introduction: Anterior Open Bite (AOB) is a malocclusion, associated with alterations in tongue´s position and/or function, which are highly regulated by the brain cortex. Objective: The aim of this case and control study was to determine the activity of the brain cortex of children with AOB and normal vertical overlap (NVO) at rest and during phonation and deglutition. Design: Thirthy three children (16 with AOB and 17 with NVO) in mixed dentition from 8-11 years old (mean age 9,2 years old), recruited from public schools of Envigado, underwent a brain mapping that was performed by quantitative electroencephalography (QEEG) during tongue rest, deglutition and phonation. The children were also evaluated by a phonoaudiology, to determine if the AOB affects motor process of phonoarticulating organs, breathing and phonation. Data were analyzed using the U Mann-Whitney test and T Student. Results: Higher brain cortex activity was found during the rest position of the tongue, in children with AOB (p<0.05) when compared with children with NVO. Conclusion: The brain cortex has an important role in the regulation of tongue functions and position at rest. According to the results of this investigation,