Originally Posted by kassierae
My dentist(very highly qualified) also said that it is better for a horse to be done consistently for 2-3 years and then checked the next year and only done if necessary.
The point of checking every 6 months is to catch problems before they get serious. Being prey animals, horses have evolved to hide pain until it is severe (because it makes them weak and look tasty to predators) so it is up to us to make sure we catch problems early.
Check out this article The Horse | Does Your Horse Need a Dentist?
about why dentistry is important, as well as how to find a dentist. It is illegal in many states for them to practice dentistry without direct veterinary supervison, and always illegal for them to use any kind of sedation if they are not a DVM. I feel that equine dentists are the way to go, but there are far more poorly trained "dentists" out there than there are good ones.
And another article on why to have frequent check ups and what questions you can ask your dentist The Horse | Equine Dental Care is More Than Just Floating Teeth