You'll finally get to move out of the studio apartment you've been sharing with three other dental school students for several years.
General practitioners make around $150k a year. If you specialize in a certain field, you can make more. For example, orthodontists and maxillofacial surgeons make around $170k. Like any other profession, you'll make more money in a metropolitan city and less in a rural area.
If you own your own practice, you'll have to think about the overhead of having an office, staffing your office, paying for equipment, and dealing with insurance companies. Insurance companies can be pains in the butt. A lot of people think that their dental insurance is like their medical insurance. Not the case. Medical insurance covers most of the procedures, whereas many patients find that their root canal or whatever procedure actually exceeds their annual maximum. The result is that the dentist is unable to preform the procedure unless the patient pays for it. Also, some insurance companies deny procedures if they are for cosmetic reasons. So much for that gum tuck you've been saving for.
If you own your own practice, you'll have to negotiate with insurance companies or your clients to pay for certain procedures. Factor that tidbit in when you are daydreaming about owning your own practice.
And the real home run here happens when dentists can own their own buildings, hire lots of junior dentists to whom they pay $50 an hour, and bill their time at $100 an hour or more. Lotsa dental millionaires out there.