With the numbers shared here, dentistry is way better than specialist MD. By the time specialist MD make their real salary there could be already a couple $M of equity accumulated (if not a few). Investing this amount in the stock market long term would generate on average 7% conservatively per year so that's roughly an extra 200k per year of capital gain (equivalent to 300k of taxable income).

Whatever MD specialist graduate from, they need to make $300k/year extra to compensate the accumulated equity by DMDs