how do I stop this behavior?

Dr
Lately when my 4 yr old daughter gets angry or frustrated she will tense up her body and shake while her face is scrunched up and she grits her teeth really hard. Now I don't mind her being upset, I don't mind her expressing her anger, but the teeth gritting is pissing me off. Makes me cringe every time! She does it so hard and loud it sounds like she's could break a tooth! I find it upsetting and I really wish she would stop before she does some damage. Any advice as to how to handle this new behavior?