Lets break it down quickly:
After graduation, you will probably find a job as an associate for 120k gross per year.
120k, after taxes is 80k that you have left.
the min payment on these types of loans are usually around 4k per month.
4 times 12 months is 48k
80k-48k= 32k
32k - (lets say 20k if you live very frugaly with no family to support gone for food, gas, utilities, rent, life)= 12k
So now your measly 12k in savings, over 2 years will get you 24k. The is no office that can be bought for that.
Another option is to open a business straight out of college.
So 400k of debt plus 500k for a cheap business will be around a million probably after you can actually get the place running.
Now imagine, a dentist who has a limited scope on how to run a business, which most dental students do, runs for about 2-3 years, burning through money. You close down.
YOU are left with a million in debt, and now have to work the rest of your life as a dental associate, chipping away at the debt you will never pay off.
Please think of this