Do not worry about the money. Concentrate on the 4 years ahead of you. Graduate, get an associateship job to get your feet wet, and then buy an existing practice. (I'm against opening from scratch, but that's a different thread). The most important advice given to me was in the final months of my dental school. My adviser told me to: "treat your patients right, explain what you are about to do, do the best you can, and the money will take care of itself." Oh ya, it helps if you don't think you are Gods gift to the whole world. Here is some info:
As others have mentioned, the overhead is somewhere between 50-85% in most GPs offices. Personally, I don't understand anything over 65% but some claim that. I'd open a gas station if it was that bad.
My office, operates some where between 55 and 60%. I watch very carefully how we spend our money. The staff knows that if I have extra money at the end of each month, they get a bonus. So, they watch it too. I used to shop for supplies from an Internet based supplier. This was saving me 20-30%. Now the big guys are actually matching those prices for me. (we have a large account with one of the big suppliers).
Also, do understand that most business owners ( not just dentists) put a lot of their expenses through the business. There a lot of legal loopholes in the tax code that you can take advantage of. I pay a retainer to an accounting firm that specializes in dentistry. My accountant bill is around $6k a year. Worth every penny. I love my accountant
(only the kosher way a man can love another man
).
Don't ever not report income, that is illegal. But you can be creative. The IRS allows for this. For example, my wife's Range Rover is a company car (we have a car for personal use and two for the business). She is an employee of the business. She shops for the office, pays the bills, does the banking, etc. (Stuff you don't want staff doing. You know, personal financial stuff. No need for everyone in the office to know how much is in the bank or what you have on the credit card statement). According to some weird IRS code, I get some extra tax benefits for using this vehicle. It all has to do with the weight of the truck. The liberals are about to change that rule.
Also, do remember that most dentists include auto expense, health insurance, medical out of pocket expense, meals and entertainment, travel cost for CE courses, etc as part of the overhead.