Purpose: This study investigated the possibility of objectively evaluating denture tolerance with different designs of upper major connector through electroencephalographic examination.
Methods: Nine healthy dentate subjects wore five designs of palatal plates (All palatal type, Anterior palatal type, Horseshoe type, Palatal bar type, and Palatal strap type). Electromyograms (EMG) from the masseter and the posterior temporal muscles during mastication and electroencephalograms (EEG) before and after mastication were simultaneously recorded and analyzed. In addition to evaluation by visual analogue scale (VAS), questionnaire surveys consisting of five comfort parameters were also done.
Results: VAS values showed uncomfortable feeling for all questions on wearing each type of palatal plate, particularly the Total palatal type, Horseshoe type, and Palatal strap type. There were no significant differences between control and all palatal plates in EMG evaluations. After mastication, %alpha in EEG decreased and %beta increased, both significantly, compared with those before mastication. The slope of 1/f fluctuation in alpha-wave increased after mastication significantly. The variation of EEG (%alpha, %beta and 1/f fluctuation in alpha-wave) before and after mastication were similar to the results of VAS value.
Conclusions: Denture tolerance with different design of upper major connector influenced the higher center of the brain and suggested that the possibility of detecting changes might be indicated electroencephalographically.