Influence of experimental palatal plate on mandibular position during continuous [n] phonation and at the physiologic rest position.

The purpose of this study was to clarify the influence of an experimental palatal plate on the mandibular position during continuous [n] phonation and at the physiologic rest position. Twenty healthy dentulous volunteers (10 males and 10 females, mean age of 24.4 years) were investigated. Three kinds of experimental plate with a thickness of 3 mm, 5 mm, and 8 mm were fabricated and used for each subject. The mandibular position was recorded by a K7 kinesiograph during continuous [n] phonation and at the physiologic rest position under normal conditions and when the three kinds of plate with different thickness were worn separately. The results showed that the mean interocclusal dimensions during continuous [n] phonation were 0.5 mm vertically and 0.4 mm anteroposteriorly under the normal condition. After insertion of an experimental plate, the interocclusal distance increased a little, but the difference was not statistically significant between the normal condition and any of the three experimental conditions. No significant difference was found between the male and female groups. Furthermore, no significant difference in the interocclusal distance at the physiologic rest position was found between the above comparisons. Within the limitations of this study, we concluded that the mandibular position during continuous [n] phonation and at the physiologic rest position was not significantly influenced by the experimental plates.

[Application of sublingual bar to removable partial denture of a patient complaining of major discomfort to lingual plate].

PATIENT: A 62-year-old man complained of discomfort during insertion of lower removable partial denture (RPD). Existing denture was highly objectionable to tongue and intolerable to wear due to volume and contour of its lingual aspect. The treatment plan included fabrication of an interim denture and altering its shape until it did not lead to discomfort, followed by fabrication of a final denture. Consequently, RPD using sublingual bar was found to be the most comfortable to wear and was fabricated as final denture. The patient was ready to insert the final denture and restoration of masticatory function was accomplished. DISCUSSION: In cases with unfavorable anatomic conditions such as a lack of mouth-floor depth, lingual plate should be applied as first choice, and when it is not well tolerated by the patient, sublingual bar should be applied. CONCLUSION: Sublingual bar is suggested to be one of the least objectionable major connectors.

Influence of experimental palatal plate on mandibular position during continuous phonation of [n].

PURPOSE: This study aimed to determine the influence of the thickness of a palatal plate on the mandibular position during continuous phonation of the sound [n]. METHODS: Eleven healthy volunteers (10 males and 1 female; 24-36 years of age, mean age 26.4 years) were recruited from dental students. They were instructed to pronounce [n] continuously under six conditions: wearing a palatal plate with a thickness of 0.3, 1.5, 3.0, 5.0, and 10.0mm, and without a plate (control). Mandibular movement during pronunciation was simultaneously recorded by a K-7 mandibular kinesiograph. Their mandibular positions in the physiologic rest position were also recorded. The distance between the incisal edge of maxillary and mandibular anterior teeth both in vertical and antero-posterior directions during continuous phonation of [n] (interocclusal distance) under all six conditions were measured and compared. RESULTS: Interocclusal distance tended to increase in both vertical and antero-posterior directions as the thickness of the palatal plates increased. There were statistically significant differences in the mandibular position both in vertical and antero-posterior directions during continuous phonation of [n] between the control condition and those wearing a palatal plate with a thickness of 10.0mm. CONCLUSION: The mandibular position determined by the phonetic method employing continuous [n] as a test pronunciation was affected by the thickness of the palatal plates inserted into the mouth. However, its influence was not significant when the thickness of the palatal plates was 5mm or less.