pH: A Surprisingly Common Cause of Cavities

How does the pH of your mouth affect your risk for cavities?


Most people know and understand that a diet high in sugar can be detrimental to their oral health. What a lot of people are unaware of is the dangerous effects of acid to tooth structure.  In recent years, we have seen an increase in cavities among adults with good oral hygiene and diets low in sugar.  How does this happen?  It’s all about the pH!

Tooth decay starts with a process called demineralization, which is the softening of enamel or dentin surfaces caused by acid. Just as acid can etch the surface of glass, it will damage and soften the surface of tooth enamel, making it much easier for bacteria to penetrate and cause decay.  In a healthy mouth with a neutral pH or 7.0 or higher, it takes a long time for bacteria to produce enough acid to cause a cavity.   Research has shown that demineralization of enamel occurs when the pH drops to 5.5.

Prolonged exposure of your teeth to any acid consistently weakens enamel, allowing cavities to form in an otherwise healthy mouth. All carbonated drinks are very acidic, ranging from 2.5-4.0.

Is your water causing cavities?


If it’s sparkling water, then it definitely could be.  All sparkling waters have a very acidic pH, in the same range of sodas.  If you’re using a reverse osmosis filtration system, even your tap water could become acidic and increase your risk for cavities!  Most pH measurements of RO filtered water show a pH in the range of 5-7.  The only way to know your specific filter’s water is to have it tested.  And pH testing of various brands of bottled water shows that even some of those are acidic.  We found that the tap water in Prosper ranges from 7.2-9.4 pH levels (Town of Prosper Water Quality Report 2014).  It’s important to remember that enamel begins demineralization (or dissolving) at a pH of 5.5 or lower, so anything that will be exposed to your teeth for a long period of time should be above pH 5.5 in order to prevent cavity formation.

 What can you do about it?

Here are a few tips to improve the pH in your mouth and decrease your risk for cavities:


  1. Acidic drinks (anything below pH of 5.5) with meals or snacks only.
  2. Only drink neutral drinks (pH 7.0 or above) in between meals.
  3. Avoiding adding lemon juice to your drinks.
  4. After an acidic drink, chew xylitol-containing gum. Our favorite brand is Ice Cubes gum. It comes in a wide variety of flavors, is available in most grocery and convenience stores, and contains almost 2g of xylitol per piece. Not only does xylitol kill cavity-causing bacteria, the chewing motion stimulates saliva production, which brings the pH in your mouth back to neutral.
  5. Know your drinks.  In our experience, most of our patients have no idea that their favorite drink is very acidic and damaging to enamel.  You can test your beverages yourself with a pH testing kit or search the internet for common drinks.  Most food and drinks have an MSDS sheet (Material Safety Data Sheet) that includes their pH levels.  For a comprehensive list of beverages with their pH level, please follow this link to the website of Robert Shelton, DDS, MAGD.  He has compiled a very thorough list and was gracious enough to share with us.  Thank you, Dr. Shelton!
Evian 8.10
Music Mountain 7.88
Prosper Tap Water 7.2-9.4
Fiji 7.50
Nestle “Pure Life” 6.2-7.60
Saliva 7.40
Dentin dissolves below 6.50
Spring by Dannon 6.40
Dasani 6.03
Sam’s Choice 5.90
AquaFina 5.67
Enamel dissolves below 5.50
Deja Blue 5.49
Ozarka 5.49
Dasani Lemon 3.48
Fruit ² O 3.10

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