Ideally, you should brush your dog's teeth twice a day. At a minimum, you should brush them thrice a week to reduce bacteria and tartar. Daily brushing helps to prevent periodontal disease in your dog, thus reducing the likelihood that your pooch will suffer from painful dental problems. It is best to get your puppy used to tooth brushing early on as it can be more difficult to get an adult dog used to the process. However, many adult dogs can still learn to tolerate tooth brushing, or even enjoy it if rewarded afterward.