I have a hole directly behind my two front teeth. Its a hole in the roof of my mouth. I cant feel it with my tongue, its so small, and I cant see it, but I can suck air out of it by closing my mouth and sucking towards the front of my mouth. I can also push air out of it by holding my nose while blowing out (as done on an airplane), which clogs my ears, naturally. I cant always suck air out of it, but I can always push air out using the method of holding my nose and pushing out air without letting it out of my nose or mouth. The taste around the area when this is done is similar to the taste of blood, but when I wipe the area with a white tissue, nothing shows on the tissue. If it wasnt for me making a suction in my mouth in a certain way as I knowingly do now, I would have never known the hole was there, but Ive known about it now for a year.
Dear friend. Thanks for sharing your concern. Your history suggests that the hole could be a simple cavity in your teeth, or it could be a well-developed sinus tract. This can lead to infection from your mouth to your nose. Carious teeth always has lots of bacteria, therefore it is best to get it clinically evaluated and treated. Hope it helps. Thanks. Take care.