This has the potential to turn into another 100+ post thread debating this topic, haha.
From my point of view - there's no way of knowing. We can look at trends and make predictions about what will happen to dentistry over the next 20 or 30+ years, but there's no one here that can accurately predict the future.
My personal opinion is that yes, people will still see dentists and we'll all be reasonably employed (many factors play into this, I'm not going to list them all off). This requires hard work, having a good head on your shoulders, and living within your means.
The more pressing issue, in my opinion, is the cost of the education. You can come out of school and get a great job, but if you're buried in unbelievable amounts of student loan debt, that could make things interesting.
I'll also add, do not go into it for the money. This has been posted time and time again. You pretty much have to own a practice, be in the middle of your career, and have your debts payed off to make a 200+ salary. If this concerns you, then I'm not sure what to tell you. Dentistry does not equal instant money.