[yorkietalkjilly]

Have the vet check him thoroughly as you have no idea what may be going on causing this - he could be ill and this is the only sign so far. Please don't assume he is okay.

Once the vet check is complete and totally clean bill of health, I would try this. Stop the growling and teeth showing at once. If you must and he won't respect you any other way, say "No"(please no anger/frustration), place your hand in the dog's back neck skin, gather it up and hold - just like another dog will do when disciplining a fellow dog. Don't choke or hang the dog - just grab and hold, being careful not to pull on the trachea from too much tension. If he hasn't enough skin there to hold it without causing throat tightness, just gather up the hair w/out pulling it. Say "No" first and then just sit there calmly and hold until the dog gives in and looks away or relaxes. Allow him to move away from you if he wants after that so collect and calm himself. Keep eye contact with the dog at all times until he looks away while you are holding him by the neck skin or hair and don't hurry the session. He must back down and not you. You are not hurting him just teaching him you have ultimate sway in any situation and it is a good thing for him to quietly learn. Once he has given in, break the eye contact, get up and matter of factly go about your business. This let's the dog know that once he gives up, all is okay and the scene is over and no continuing tension - live just flows on nicely. He will learn that once your hand touches his neck, a look away or give up and all will go back to normal. Eventually, he will learn not to growl/show teeth in the first place as he knows it will lead to a moment of correction and he will strive to avoid that.

That technique is for emergency situations only but a better way is to engage in a good behavior modification training program there at home(you can ready about it on the net and here in our Library) and get the dog used to looking to you, and not itself, as leader. Plus, this type training forges a close bond with you and your dog, is fun and rewarding for both and teaches the dog to automatically respond to your command so a simply "no" or "uh oh" will stop any aggression.

I hope this doesn't anger or upset you and I posted just what I would try if I were in the situation. So many people seem to ask for some help and then get offended for giving one's thoughts. But I would not think that a growling/teeth showing dog is normal and would have him physically checked out first. We do not need to and should not want to live with aggressive dogs. It sure can escalate from there when they see no one disagrees with that type of behavior.