[Influence of experimental palatal plate on mandibular position during continuous [n] phonation in complete denture wearers].

OBJECTIVE To clarify the influence of an experimental palatal plate on the mandibular position during continuous [n] phonation and at the physiological rest position in complete denture wearers. METHODS Ten complete denture wears volunteers were investigated. Two kinds of experimental palatal plate with a thickness of 3 mm and 5 mm (from the denture basal surface to denture polished surface) were fabricated and used for each subject. The mandibular position was recorded by a K7 mandibular kinesiograph during continuous [n] phonation and at the physiological rest position under three conditions: wearing a palatal plate with different thickness of 3 mm, 5 mm and without a plate(control). The interocclusal distance both in vertical and anteroposterior direction during continuous phonation and physiological rest position under all three conditions were measured and compared. RESULTS Under the control condition without wearing of a plate, the mean values of interocclusal distance (IOD) during continuous [n] phonation were (1.69±1.26) mm vertically and (1.74±1.18) mm anteroposteriorly. After insertion of the experimental plates, there was an increase in the IOD during continuous [n] phonation, but this difference from the normal condition was not statistically significant. The mean IOD at the physiological rest position in these 2 directions were (2.91±2.28) mm and (2.56±1.88) mm, respectively. After insertion of the experimental plates, there was a decrease in the IOD, with the 3 mm plate, (2.52±1.88) mm vertically and (2.46±1.64) mm anteroposteriorly; with 5 mm plate, (2.45±1.70) mm vertically and (2.22±1.31) mm anteroposteriorly. No significant differences were found between the control and 2 experimental conditions. CONCLUSION The mandibular position during continuous [n] phonation was not influenced by the experimental palatal plates and physiological rest position was also not affected by experimental palatal plates.