Kinda depends on what you want to teach- a lot of public high schools don't have dentistry as a course offering. A college degree is a requirement for the vast majority of public school teaching positions, and a teaching license/certificate is almost always a requirement. Usually you have to pass the Praxis tests to get the license these days. Which, incidentally, it helps to have been to college to pass. Sometimes you can get what's called "lateral entry" if your experience in business/industry/etc gives you a qualification to teach a certain thing, like computer repair for example. My two cents- getting into this might be kind of tough, unless you are willing to get the degrees and do what it takes. And, I've taught community college one semester, and its a bit different from high school. Good luck whatever you decide to do....my one desire is to teach for the public school system.