You searched for: “bruxophobia
bruxophobia (s) (noun), bruxophobias (pl)
An abnormal aversion of grinding the teeth together because of the damage or pain which excessive teeth grinding or jaw clenching might cause: Bruxophobia occurs when someone is afraid that he or she could have oral health complications brought on by dentition grating, therefore causing impairment, injury, or other oral health complications.

Because pressing the two jawbones together often occurs during sleep, most people are unaware that they grate their teeth, however a dull, constant headache or sore jaw when someone wakes up is a revealing symptom which can cause bruxophobia.