"Lougle Its a dog so do you really think you saying gentle and no teeth is going to prevent an incident."
Yes, I do believe that teaching a dog to be gentle, and teaching it that teeth in play or affection is inappropriate, can help to prevent an incident.
It's called 'bite inhibition'. He has gradually worked his way from being extremely bitey (normal, typical puppy biting) to thinking about his teeth. If he gets too excited and starts to mouth, a simple 'no teeth, Patch' is enough to make him stop, deliberately open his jaws, and lift his mouth off of whatever he had in it. Normally my hand.
The same goes for when he is greeting my 3 children in the morning. He is delighted to see them, so gets excited. They squeal, so he gets more excited. I've been teaching him 'gentle' - get your face away from theirs you big oaf, and 'down' - stop jumping all over them.
Dogs are highly intelligent, you know. They are no different from humans in the sense that they all have moments where they have less patience than others. But in general, I'd say they are far more even-tempered than humans.