In the quiet arithmetic of daily habit, what we drink shapes the very structure of our teeth over time. Researchers at Purdue University have now measured what many suspected: unsweetened sparkling water disturbs the mouth's delicate acid balance far less than sugar-sweetened soda, and the mouth recovers its equilibrium within twenty minutes. Presented at the American Society for Nutrition's annual meeting in July 2026, the findings offer a measured reassurance to those who have already made the switch — while reminding us that moderation, not substitution alone, is the wiser path.