I am a pediatric dentist and I recommend the following brush to my "new moms" with human babies...so I of course use this on my own furbabies!!!
Amazon has them and you can search for "banana baby toothbrush" Kushies makes it. I am putting the link in here..but if it doesn't come out you can do a manual search on Amazon to see it.
Baby Toothbrush
Hope that helps!!
Karen, Ozzy and Harley