Normal pH in our mouth is about 7.0, which is slightly more acidic than water. When we drink sugar-sweetened soda, the bacteria in our mouths get exposed to sugar; they metabolize it and produce acid. The acid causes the pH in our mouth to drop. At a pH of 5.2 or below, the acid begins to dissolve the hard enamel, the hard outer protective coating of our teeth. Over time this leads to erosion of our teeth that causes cavities and painful toothaches!
The best way to prevent cavities induced by sugar-sweetened soda is to drink it at one sitting along with the meal than sipping it throughout the day. Better yet, drink it through a straw in one sitting, this will help bypass contact of soda to your teeth and reduce exposure. Reducing the amount of frequent sugary beverages and brushing after meals and before bed will reduce risk of cavities significantly.