Definitely not teeth, although the teeth are the hardest part of the body, but note that teeth are not bones, teeth are just 1 organ of the body. The hardest bone in the body is the skull, the bones that wrap around the entire brain. They protect the medulla, blood vessels, lymph and nerves inside the brain. The skull includes the parietal bone, occipital bone, temporal bone and frontal bone, etc. The hardest of these bones are the parietal and occipital bones. And the skull belongs to the flat bone, of which its coverage capacity and force area, it can reduce the external impact on it.