ELECTROMAGNETIC ARTICULOGRAPHY AS A METHOD FOR DETECTING THE INFLUENCE OF SPIKES ON TONGUE MOVEMENT

In orthodontics dysfunctions of the tongue are discussed as a factor i n the development of malocclusion. A new objective method for examinin g tongue movement is the electromagnetic articulography (EMA). This en ables movements of the tongue to be followed using the principle of in ductive distance measurements. A helmet made of acrylic material serve s as a carrier for three transmitter coils. These are located in front of the forehead, in front of the chin, and at the back of the neck. R eceiver coils are fixed to the tip of the tongue and at two points on the dorsum of the tongue. The distance between the receiver and the tr ansmitter coils is calculated by means of a personal computer. The mov ement trajectories are displayed on a computer screen in x-y-coordinat es. Tongue movements of one patient with an anterior open bite are sho wn during characteristic test sounds and during swallowing. The first examination took place without any orthodontic appliance. in a second series in the same session, tongue movement was recorded under the inf luence of an orthodontic appliance with spikes. While the patient show s vertical combined with sagittal components in the movement pattern o f the tongue without an orthodontic appliance, the same patient, under the influence of an orthodontic appliance with spikes, shows a change of the rest and work position of the tongue and in the pattern of ton gue movement with a more posterior position of the tongue, and with an increase in the vertical and a decrease in the sagittal components of the movement pattern.