Department of Orthodontics I, Hefei Stomatological Hospital, Clinical College of Stomatology, Anhui Medical University, Hefei, 230001, Anhui, China.
Department of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an, 710032, Shaanxi, China.
BMC Oral Health. 2023 Feb 14;23(1):98. doi: 10.1186/s12903-023-02767-9.
To achieve different central preset force levels requires various fine-tuning efforts and may elicit different uptight responses. The mandibular lever system has a distinct regularity in the fine-tuning function of the upper limbs. The purpose of the present study was to detect whether the uptight responses elicited from motivating clenching differ from those induced by motivating forearm raising at different force levels.
Twenty-five healthy females were enrolled in this study. The target was low, medium, and maximum force levels with or without visual feedback and/or maintenance effort. Surface electromyographic (SEMG) activity was recorded from the bilateral anterior temporalis and masseter or left biceps brachii muscle (BicL), and the T-Scan III System synchronously recorded the sensitive force values. The uptight responses and task difficulties were recorded for occlusal and left forearm lifting tasks using a unique visual analogue scale.
The highest uptight response value was achieved at a low clenching force level with visual feedback requiring no maintenance effort but at a maximum forearm-raising force level with visual feedback and maintenance effort. The SEMG activities of both jaw-closing muscles and BicL were associated with the central preset force level (P < 0.001). However, the maintenance effort only increased the jaw-closing muscles' SEMG activity at the maximal force level (P < 0.001).
Clenching at the central preset lower force level with visual feedback is prone to elicit a higher degree of uptight response. The constant need for a low-intensity bite can have a negative effect on an individual's mood.
实现不同的中央预设力水平需要不同的微调努力，并且可能引起不同的紧张反应。下颌杠杆系统在上肢的微调功能中有明显的规律性。本研究的目的是检测在不同力水平下通过激励咬牙和激励前臂抬起引起的紧张反应是否不同。
本研究纳入了 25 名健康女性。目标是在有或没有视觉反馈和/或维持努力的情况下达到低、中、最大力水平。双侧前颞肌和咬肌或左侧肱二头肌（BicL）表面肌电图（SEMG）活性被同步记录，T-Scan III 系统记录敏感力值。使用独特的视觉模拟量表记录咬合和左前臂抬起任务的紧张反应和任务难度。
在需要维持努力的最大前臂抬高力水平和需要维持努力的最大视觉反馈力水平下，最大 uptight 反应值在低咬牙力水平下达到最高。两种闭合肌和 BicL 的 SEMG 活动均与中央预设力水平相关（P < 0.001）。然而，仅在最大力水平下，维持努力会增加咀嚼肌的 SEMG 活动（P < 0.001）。
在有视觉反馈的中央预设较低力水平下咬牙容易引起较高程度的紧张反应。持续需要低强度咬合可能会对个人的情绪产生负面影响。
