A Colosseum is a large building, like a stadium or theatre, which is used for entertainment, sports and others. The picture shows once such ancient amphitheater in Rome, but it is neither carving nor real tooth, it is simply a CGI, i.e. computer generated imagery. The ‘colosseum tooth sculpture’ was in fact a part of toothpaste advertisement campaign for Maxam, the design of which was envisioned by agency JWT Shanghai.
As you can see the original two pictures in the image section below, the idea of this toothpaste advertisement campaign was to convey this “Roman Civilization Cavity”, i.e. not to let germs settle down on your teeth, or else you will have to end up with such a “Colosseum” cavity.
The two CGI sculptures related to Civilization-Egypt and Civilization-Rome.
Therefore, the CGI picture neither shows a real tooth, nor a colosseum carved into it. It is not so amazing fact, but a good health campaign nevertheless!