I learned from previous Yorkies that their teeth can be a problem if I don't pay close attention to their development. This time I had the baby teeth pulled earlier. I also knew what to watch out for ... the double teeth thing. I'm a freak about brushing their teeth, now. I've been looking for the perfect little toothbrush for years, and I finally found it. I bought the Colgate Wisps (for humans on-the-go) and popped out the little ball of mouthwash or whatever it is, and snipped off the sharp pointy end. It's the perfect size for my Yorkie puppies' little mouths. The bristles are nylon/plastic ... not too stiff and not too soft ... just right.