Would you like more information on tooth whitening protocols, safety, and patients’ most commonly asked questions? Feel free to check out our treatment information on tooth whitening below!
There are a number of ways to whiten your teeth. All work by removing the stain that builds up within your tooth enamel over time. As stain accumulates, your teeth start to appear more yellow, brown or grey. The particles that cause staining soak deep into your enamel where your toothbrush can’t reach them. Here are some options for tooth whitening (though not all are healthy for your teeth):
Charcoal toothpastes. These toothpastes have become very popular over the past 5 years. They work because charcoal particles are abrasive and therefore are more effective at removing surface stains from teeth. This is the same principle behind stain removal with polishing at your routine cleanings. However, you may get your teeth polished 1-2 times per year – you don’t want to be using abrasives on your tooth enamel every morning and night. I generally recommend to either avoid charcoal toothpastes or to use them very sparingly.
Hydroxyapatite (hA) toothpastes. This kind of toothpaste is the “new kid on the block” so to speak. Although hA toothpastes have been popular in Japan for decades, they’ve only recently become available in North America. Hydroxyapatite is the main building block for tooth enamel. This means that when you brush with hA toothpaste, you’re restoring and fortifying your enamel with a natural ingredient. Because hA gives enamel it’s whitish colour, brushing with it will whiten your teeth.
Dental Cleanings. When plaque calcifies, it becomes tartar. Tartar buildup makes our teeth more yellow. Because tartar is porous, it soaks up stain. When you have a dental cleaning, your Hygienist removes all tartar from around your teeth including any stain within it. The additional polish removes superficial stain from your enamel!
Peroxide Tooth Whiteners. Whitening toothpastes and commercial and medical-grade whiteners all use peroxide chemistry to whiten your teeth. How does that work? Well, when peroxides (such as commonly used carbamide peroxide) contact your saliva, molecular oxygen is produced. This molecular oxygen can move into deeper layers of your enamel to displace and remove stain particles. When patients whiten over the course of 1-2 weeks at home, they gradually eliminate stain from the deep layers of their tooth enamel. Are peroxide whiteners safe? Read on to find out more.
People want the best. If you’re trying to brighten your smile, you want to use something that’s going to deliver big improvements. So, which whitening product does that?
Well, if we’re restricting our discussion to whitening systems, whether at-home or in-office, then we’re talking about peroxides. The chemistry is the same for all of these methods but they all vary with respect to concentration and whitening time.
In theory, all of these products should have the same ceiling in terms of maximum whitening. However, some will reach that maximum tooth whitening point faster than others. What makes a product work more quickly is concentration and contact time. If you sit in a dental chair for only 45 minutes with whitening gel and trays in place, that solution needs to have a high concentration of peroxide (i.e. 18 – 30%) to be effective. In contrast, at-home whitening systems (still using peroxide gels and custom trays) tend to have a lower concentration and require more time to achieve maximum tooth whitening effect. This may involve whitening for 3-4 hours each night over 1-2 weeks.
Even though in-office whitening is heavily marketed, it is not superior to at home whitening systems. It’s also important to note that in-office, “spa whitening”, using an “activator” light is no better at whitening your teeth than are conventional whitening systems. In fact, the light produces additional (temporary) whitening by dehydrating your enamel. This causes your enamel to appear more chalky and opaque, so your teeth appear to be brighter. However, after you leave the dental office, your enamel re-hydrates fully after 30 minutes. At that point, only the whitening effect of the peroxide gel remains.
The take home message here is that high all in-office and at home whitening systems utilize pretty much the same peroxide chemistry to whiten your teeth. They all have the same ceiling or maximum effect. Concentration and contact time will determine how long it takes for you to achieve that maximum tooth whitening.
The ingredients in whitening gels and toothpastes are certainly safe for your teeth. They do not alter the structure of your tooth enamel. They whiten your teeth by loosening particles that cause staining deep within your enamel.
But, are peroxide whiteners safe for your gums?
Hydrogen peroxide in whitening gels can have harmful effects in high concentrations over long periods of time. They can be cytotoxic, which means they can have harmful effects on the soft tissue cells in your mouth.
Research has not shown long-term harmful effects on gum tissues in humans after teeth whitening. In fact, a study of patients using excessive whitening protocols for over 6 months did not show any harmful effects even 7 years later. A useful article on whitening safety by tooth whitening research expert, Dr. Harold Heymann is available here.
Ultimately, the best advice is to follow your Dentists instructions and to limit teeth whitening to short durations. Patients should generally avoid whitening for longer than 7-10 days at a time. They can do a 1-2 day whitening boost every 6-8 months.
You definitely don’t want to overdo it with whitening. The main reason is that tooth whitening can cause a big, short-term increase in tooth sensitivity. This sensitivity gradually subsides after whitening. For an at-home whitening protocol, you wouldn’t want to whiten for longer than 10-14 days. Again, this is dependent on peroxide concentration. If you’re up around 30% peroxide then 1-3 nights of whitening will do the trick. If you’re in the 12-17% range, 10-14 evenings of whitening will work nicely.
Once you’ve reached the maximum effect of whitening gels, it will fade very slowly with consumption of things like tea, coffee, chocolate, berries, etc.,. Generally, if you want to give your smile a boost, you should re-whiten no more frequently than every 6-8 months.
When molecular oxygen from the peroxide whitener starts to loosen and remove stain particles from inside your enamel, your enamel becomes more porous once again. Clogged or stained enamel is actually a better insulator against sensitivity to extreme temperatures and acidic foods. When you unclog your enamel, you’ll notice that (for a short time) certain foods and beverages will cause you to experience sensitivity.
Theoretically, the potential cytotoxicity of peroxides against gum tissue could cause irritation and recession. However, research has never demonstrated recession in tooth whitening subjects. The best practice is to use gels sparingly and make sure they don’t sit in contact with your gums for long periods. People are often told that whitening gels must make contact up to the gums to ensure whitening of the whole tooth. In fact, this is not necessary as the molecular oxygen from peroxides can move freely throughout your enamel. This means that you can whiten enamel even if the peroxide gel is not in direct contact with it.
As an interesting aside, whitening sensitivity is much higher in patients that already have gum recession. This may be because of contact between the whitening gel and root dentin (which does not benefit from insulation by enamel).
In-office whitening protocols always cost money. These costs range from $200-$500. Again, these “spa” whitening approaches are no more effective than standard at-home whitening systems. They work using the exact same chemistry as other whitening systems and produce an identical effect at a significantly higher cost.
Unfortunately, there is not a single whitening product that can whiten the porcelain in dental crowns, dental fillings or veneers. In some cases, minor whitening will not cause a noticeable disparity between the colour of your teeth and artificial prosthetics like crowns. However, if you experience a significant shade change with whitening, your dental prosthetics may stand out more.
This brings up a thought about strategy prior to treatment for dental crowns, fillings or veneers. Generally, we recommend that you whiten your teeth prior to these procedures if you’re somebody who regularly whitens their teeth. This way, you’ll achieve maximum brightness so your Dentist will shade match any dental restoration to the brightest version of your teeth.
No. Peroxide gels do not alter the porcelain in your veneers or the composite resin in your fillings in any way.
I touched on this above but I’d like to go over it again. This is a common question that my patients ask me. The dental marketing machine suggests that the light that Dentists use with some whitening systems is an “activator” to enhance the effect of peroxide whitening gels. In fact, the light heats and dehydrates your tooth enamel. When you dehydrate enamel, it becomes more opaque and chalky and less translucent and greyish. So the light gives your whitening procedure a slight “boost” however, this additional whiteness fades 15-20 minutes later as your enamel re-hydrates on your drive back home.
A helpful research paper on the lack of a true improvement in whitening with activator lights can be found here.