I had a pocket forming where food would foul and caused inflammation & bleeding of the gum between molars. Regular professional teeth cleaning in intervals of 3 months has brought my gums to a very healthy state!
A friend of mine started to show bad breath and when he flossed it would start to bleed between molars - very similar to what I had experienced. He tried MMS ('Miracle Mineral Supplement') discovered by Jim Humble. This is NaClO_2 as a 28% solution in water. You put maybe 10-20 drops of this solution into an empty glass and add 3X as much lemon juice (or 4X as much vinegar), let it sit for 3 minutes and then DILUTE with plenty of water. The reaction of the sodium chlorite with an acid forms chlorine dioxide (ClO_2) that goes into solution and will oxidize pathogens, thereby killing them instantly. I use 15 drops of MMS and add plenty of vinegar and after 3 minutes I almost fill the glass up with water. Use this to rinse your mouth, squish it around and then spit it out. After only one week my friend's breath was like an ocean breeze and he reported that the bleeding stopped almost immediately. You can also disinfect your tooth brush by dropping a few drops of MMS solution and juice/vinegar onto the brush and let sit until you use it the next time. I do this with my Sonic toothbrush regularly.
MMS was reported to also work on cankers in the mouth and on the tongue.
High ppm colloidal silver may also help. But if there is no betterment, then see a good dentist. With regard to root canals, Dr. Hassar from Reno, NV told me that in his practice he has never seen a single extracted root-canal-treated tooth that wasn't infected! I have two root-canal-treated teeth and one day I'll get rid of them. A root canal treatment only removes the central nerve fibers but does not seal the millions of fibrous channels in the root tip, which then will be harbored by anaerobic bacteria.
There is a correlation between dental health and heart disease, so don't wait too long!
With best wishes, Stephan