The quest for a whiter and brighter smile dates back to ancient civilizations. The Egyptians equated white teeth with wealth. So, they mixed wine vinegar with crushed pumice stone and brushed it on their teeth with frayed sticks. The Romans also valued a bright smile but used a less desirable method. Their technique involved using urine! Luckily, it was quickly discovered that it was the ammonia found in urine that acted as a bleaching agent. Thankfully, that practice was abandoned. It wasn’t until the 1980’s that a safe and effective way to bleach our teeth was perfected. Since then, tooth whitening has become the number one cosmetic dentistry procedure performed today.
There are several reasons that our teeth can appear dull or yellow. Genetics plays a large role in determining the color of your teeth. If your parents had a yellow tooth color, chances are your teeth will not be bright white. Just as each person has a specific skin tone, teeth have different shades that make up the color of the enamel. Brown, yellow and gray are some of the natural shades of otherwise white teeth, and the depth of color varies across a spectrum from light to dark. Teeth also look yellow when the enamel is thin and the dentin underneath shows through. Dentin is a deep yellow to brownish material inside your teeth under the enamel, and it’s often responsible for the yellow color you see when you look in the mirror. Thick enamel covers up the dentin but teeth ultimately turn yellow as you get older, when enamel thins and lifestyle choices such as drinking coffee or smoking can further discolor your teeth.
If you look at your teeth under a microscope, you can see that the enamel is made up of tightly packed crystal structures called rods. Even though this layer appears smooth to the naked eye, it is actually porous. It is possible for stain to get deep into the enamel by seeping into the rods. In order to remove these stains, a chemical must be used to get down to where the stains are and break them up using a chemical reaction. There are two types of staining that appear on teeth. One type is called intrinsic staining because it is deep inside the tooth structure affecting the enamel rods. In contrast, extrinsic stains are those that stain the outer portion of the teeth and are caused by food and drinks, such as coffee, tea or red wine. In general, it is easier to remove extrinsic stains.
So, what is the magic behind bleaching? Whiteners use bleaching chemicals to get down into the tooth enamel and set off an oxidizing chemical reaction that breaks apart the staining compounds. The most common chemical agents are carbamide peroxide or hydrogen peroxide. When used in the mouth, carbamide peroxide breaks down into hydrogen peroxide and urea, with hydrogen peroxide being the active whitening ingredient. The hydrogen peroxide goes through the tooth surface and oxidizes the organic composites (which cause the staining) that exist in tooth enamel. This oxidation results in smaller remaining molecules that are much lighter in color compared to the original organic composites. The end result is whiter teeth!
There are different methods of starting this process which include over the counter products and professional bleaching. Dentist supervised bleaching is preferable for a number of reasons. Before beginning the bleaching process, it is best to have a check-up to see if you are a good candidate for bleaching. Existing restorations, such as crowns or bonding, will not bleach and will remain the same color. They may need to be replaced if the new, whiter tooth color no longer matches the older dental work. Teeth that have yellow undertones bleach easily, but grey tones are more resistant. Also, it is important to have teeth and gums that are healthy and free from cavities and gum disease before beginning the process. In our office, we offer a safe and effective bleaching system called White for Life. After determining that you are a good candidate, we will take an impression and make custom fitted bleaching trays. You will be given a 22% carbamide peroxide whitening gel to use for approximately 2 weeks. After you have reached your desired shade, you will be given a touch-up kit at every 6 month recare appointment to keep your beautiful ,white smile.
Over-the-counter bleaching systems are available, but typically have a lower concentration of bleaching agents. It may take longer to achieve the desired results.
Whitening toothpastes generally work to help remove extrinsic surface stains. Because they do not contain the bleaching chemicals, they do not change the color of the teeth. They may remove some surface staining but visible results are minimal.
Most studies confirm that tooth whitening is safe and effective. Products with higher concentrations of hydrogen peroxide will also contain fluoride to help offset any potential side-effects. Tooth sensitivity can occur but can be reversed by either using fluoride or bleaching less often. Gum irritation may occur if the chemicals come in contact with your gum. The irritation is usually mild and reversible. To avoid this, be sure to carefully place the product in the tray and do not overfill it.
With a multitude of products available, it is difficult to know what is best for you. When you come in for your check-up, we are more than happy to discuss all of the options available to you. We love nothing more than helping you achieve the bright, beautiful smile you deserve!
This article was written by Courtney