$200 for a cleaning? I don't know where you live, but I live in one of the highest cost of living areas in the country and a cleaning DOES NOT cost that much--yet. I'm certain that there are dentists in your area who are not that expensive. You can get a cleaning done for free, in fact, at the community college here--by the techs in training. Which might not fill the bill as a before-kindergarten check up, but it's at least one way to keep the cost down.
Also, dental visits--even braces--are covered by the health insurance states offer to cover the children of no and low-income families who otherwise don't have/can't afford insurance. If there is a child today, in America, without health or dental insurance it truly is the fault of the parent. You do have to go to the trouble to sign up, and you have to go to the drs who participate in the plans. But the programs are there, and we--the people of America--are paying for them. So if you know someone who isn't getting their child appropriate medical, dental care, please encourage them to find out what's out there for them. And if it's a case of the family can afford coverage, but chose not to--because it's more important to have a big screen tv, a fridge stocked with beer, etc (I know families like that)--well, kudos to the schools for making it impossible for them to neglect their children's needs