Here’s the bottom line… Decay occurs because acid (mainly lactic acid) interacts with the minerals in our teeth (mainly calcium and phosphorus in a crystalline form) and, over time, causes these mineral crystals to literally dissolve from our teeth into our saliva.
So that’s what causes tooth decay.
But to really know how to ideally stop tooth decay and remineralize cavities, we must grasp how the process of decay occurs. And to understand decay, we have to first understand what our teeth are made of and the structure of the minerals that make up our teeth.
Our teeth are like a honeycomb…
Do you recall from the first article in this series, how to stop cavities and reverse tooth decay, how the analogy of the tug-o-war provides a helpful illustration how minerals are removed from and replaced back into our teeth?
In this article, let’s lay down another analogy for the structure of our teeth. We’ll use this analogy throughout this series on how to stop cavities and remineralize tooth decay.
Despite our teeth feeling very smooth and glass-like, they are actually like a microscopic honeycomb structure. If you think of a honeycomb, it has a combination of lots of holes with rigid structure around each hole. Our teeth have a similar structure.
The analogy of a honeycomb is good but a little misleading simply because the honeycomb is mostly open space with a little structure (so bees can fill the holes with honey). In contrast, our teeth are mostly mineral crystals built into this tightly packed crystal mineral matrix. Throughout the matrix are tiny holes.
The crystals form into long, slightly curved ‘rod-like’ shapes. As you’ll see below, when a tooth demineralizes, like little ‘coal miners’, the decay follows down these crystal rod pathways.
This combination of mineral matrix and tiny holes will be important as we dive into how the process of decay progresses.
What are our teeth made of?
Our teeth are 86% minerals, 2% proteins, and 12% water.
The main minerals involved with building our crystal mineral matrix are calcium and phosphorus in a natural structure called hydroxyapatite (high-drocks-ee-appetite) or HA for short.
Hydroxyapatite is a molecule that contains 10 atoms of calcium and 6 atoms of phosphorus (in the form of phosphate) with some oxygen and hydrogen (hence the ‘hydroxy’ part). When HA connects with itself, the crystal rods that make up our teeth are formed.
Those of you who nostalgically look back to high school chemistry class, the formula is Ca10(PO4)6(OH)2.
Carbon, sodium, fluoride, and other minerals also play a part in the structure, but to a much, much smaller extent.
How we lose minerals from our teeth…
Calcium and phosphorus are dissolved from our teeth through exposure to acids. The acids that cause this come from two main sources: acids from foods/drinks and acids from the ‘bad bugs’ implicated with tooth decay.
As we discussed in ‘How to drink kombucha and NOT destroy your teeth‘ and ‘Can brushing after a meal damage my teeth?“, it’s important to keep in mind that regardless of the source, acids cause the minerals to dissolve from the crystal matrix structure that makes up our teeth.
Life seeks balance. So, when an alkaline mineral like calcium has the opportunity to ‘connect’ with an acid (and thereby ‘balance’ the low pH of the acid), it’s simply going to happen.
With this in place, let’s shift our attention to the focus of the rest of this article: the process of tooth decay.
How teeth decay…
To understand how teeth decay, let’s take a quick side jog to gum disease…
Those of you who have read our work on gum disease know that certain bacterial species really love to colonize and multiply inside deepening gum pockets. In this way, they can do their dirty work under the cover of our gum tissue and not be exposed to disruption by routine, unconscious oral hygiene habits.
After all, if they tried to undermine our health ‘out in the open’ without the cover of a deeper pocket, their efforts wouldn’t work over time.
It’s just too rough of an environment for them with all the healthy components in saliva and our efforts to stop their colonization efforts. Not surprisingly, the bugs implicated with tooth decay apply a similar strategy.
Decay happens ‘under the surface’ first…
In the first article of this series, we discussed how we take a holistic, two-pronged approach to address tooth decay. In this article, we are going to focus on the ‘in the mouth’ approach and leave the ‘whole body’ approach for a later discussion.
Ok, so in the mouth, certain bacteria strains, mainly strep mutans, are the culprits that ‘cause’ minerals to be lost from our teeth. The reason strep mutans are ‘to blame’ is simply that the waste produced by this strain of bacteria is lactic acid.
Like we just covered, acids dissolve minerals from teeth.
Remember how in the article ‘Can some plaques actually help our teeth stay healthy?‘ we discussed the importance of keeping our plaque colonization in our mouths in the early stages and not allow colonization to reach mature stages of development?
The reason is because in mature plaque formations (of strep mutans), the pH of the inside of the plaque can be maintained at a much lower (more acidic) level. Therefore, the damage to our teeth and gums can be many times greater, as the plaque has time on its side.
In addition, as plaque colonization matures in an area, it increases the amount of time that acidic waste can sit right against the surface of our teeth.
As minerals are removed from the region, the plaque colony can inhabit the new terrain exposed from the demineralization. Like a mining camp, strep mutans works its way into the tiny holes in the surface of our teeth and begins to dissolve under the surface of the tooth in ‘stripes’ along the crystal rods that form our teeth.
In this way, the bacterial colonization can occur ‘under the cover’ of the protection of our surface enamel.
Our saliva can’t access the demineralized region under the surface, so our saliva is unable to remineralize the subsurface decay.
One key to stopping tooth decay…
However, the gang of bad bugs implicated with tooth decay still need to eat (sugars), so they keep a tunnel-like pathway open ‘to the surface’, a supply chain if you will, in order to draw their food down to their work site.
This will be an important piece to the puzzle later in this series when we discuss how to use this supply chain system to actually get the help of bad bugs in the damaged area to remineralize areas of decay.
Keep in mind, all this decay is going on under the surface.
This decay wouldn’t yet be called a ‘cavity’ by the public, as the surface of the enamel is still intact.
However, under the surface, plenty of minerals have been lost from the structure, causing what dentistry calls the ‘white spot lesion’, which is the tell-tale sign to any dentist that active decay is occurring at that site.
If the demineralization team continues to win the tug-o-war at that site, eventually the honeycomb structure will lose enough minerals that the whole structure in the area is dissolved and the actual cavity finally forms.
The good news is even if decay has progressed to the point of an actual cavity (hole) in the tooth, our efforts to remineralize the region can still work.
It’s important to clarify that remineralization can occur to any tooth that’s been decayed.
However, if a cavity (hole) is present, we don’t see proof that remineralization can refill the hole. Yes, we can harden the existing structure and stop the decay, but to expect a hole in the tooth to refill isn’t supported by the literature (from our research).
But this is really ok because what’s most important is that we stop the decay from progressing and strengthen the damaged region to become resistant to future decay.
Just in case you jumped to the end of the article for the recap, here’s a rundown of the important points:
- Our teeth are made of a natural compound called hydroxyapatite, which is composed mostly of calcium and phosphorus.
- Hydroxyapatite is formed into long crystals.
- The pattern of the hydroxyapatite crystals and tiny holes creates a honeycomb-type structure.
- Acids cause minerals to dissolve from our teeth.
- The main ‘bad bug’ implicated with tooth decay is strep mutans, which produces lactic acid.
- Strep mutans works its way under the surface of the tooth and establishes a ‘subsurface demineralized region’.
- Dentistry calls this a ‘white spot lesion’ because of the way these subsurface demineralized regions look to the naked eye.
- We can use the ‘strep mutans supply chain’ to our advantage to help remineralize subsurface decay.
With this baseline of information in place, we can discuss a multi-approach strategy to stop cavities and reverse tooth decay.
What about you? What did you learn from this article?
As always, please share this article if you know someone who may benefit from this series.
Feel free to check out the next entry in this series: The perfect storm for decay – the interplay between pH, sugar, saliva and plaque.
Helpful, Related Resources:
How to stop cavities and reverse tooth decay [article]
How to drink kombucha and NOT destroy your teeth [article]
Can brushing after a meal damage my teeth? [article]
Can some plaques actually help our teeth stay healthy? [article]