Teeth Hurt When Eating Sweets But No Cavities

Written & Reviewed by Dr David Chen

Your teeth hurt or feel sensitivity when you eat sweets but you were told that you don’t have cavities. If there is truly nothing wrong with them then why are you feeling symptoms? Could your dentist have made a mistake?

There has to be SOMETHING wrong with your teeth since your they hurt right?

macarons with raspberries

Well you’re not wrong in that something is going on with your teeth. There are so many other conditions which affect your teeth than just tooth decay. Although for this particular case, we can think of two reasons.

When you eat sweets your teeth probably hurt because of dentin hypersensitivity or demineralization of teeth.

Eating sweets can trigger dentin hypersensitivity

You don’t necessarily need to have a cavity for you to feel sensitivity when eating sweets. The acidity and tonicity of your treat can trigger sensitivity signals in your tooth nerve.

This can be explained by the hydrodynamic theory which was first proposed by Brannstorm. The theory states that stimuli cause fluid movements within the dentinal tubules, which can be sensed by receptors. Depending on the type of stimulus, the fluids will flow either towards the nerve or away from it.

hydrodynamic theory schematic diagram
Credit: Ji won Kim and Joo-Cheol Park

Direction of fluid movements:

Essentially what happens when you eat sweets is the fluids within the dentinal tubules get pulled away from the nerve. The receptors sense it and triggers a sensitivity signal.

Sweets can cause teeth to demineralize

The sensitivity that you’re feeling from eating sweet treats could very well be the result of your teeth demineralizing. This is the process where your teeth are losing minerals because they’re dissolving due to the acidity of sweet foods.

demineralization remineralization of teeth
Credit: Sangi Co

Your teeth are hurting because the acid from sweets are dissolving the minerals from the surface of your enamel. Doesn’t it already hurt just hearing those words?!

Why does the enamel demineralize?

Your enamel is predominantly (97%) composed of the mineral hydroxyapatite [Ca10(PO4)6(OH)2]. We can break it down further into its individual mineral components, calcium and phosphate.

If you recall the “Got Milk?” campaign from the early 1990s, it centered around drinking milk to get enough calcium. The entire premise was that the mineral was important for building strong bones and teeth.

Now that you understand your tooth is practically made of the minerals calcium and phosphate, demineralization is not good. As its name implies, you’re practically losing calcium from your teeth when this process occurs. Your teeth are weakening since they’re becoming calcium deficient.

The entire demineralization process occurs whenever the pH in the mouth drops below the critical pH level of 5.5; That is the threshold for when hydroxyapatite starts to dissolve. Yes, hydroxyapatite is acid soluble but not water soluble which is why it stays intact in neutral saliva.

Do sweets really have acids in them?

Sweets are definitely acidic because they will lower the pH of your mouth when you consume them. The definition of an acidic substance is one which has a low pH.

As an example, undiluted orange juice has a pH of 3.9 which is in the acidic range and also below the critical pH of hydroxyapatite. Yes, what you’re thinking is correct. If you drink orange juice it will dissolve your enamel.

Candy chemistry
Credit: ScienceWorld

The image above shows a couple of candies and various foods and where they fall on the pH scale. As you can see candies, sodas, lemon juice, and battery acid are all in the acidic range. The worse part is that they’re all below the critical pH level of enamel.

How acids dissolve the enamel

Acids have a high concentration of H+ ions. These ions actually pull the phosphates out of the tooth along with calcium. The H+ specifically interacts with the phosphates (PO43-) to form various hydrogen phosphates which actually acts to buffer the oral environment.

Phosphate buffering system in saliva
Credit: Crest

Since the minerals are being pulled out of the tooth, we call the phenomenon demineralization.

An interesting concept that we would like to present to you is that your teeth serve as sacrificial pawns. Your body prioritizes keeping the mouth in a neutral pH and will sacrifice your teeth in order to draw phosphates out of it to buffer the acid.

Your teeth is akin to “my sister’s keeper“.

Significance of demineralization

Just to drive the point home, you should be concerned about demineralization of teeth because your teeth are weakening. In fact, it is the precursor to tooth decay. You can even consider it as a pre-cavity.

If you permit the teeth to continually demineralize, it will eventually lead to a cavitation in the tooth. Once the tooth becomes cavitated, it will be officially considered a cavity since there is a hole in it.

In case you were wondering why this is not considered a cavity is because it is subclinical. That implies that the symptoms are not really clinically detectable. For a cavity to be considered one, it needs to have a visual hole or can be seen on dental x-rays.

Since demineralization is just the beginning, it doesn’t show up on the x-ray and that is why your dentist told you that there was no cavity. However what that means is since you’re feeling sensitivity when you eat sweets, a cavity is trying to form!

What you should do about it

Despite there not being an actual “cavity” yet, your tooth is experiencing unfavorable conditions. You shouldn’t ignore it because it can get worse and we don’t want you to be in pain.

Here is what you should do if you’re feeling pain from eating sweets:

  • Minimize the intake of sweets.
  • Use a desensitizing toothpaste.
  • Use a remineralizing toothpaste.

Decrease the amount of sweets

If eating sweets cause your teeth to feel sensitive, it may be a sign that you should decrease the consumption of them. Sweet treats don’t provide the same nutrition value as whole foods such as leafy green vegetables.

You should try to replace some of that sugar with more vegetable intake instead! It’ll keep your teeth and your body healthier. Aside from that don’t forget that having too much sugar can potentially lead to diabetes.

We believe it is a win-win situation if you just cut sugar out of your diet. Your body and your teeth will thank you in the future.

Desensitize the nerve with toothpaste

If your teeth are feeling sensitive due to dentinal hypersensitivity, one way to treat it at home is with desensitizing toothpaste. There is a particular ingredient within some sensitive toothpastes called potassium nitrate, which can desensitize the nerve directly.

Sensodyne gentle whitening

What potassium nitrate essentially does is render the nerve unexcitable so that it does not fire signals. Despite the tooth still being exposed to the sweets stimuli, your body just won’t react to it.

However you should be aware that you must use the toothpaste for at least 2 weeks for you to see results. After that you need to continue using it so that the effects do not dissipate. The desensitizing effect should also increase all the way up to the 12th week as well.

Remineralize the teeth with toothpaste

Fortunately demineralized teeth can be reversed by remineralizing them. Since your enamel is losing minerals, all you have to do is add the minerals back in.

There are two common types of toothpastes which can remineralize your teeth:

How fluoride strengthens your teeth

Fluoride can help your teeth via multiple mechanisms and all you need to do is brush with it twice a day everyday.

  • Inhibition of demineralization. Fluoride ions replace the hydroxyl group and transforms hydroxyapatite into fluorapatite. It becomes more stable, harder, and less soluble.
  • Enhancement of remineralization. Fluoride is more readily taken up by decayed enamel than non-decayed. It pulls in calcium and phosphates to initiate remineralization.
  • Inhibition of bacterial activity in the plaque. Fluoride effectively inhibits the carbohydrate metabolism of acidogenic oral bacteria.
Demineralization with fluoride present
Credit: Crest

Nano-hydroxyapatite can repair your teeth

Toothpaste with nano-hydroxyapatite are highly biocampatible because it is biomimetic. If you needed further convincing, look no further than the fact that your teeth are made of hydroxyapatite.

How it helps to protect your teeth:

  • Repairs demineralized sections of tooth. The nano-hydroxyapatite molecule inserts itself into the damaged parts to fill in all of the voids.
  • Serves as a reservoir for calcium and phosphate.
  • Creates a “sacrificial layer” of hydroxyapatite over the enamel. This layer receives the brunt of the acid attack first and dissolves before the enamel does. When it dissolves, it releases calcium and phosphate which can be used to remineralize the tooth and also buffer the oral environment.
tooth remineralization schema with hydroxyapatite
Credit: Lijie Chen, Suma Al-Bayatee, Zohaib Khurshid, Amin Shavandi, Paul Brunton and Jithendra Ratnayake

The Verdict

Aside from cavities, your teeth can also feel sensitive after eating sweets if you have dentinal hypersensitivity or demineralized enamel. Despite not being cavities, it doesn’t mean that you should ignore them because it can get worse or even lead to decay.

What you should do is immediately reduce the sweets intake. Then you should also use a desensitizing and remineralizing toothpaste. That should help your teeth repair itself and get stronger. Once it does, your teeth should stop hurting when you eat sweets.


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