[Possibility of functional exploration of mastication from acoustic signals]

The chewing abnormalities are frequently evoked during odontological and medical examinations. Unfortunately, few means of investigation are available to appreciate the functional disorders. The aim of this paper was to assess masticatory parameters from observation and audiosignals of mastication with a simple analysis of records. In a first time, sixty five students (mean age = 20) applied the sugar test for the salivary capacity (dissolution time = 2 to 3 minutes). Then the chewing movements were analysed with three types (I, II, III) of salt or sweet cookies. The total duration of activity was 29.8 and 28.2 seconds respectively for the tests I and II, only 18.2 seconds for the test III. The number of cycles were 32.5, 28.1 and 19.2 mastications for respectively I, II and III tests. The later type (III) had a softer consistency than the formers. The duration Dc of masticatory cycles was constant for the same type of aliment. The values were between 0.70 for the test II and 0.90 second for the I and II ones. Signal analysis showed an important and rapid decrease of amplitude AS with an exponential-like pattern. The time constant appeared in relation with the softness. Thus, our method allows to characterize the pattern of mastication and could be used for appreciation of degrees in salivary and/or cranio-mandibular functional abnormalities.