The Magic School Bus and the Missing Tooth is a Level 2 Scholastic Reader, and is written with "vocabulary and sentence length for beginning readers", as per the information on the back cover of the book. It's an educational picture book, and stars the cast of the Emmy award winning television show, The Magic School Bus(which I highly recommend to anyone teaching or raising young children).
The book begins when Wanda brings a small, sharp tooth in for show-and-tell, and the class sets out to find out to what species the tooth belongs. Ultimately, the book examines human, horse, mouse, and cat teeth and features helpful diagrams and factoids.
I would recommend The Magic School Bus and the Missing Tooth to parents reading to their toddlers or young children just learning to read; the book could be particularly interesting to those with a preexisting interest in the Magic School Bus franchise and particularly useful to parents whose children will soon be attending their first dental visit.