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The Critical pH of Enamel: What is it? Why it's important.

The critical pH level of enamel is the threshold for when it begins to dissolve and lose tooth minerals, often leading to decay or erosion. All of these unfavorable effects begin to occur once the pH in the mouth drops below the critical level of 5.5


Enamel critical pH: Things to know


 

What is it?

The critical pH of enamel is 5.5 and it represents the threshold for when enamel demineralizes if the oral pH decreases below that level.


What happens during demineralization: Enamel demineralization is the loss of tooth minerals, calcium and phosphate.

  • Put another way, you can think of it as the enamel dissolving and releasing the individual minerals within the tooth back into the oral environment.

  • Yes, your tooth is losing minerals!


demineralization and remineralization of teeth schema
Credit: Sangi Co.

When it happens: The dissolution of enamel typically occurs when the oral pH decreases below 5.5 in other words when it gets very acidic. You can compare this to the natural resting salivary pH which is closer to neutral (6.7 pH).


Exception: While the critical pH of enamel is around 5.5 teeth that are adequately fluoridated often have an improved critical pH of about 4.5 instead.

  • This means that teeth with regular exposure to fluoride require about 10x more acidity to make it dissolve.

  • It is 10x because pH is on a logarithmic scale.



 

Why it's important

The critical pH of enamel is important because below this threshold is when the tooth begins to demineralize. When left unchecked, it will either lead to tooth decay or enamel erosion.


Leads to tooth decay: The very first stage of tooth decay is enamel demineralization and it starts when the pH goes below the critical level. When this happens, the enamel begins to look chalky white like the photo below.


molar with demineralized chalky white enamel
molar with demineralized chalky white enamel

When left untreated, these chalky demineralized areas will begin to turn brown and eventually become full blown tooth decay. Once that happens, the condition becomes irreversible.


Leads to enamel erosion: Erosion of tooth enamel will occur if it becomes excessively and frequently exposed to acidic challenges. The teeth will start to look more yellow because of the loss of the enamel layer thus revealing the more yellow dentin layer.


enamel erosion by gum line
enamel erosion by gum line

The erosion process is near identical to the formation of decay, it's just that the etiology or cause is different.

  • For cavity formation, it is due to excessive sugar and bacteria.

  • For erosion, it is from extreme acidic challenges such as eating limes/lemons, bulimia, or excessive vomiting.


Ultimately, both of these conditions lead to loss of tooth structure which is not good.


 

Actionable takeaway

Knowing what the critical pH of your enamel is will arm you with knowledge to make smarter and healthier decisions in regards to your mouth.


Eat less acidic foods: Consuming less acidic foods will reduce the amount of time that your mouth spends below the critical pH level. Perhaps it would behoove you to look up the acidity or pH of all of the foods and beverages that you consume.


Various candies and their pH levels
Credit: ScienceWorld

Maintain oral hygiene: Brushing, flossing, and mouth rinsing can help raise the pH of your mouth above the critical pH level. What this does is stop the demineralization process.


pH in mouth after rinsing chart of various mouthwashes

The chart above is from a study which showed that rinsing after an acidic challenge helped to raise the pH back up. Yes, even rinsing with plain water will help!


Remineralization is possible: The good news is that teeth can remineralize and recover from early demineralization. This means that if you can raise the pH back above the critical level, your teeth can regain lost minerals.


demineralization and remineralization of teeth schema
Credit: Adam heller


At the end of the day, don't forget that if you need help you should see your dentist. Our dentists in Long Island City can help restore lost enamel with dental bonding or give you more tips on how to prevent it.

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About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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