Carbonated water, also known as sparkling water or seltzer, is water infused with carbon dioxide gas under pressure, creating bubbles and a tingly sensation. While a slight risk of dental erosion exists due to its mild acidity, the potential for damage from unflavored sparkling water is generally low. This low risk is only amplified when the beverage is consumed constantly throughout the day or when flavorings are introduced.
The Chemistry of Carbonic Acid and Enamel Erosion
The mechanism by which carbonated water introduces acidity into the mouth is purely chemical. When carbon dioxide (\(\text{CO}_2\)) gas is dissolved in water (\(\text{H}_2\text{O}\)), it forms a weak acid known as carbonic acid (\(\text{H}_2\text{CO}_3\)). This reaction lowers the beverage’s \(\text{pH}\) level. Plain carbonated water typically exhibits a \(\text{pH}\) ranging from approximately 4.5 to 5.5, which is lower than tap water’s neutral \(\text{pH}\) of 7.0.
The primary concern for dental health is demineralization, the dissolution of minerals from the tooth enamel. Tooth enamel is composed largely of a mineral called hydroxyapatite. Enamel begins to dissolve when the oral \(\text{pH}\) drops below the critical \(\text{pH}\), which is typically around 5.5.
When the teeth are exposed to a \(\text{pH}\) below this critical level, the hydrogen ions from the acid pull calcium and phosphate ions out of the enamel structure, leading to dental erosion. Because the \(\text{pH}\) of plain sparkling water often sits near this 5.5 threshold, it has the potential to initiate demineralization. However, the mild nature of carbonic acid means the erosive potential of plain seltzer is minimal compared to other common drinks.
Comparing Plain Sparkling Water to Other Common Drinks
The risk of dental erosion from plain carbonated water should be compared to other beverages. Tap water, which is essentially neutral with a \(\text{pH}\) of 7.0, poses no threat to enamel. In contrast, many popular drinks have significantly lower \(\text{pH}\) values than plain sparkling water, creating a far greater risk of enamel damage.
For example, typical orange juice has a \(\text{pH}\) of about 3.5 to 4.5. Regular soda is even more acidic, often measuring between \(\text{pH}\) 2.5 and 3.5. This difference in \(\text{pH}\) is profound because the \(\text{pH}\) scale is logarithmic.
Studies show that while plain carbonated waters are “minimally erosive,” they are dramatically less damaging to enamel than many sports drinks or fruit juices. The absence of sugar in plain sparkling water is another factor that makes it a less harmful choice than soda. Sugars feed oral bacteria, which then produce their own acids, compounding the beverage’s inherent acidity and increasing the risk of decay.
How Flavorings and Citric Acid Elevate Dental Risk
The significant dental risk associated with carbonated water comes from added flavorings. Many flavored seltzers include ingredients like citric acid, malic acid, or phosphoric acid. These added ingredients are far more potent than the naturally occurring carbonic acid and drastically lower the beverage’s \(\text{pH}\).
The addition of these flavoring acids often pushes the \(\text{pH}\) below 4.0, where dental erosion accelerates. For instance, some lemon-flavored sparkling waters have been measured with a \(\text{pH}\) as low as 3.03.
Even products labeled with “natural flavors” can contain these highly acidic compounds without explicit mention on the label. This makes flavored carbonated waters much more aggressive toward tooth enamel than their unflavored counterparts. The combination of carbonation and added fruit acids creates a highly erosive environment that can quickly begin to wear down the tooth surface with frequent consumption.
Simple Strategies to Protect Teeth
Simple habits can mitigate the potential for dental erosion. One effective strategy is to use a straw, which helps bypass the front teeth and reduces the direct, prolonged contact of the acidic liquid with the tooth surface. It is also beneficial to consume carbonated water alongside a meal, rather than sipping it throughout the day.
Eating stimulates saliva production. Saliva is alkaline and helps to quickly neutralize the acids, restoring the oral \(\text{pH}\) to a safer level. After finishing an acidic drink, rinsing the mouth with plain tap water helps wash away residual acid.
Acid temporarily softens tooth enamel, making it vulnerable to abrasion. Instead of brushing immediately, wait at least 30 minutes after drinking any acidic beverage. This allows saliva time to begin the natural remineralization process.