What You Need to Know About Teeth Whitening
Teeth whitening is the most popular type of cosmetic dentistry undergone by millions of Americans each year. Even with great oral hygiene and consistent dental visits, teeth tend to discolor over time. Many people use teeth whitening to maintain a bright white smile throughout their lifetimes.
Why Do Teeth Change Colors?
Several types of changes occur in our lifetime that can cause teeth to appear darker or more yellow in color. Some of these changes are preventable, and some are not. However, the good news is they generally all respond well to whitening products!
A quick dental anatomy review will help you understand these changes and the mechanism of true teeth whitening. Teeth consist of a hollow chamber containing nerves and blood vessels (called the pulp), surrounded by a yellow hard substance called dentin. Dentin makes up the majority of every tooth. Enamel covers the dentin, forming a hard shell over the portion of the teeth not encased in jawbone (all but the roots). Enamel is white in color and slightly translucent.
Changes to the exterior surface of enamel can lead to a darker appearance of the teeth. By understanding these, you may be able to make different choices to prevent dark stains from continuing over your lifetime.
1. Surface Staining – Dark pigments from the substances we eat and drink can accumulate on the enamel surface, causing external (also called extrinsic) staining. Anything dark can cause extrinsic stains, but the particular culprits are significant intake of coffee, tea and tobacco products. The amount of surface stain accumulation can vary based on the enamel’s surface texture. Glassy smooth enamel is more resistant to stain collection than rough, pitted enamel.
2. Enamel Thinning – Another particular danger to the appearance of tooth color is thinning of the enamel. As we mentioned in our dental anatomy review above, enamel is white and slightly translucent. This means that when enamel wears away or becomes thinner, you begin to see more of the underlying yellow dentin. The most common culprit of enamel thinning is acid erosion. This can occur as the result of a high intake of acidic beverages (like sodas, fruit juices, sports drinks, lemon and lime-flavored waters, etc…). It may also be a side effect of severe acid reflux or GERD. The bad news here is that enamel cannot regenerate or regrow. When it’s gone, it can only be replaced with dental restorations.
Teeth can also become darker or more yellow due to changes within the teeth. You cannot prevent these changes, but you can understand them and address them with your dentist to achieve the white smile you desire.
1. Natural Aging Changes – Unfortunately, teeth naturally become more yellow over time. This is a natural aging process in which the core substance of teeth, dentin, grows thicker. The natural thickening of dentin occurs in response to the normal wear and tear associated with chewing for many decades. As the dentin thickens, its yellow color becomes darker and more opaque. Because of enamel’s translucence, the darkness underneath shows through, giving an overall yellow appearance.
2. Traumatic Effects on a Tooth’s Internal Structures – Injuries to a tooth or teeth can also affect changes to the inside of a tooth. After undergoing severe shock, stress, or pain, the nerve and blood vessels inside the tooth may react to the trauma in one of two ways. One option is to shrink and close off, making the overall tooth appear dark grey or dark yellow. The other response is to grow and dissolve the tooth from the inside out. This makes a tooth appear purple or even pink in color due to the show-through of blood vessels. (This is a process known as internal resorption.)
Most Common Culprits of Discoloration
Now that you understand the how of tooth discoloration, this list of common culprits will make sense. It will also help you make decisions about how to reduce your risk for yellowing.
1. Food and drink – There is no question that what we put into our mouths affects the color of the teeth. In addition to avoiding dark-colored substances, you should also consider the pH of your diet. By avoiding acidic foods and drinks, you will preserve the thickness of your enamel, which helps you maintain a whiter appearance of the teeth.
2. Tobacco – The dark particles in all types of tobacco collect as external stains on the teeth. In particular, smoking has a drying effect on the inside of the mouth. This dryness worsens the staining ability of tobacco because it makes adherence to the enamel easier. (Imagine the stickiness of a dry mouth attracting stains on the teeth.)
3. Age – Aging is one culprit we cannot prevent, but we can attempt to fight the natural yellowing inside the tooth by working to protect our enamel on the outside. Avoiding acidic diets, treating any acid reflux issues, and consistently using fluoride oral care products helps you strengthen your enamel.
4. Trauma – Not all trauma is avoidable, but you can prevent some of it by wearing an athletic mouthguard during any participation in contact sports. Mouthguards soften the blow of injuries to the teeth and reduce the effect of force by absorbing it.
5. Medications – Medications can affect the color of teeth during their formation. This means that pregnant mothers and young children should not take certain medications like Tetracycline and other antibiotics shown to affect tooth formation. The dark colors incorporated during the tooth’s development create intrinsic staining. Prescription mouthrinses containing the antibiotic Chlorhexidine can also lead to external stains on the teeth.
Who Should NOT Whiten Their Teeth?
While teeth whitening is generally safe, there are a few precautions. It is simpler to describe who should not whiten his or her teeth. If none of these restrictions apply to you, then you should be able to safely whiten your teeth.
Pregnant and Nursing Mothers
Scientific research has not been able to prove that the ingredients in teeth whitening products are safe for fetuses and infants. Because we know that everyone tends to swallow a small amount of the whitening ingredient during the process, we cannot guarantee that it will not have any effect on your baby. For that reason, doctors and dentists alike recommend that you wait until you have finished nursing to perform any type of teeth whitening.
Those with Crowns or Veneers
Only natural teeth will change color in response to whitening products. If you have tooth-colored fillings of composite resin, dental crowns or veneers, they will NOT whiten. In fact, attempting to use teeth whitening products when you have existing dental work on front teeth, may actually make them look worse. This is because the natural teeth will whiten, and the dental work will not. This will make fillings or crowns appear darker relative to your natural teeth.
Those with Untreated Dental Problems
People who have large cavities or severe gum disease should not use teeth whitening products. Doing so could aggravate the existing problems and lead to worsening pain. You should always have dental problems fixed before trying to whiten your teeth.
How Does Teeth Whitening Work?
If you do any research on teeth whitening, you will find that there are a wide variety of products and claims in the way that they work. There are actually only two ways to whiten the teeth. If a product does not fall into one of these categories, you should not expect to achieve noticeable results.
True Teeth Bleaching
Despite claims made by marketers of various over-the-counter products, only one chemical can cause an actual change in the color of the teeth. Hydrogen peroxide, and its close relative carbamide peroxide (which quickly breaks down into hydrogen peroxide), penetrates enamel and oxidizes dark pigmented molecules within the hard tooth structure itself. By breaking down darkly colored molecules, it literally bleaches the underlying tooth color to a whiter shade.
The teeth whitening industry undergoes constant research and evolution. At this time, however, only peroxide chemicals show true whitening ability.
Superficial Stain Removal
Without a peroxide chemical, the only way a product could deliver on any teeth whitening claims is through the removal of superficial stains. In general, most people continue to accumulate dark spots on the external surface of their teeth throughout their lifetimes. We can polish away these shallow stains in a few different ways. With consistent polishing, you can prevent significant staining from continuing to build up over time.
Polishing away surface stains involves the use of very mild abrasive particles. The goal is to remove only stains and not enamel, too. Anyone who uses sandpaper knows that using a coarse abrasive material will actually make the surface texture rougher. Using a very fine abrasive material, however, will smooth and polish without removing the underlying enamel.
What are the Different Types of Teeth Whitening?
The number of teeth whitening options can make your head spin. Understanding the mechanism of teeth whitening helps you to understand the various methods, described here.
Whitening toothpastes contain mild abrasive particles that provide a very fine sandpaper effect, gently scrubbing away the surface stains that collect each day. They do not change the actual color of the underlying tooth, but by removing dark particles on the exterior, whitening toothpastes can give the appearance of whiter teeth. These toothpastes are also wonderful for maintaining a white smile after you perform true teeth whitening.
Over-the-Counter Whitening Strips
Many over-the-counter whitening products contain the right active ingredient and produce noticeable changes. The type of product that consistently performs the best is whitening strips. The strips contain an embedded whitening gel that easily sticks to the teeth for the prescribed amount of time. Crest Whitestrips are the brand with the highest name recognition because they have been around the longest, however several other brands make whitening strips with great results.
Professional Take-Home Whitening Trays
In order to achieve the best success in teeth whitening, you should always work with your dentist. Dentists consider professional take-home whitening in custom-fitted trays to be the “gold standard”. By making the trays from a replica of your teeth, the custom fit holds whitening gel in the perfect position for optimal results. The custom trays will last for many years, allowing you to simply purchase the whitening gel as needed for maintenance.
Patients love take-home whitening because it puts them in control of their results. It is also the best option for patients with special considerations, like tooth sensitivity.
In-Office Whitening Systems
For those who need the fastest whitening results, a professional in-office treatment is the right choice. In-office teeth whitening systems use a high strength whitening gel to produce visible color change in about an hour. This is a wonderful option for anyone with a special event less than a week away, or may not have time for home treatments to take effect.
These systems vary in the strength of their active ingredients and the additional use of lights or lasers. Because the active ingredient is so strong in in-office systems, a dental professional must apply a protective barrier over the gum tissues and monitor the entire process. Lights and lasers may produce an accelerated whitening effect by heating and/or activating the system’s particular gel.
Whitening Products to Avoid
Because peroxide chemicals are the only true bleaching agents for now, you should avoid products claiming to be peroxide-free. They will not hurt you; they just will not give effective results.
We cannot stress strongly enough that you must also avoid DIY or homemade recipes for teeth whitening. These typically contain ingredients that do not have enough research supporting their safety, like activated charcoal, or those that will damage your teeth, like lemon juice.
There are many over-the-counter products that claim to whiten and do contain a peroxide chemical. However, they also do not keep the active ingredient on the teeth for an extended period to allow for change. This includes whitening mouthwash, whitening floss, and whitening chewing gum. These should be safe, but they will not produce noticeable results.
Is Teeth Whitening Safe?
As long as you use an ADA-approved whitening product according to its specific instructions, you can assume teeth whitening is safe. It is always best to seek your dentist’s advice on any type of whitening option to confirm that you will not experience major side effects. The most common side effects of teeth whitening include sensitive teeth and gum irritation, but these are temporary and should subside as soon as you stop the whitening process.
Teeth Whitening: Your Next Steps
Whitening your teeth is a simple and effective way of improving your smile. Many people feel increased confidence after attaining a brighter, whiter smile! We invite you to schedule your consultation today to determine the best and safest teeth whitening method specific to you.