We had to have Millie’s teeth cleaned when we got her. Her teeth were horrible. I think she was always fed canned only and was never given chewies. She's just around 3 years old, but our vet said she had the teeth of a much older dog. Now they're shiny & white and her breath is not nauseating anymore. Chester's 5 and his teeth are still clean and pretty. We used to brush every day, but now we're down to once or twice a week. Everyday they get one dental chew that's treated with enzymes that we got from the vet, and they also get other chewies.