If wondering about shark teeth seems rather wonky, consider: Tooth loss from gum disease is a major problem, here and abroad, and dentures or dental implants are far from perfect treatments.

• 如果想了解鲨鱼的牙齿似乎相当困难，考虑到：在国内和国外，牙龈疾病造成的牙齿损失是一个主要问题，并且假牙或牙齿植入技术，离完美的治疗还很远。