Purpose: The aim of this study was to investigate the changes in interocclusal distance
during the pronunciation of /m/ and /s/ sounds in the Portuguese language, in partially
edentulous patients before and after insertion of new dentures. Materials and Methods:
Subjects were divided into a control group consisting of 18 completely dentate patients and
an experimental group consisting of 18 patients who were edentulous in the maxilla and
classified as Kennedy Class I in the mandible. The experimental group had new dentures
placed and the occlusal vertical dimension corrected. A magnetic jaw-tracking device
measured the interocclusal distance during pronunciation of the /m/ and /s/ phonemes.
Interocclusal distance evaluations were carried out in a single session for the control group.
In the experimental group, the measurements were carried out before insertion of new
dentures; immediately after insertion; and after 6 and 24 hours; 2 days; 1 and 2 weeks; 1, 2,
3, and 6 months; and 1 year. Results: Comparison between groups revealed significant
difference in interocclusal distance for the /m/ sound both before and after insertion of
dentures up to 2 months. For the /s/ phoneme, there was no difference between the groups
before prosthesis insertion, or after 3, 6, and 12 months of prosthesis use. There were
significant differences for the /m/ sound only at 6 and 12 months after new denture
insertion, and for the /s/ sound at all periods evaluated. Conclusion: Insertion of new
dentures, with the vertical dimension corrected, changes the interocclusal distance of
speech during phonation of /m/ and /s/ sounds. Int J Prosthodont 2003;16:533–537.