Very straightforward, is chewing on ice bad for your teeth?
How often would it take to cause any permanent damage?
Funny you should ask.
Some Ice machine companies now rate their ice as “chewable” and “non Chewable”.
Different ice machines produce ice at different strengths.
Hoshizaki, an outstanding ice machine, (in and out burger) makes the strongest ice. It eats up blender blades. Bars that have this brand machine have special grinders/crushers for their Margarita or blender ice to save the bar blenders blades.
Hence:
Yea, chewing on ice is bad for your grille, even worse with some brands of ice machines that the business may use…
Wow, where can I get me some chewable ice? Why isn’t this stuff being marketed? I stopped eating ice even though I love it so much because my teeth went horribly wrong and ice couldn’t be helping. But I do miss it…
Purely anecdotal, but that’s what my orthodontist told me.
A dentist relative of mine has told me that chewing ice is bad for your teeth. My dentist says the same thing. The first time I went to him I asked him if he could tell what bad habit I had by looking at my x-rays. I was asking him because I have a tendency to grind my teeth in my sleep. To my surprise, his guess was that I chewed ice. (I don’t do it anymore.) I asked, “You can tell by looking at the x-rays?!” Yep.
Don’t chew ice.
Wow thanks for the replies. Lately I have chewed at ice while at work, but no more! 
OK, so why is chewing ice bad for your teeth? Or, why is it any worse than chewing carrots or any other reasonably hard food?
To follow up on the “different strengths of ice” thing…
I chewed ice as a child, and was given a stern talking-to by my orthodontist. I still do it, but only when the ice is half-melted and offers about as much resistance to my teeth as a stalk of celery. Am I still doing damage to my teeth?
(Yes, I should ask my dentist, but I’m not scheduled for another appointment for several months.)
This part I dont quite remember when my dentist told me: I think it’s because ice actually has less give than say a carrot which is tough but not brittle.
This part I do remember: It can cause teeny, tiny fractures in the protective outer coating of enamel that your teeth have. Once that shield is compromised, it can lead to more serious decay of the softer dentin part… or something.
(sigh Okay, I don’t remember that well after all.)
Anyway, I had a tiny little crack in my enamel that was making my tooth really sensitive to temperature for awhile. He told me to quit chomping on the hard brittle stuff.
According to my dentist, it’s how you chew ice. We chew it on our molars, our “long time chew” teeth. Most of the time, we bite with the front teeth, tear with the canines and use the molars to grind partially chewed food into easily swallowed pulp. Chewing ice doesn’t follow this. We sweep it back to the molars still hard and intact. And many times the ice is harder that the tooth, especially if you have “soft” or weak teeth.
IANADentist, but I was an ice chewer. Now I have crowns on all my molars.