Department of Orthodontics, University of Washington, Seattle, USA.
Department of Orthodontics, University of Washington, Seattle, USA.
Arch Oral Biol. 2024 Jan;157:105845. doi: 10.1016/j.archoralbio.2023.105845. Epub 2023 Nov 7.
Chewing, swallowing, and respiration are synchronized oropharyngeal functions. This study aimed to analyze the dynamics and coordination during natural chewing and swallowing in relation to respiratory phases.
Eight oropharyngeal muscles in minipigs were recorded using electromyography, X-ray fluoroscopy, and nasopharyngeal dynamics. Chewing cycles and swallowing episodes were analyzed for timing and activity amplitude along respiratory cycles. Digastric and middle pharyngeal constrictor were used as zero-points for timing analysis in chewing cycles and swallowing episodes, respectively. The beginning of these cycles and episodes were used as the zero-point for timing analysis in respiration during feeding.
The timing of jaw closing (57.8%) was longer than opening (42.2%) during chewing. Muscle activity occurred 20% later than digastric onsets and 15% earlier than jaw closing phase. Duration of muscle activity was shorter in ipsilateral than contralateral sides except for palatal muscles. Pharyngeal, palatal, and hyoid muscles showed longer durations than tongue muscles in jaw opening (p < 0.05). Palatal and hyoid muscles showed 2-phased activity in chewing while hyoid muscles showed higher amplitude in chewing and swallowing than other muscles. About 80% of the chewing cycles and swallowing episodes occurred in expiration. Nasopharyngeal airflow velocity increased from jaw opening to swallowing while airflow pressure decreased.
These findings indicate key activity of palatal and pharyngeal muscles mostly in chewing. The respiratory cycle changes in chewing and swallowing simultaneously with the activation of the tongue, palatal, and pharyngeal muscles. These findings will be useful for further understanding the mechanisms in swallowing and breathing disorders.
咀嚼、吞咽和呼吸是同步的口咽功能。本研究旨在分析与呼吸阶段相关的自然咀嚼和吞咽过程中的动力学和协调性。
使用肌电图、X 射线荧光透视和鼻咽动力学记录 8 种猪口咽肌。分析咀嚼周期和吞咽事件的时间和活动幅度，以及呼吸周期。咀嚼周期和吞咽事件的时间分析以二腹肌和中咽缩肌为零点，分别用于咀嚼周期和吞咽事件的时间分析。这些周期和事件的起点用于咀嚼过程中呼吸的时间分析零点。
咀嚼时，下颌关闭的时间（57.8%）长于下颌打开的时间（42.2%）。肌肉活动比二腹肌起始晚 20%，比下颌关闭阶段早 15%。除了腭肌外，同侧肌肉活动持续时间短于对侧。在张口时，咽肌、腭肌和舌骨肌的持续时间长于舌肌（p<0.05）。腭肌和舌骨肌在咀嚼时表现出 2 相活动，而舌骨肌在咀嚼和吞咽时的振幅高于其他肌肉。大约 80%的咀嚼周期和吞咽事件发生在呼气期。鼻咽气流速度从张口到吞咽时增加，而气流压力下降。
这些发现表明，腭肌和咽肌在咀嚼过程中起关键作用。咀嚼和吞咽时，呼吸周期的变化与舌、腭和咽肌的激活同时发生。这些发现将有助于进一步了解吞咽和呼吸障碍的机制。
