The adult jaw is a vastly different environment from the embryonic version, however, and scientists have been unsure whether it would provide the correct signals to a developing tooth.

• 但发育成熟的颌与胚胎时期的颌相比，是个完全不同的环境，因此，科学家一直无法确定，成熟的颌是否可以提供正确讯号给发育中的牙齿。