Nothing speaks of health, vitality and a certain youthfulness as the flash of a brilliant white smile. After all, one of the very first things you are apt to notice when you meet someone new is their smile. In contrast, a person who has teeth that are dingy yellow and stained from years of coffee and tea drinking, does not project the same health and vitality and may very well be too embarrassed to even smile broadly.
Not smiling can even negatively affect your health, as studies show that not only does smiling lower stress and gives your mood a boost, but actually influences other people’s perceptions of how friendly and likeable you are. Plus, when you smile, others around you are apt to feel more cheerful and upbeat.
So it’s not too surprising that we are willing to spend money, and a lot of it, to get whiter teeth and a brighter smile. The American Academy of Cosmetic Dentistry estimates that spending in the U.S. on over the counter whitening products was more than 1.4 billion dollars over the last year alone, with some 37 million Americans using tooth whiteners in 2020.
But what are the risks, if any, to using these over the counter teeth whitening products? Can they do more harm than good? Let’s look a bit closer at this class of very popular over the counter products.
Before we do that, let’s do a quick review of dental anatomy, so you can better understand how these products work and why they may put your teeth at risk.
Your teeth are composed of three layers: the first layer is the outer protective shell known as the enamel, the second layer is called the dentin and comprises the bulk of the tooth’s tissue. The dentin is a protein, collagen rich layer that supports the enamel and keeps the enamel shell from cracking when exposed to the forces of chewing. The third and innermost layer is the dental pulp or the living layer of your tooth that is filled with blood vessels and nerve endings. The dentin also works to protect the pulp from bacterial invasion. Finally, the root of each tooth is coated in a collagen substance and held into the bone with collagen fibrils.
The most popular brightening products are tooth whitening strips, which all contain a chemical whitening agent, most commonly hydrogen peroxide, which are applied to the surface of the teeth and left there for about a half hour at a time twice a day. Most product directions have you continue daily treatment for 14 days.
But a relatively recent study, published April 2019 in the journal Experimental Biology, found that hydrogen peroxide can actually damage the layer of dentin found directly beneath the protective enamel layer of the tooth. Prior to this research, studies of tooth whitening strips focused on the tooth’s enamel, which contains very little protein. The results of the research showed that hydrogen peroxide actually broke down the collagen proteins in the middle dentin layer into smaller fragments. The researchers point out that they do not yet know if this damage to the dentin’s protein is permanent or might be reversible.
There are some brands of teeth whitening strips that contain other chemicals, specifically chlorine dioxide, which is an acid that is also used to disinfect swimming pools. Chlorine dioxide eats away at the enamel and should be completely avoided.
Also, if not used according to directions, specifically when teeth whitening strips are left in place too long, whitening strips can produce sensitivity of the teeth and gums, which generally resolves itself over time.
Tooth discoloration can either be due to external stains embedded on the surface of the enamel or from internal staining in the deeper layers. External staining is typically due to food and drink sources like coffee, wine or berries. Although these substances can stain the enamel they are more easily removed by whitening and professional cleaning. Internal staining results from injury to the teeth, medications or high doses of fluoride and these stains are very difficult to remove with the use of superficial whitening methods.
If you are concerned about the appearance of your teeth, it’s best to seek the opinion of a professionally trained and licensed cosmetic dentist, who can prescribe the safest and most appropriate course of treatment. Of course, good nutrition is vitally important as well, particularly an adequate intake of collagen, to strengthen the teeth, gums and supporting tissues.