[AKA_Monet]

Your mandible and your sinuses are connected. If you have an infection in one, it can transfer to an infection in the other. And it could be exacerbated with bruxism--grinding of your teeth...

My dad, a dentist, has gotten on my case about my bruxism... And I have dull pains in my back teeth. He said that if I have anymore pain and I cracked my tooth, the only way I can alleviate the pain is to have a root canal with a crown... But I'd probably grind that thing down, too...

And abcess is very obvious, because it hurts like the beejesus and there is inflammation and swelling around the infected tooth or teeth. A root canal can be done depending of the extent of the abcess growth, but it will not be done until antibiotic treatment, dialation and curettage or other things that are done... The absolute last resort is an extraction (removal of the tooth). If you did have an abcess, you would not be able to open your mouth and your entire side of your face would be swollen as if someone sucker punched you... That's why your dentist told you correctly...

My suspicion, you are grinding your teeth down to the "bone" or bottom of your filling, that cutting into your dentin and causing a clenched jaw pain. If you do not have a bruxist device, you need one. You need to wear it all the time, except when eating. And you probably need to floss more... And for some reason those new sonic tooth brushes work very well in removing plaque and you need a better toothpaste.

Also try making a paste out of baking soda and hydrogen peroxide and brush with that for 2-3 weeks to reduce your level of plaque build up around your gums... Because your gums are red when you have inflammation and they probably weren't that's why the dentist said you did not have an abcess...

Disclaimer: I am not a M.D. or a D.D.S. so I am unqualified to give you the best advice. But it is a start and you can have questions to ask when you visit your doctors...