grind one's teeth
gnash one's teeth
gnash the teeth

I ground my teeth and stayed there to the end.

He ground his teeth at the incredible feel of her.

She ground her teeth with the effort it took to leave the thing alone.

He ground his teeth together and went on with difficulty.

I ground my back teeth together to keep from screaming.

Richard pushed back from the table as he ground his teeth.

He ground his teeth, or I told myself that was the sound.

She ground her teeth so the sound could be heard by everyone.

He ground his teeth at the pain but made no sound.

But the senators and people ground their teeth at them.