The syringe you're talking about usually works very well. fill a glass with warm salt water, draw it up into the syringe and place the syringe very close to the hole. The force of the water should flush out the hole, You'll probably be surprised how effective it is. Usually you should begin using the syringe 1 week after surgery and from then on after every meal until the hole is gone. YOU DONT WANT THE HOLE TO CLOSE UP WITH FOOD TRAPPED UNDRNEATH THE GUM. Yes it could become infected if you leave the food particles in there.