Effect of Removable Complete Dentures on the Fundamental Frequency of Speech

Abstract

Introduction: Removable complete dentures alter the spectrum of speech sounds by changing the elasto-plastic properties of certain areas of the oral cavity walls, and the geometric characteristics of the vocal resonator. These relationships predetermine largely the aims of conventional studies on the effect of prosthetic dentures on speech function.Aim: To investigate the effect removable dentures have on the fundamental frequency of speech during different stages of the adapta-tion period.Materials and methods: We analysed 96×2 digital sound recordings made by 64 patients (32 male and 32 female). Each patient was asked to say ‘three, two, one, zero, start’ three times: before denture placement, after denture placement, and after a two-week adaptation period. The pitch contours of F0 and the numeric values were obtained using the Speech Analyzer - SIL Language Technology software.Results: Immediately after denture placement, in male patients F0 increased by 12% on the average, and in female patients – by 10%. Two weeks after denture placement, F0 regained its normal value (p<0.05). The mean value of F0, whose raising can be interpreted as an acoustic correlate of temporary psychological stress, returned to normal after a brief adaptation period (in this case – 14 days).Conclusions: The results on the systematic changes of F0 in the course of the complete denture prosthetics are indicative for the systematic speech impediments before, and the absence of such impediments after (in case of successful prosthetics) the adaptation.

Keywords

• complete denture
• fundamental frequency
• speech