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To Eat or Not To Eat... Between Meals

Author: Shirley Chen


There have been lots of mainstream media discussions around how the frequency of eating affects body weight. In comparison, much less is talked about by the general population with regards to the frequency of eating and its effect on oral health. Our teeth are important to us. They allow us to chew and talk, contribute to modern-day aesthetic views, and support our cheeks and lips which form parts of our facial structure. Let us take a look at how our teeth are affected by how often we eat.


Enamel is a mineralized substance that can be demineralized or remineralized depending on the acidity of the surrounding environment. When acidity increases, which means when the pH decreases, demineralization of enamel occurs and can lead to cavities.1 The threshold of pH is 5.5. Below pH 5.5, demineralization and weakening of the enamel occurs.1 Above pH 5.5, remineralization and strengthening of enamel occurs.


The increase in acidity is due to the production of acids from bacteria in the mouth. These acids are actually waste from the bacteria when they feed on simple carbohydrates. Therefore, one of the major sources of the increase in acidity in the mouth is from eating simple sugars.1, 2


It takes about 5-10 minutes after exposure to simple sugars for the pH in the mouth to drop below 5.5 and for demineralization to begin.1 After the acids are removed from the mouth, the pH increases, eventually to above 5.5. This increase takes about 30-60 minutes, depending on the individual.1 The changes in pH in response to sugars is termed the Stephan curve1, 2, shown in Figure 1.


Fig. 1. The Stephan Curve1


From the concept behind the Stephan Curve, we can conclude that in terms of oral health, it is better to eat carbohydrate-containing foods less frequently throughout the day, in order to increase the time that remineralization is occurring.1 Therefore, it is recommended to eat sugary foods during or immediately after mealtime, and none in between meals.1



References


[1] Dentalcare by Crest and Oral B. (n.d.). Caries Process and Prevention Strategies: The Environment. Retrieved May 23, 2021, from https://www.dentalcare.com/en-us/professional-education/ce-courses/ce371/physical-traits


[2] Dawes, C. (2006). Why Does Supreagingival Calculus From Preferentially on the Lingual Surface of the 6 Lower Anterior Teeth?. J Can Dent Assoc, 72(10), 923-926.