Some of Teddy's baby teeth didn't fall out naturally. He had to have some retained baby teeth pulled when he was neutered which was when he was about 7 months old.
A "puppy book" sounds like such a cute idea! I just put Teddy's in a tiny ziploc bag with his name and the year.

I keep it in his medical folder for safe keeping.
The four canines were pulled and the others fell out naturally.