Rest vertical dimension determined by electromyography with biofeedback as compared to conventional methods

This study was undertaken to determine if electromyography with biofeedback can be utilized to produce a more reliable determination of rest vertical dimension than conventional methods such as phonetics and swallowing. It was found that: 1. Electromyography with biofeedback appeared to produce a more consistently reliable determination of rest vertical dimension than conventional methods when used with edentulous subjects. 2. Determinations of rest vertical dimension by individual dentists using phonetics and swallowing had wide variations in two of the five patients in a range of up to 6 mm. An error of this magnitude could easily cause an intrusion upon the interocclusal distance and resultant failure of treatment. Since this study was limited to five patients, a more expanded study is necessary to determine the validity of electromyography vs. conventional methods for determining rest vertical dimension. Both methods have questionable aspects in relation to the time of day, patient's understanding of each technique, and past dental history. However, the most critical problem of the electromyographic technique is the feasibility of its use in a private practice in light of the excessive cost of the required equipment.