How best, other than a grain-free wet food diet, to keep teeth clean? She had her teeth cleaned in Jan. but she is about 3 yrs old now & I want her teeth to stay healthy. I haven't tried brushing yet, as I'm not sure how/the brand to use, etc. so (other than treats which she doesn't like, as I tried many healthy ones & none worked for her) how can I assure good teeth hygiene? thanks.