Speech intelligibility in patients with complete dentures according to the material used

The principal purpose of this study was to investigate the speech of two edentulous subjects fitted with a complete maxillary prosthesis made of three different palatal materials: aluminium, resin, stellite. The study was performed using two speakers fitted with a prosthesis (a man and a woman). They took part in the acoustic recording of logatoms read by themselves while wearing various prostheses. These recordings were tested from the auditory point of view by a series of six listeners (four men and two women) in an anechoic room. After 144 different tests, a speech reception threshold (SRT) was defined for each speaker and each different prosthesis. This SRT shows a level of speech intelligibility defined so that the lower the SRT, the more intelligible for the listener. The results show that: (i) both the material and the listener influence SRT: (P < 0.05); (ii) an interaction between the material factor and the speaker factor appears. (P < 0.05); (iii) The hierarchy factors influencing SRT are most important in the order: Listener --> material --> speaker; and (d) The group fitted with a metal prosthesis (aluminium, stellite) was more intelligible regarding the way they were perceived by others.