I had a similar talk with my dentist, where I was optimistic about future and he put me back into reality. He took a piece of paper and started drawing tooth in

I had a similar talk with my dentist, where I was optimistic about future and he put me back into reality. He took a piece of paper and started drawing tooth in its complexity - nerves, blood supply, several completely different and 'living' layers (somehow I pictured teeth as something rather simple, like a piece of hard stone inserted into gums), and then he said, do you think a simple chemical can rebuild all this interplaying complexity?