Slim The Hammer Man once told me a story that even he was skeptical of The Atom’s steel biting ability, so one day he asked The Atom to bite a nail in half in front of him. The Atom agreed without hesitation and picked a nail up from a nearby table to have a go. “Not so fast” said Slim, who then put that nail down and took another nail that he had inspected out of his pocket. Slim then physically placed the end of that nail between the Atom’s teeth “just in case.” Atom then bit down and with a loud “Crunch!” the nail was now in two pieces. There’s no getting around that one, The Atom was the real deal.
The Mighty Atom supposedly had a set of teeth that were twice as thick as a normal person. Sure seems like that’s the case since he could easily bite nails and chain links in half as if they were no more than bread sticks.