Evaluation of shifting of linguopalatal pressure

―Effect of palatal plate thickness on lingual movement during swallowing―

Abstract

A palatal augmentation prosthesis (PAP) is essential in assisting dysphagic patients with lingual function including swallowing． The purpose of this study was to establish a method of evaluating lingual function and to clarify the effect of palate plate thickness on lingual movement during swallowing．The subjects were 10 healthy adult men (mean age: 26.5 years)．Experimental PAPs of two thicknesses (1mm (thin PAP) and 5 mm (thick PAP)) were fabricated for each subject．Pressure sensors were secured in cavities prepared on the anterior，lateral，central and posterior portions of the experimental PAPs，and linguopalatal pressure during the swallowing of test food (3g mashed pumpkin) was measured with a computerized manometric system fitted with an ultrasound device developed by ourselves．The following were our findings．

1．This system made possible the recording and analysis of linguopalatal pressures and of the order of appearance of linguopalatal pressure at the sensor sites during the processes of food intake，mastication and swallowing．

2．The maximum linguopalatal pressure on the anterior portion during swallowing was less with the 5 mm experimental PAP than with the thin one，whereas that on the posterior region was greater with the thick PAP．

3．The duration of the anterior linguopalatal contact (LPCD) during swallowing with the thick PAP was shorter than that with the thin PAP，while the posterior LPCD was less with the latter．

4．The pressure integral of the anterior portion during swallowing with the thick PAP tended to be less than with the thin PAP，but that of the posterior portion of the thick PAP was the greater．

5．The first portion of the palate where linguopalatal pressure was detected during swallowing was the anterior portion in 6 of the 10 subjects with thin PAPs，and in 7 of the 10 with the thick PAPs．In all cases，linguopalatal pressure appeared initially on the anterior or lateral portion，and the order of appearance in each individual was not affected by PAP thickness．

6． The maximum linguopalatal pressure during swallowing showed no consistent order，differing considerably between individuals．Moreover，the order of the pressures at the sensor sites did not vary with PAP thickness．