Dental Health Without Money

My wife and I lost everything in 2008-9.  We now exist on Social Security and a few odd jobs every month.  Throughout most of our lives we've been regular consumers of dental services:  fillings, bridges, cleanings, gum work, you name it we've had it, over and over again.  Now we have no money.  We're just above the income level that would qualify us for free county dental services.  

What would you advise us to do (other than flossing and brushing) to best maintain dental and gum health in this situation, which we probably share with tens of millions of other Americans in 2011?  I'm inspired to ask this question by the fact that I'm presently suffering from a painful dental abcess (abscess) that's in its fourth week.  On Friday I was quoted a $310 price for pulling the tooth.  I've already had one financial emergency this month.  That $310 will mean maccaroni and cheese for Thanksgiving.  

How can I avoid getting into this situation again at minimum expense?