The influence of maxillary central incisor position in complete dentures on vertical bar s vertical bar sound production

Statement of problem. The insertion of prosthodontic restorations often lea ds to speech defects, most of which are transient but nevertheless a source of concern to the patient. For the dental practitioner, there are few guid elines on designing a prosthetic restoration with maximum phonetic success. Purpose. This study investigated the effect of different maxillary central incisor positions on phonetic patterns. Material and methods. The inclination angle of central incisor blocks in du plicate complete maxillary dentures was changed in a range of -30 degrees t o +30 degrees from the original position (0 degrees). Test words and senten ces were acoustically analyzed. Spectral parameters such as first peak, noi se band (defined by upper and lower limits of the most intensively blackene d frequency area), Fast Fourier Transformation power spectrum, energy spect rum, and time were investigated. Influences of oral stenosis, hearing, and age as cofactors on /s/ articulation were also taken into account. Results. The change of incisor block angle in both directions usually cause d a poorer execution of the /s/ sound. The labial angulation seemed to have a greater effect than the palatal angulation. The most significant changes were those in the noise band and energy spectrum. Conclusion. Immediate phonetic adaptation of prosthetic restorations in the maxillary incisor region can be achieved only if the original position of the natural teeth is transferred to the denture, Although these misarticula tions are, in most cases, likely to disappear within a few weeks, they may persist and even lead to psychosocial problems. A better understanding of t he causes of misarticulation and the limits of adaptation according to cert ain morphologic parameters of dentures is important.