There are so many factors that determine the earning potential of either of these professions like how many hours one works, speed/efficiency, and overhead costs to name just a few.
I assume that the average radiologist or endodontist will never be without the essentials: food, water, and shelter. Plus have enough to indulge in many non-essential wants.....if their money is managed correctly.
In any case, if you are interested in pursuing either career....with hard work, you'll be among the highest paid professionals in the country. It all depends....