Odontalgia (9)
I believe the answer is:
toothache
'odontalgia' is the definition.
(I know that odontalgia can be written as toothache)
This is all the clue.
(Other definitions for toothache that I've seen before include "Oral discomfort" , "Odontalgia" , "Cause of sore mouth" , "It causes grief" , "Dental problem" .)