I have tried the CET solution and the toothpaste with both soft brushes and rubber nubs but neither did a thing for my dog. This is simply a miracle in a bottle. I should also mention my dog broke a few back teeth on a bone so the protective coating is off and it's bare tooth. In week one the canines went from dark orange to mostly white. Week two they looked bright white. The back teeth are much improved after the third week and I will give it a month of daily treatment before going to the twice weekly regimen. Like any dog owner, I do worry about everything I put in my dog's body and this is no different. It says all natural, which I like, but you just never know when it comes to animal products. The company hasn't been around for a long time, but I weighed the pros and cons between using it and the effects of tartar on my dog's organs. Also, it is now being sold at my local feed store and he is very particular as to what products he offers.
Also, if you have an older dog and are worried about anesthesia, this is worth a try for a month or two. I wish it was around back then for my previous dog.
4/18 Update. I've been using this every day for a month now and even the broken teeth look clear of tarter. I am now doing it twice a week. My suggestion is after a month, gradually lessen the treatments while monitoring teeth and breath. Like all medicines, the least amount of sessions with satisfactory results is the healthful rule.
8/30 Update. Some people have asked for the ingredients, so here they are...
Teeth Gel: Purified water, corn alcohol, natural mint, glycerin, natural cleanser, aloe vera leaf juice, carbopol, chlorophyllin, green tea leaf extract.
Update 3/21/12 After buying a new bottle a month ago(from a reputable source), it does not work as well as it used to. I am not sure if they changed the formula around but it definitely isn't the same stuff I had been using. I even asked my vet and they weren't sure how it ever worked to begin with based on the ingredients. It did work for a few months so I'm not sure what to think now. I am now reluctantly back to daily brushing using CET tartar formula toothpaste.