Yes, the government should provide financial incentives to help people who want to apply their skills and talents to helping others. Setting up a mobile dental clinic in Appalachia is brilliant. This dentist is helping the population by providing important health services for free. Yes, the government needs to back up efforts such as this.
I think people who choose to start Dental trucks and services should start some sort of a charity. That way people who want to support it can do so if they wish to. Also taxpayers will not be forced to pay more for something that they might not want to. For example I wouldn't mind donating $5 for the cause but someone who doesn't make the extra money might not have the funds with all their other expenses.
A healthier population will ultimately costs lest in terms of medical care. Regular check ups and basic dental care can prevent more costly issues later on. Even if that population has no dental insurance, at some point someone will need emergency medical/dental care and that will cost someone else. If a dentist is willing to give of his or her time, he or she should absolutely be given some financial incentive to do so.
The point of the Affordable Care Act was to make sure that everyone had at least access to basic care. More doctors and dentist should help people who do not have the money or the insurance to go to the dentist. It is a good service and this would be a good use of governtment incentives.