What is the best way to try and get rid of a dental fistula? are there any ways to combat this kind of infection? i'm using salt water/tea tree oil...

See oral surgeon: It will probably need surgical help to be successful... Especially if it is larger than a pin size hole.

Treat the cause: You need to see a dentist who can treat the cause of the infection which may be resulting in the fistula. All the antibiotics, salt water, or tea tree oil will not treat the problem, just mask the symptoms. The sooner you seek care the sooner you will feel better.

Endo?: It sounds like you have a root canal problem, or a periodontal abcess problem, or a combination of boyh. See a dentist.

3 things: Extraction, root canal, possibly treating your gums. Most likely the first two. Tea tree oil and salt water will not fix your problem!

Only a dentist can: A fistula is nature's way of trying to get rid of the infection by having it drain to the surface. However, in this case a human, specifically a dentist, will be better than nature in resolving the problem by removing and treating the cause of the infection. No salt water rinses, tea tree oil, magic potions or even antibiotics alone will solve your problem. See a dentist for treatment.