Filling canine with hole at the front, cutting into infected area (6)
I believe the answer is:
stodgy
'filling' is the definition.
(stodge means filling food)
I don't understand the rest of the clue.
(Other definitions for stodgy that I've seen before include "(Of food) heavy, rich" , "Dull and heavy" , "(Of food) solid and heavy" , "Heavy to eat" , "Heavy and unappetising" .)