I took care of my four corners in 2006 after having a major event months prior. That black "goo" is what will drip, drip, drip into your immune system and kill you over time. I'm still piecing it all together, but removing some or most of this problem has allowed me to get back over the hump. If you have mercury fillings, get them out as well and get any "gum disease" under control too. It is my opinion that the combination of my cavitations, bacteria from pockets around my teeth from my pre-gum disease, and mercury fillings, wore me down until I had a major wake-up call when the stress got too high.
For those of you who are contemplating taking care of this, realize that the black goo is a ticking time-bomb.