I don't have any answers for the teeth. Brushing is good for prevention but not for curing a problem. So let's move on to the ears. You can clean them with alcohol or a pet ear cleaner, but this will not cure what is wrong with them. And since it could be any one of several causes, we cannot really say how to treat (that is where the vet comes in) If it is mites, you can get medicine over the counter but if it is fungal or bacterial there is nothing to do without prescription medication. You can keep them clean but the longer it goes without proper medication the further into the ear canal it will move. Sorry, but even with all my practical experience and schooling in the field of animals, this is the best I can do.