Heres a question. Are you giving your little one rawhide? I didn't realize that rawhide is a no no for yorkies and Chloe had AWFUL breath. Turns out it was a piece of rawhide stuck in between her back teeth and even with brushing it stayed put. Well lets just say rawhide does NOT improve over time. I did get it out once I discovered it but it was sooooo smelly. Had to take her to get checked over and she was fine but learned that rawhide is a bad idea. Also a suggestion for getting a puppy used to getting their teeth brushed. You can buy gloves that have what looks like velcro on the pad of the thumb and forefinger, you use them in combination with a special paste that comes in a jar and is very thick. By rubbing the teeth with your gloved finger they are less intimidated and later will be more accepting of an actual toothbrush. Worked great with Chloe