My 5year old Maine Coon had gingivitis. We tried an antibiotic and greenies, but she ended up having to have her teeth cleaned. With the blood work and cleaning, it was about $300. I'm faithful giving her the greenies after she eats(twice a day) our Maine Coons eat only raw meat. We get it from My Pet Carnivore. It's not cheap, but neither is the high quality cat food. Hopefully the greenies will keep the tarter off now that they're clean. Their favorite meat is rabbit and chicken super mix. On Sunday they get ground turkey necks. All their meat includes bones and organs, plus we add vitamins, egg yolks and salmon oil to it. There is a lot of info on raw feeding on the Internet. I'm sure my cats would not let me brush their teeth.