Some soda (and flavored iced teas) are very acidic. When you eliminate these drinks, you should expect less erosion of your teeth. Also, your body will have an easier time maintaining blood PH; it won't pull as much calcium from your bones and teeth to raise PH. Carbonation might also lead to accumulation of carbonic acid, causing the body to work even harder to maintain blood PH.

The above is irrespective of whether the soda has sugar, corn syrup or low cal sweetener.

All this comes from memory; I wish I had time to cite references, sorry! Until I do, you should think of this as BS or verify it on your own.