he likes to grab with the teeth
Well the obvious is that he 'has' been doing a long time and was 'allowed' to do so. I would be VERY concerned about the added bite to the action.
That said.
Small spray bottle with PLAIN WATER in it. When he comes up tell him NO and spray him with water,ONCE.
Do not go crazy and keep spraying him, just one quick spray. Do not threaten him with the bottle just pull it out spray and immediately put it away off to the side.
He licks, NO, and ONE spray on his mouth/nose area, done.
My guess is this dog, who is by no means dumb, will stop this nasty habit after one day.
The day he does it to the neighbor kid or a friend who doesn't like dogs and you'll have a lawsuit on your hands, and god knows with all these new bad dog laws, you might find your dog on death row because of it,.....should encourage you to DO something now about this.