Page 62 - Impact of implant retained overdenture treatment and speech, oromyofunction, social participation and quality of life.

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Chapter 2
Discussion
The use of dental implant treatment to solve retention problems in conventional rehabilitation is now common in dental practice. In the present study, we examined the possible impact of this treatment on articulation, oromyofunctional behavior and OHRQoL. More specifically, the effect of modifications of the denture during the conversion from a conventional removable denture, a provisional retained denture and finally a fully connected implant-retained overdenture in the mandible. The difference between rehabilitation with fixed dentures and overdentures is that in overdentures the anchoring of the overdenture is placed in the denture to fit over the bar (on implants) (Figure 2). When patients present with atrophy of the jaw, the bucco- lingual width of the denture can be too small to fit the supracrestal anchoring device. The technically required minimum dimensions of the bar, as well as the dimensions of the attachment system inside the overdenture, forces the dental technician to modify the shape of the overdenture. In most instances the overdenture is wider than the existing prosthesis. Therefore, the shape of the overdenture can be slightly different to the shape of the initial removable denture. This may, despite the improved retention of the denture, affect the way the tongue is positioned in the mouth to produce the speech sounds. This possible influence can be both positive (improved retention) and negative (difficulties in tongue movement and positioning to shape the airstream into speech sounds). Articulation errors occurred in all stages of the treatment but there were no significant differences between the stages. This finding is confirmed by the evaluation of the spectral characteristics of the /s/ sound between the stages. We found no significant differences of the spectral moments. This is not completely in line with previous findings of spectral analysis in dental patients. However, it is important to notice that previous studies compared different groups of patients (e.g. control group and study group) and in our study we observed the possible changes within the patient.15,18,34 It is important to notice that the /s/ sound is the most vulnerable sound in all stages of the treatment. Besides problems pronouncing the /s/ sound, the /t/ and /l/ were affected in at least one patient during the whole treatment. This is not completely in line with previous research on fixed dentures and overdentures on implants in the mandible.12 Research by Jacobs et al. found that patients mostly presented with problems pronouncing the /s/ sound when treated in the maxilla and problems