We took our 5 year old German Spitz while ago to vet dentist in order to remove tartar buildup in her teeth, which we now plan to do more often. There was already few teeth needed to be removed, which is unfortunately common problem with her breed. We also brush her teeth every now and then. I think it's good idea to do occasional check ups with e.g vet dentist as your dog gets older, though I'm not sure is the teeth brushing thing necessary for every dog.