Why are my teeth yellow? Why are my teeth brown? Why are my teeth extra white in these spots?  Questions about tooth color are some of the most common questions I’m asked as a dentist. Whether you’re trying to find the secret to a Hollywood white smile or simply have a yearning to learn about tooth shades, read on!


Diet is the most common factor people think of when it comes to the color of their teeth. Teas, coffee, colas, and wine all contribute to the external stain that can accumulate on the outside of your teeth. Have a coffee habit that’s impossible to kick? Don’t worry! The stain that accumulates on the outside of your teeth from diet can be polished away by your dentist or hygienist at your routine dental cleaning.


As we age our teeth naturally become more yellow due to the wearing down and thinning of the outer enamel layer of teeth. When the enamel is thinner more of the underlying dentin’s yellow color shines through.


And the reasons to put down that cigarette just keep on coming!  Beyond harming nearly every organ in the body and causing many diseases, smoking also stains your teeth.  If you’ve considered quitting smoking in the past but don’t know where to start, try calling 1-800-QUITNOW.  The number is easy to remember, it’s free, and they’ll help you put together a personalized quit plan.


Maybe you had an unfortunate accident involving your face meeting your bicycle’s handlebars as an adolescent. Maybe you had an unfortunate accident of your face meeting Big-John’s fist at the local bar. (Remember, I’m not here to judge people.) Regardless, trauma featuring blunt force to teeth can absolutely result in teeth discoloring over time. Often following trauma to a tooth, the nerve running along the length of the tooth’s core will die. Over time the dead nerve will atrophy, or breakdown, and leak red blood cells. It’s the color from these leaked blood cells which causes a ‘dead tooth’ to darken over time. When the dead nerve is removed from a tooth through a root canal, the tooth can also be internally whitened, or bleached, reversing some of this darkening.


Discoloring from amalgam, aka ‘silver’ fillings

Amalgam fillings, commonly referred to as ‘silver’ fillings, can also stain a tooth over time.  It’s because of this staining and general show through that amalgam fillings are rarely used on front teeth – even on the tongue-side. Given this discoloration that can result from amalgam fillings, you may wonder why they would be placed at all instead of a white tooth colored filling, called a composite. In some areas of the mouth and in some circumstances (for example on a back tooth with a very large cavity in which the filling material will now make up a large part of the tooth) an amalgam filling will hold up and last longer than a composite filling will. Similarly, an amalgam filling can be more forgiving if you have less than ideal oral hygiene habits. This is a very minimal explanation of just a few reasons why our practice still encourages the use of amalgam restorations in situations when they make the most sense for our patient. I could probably write a whole blog on this topic alone!

Excessive Fluoride

When forming teeth are exposed to excessively high levels of fluoride they can develop white spots known as fluorosis. These areas of the teeth aren’t as strong as the surrounding normal enamel, and area at a higher risk of developing a cavity. Fluoride added to city water is carefully regulated so the ideal amount to prevent cavities is present and will not cause fluorosis. Fluorosis can result from living off well water, which can naturally contain high levels of fluoride in some areas of the country.


Taking tetracycline while your teeth are developing is another way teeth can be formed discolored. Tetracycline stain results in darker, brown/grayish colored teeth. Interestingly, tetracycline stain will result in discoloration in a band or strip across teeth that correlates to what part of each tooth was developing while the tetracycline was taken. It reminds me of how the wood in the growth layers or age rings of a tree will record evidence of floods, droughts, and other environmental occurrences that occur during its lifetime. Tetracycline stain can be somewhat reversed by bleaching, however not very well. Completely treating the esthetic concerns of tetracycline stain generally means masking the stain in some form. Therefore, depending on the severity of the stain and other dental factors, treatment can range from overlaying composite veneers on the affected teeth, to lab fabricated porcelain veneers, to full coverage crowns.


In conclusion

There are many reasons for variation in tooth color.  Some of these are beyond our control while others are factors we can address if we so choose.  Thanks for reading this most recent entry in our exciting dental blog. I hope you learned something new!!

– Dr. Kjersten Heron
posted 5/4/16

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