Don't play tug with a dog.

  I have always played tug with my dogs who were interested, from the time I was a child. IMo it's a great relationship building game, a great way to build drive, a great way to teach impulse control, a great outlet and a great reward. You could say, I'm a big proponent of the game :) Willingness to tug is actually a reason I have picked several of my dogs. Similar to Liesje, I don't have any specific "rules" for tug and generally, I allow the dog to win as long as they are really into it.  I have never known a dog who developed behavioral issues because of playing tug.

AgileGSD

I have never known a dog who developed behavioral issues because of playing tug.

I think it is the dogs that already have the behavioral issues that have problems with it. 

 My vet doesn't think you should play tug because of the potential risk to the teeth.  He has seen the back end of what can potentially happen so I can understand his reasoning, though I have chosen not to follow his advice.  Kirby enjoys his game of tug too much.  He has even gone so far as to try and push toys in my mouth to initiate the game.  I could see how his play could be unsettling to some people though.  He is a major growly pants, especially when he tugs.  Then again he also growls when he fetches and is running after the toy... XD

I'd be interested to know more about the problems with teeth.  Being in Schutzhund I'm not sure I know of a dog that does not play tug on a regular basis but am not aware of damage to the teeth.  I think playing rough tug with a dog that is teething or has bad teeth is a no-no, common sense.  But normal dogs?  My dogs tug with each other many time a day much harder than I tug with them.  They also like treats or raw things where they get to tear and tug.  I haven't been tugging with Pan while he's teething, but he still tugs with Nikon.  He just let's go if it gets too rough.  Their teeth are made for pulling and tearing.

The growling...maybe I'm weird but I do not mind it at all.  The dogs growl with me when we tug, I kind of fake growl at them, and they growl at each other like they're being paid for it, but it's all in good fun.  Never had one of my own dogs resource guard something from me or snap at me.

While I too think that playing tug with a teething pup or a dog with very bad teeth is not a great idea, I am more inclined to worry about the heavy chewing my dogs do than the tugging they do. Zipper's teeth at seven years old are quite worn visually because he is an extremely avid chewer (he chews on bones probably four hours per day, not counting when I'm not home). He loves chew bones, and admittedly his teeth have shown wear because of it. I haven't seen any damage done to any of my guys with any tug games yet. I've seen more teeth damage from catching frisbees or hard balls as well, but not from tug.

Interesting viewpoint, I hadn't heard it as a consideration, but I'm not sure it's all that accurate.

Yeah most of the teeth injuries I've seen have been from bad "catches" on the sleeve (tooth gets jammed or stuck in the jute), or dogs gnawing on their crates/kennels.  None of mine chew their kennels but I do check Nikon from time to time to make sure he didn't get jammed and the next time he's out for anything at the vet I will have a set of x-rays taken of his dentition for a baseline.  All my dogs will chew bones and other chewing toys indefinitely so they have set times with those.