A family member of mine is a dentist. I think it's possible 🙂 However, remember it's a physical job. Some of the work can be affected by age-related processes, or accelerate them: arthritis (hands), back pain (8 hours a day of hunching), vision problems (bright lights), stress and related health conditions (you're right up in people's faces all the time, and they usually see you when they're in pain; bill collection & office management; competition; in your case, developing and keeping a practice [even if you buy one]). Some accommodations can help - a good chair; staying fit; hiring reliable and competent staff - here you've got an edge 🙂 I guess some of the actual labour has been lessened by technologies (compared to how my family member worked for many years), but at the end of the day, you're still hunching over people who are in pain, day in, day out. It's not a job I'd want to do very late in life. It'd be a tough spot to have to work deep into typical retirement age while facing some of those health issues. If you're in good shape (no personal or family history of MSK issues), and could afford to work for just 10-15 years, sure.
Edit: so I asked my relative what they thought about someone starting to practice at 50. They were less than optimistic about it (putting it mildly), but for different reasons than the ones that came to me: they said the overhead is unreal, and that to have a good bet of making back what's required to keep the practice going takes experience and judgement, and there's not a lot of (financial) margin for error with just ten years to work. Their recommendation was to think about becoming a hygienist instead (where we are, hygienists have some independent scope of practice).