The relationship between vertical labial closing pressure and age

Abstract

【Objective】Many physical functions including feeding/swallowing are affected by aging．It has been reported that the function of the tongue and masticatory muscles declines with age．However，the alteration related to normal labial force，which has been achieved through the process of long-term physical development，has not been clarified．Thus，we considered it significant to document the variation in labial function．The purpose of this study was to examine the relationship between vertical labial-closing pressure and age in elderly people．

【Subjects and Methods】One hundred and thirty seven subjects who had no feeding/swallowing disorders were chosen from among 311 senior citizens who participated as volunteers over the age of 60．They consisted of 31 men (mean age 69.5 ± 5.3 years) and 106 women (69.3 ± 5.5years)，all of whom maintained posterior occlusal support with their natural dentition and had no defect in the front teeth．Water-repellent pressure sensors that employed a strain gauge transducer were embedded in a smooth-surface acrylic plate．The device was used to measure the labial-closing pressure when taking food，and effortful maximum labial pressure．The maximum lingual pressure against the bubbleshaped sensors on the palatal palate was evaluated，using the “Handy Manometer” developed by Hiroshima University．In addition，grip strength as an indicator of physical ability and height and weight as a constitutional indicator were also measured．

【Results】The mean value of vertical labial-closing pressure when taking food and effortful maximum labial pressure showed no relation to age．However，the mean value of lingual pressure and grip strength showed significant decreases with age (lingual pressure：r ＝ －0.346，p＜0.001，grip strength：r ＝ －0.201，p＜0.05)．We presumed that vertical labialclosing pressure was maintained at a constant level even in the elderly，because the sequence of labial-closing movement，necessary for feeding from ingestion to swallowing，is greatly repeated over a period of time．Moreover，we presumed that the labial force is maintained to compensate for the decline in lingual function with age．

【Conclusion】This study suggested that labial function is difficult to be influenced by age．