I too had a hole in my sinus after tooth extraction, a rather large one - he placed some collagen piece to allow for bone growth but apparently my body rejected it (it was painful removing it because the sinus were attaching to that piece).
The bone apparently never grew in that area, it looks like the hole closed up with a thin layer of skin and now the sinus has a drop on that area which may allow for bacteria growth in that area.
I always spray Colloidal Silver , never had any pain but I'm gonna see if I can get an oral surgeon fix that area if its possible.
Sometimes I can taste the food in my sinuses and dripped onto my throat. Eating spicy foods was incredibly uncomfortable as the cayenne seeped onto the sinus.
My dentist told me not to do a nasal rinse until the area has healed.