Articulation distortion in Mandarin-speaking individuals with complete arch maxillary implant-supported fixed dental prostheses

Abstract

Statement of problem

Implant-supported fixed dental prostheses (IFPs) have been increasingly used to restore edentulous jaws, yet few studies have utilized acoustic analysis for objective evaluation of postrestoration speech outcomes.

Purpose

The purpose of this clinical study was to assess speech articulation in edentulous individuals before and after the provision of IFPs by combining the results of subjective evaluations and objective acoustic analysis parameters.

Material and methods

The study included thirty-four individuals who had an edentulous maxilla and had been provided with an IFP for over 6 months, along with 6 dentate controls. Acoustic analysis was conducted, and mean opinion scores (MOS) were rated from recordings. The participants were interviewed about perceived speech changes. Changes in the parameters were evaluated using the paired t test or Wilcoxon signed-rank test (α=.05). A comparison between dentate controls and edentulous individuals (with or without prostheses) was made using an independent t test or Mann-Whitney U test (α=.025).

Results

Following restoration, the center of gravity (CoG) changes occurred in 11 of 12 consonants in edentulous individuals (P<.05). Prosthesis use allowed the CoG of all affricates and fricatives to appear larger and closer to control values. Before restoration, the CoG of 9 of 12 consonants in edentulous individuals differed from controls (P<.01); after restoration, this reduced to 3 out of 12 (P<.01). MOS improved in 10 of 12 consonants (P<.01), nearing a score of 4. Despite restoration, the CoG of alveolo-palatals [tɕ^h], [tɕ], and [ɕ] remained different from controls (P<.01). Most participants were satisfied with the improvement, with few reporting discomfort with alveolars [s] and [ts^h].

Conclusions

IFPs can enhance speech in edentulous individuals, yet articulation distortions of alveolar and alveolo-palatal consonants persist. The improper palatal shape of IFPs or an abrupt joint between the IFP and atrophic natural bone may contribute to these distortions.