(A). pH 4.5-5.5
(B). pH 5.5-6
(C). pH 6-6.7
(D). pH 7+
First of all, what is pH? pH is the symbol of hydrogen ion concentration expressed in numbers, corresponding to the acidity or alkalinity of an aqueous solution. The range is from 0 (pure acid) to 14 (pure base). Therefore, the lower the number the more acidic the solution. Why do we have to learn about pH in dental hygiene? Because acidity is destructive for the oral cavity. Some food are very acidic by nature - orange juice, sugary food, lemon, wine, sparkling water. But more importantly, food left in the mouth is “consumed” by bacteria and leave acidic byproducts, that is why rinsing and brushing is critical.
Critical pH is the pH at which hydroxyapatites in dental structures start to dissolve.
- Normal pH of the mouth: 6.2-7.
- Critical pH for enamel demineralization: 4.5-5.5.
- Critical pH for root demineralization: 6.0-6.7. Roots demineralize easier than enamel.
Answer: (A). pH 4.5-5.5
BONUS QUIZ! What is the pH of a normal toothpaste? If you have guessed 9, you are a genius! Toothpaste has a pH of around 9. This is because we want to keep raising the pH of the mouth to prevent demineralization.
I hope this helped you understand the process of caries formation for the dental hygiene board exam (NDBHE, NDHCE). And now, you can explain to your patient the reason they have to rinse their mouth continuously and brush their teeth – to get rid of the food that will be eaten by bacteria that in turn will "poop" acidic by-products. So again, raise the pH!
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