Of course you can, but it's seldom done. If you go into general practice, it's hard to give it up. You go to work at 8:00 leave at 5:00 and have weekends off. Most calls at night can be handled by telling the patient to just come to your office in the morning. Your kids are in school and you're used to seeing them every day. Your wife is used to you coming home every afternoon. And she's also used to your salary of $100,000 to $200,000.
Then you do an oral surgery residency for 4-6 years. You now take a pay cut to $40,000 and you spend every 2nd-3rd night in the hospital. You can go a week without seeing your kids, and your wife is home alone every 2nd-3rd night. You show up to work between 5am and 6am and come home at 6pm-10pm unless you're on-call which means you spend the night at the hospital. You're now an employee instead of running your own practice and you answer to many people.
This is why it seldom happens.