My friend needs a new tooth. She is on disability for a number of health problems. She is on Mass Health and has no dental insurance. Her dentist did a root canal on a tooth and didn't remove the filling on that tooth despite her asking them "won't the tooth fall apart?" at the time. Sure enough, a couple of months later, the tooth fell apart. The only solution now is to pull the tooth and put in an implant, which costs $1,000 (according to the dentist she sees). She can't afford this in any way, shape, or form. She'd been holding the tooth together with over the counter temporary filling material for months, until recently (see update, directly below).
Update, 3/12/12: She finally had the tooth extracted about a week or two ago. She still can't afford the implant, and the longer she goes without a tooth there, the more the bone recedes and the harder it is to do the implant (without needing bone grafts and such things). So the situation has gotten a little more urgent.