This study aimed to analyse occlusiosonograms from the same edentulous patients (a) wearing old complete dentures and (b) after adjustment of the occlusion of new dentures. Occlusiosonograms of subjects with a complete natural dentition and of edentulous patients wearing complete dentures were compared. Gnathosonic examination was carried out by means of piezoceramic transducers linked to an IBM PC/AT computer. Evaluation of occlusiosonograms was by mathematical analysis of frequency. Differences in the characteristic shape of occlusiosonograms and their frequency between the groups were demonstrated. Lack of stabilisation of old dentures was visible in some cases.