Everyday Questions: How At-Home Teeth Whitening Works

{Sorry to keep boring you all with details of my house move, the snow has meant that my internet has still not been installed. This may result in me being slow to reply to emails and the occasional slightly late post, so I’m very sorry if it does!}

Today’s post was requested by the lovely Anna, who writes at Skin & Blister blog. You should definitely pop over and have a look, her blog gives me life envy and she’s basically just all-round awesome. Anyway, Anna asked me a while ago on Twitter how teeth whitening treatments work, and I love answering new questions, particularly ones I’d never thought to wonder about myself, so thanks Anna, this is for you!

First, your teeth. Your teeth are made up of layers; right in the middle you have the pulp, which is the soft gooey centre of your tooth. If you tooth was a chocolate box chocolate, this would be the nougat centre, it’s where all the blood vessels and nerves that supply the tooth are located. Coating the pulp is the dentine layer, dentine is a porous substance, it’s hard as bone but filled with teeny tiny channels that can supply the tooth with cellular material. Finally, coating the outside is your hard shiny white enamel.

Throughout the day, as you live your life, a film builds up over the enamel coating your teeth. This pellicle layer is formed by glycoproteins found in your saliva, and it’s necessary to protect your enamel. It forms a barrier, underneath which your enamel can be strengthened, and it offers something of a shield against the effects of acid on your teeth. It is also partly what you’re scrubbing at when you brush your teeth, as well as obviously trying to keep your gums and the gaps between your teeth free from bacteria and other gunk, and providing a source of fluoride, and all the other useful things toothpaste does. A lot of everyday whitening toothpastes have tiny abrasive crystals in, in addition to all the usual ingredients, and these act a bit like an exfoliating body scrub; the idea is that they make it easier to scrub away any dirt or plaque or stains.

However, your enamel can also become discoloured over time. Tiny particles can infiltrate your enamel, like miniscule soldiers on undercover missions behind enemy lines. This can lead to your teeth starting to appear stained, and this is when you might be tempted to bring in some big guns.

Over-the-counter teeth whitening treatments work in a fairly straightforward way, they include a chemical, carbamide peroxide, which reacts with water in the mouth to become the seriously bad-ass hydrogen peroxide, more commonly known as bleach. Hydrogen peroxide is your super soldier, heading into battle with the infiltrated stains. It’s an oxidising agent; this means that it is an electron thief. Its battle technique is to react with other molecules by pulling electrons away from them. This oxidisation process appears to break-down the molecules that have infiltrated our enamel and are staining your teeth. Result? The enemy has been vanquished and your teeth look whiter. I actually find this amazing, something as simple as pulling away a TINY electron can destabilise whole molecules, and change everything in a reaction. This is why chemistry is so cool.

However, nothing is ever so simple; and while this is seriously cool from a proper nerdy chemical point of view, there are some things to be aware of with teeth-whitening kits. The biggest issue is that peroxides are not the nicest of chemicals. Sure, they’re fantastic in a deep-enamel tooth battle, but they’re fairly vicious and not so fun if they spend too long touching your teeth, and they definitely won’t be fun if they come into contact with your gums, particularly if you have any gum disease, although even healthy gums won’t enjoy exposure to peroxides. Most at-home kits come with strips to apply to the teeth, thus hopefully avoiding exposure to the gums, but this is still a concern. You also want to avoid peroxides getting into any cavities you may have, so you should only really go ahead with home whitening if you know you have good healthy teeth going on.

That is the basics of how at-home teeth-whitening treatments work, they contain peroxides to engage in battle with your stains, using the awesome chemical power of oxidisation. Chemistry IS awesome, see?

I want to finish this with a Very Important Note though: I am not in any way a dentist; I’m just an over-excited nerd who likes to know how things work. This is the basic, and kind of amazing, chemistry behind how at-home treatments make your teeth whiter, but if you have any questions or concerns about using them, your dentist really is the person to talk to. These blog posts are never intended to contain advice about what you should and shouldn’t take and do, for me it’s ALL about the how and the why and the wonder.


5 thoughts on “Everyday Questions: How At-Home Teeth Whitening Works

  1. Thank you so much for writing this!!!
    I really appreciate it and will now imagine small battles occurring in my mouth.
    Weird and marvellous in equal measure x

  2. Fantastic as always Katie! Two other things: 1) I am not bored at all by your house move and 2) I am with you on Anna’s awesomeness and the life envy thing! Xx

  3. Boo to the lack of Internet still! It’s such an exciting thing to look forward to (or is that just me) that it’s always a little disappointing when it’s delayed. I hope it gets sorted soon. I’m not bored by your move, and whenever you post is fine with me! That notification from my gmail that there’s a new post is always the best start to my day!

    This was, again, an incredibly interesting post. Not so sure I’m going to try a teeth whiting kit out after this!

  4. Pingback: Weekly Round-Up (Jan 28 – Feb 3) | Science Communication Blog Network

  5. Pingback: Everyday Questions: How At-Home Teeth Whitening Works | Science Communication Blog Network

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