ACV is in general good. The reason for adding baking soda is to neutralise the acid in it and make it buffered (non -acidic). I have been feeling much better with buffered ACV. Also since the acid is neutralised, it does not bother the teeth....
I got this recipe of ACV+baking sada from a guy named TED who posts on EarhtClinic. Greay guy and great remedy... read it all and then try it if convinced.