Objectives: The aim of this study was to examine the effect of TMJ Balancing Appliance (TBA) on healthy humans by using power spectral analysis of Electroencephalogram (EEG). Methods: 50 healthy volunteers participated in this study. A thirty-two channel EEG device was used for this study on 50 subjects (28 males, 22 females; mean age=25.3 years old). Results: 19 channel was measured and analysed. The relative power values in ${\alpha}$, ${\beta}$, ${\gamma}$, Senorimotor rhythm (SMR), mid-${\beta}$, high-${\beta}$ band and concentration index ((SMR wave+Mid-${\beta}$ wave)/${\theta}$) increased insignificantly. Relaxation index (${\alpha}$/High-${\beta}$ wave) increased significantly (p<0.05) comparing to the before the TBA application. After the TBA application, the relative power values in ${\alpha}$, ${\beta}$, ${\gamma}$, SMR (Senorimotor rhythm), mid-${\beta}$, high-${\beta}$ band and concentration index ((SMR wave+Mid-${\beta}$ wave)/${\theta}$) increased insignificantly. Relaxation index (${\alpha}$/High-${\beta}$ wave) increased significantly (p<0.01) comparing to the before the TBA application. Conclusions: These results suggest that TBA application causes significant changes on relaxation index. Application of TBA shall regulate the function of the cerebral cortex increase parasympathetic nervous activity.