你的牙医会用一个设备来阻止你紧闭牙关。

Your dentist will fit you with a device that prevents your jaw from clenching.

尽量避免屈尊俯就或防御性的动作，如抱臂或紧闭牙关。

Try to avoid gestures that are patronizing or defensive, like crossing your arms or clenching your jaw.

他咬紧了牙关只是哼，在那座空廓落落的大厅上转圈子。

He paced round the hall grinding his teeth and groaning.