I like the Ionic HyG. I have been using for several years. Teeth looked good with very minimal tartar at last cleaning. (No longer have dental insurance). This uses the positive/negative ion concept to break the bond of plaque from your teeth.
There was also a post on the Yahoo Groups Iodine Off-Topic group about using malic acid to brush teeth as it gets off the tartar and kills bacteria. Am interested in trying, since I use malic acid in my daily water.