Conservation of intraoral pressure changes during swallowing

Background/purpose: A relationship between malocclusion and intraoral pressure is suspected but ill understood. This study explores intra-oral pressure changes during normal swallowing to assess differences in patterns of command saliva and water swallows. Materials and methods: We used a custom-made appliance fitted with miniature pressure transducers located along the midline at the anterior-, mid-, and hind palate to measure absolute pressures during command water and saliva swallows. Data were obtained from eight healthy volunteers (six males, two females; 24-35 years) with full permanent dentitions. Following accommodation, volunteers performed 10 mL water and saliva swallows on command. Each volunteer performed the swallows three times on 5 separate days, yielding data from 15 swallows for each individual. Results: Each participant had a distinct pressure response during swallowing. At all three locations, negative pressure amplitude was greater than positive pressure amplitude, with no significant difference between swallowing saliva and water. There was a larger rate of negative pressure development (P<0.01) and a larger value for the pressure-time integral (P<0.05) at the front of the palate during water swallowing. During water swallowing, the root mean square pressure integral (index of work) at the front of the mouth was larger (P<0.05), and there was a significant front to mid palate pressure gradient (P<0.05) that was not evident during saliva swallowing. Conclusion: We tested the hypothesis that a liquid with a low viscosity (water) requires less lingual propulsive deformation than a higher viscosity liquid such as saliva. Although saliva is a more complex fluid than water and varies between individuals, participants produced personally distinct and consistent signature pressure patterns and retained these for both liquids. Copyright (C) 2012, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.