What's the deal with whitening teeth with charcoal?
Being a dentist, much of my online activity is understandably devoted to teeth. So when it comes time to logging on to the data-mining juggernaut of Facebook, much of my feed is inevitably flooded with sponsored posts relating to all things dental and in particular, tooth whitening. One of the more interesting developments in this regard in recent years has been the proliferation of ads relating to the use of charcoal-based products to whiten teeth. These ads instantly catch the eye as they typically involve a somewhat dramatic image of someone's pearly whites covered in a deep black substance, followed by bold claims of near-instant tooth whitening. The underlying comments sections are carefully manicured to be full of enough testimonials and interested parties to make one wonder if maybe it could all really be true.
And don't let dentists tell you otherwise! After all, this is a secret that us dentists don't want the general public to know about. If the secret got out it would smash our tightly-held tooth whitening cartel and we couldn't let that happen. And on it goes as with much modern social media marketing, where the truth lies lost somewhere in a haze of equal opinions, vested interests and claims that we really truly just want to believe. So before we get to the evidence and chemistry behind charcoal, here's my own opinion: Having your teeth coated with a charcoal-based substance IS likely to noticeably increase the whiteness and opacity of your teeth... for about 15 minutes. (I say this somewhat tongue-in-cheek and I'll get to why this may happen in a minute...)
The bottom line is that there is simply no credible evidence to support the use of charcoal to change the color of teeth. In any form. At all. Sorry to be a buzz kill! Moreover, the theory behind how charcoal could genuinely whiten teeth (according to its proponents) would seem pretty darn implausible. The key claims regarding charcoal relate to its large available surface area and its resultant ability to absorb 'stains' from the surrounding environment. The problem is, this is just not how teeth work. Teeth may be stained internally, in which case stains are integrated into the highly mineralised structure of a tooth and cannot simply be 'sucked out' by applying an agent to the surface. Teeth can also be stained externally, in which case stains form part of a firmly adherent pellicle or plaque which must be physically removed. Which brings us to how using charcoal could more plausibly actually have a visual impact on teeth. It should be noted that neither of these two mechanisms would represent a true whitening of teeth:
Abrasion - a charcoal grit could be quite abrasive and like anything abrasive, it could act to physically remove external stains from the teeth if it was used forcefully under pressure such as with tooth brushing. Sounds great! Unfortunately, using any such abrasive in an uncontrolled manner caries a very real risk of damage to the tooth enamel. And any damage to enamel is for life - once gone it is never coming back!
Dehydration - this one is the real party trick and is perhaps the origin of the whole charcoal phenomenon. Tooth enamel is permeable and when, as in the normal course of events, it is bathed in fluid such as saliva, it maintains a translucent appearance. When enamel is kept dehydrated, it temporarily loses its translucency and this may be seen following application of a charcoal substance. A loss of moisture causes enamel to scatter light and appear opaque and 'chalky'. This can temporarily lead to a perceived increase in 'whiteness' which can give quite a stark effect initially, but reduces as the tooth rehydrates - over the course of about 15 minutes.
But why not just give it a shot?
After all, just because there is no evidence (or plausible theory) behind something, it doesn't mean that it might not work, right? On the plus side, the financial outlay for these products is quite minimal and if used cautiously, the potential for damage would seem to be small. The potential side-effects that would concern me are related to abrasion of tooth enamel, which would perhaps be more of a concern with repeated usage, and the possibility that fine charcoal dust could be aspirated (breathed in) and cause damage to lung tissue. Although the latter may be more theoretical, risks such as this should be kept in mind when exploring unsupervised and largely unstudied treatments.
The need to believe
Although these ads might instinctively seem like rubbish, their power can immense and they do seem to work. They start off by claiming something that we desperately want to be true (we want whiter teeth) and a whole bunch of our peers seem to be going for it. The price point is so low that we think we have nothing to lose so why not give it a go? And then there's the interesting after-sales phenomenon - that we all have a bias towards believing in a product and its effects after we have purchased it. Admitting to the failings of a product that we have invested in (both financially and intellectually) is admitting to our own failings and the fact that we may have been duped. In Australia, we saw this effect in action some years ago with the rise and fall of 'power bracelets'. Many individuals who paid for and proudly wore these bracelets continued to swear to their powers long after these claims were debunked by the ACCC and others.
How can teeth be whitened?
The good news is, there ARE a number of ways to whiten teeth. What might be the best approach for an individual really depends on what is responsible for discoloration in the first place.
Cleaning - although this might sound simple, teeth can have external plaque, tartar or stains which can cause discoloration. Removal of surface stains with a dentist or dental hygienist may not represent true tooth whitening but can certainly have a significant effect on appearance.
Veneers - this involves covering the visual surfaces of teeth with a thin layer to improve the cosmetic appearance. Veneers can have a dramatic positive impact but this does involve bonding to the tooth surface and it is not reversible (others may argue with this point, but they are wrong!). Veneers are often reserved for cases where non-invasive treatments like bleaching or alignment are unlikely to create the desired result. This may include previously filled, worn or deeply discolored front teeth.
Bleaching - this is usually what we think of when we discuss whitening teeth. Bleaching involves the use of a peroxide-based substance to lighten the inherent color of teeth. Also results can vary among individuals, bleaching can certainly be effective. Bleaching agents can be divided into over-the-counter products, products for use at-home under the supervision of a dentist, or in-office bleaching agents. Higher concentrations of bleaching agents may be more effective in whitening teeth but may also be dangerous if not used appropriately. As such, higher strength agents are subject to strict regulation and should not be used without a dentist's supervision.
Dr. Aaron Martin is a registered dentist and principal dentist at Dentists of Alphington. The contents of this blog represent the thoughts and opinions of the author and should not be considered as a substitute for professional advice in any way. Any information provided is broad in nature and may not apply to an individual's circumstances. Individuals should seek their own advice from a health professional prior to any treatments or decisions.