I’m wondering what happens to different molecules on teeth, what toothpastes are made of, how does it fight sugar etc.
In: Biology
The weirdest thing to find out about toothpaste is that it‘s main active ingredient (sodium laureth sulfate) is the same as in modern liquid soap and shampoo.
Sorry to break this to you but toothpaste plays a minor role in dental care. Lots of research suggests this. Toothpaste is just abrasives held together by a detergent like binding agent, plus fluoride or other minor active agents. It is the brush that removes the plaque and abrasives just help in that, like sand helps grinding. Fluorides for sure help prevent cavity by renewing enamel regularly, especially if water isn’t fluoridated. Toothpaste just works by giving mint fresh breath and making it feel good.
Toothpaste is a mild abrasive (really more of a polishing compound) and a soap-like ingredient (or two) to cause it to make lots of little bubbles into a foam, and usually (but not always) a pleasant smelling and/or tasting flavor.
You don’t ‘fight sugar’ with it. You suspend the plaque and other bits of food in the foam, which lets you spit it out of your mouth easier. The physical bristles on the brush get into the tiny crevices of your teeth/gums/tongue and that is what dislodges them. You can brush your mouth with water, nearly as effectively as with toothpaste–it is just messier, as the foam doesn’t want to run out of your mouth whenever you open it to breathe or to adjust the head of the toothbrush. The foaming agent is also usually what is classified as a ‘surfactant’ which just means that it can get ‘under’ the plaque, and coat the teeth as you brush to prevent the plaque from re-adhering. But, with enough water and time brushing–this is unnecessary.
‘Plaque’ is what happens to food that the enzymes and bacteria in your mouth consume, and then eliminate, and that adheres to the enamel of your teeth. It also creates an area where those bacteria/enzymes can stay in relative safety, and then they create more and more plaque. It is also acidic, which is what wears down the enamel and lets them gain access to the much softer parts of the tooth. And, once they are inside the damage cannot be repaired. You can only slow down the progress. This is why we fill those holes–called cavities–with a compound, so that the bacteria cannot get food and continue the cycle.
This is why the crevices on the ‘crown’ of the molars are usually where cavities form. It is hard to get in there, and it only takes a little bit of time to get those bacteria/enzymes working and making more plaque.
The fluoride in toothpaste reacts with the enamel – which has a substance called hydroxyapatite one the surface. This substance is covered in OH groups that can react with acids to make water and slowly dissolve away. Acids are formed when bacteria metabolize sugars. The fluoride reacts with the hydroxyapatite and converts it to fluoroapatite, which is resistant to reaction with acids, slowing decay of the enamel.
National Geographic did a great series of videos on called “ingredients”, which are awesome, and they did one on toothpaste
[https://video.nationalgeographic.com/video/ingredients/00000157-29d1-da6e-abf7-7bfdaf1a0000?source=searchvideo](https://video.nationalgeographic.com/video/ingredients/00000157-29d1-da6e-abf7-7bfdaf1a0000?source=searchvideo)
First, we need to understand WHY we brush our teeth. In your original question – how does it fight sugar? It doesn’t. Sugar doesn’t harm teeth. Sugar (and other leftover food bits) feed bacteria, and bacteria harm teeth. The bacteria in your mouth eat various compounds in your food (they love sugar). Their waste products include the gross crud you can scrape off – plaque. The plaque is acidic and dissolves your teeth. Once the plaque has been there long enough, it essentially crystallizes into tartar – a hard to remove buildup that is well cemented to the tooth enamel. The tartar is not smooth like the underlying tooth enamel, and when it rubs on your gums they get inflamed and start to retract. Retracting gums exposes more tooth, and thus more buildup can occur further under the gum line.
Now that’s out of the way: Toothpaste weapons:
1. Flavour, usually mint – makes brushing less disgusting. Try brushing without toothpaste and note how quickly you discover how your mouth actually tastes. It’s unpleasant.
2. surfactants – SLS, etc. helps emulsify lipids to get oily residue to dissolve off teeth…also causes the foamy reaction which serves practically no purpose other than to help spread the paste around
3. abrasives – often baking soda or other hard minerals: They aid in your toothbrush action actually being able to scrape the schmutz off your enamel while not harming the enamel. The trick is to have grit that is harder than plaque and tartar, but softer than enamel so it scratches the bad, but leaves the good…Think of it like really soft sandpaper.
4. Fluoride – This is the big one. It’s relatively complicated but the long and short is, the fluoride compound sticks to the enamel, and when bacteria come along and poo their acid, the acid reacts with the fluoride rather than the tooth itself. It’s a sacrificial layer that keeps teeth strong
5. Pain-killers – Sensitive toothpaste has ingredients that reduce tooth pain and sensitivity to sweet, acid, hot, and cold.
6. Colour and sparkly stuff – makes the paste interesting in the hope that kids might like it.
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