In part one of the Whitening Wisdom series, we discussed how lots of foods - even very healthy ones can cause teeth staining. In this article we will go through a whole range of common whitening methods, teeth whitening home remedies, internet whitening fads and the professional whitening options. Getting to the bottom of which teeth whitening technique works bests and what doesn’t work at all can be tricky - if you’ve been doing your own research then this article should be a good resource for you.

To make things easier we have split the main whitening treatments into four categories:

• Natural Teeth Whitening Remedies
• Over The Counter Whitening Products
• Internet Based Whitening Products
• Professional Teeth Whitening

Natural Teeth Whitening Remedies

Natural teeth whitening remedies have been around for centuries. The ancient Egyptians used pumice and vinegar, and the Romans believed that urine was effective at teeth whitening. Thankfully the popular natural teeth whitening remedies are much more civilised in today’s age!

The most common options that are claimed to be effective at whitening teeth are:

• Oil Pulling
• Charcoal Brushing
• Turmeric Brushing
• Baking Soda Brushing
• Lemon Juice Teeth Whitening
• Apple Cider Vinegar Rinses

Oil Pulling

Oil Pulling is usually done with coconut or sesame oil - there may be some oral health benefits to oil pulling (see our article here), however it is certainly not effective at whitening teeth in the true sense of the word.

The idea behind oil pulling is to dislodge the bacteria that create plaque build up on the teeth. As we found in the article - oil pulling can be helpful for this purpose, and by reducing the bacteria’s ability to stick to the teeth - your teeth may look cleaner.

For a tooth to be whitened - the chemical compounds called chromophores that cause the stains must be broken down and removed (for more information on this read Whitening Wisdom Part One). Oil pulling does not generate a chemical reaction that can break down chromophores and remove them from teeth.

Oil pulling certainly may help your teeth look cleaner, but it will not actually whiten them - any claim that oil pulling is effective at whitening is misleading.

Charcoal Brushing

Brushing with activated charcoal has become popular over the last few years - online stores selling charcoal based toothpastes and toothbrushes have popped up everywhere! Activated charcoal is great for adsorption - which means it attracts other molecules and binds with them.

Activated charcoal bonds to a whole range of things including harmful chemicals, heavy metals and toxins from bacteria like the ones that cause food poisoning.¹ It also can bind to useful things like Vitamin C and Vitamin B6.² Many manufacturers of activated charcoal whitening products claim that these adsorption properties enable ‘toxins’ and ‘chemicals’ that stain the teeth to be removed, resulting in a whiter smile.

As we know from Whitening Wisdom Part One, the main cause of tooth staining is from chromophores in food, usually these come from very healthy chemical compounds in fruits and vegetables - not toxins! The adsorption effect of activated charcoal only works best in the gastro-intestinal tract, which is why it is good for treating food poisoning symptoms. It will not absorb ‘toxins’ from your teeth and make them whiter.

The only way that charcoal whitening can make your teeth whiter is through abrasion - the charcoal particles are brushed onto the surface of the teeth scraping any plaque, biofilms and potentially some of the enamel away. This scraping and abrasion could potentially leave the teeth looking slightly whiter - however because the charcoal is not actually treating the stains in the teeth, the effect is likely to be very small. The abrasive nature of charcoal does pose a real risk to the health of your enamel.³

If you use activated charcoal for whitening, sorry to say that it doesn’t really work. Stick to using activated charcoal tablets for relieving the symptoms of food poisoning on your next holiday instead.

Turmeric Brushing

Turmeric has a very rich colour coming from the compounds like curcumin. We discussed turmeric in Whitening Wisdom Part One as one of the easiest foods to stain your teeth - not whiten them!. In our opinion it is highly unlikely that brushing with turmeric will leave your teeth whiter. Turmeric is very abrasive, similar to charcoal meaning that it will theoretically clean away any plaque buildup on the teeth, but this will also make it easier for staining chromophores to penetrate into the enamel.

We think turmeric brushing for whitening is best avoided.

Baking Soda Brushing

Baking soda is a popular whitening method, however it should be approached with caution. Normally baking soda brushing involves mixing a paste with some water (sometimes lemon or lime juice - more on this below) and then brushing the paste onto the teeth for a few minutes.

Baking soda is mildly abrasive so frequent or hard brushing will cause damage to tooth enamel and the gums. Most people who use baking soda for whitening agree that it should be done sparingly for this reason.

Baking soda can appear to whiten the teeth because of the abrasive properties that clean away plaque build up (the same as charcoal and turmeric but without the strong colours). This isn’t a true teeth whitening effect - however when combined with hydrogen peroxide, baking soda can create a mild oxygen free radical reaction.

This chemical reaction will actually produce a true whitening effect. Keep in mind though that only dental professionals can legally supply high concentration hydrogen peroxide. Any peroxide bought over the counter will be at about a 3% concentration so the chemical reaction will be quite weak and any whitening effects very subtle.

Lemon Juice Teeth Whitening

Whitening with lemon juice is a home remedy that actually poses a serious risk to the health of your teeth. Lemons are extremely acidic with a pH around 2.0 which means it can easily dissolve tooth enamel..⁴ Lemon juice is actually more acidic than Coca-Cola which has a pH of about 2.5. Enamel can never grow back so using lemon for whitening is extremely risky.

Most advocates for lemon juice whitening suggest that the lemon juice is heavily diluted or mixed with baking soda, and sometimes hydrogen peroxide. Once the preferred mixture is prepared you are supposed to gently brush the teeth. Unfortunately any brushing whilst the teeth are exposed to a strongly acidic substance will only damage the enamel further - so we strongly suggest you avoid using lemon juice for any form of teeth whitening.

Apple Cider Vinegar Rinses

Most Apple Cider Vinegar has a pH of 2.8-3.0 - making it strongly acidic. Apple Cider Vinegar has well documented anti-microbial effects, killing off harmful bacteria during food preparation.⁵ However, this does not make it suitable for teeth whitening in any way. With a strongly acidic pH - Apple Cider Vinegar falls into the same category as lemon juice: dangerous to your tooth enamel.

Any whitening effect from using strongly acidic substances like lemon and apple cider vinegar would come from dissolving the biofilm on the enamel surface, and then the enamel itself. This is not a safe way to whiten your teeth - so we strongly advise you to avoid any of these highly acidic whitening home remedies.

Over The Counter Whitening Products

For those who have visited their dentist or local chemist seeking whiter teeth know that there are a dizzying number of products available.

What you may not know is that most of these products work the same way - by using abrasion to remove surface stains. These ‘whitening’ products are not actually altering your teeth's natural color, they simply are just scraping away the biofilm and any extrinsic stains on the tooth enamel surface.

Whitening Toothpastes

This section refers predominantly to traditional whitening toothpastes, for charcoal whitening toothpastes refer to the section on charcoal whitening above.

There are two main types of whitening toothpastes: those that contain abrasive agents to remove any stains on the tooth surface and those that contain active ingredients to chemically whiten the tooth.

The typical abrasive agents include magnesium carbonate, hydrated aluminium oxides and calcium carbonate - at Laser + Holistic Dental we recommend avoiding these types of whitening toothpastes as they make only a very small, if any, impact on the whiteness of your teeth, but pose significant risk in terms of damage to the enamel surface. Some of the abrasive agents like aluminium oxides may pose broader health risks as well so steer clear!

The chemically active whitening toothpastes will normally use either hydrogen peroxide or carbamide peroxide - both of which are used by dentists in professional whitening treatments. In Australia it is very rare to see whitening toothpastes with these ingredients - most whitening toothpastes here are actually the abrasive kind.

Be wary of products claiming clinically proven benefits of ‘micro crystals’ or ‘micro beads’ - these are simply scratching away the surface of teeth, potentially removing stains, but also potentially damaging your teeth.

Teeth Whitening Strips

Teeth whitening strips are a small adhesive plastic strip, usually with hydrogen peroxide as an active ingredient. Because these strips actually use hydrogen peroxide they can break down the stains from chromophores in food that have become embedded in the tooth’s outer surface.

These strips may be appealing because of their relatively cheap prices compared to a professional whitening tray to fit your teeth and high quality whitening gels - however we do have a few concerns about the quality of the typical ingredients, and for this reason we recommend you consider alternative options.

The main ingredients that Laser + Holistic Dental questions for safety concerns are:

• Sodium Hydroxide
• PVP or Polyvinylpyrrolidone
• PEG-8 or Polyethylene Glycol Laurate
• Sodium Saccharide
• Acrylates copolymer

Sodium Hydroxide

Sodium hydroxide is extremely corrosive, making it useful for industrial strength cleaning products - but perhaps not ideal for whitening gels. Sodium hydroxide can cause severe damage to mucous membranes.⁶ For this reason it poses a risk to the gums and saliva glands in the oral environment and can also burn the throat if accidently swallowed.⁶

At Laser + Holistic Dental we strongly recommend that you avoid using any whitening products that contain this chemical compound.

PVP or Polyvinylpyrrolidone

PVP is a synthetic compound that is commonly used in the cosmetic industry. Generally, it is considered to be safe with an acute oral toxicity dose of 50 > 100g/kg.⁷ There has been some research that suggests PVP is harmful to sperm, and because of this it may pose a risk as a reproductive toxin.⁸

PEG-8 or Polyethylene Glycol Laurate

PEG-8 can contain chemical impurities such as Ethylene Oxide, 1,4-dioxane, PAHs, lead, iron and arsenic.⁹ These chemicals are known to increase the risks of uterine, breast and brain cancers, and leukemia.^{10, 11}

While carcinogenic contaminants are the primary concern, PEG compounds themselves also show some evidence of genotoxicity.¹²

Sodium Saccharide

This is controversial chemical - that was listed as a possible carcinogen for many years. Sodium saccharide has been proven as a carcinogen in rats, however in 2001 the American FDA reversed this compound back to safe status as it was that the factors that caused cancer in rats did not apply to humans.¹³

Saccharins are only used as an artificial sweetener and do not provide any practical benefit for teeth whitening, you may prefer to err on the side of caution and avoid gels that contain this ingredient.

Acrylates copolymer

This ingredient is used mainly for adhesive purposes in hair sprays and nail products, it also commonly found in teeth whitening strips. The polymer is made up of both acrylic and methacrylic acids.

Acrylic acid is known to cause burns and irritate the mucous membranes. It may also pose a cancer risk in animals.¹⁴ There is almost no research on the carcinogenic effects of acrylic acid in humans.

Methacrylic acid is readily absorbed through mucous membranes of the lungs and gastrointestinal tract and the skin; and is rapidly distributed to all major tissues.¹⁵ It is considered highly hazardous if ingested - we think you should avoid this ingredient!

Internet Based Whitening Products

Bleaching Gels

Hydrogen peroxide or carbamide peroxide - these are the same active ingredients as the professional gels, however they are in lower concentrations than what is legally allowed for professional use with a dentist.

In Australia, the legal limits are 6% hydrogen peroxide or 18% carbamide peroxide. Anything beyond these concentrations must be administered by a dental professional to avoid the risks of chemical burns to the mouth and throat. Due to illegal business activity from some of these online companies and consequent injury claims - there have been substantial product recalls by the ACCC.¹⁶

Like all things, bleaching gels are not always of the same quality with some containing chemicals like sodium chlorite, sodium fluoride, stannous fluoride, potassium nitrate, HEMA or benzalkonium chloride. Nearly all bleaching gels purchased online will also have a very high acidity content. Hydrogen peroxide is very reactive and will degrade if not kept cool and away from light, once the gel is degraded it will be less effective at whitening and also more acidic which means it can damage your enamel. Be wary of any gels that are not kept cool and protected from light during storage and transit.

We strongly recommend that you never purchase any bleaching gels online with concentrations above the legal limit - it is simply not worth the risk.

Whitening Lights

LED Whitening lights have become a social media smash hit, turning 20-something year old entrepreneurs into millionaires thanks to celebrity endorsements and viral social media competitions.

Generally speaking, these companies are certainly good a marketing but perhaps less good at delivering long lasting, quality teeth whitening results.

These devices are concerning for a few main reasons:

1. The LED light is a gimmick.

Professional laser whitening uses a light to accelerate photochemical and photothermal reactions in the professional whitening gels. This means that the chemical reactions are quicker when the right type of light and heat is applied to the right type of gel. The LED light supplied with these devices is nowhere near powerful enough to produce an accelerated whitening effect, and even if it was - it would have to be used with a peroxide based gel (most of these kits do not have peroxide gels - more on this in the next point).

2. The gels do not use professional quality ingredients

Dental professionals use either hydrogen peroxide or carbamide peroxide - these are scientifically proven whitening gels. Because of the concentrations used by professionals, they are dangerous to members of the public who could accidentally burn their gums or throat. Australian law restricts the sale of high concentration hydrogen peroxide gels because of companies selling dangerous gels direct to consumers. When people reported permanently damaged teeth and burned gums the regulators cracked down. Now - online whitening companies are using alternative ingredients to sidestep the legal regulations.

Sodium chlorite is the most common ‘active ingredient’. At Laser + Holistic Dental we are concerned about sodium chlorite, as it is well documented as highly toxic when swallowed and has the potential to cause burns.¹⁷ Most companies do not specify the concentration of sodium chlorite in their gels. It is highly likely that people using these products will be accidentally swallowing or absorbing sodium chlorite through the mucosal tissues inside their mouths. Ongoing use could potentially have harmful effects - at this point there is no scientific research to prove this product is safe.

To link this back to the first point - sodium chlorite will not respond to the LED light to create an accelerated whitening reaction. The chemistry simply does not add up. Even in the gel does whitening your teeth without the light - we have expressed our concerns about the ingredients.

3. Misleading and deceptive advertising

The ACCC is having to crack down again on people and businesses promoting these whitening products as equivalent or better than professional whitening.

Could these products whiten your teeth? The answer is probably, however there are a lot of unanswered questions surrounding the effectiveness of the lights and the quality of the gels.

Any company claiming that these products offer the best quality teeth whitening available is kidding themselves, and the ACCC will be investigating them for potentially breaching consumer law.

So, yes these devices may work and they may be cheaper than a professional laser whitening treatment but please make sure you do your homework first! Research what sort of light they use, will this actually work with the chemistry of the gels - and most importantly are the gels actually safe?

Whitening Pens

Most whitening pens are simply carbamide peroxide gel on an instrument to apply the gel to the tooth surface. These pens are an alternative to using a tray with the gel for those who haven’t invested in proper whitening trays.

Generally speaking, a tray will allow for a more even spread of the whitening gel on the tooth surface and will also be quicker to apply. Whitening pens require manually application of the gel to each tooth so the process can be quite slow, and it also creates the potential for uneven whitening if the gel is poorly applied.

Like all other types of gels, the quality of the gel is critical. Many manufacturers only specify the active ingredients and do not list the complete ingredients in the whitening pen gels. It is possible that these gels contain a range of chemicals that we recommend you avoid. Always read the label to make an informed decision.

Whitening Mouthwashes

There are a lot of different whitening mouthwashes on the market - ranging from fluoride heavy, major brands to those focuses on natural ingredients like coconut oil and baking soda.

At Laser + Holistic Dental we avoid the use of fluoride, so naturally we do not recommend any mouthwashes that use it. Some mouthwashes also contain alcohol which is best avoided.

Generally speaking, mouthwashes in Australia rarely contain active ingredients for whitening such as hydrogen peroxide. For this reason we think it is highly unlikely that any mouthwash promoted for whitening purposes will be effective, apart from a rinsing effect similar to using water to remove any food residue.

Professional Teeth Whitening

We are going to explore the details of professional teeth whitening in more detail in the next article of the Whitening Wisdom series. The team at Laser + Holistic Dental will be looking at the following topics and answering questions like:

Bleaching Gels

What is the difference between hydrogen peroxide and carbamide peroxide gels?

Why do some gels damage the enamel and some do not?

Why do good quality whitening gels need to stay cold?

At home whitening kits

Do I need custom trays to fit my teeth?

How often should I be using my home whitening?

How do you avoid getting sensitive teeth when whitening at home?

In-chair LED whitening

How does a LED help whiten my teeth?

Can the light damage my lips and gums?

Is there UV in the LED light?

Laser teeth whitening

What is the difference between laser whitening and LED whitening?

Are there different types of laser whitening treatments?

Will laser whitening make my teeth more sensitive?

Whitening Wisdom: Part Three

The next article of the Whitening Wisdom series is available now - Fact vs Fiction on Professional Teeth Whitening

The Whitening Wisdom Series

If you would like to read part one and three, please use the links below.

Can a healthy diet damage the appearance of your teeth? Whitening Wisdom: Part One

Fact vs Fiction on Professional Teeth Whitening – Whitening Wisdom: Part Three

References

1. Gastrointestinal decontamination of the poisoned patient
2. EFFECT OF ACTIVATED CHARCOAL ON WATER-SOLUBLE VITAMIN CONTENT OF APPLE JUICE
3. Charcoal and charcoal-based dentifrices: A literature review.
4. Analyses of the Erosive Effect of Dietary Substances and Medications on Deciduous Teeth
5. Vinegar: Medicinal Uses and Antiglycemic Effect
6. Compound Summary for Sodium hydroxide
7. Polyvinylpyrrolidone
8. Detrimental effects of polyvinylpyrrolidone on the ultrastructure of spermatozoa.
9. PEG-8
10. Ethylene oxide
11. Dioxane
12. Low molecular weight polyethylene glycol induces chromosome aberrations in Chinese hamster cells cultured in vitro
13. Saccharin
14. Acrylic Acid
15. Methacrylic Acid
16. ACCC takes action on unsafe teeth-whiteners
17. Compound Summary for Sodium Chlorite