|Budget Amount *help
¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 2004 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 2003 : ¥900,000 (Direct Cost : ¥900,000)
The purpose of this study is to investigate how habit-forming mouth breathing in children influences on mastication and posture.
The subjects of preliminary study were five healthy adults under the condition of nose obstruction simulated by pinching the nose. Electromyograms (EMG) were obtained from masseter muscle, orbicularis orbis muscle, stenocleidomastoid muscle, and muscles around larynx using a surface electrode technique. Respiratory curves were obtained with amechano-electrical transducer for respiration. The EMGs and respiratory curve were synchronized. The effects of nose obstruction were examined during resting and masticating yogurt or cookie. Following results were obtained. Under the nose obstruction, disorder of respiration cycles, prolonged respiration cycle before and after swallowing, decrease of amplitude of respiration curve just after swallowing. As the results in previous studies, frequency of mastication decreased under the nose obstruction. The other hand, cycle, interval, duration of EMG of the masseter muscle showed various patters depend on the subjects. It was thought that compensatory effects based on acquired own normal function were occurred under the simulated nose obstruction.
Children with oral breathing were elected using CO2 sensor kit. The subjects were evaluated respiration mode and recorded posture of lips and frequency of mastication during eating cookie. Measuring PaCO2 by the CO2 sensor kit with nasal adapter was convenient and useful method for evaluating respiration mode. The children classified into habit-forming mouth breather showed quite low rate of mouth closure, disorder of respiration rhythm, and irregular movement of PaCO2 curve during eating cookie. The children who held mouth open at rest but could breathe through the nose under indication showed regular respiration during eating cookie. Further study regarding eating/swallowing function in cooperation with respiration in mouth breathers is needed.