Page 110 - Impact of implant retained overdenture treatment and speech, oromyofunction, social participation and quality of life.

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Chapter 4
fig. 1 the palate is an important structure in forming several consonants. This can explain the remaining speech problems. The importance of the palate plate in conventional dentures was described before by several authors.20, 21, 31 They highlight the importance of landmarks on the palate to provide the tongue with sufficient referential information to make proper contact to mold the airstream into speech sounds 31 and a strong effect of a palate coverage on speech sounds was found.20, 21 However studies on speech with fixed dentures without palate coverage are also reporting difficulties with speech. This suggests that not all speech problems in denture wearers can only be related to the coverage of the palate.12 The remaining speech problems are, as mentioned before, similar to the ones reported in literature on conventional dentures.12,14 Here it is to stress that the conventional dentures in the post-operative situation were adjusted especially with improved retention by relining of the denture. Despite that, the patients were aware of the transient period of provisionalization of the denture a certain disappointment with the outcome can be expected.
After final connection of the denture (horse-shoe design) to the implants it is striking that the /s/ sound in nine of the 25 subjects is distorted. All of the nine participants who received a horse-shoe design presented with a sigmatismus stridens. As described earlier the difference in shape of the horse-shoe overdenture in comparison to the conventional denture with palate plate is in many ways important to discuss. The production of speech depends on how the speech structures mold the airstream into a recognizable sound. In dental rehabilitation these structures are replaced and/or adjusted, which may influence speech. In the transition from a conventional denture with palatal coverage (which comprises the oral space in vertical dimension) to a horse-shoe overdenture without palatal plate (which comprises the oral space in horizontal dimension), the tongue needs to find back the proper contact places and referential points to be able to mold the airstream in the same way as before. In the majority of the participants this was no problem, especially because a proper adaptation period was respected. Still some participants suffered from problems producing the /s/ sound. This is in agreement with previous studies on overdentures and fixed dentures in the maxilla.11,14 It is obvious to state that the /s/ sound is the most vulnerable sound in rehabilitation of the maxilla. This was already reported by other authors.11, 12, 14, 15, 22