Odds of Hanging On
Once you're in, you're in. If you make a name for yourself as doing good work in a dental practice or fly solo in an office of your own, you'll develop a loyal following that will recommend you for generations to come.
Keep up with the latest technology. Push that Invisalign and whatever comes next. Maybe laser braces are the next thing? Perhaps Apple will get involved and you'll be able to play music in your mouth.