Somewhat prudent is tooth doctor (7)
I believe the answer is:
dentist
'doctor' is the definition.
(I know that dentist is a type of medical specialist)
'somewhat prudent is tooth' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'DENTIST' can be found hidden inside 'prudent is tooth'.
(Other definitions for dentist that I've seen before include "Person qualified to treat teeth - tends it (anag)" , "Open wide for him" , "Doctor of teeth" , "Practitioner who looks down in the mouth?" , "Repairer of teeth" .)