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How do teeth turn yellow?

Park Ridge cosmetic dentists

Answers to the questions posted on Reddit “How do teeth turn yellow? Is it possible to simply brush your teeth for an hour to turn them (very) white ?


I am very happy to see so many replies. This suggests that there is a great interest in how to better take care of teeth. I am a practicing Prosthodontist: specialist in implants, aesthetic and reconstructive dentistry. I hope the following helps clarify some of the confusion as to what makes our teeth yellow, how to brush, what to brush with, and, lastly, are veneers worth it, or to just go with implants.

Q: What makes the teeth yellow?

A: There may be many reasons why teeth get yellow. The outer layer of the tooth is called enamel, the hardest tissue in our body, approximately 1-1.5mm thick. The thickness of the enamel layer changes throughout our lives and gets thinner as we age. The thinner the enamel, the more yellow teeth appear as the second layer of the tooth, called dentin, dominates the final shade. In my practice, we will always evaluate the thickness of the enamel layer to see how successful whitening can be. If enamel gets to be too thin, no whitening systems will work. Diet also makes our teeth more yellow. Anything from coffee, tea, smoking, red wine may contribute to superficial staining of teeth. If the thickness of enamel is within normal limits, superficial stains can be removed with professional whitening and the result will be guaranteed. Think of enamel as a sponge that has dried like a rock. The stain will not penetrate far into the enamel because the structure is not very permeable, and if it does, it will be easily removed.

At the same time, there is another group of patients with congenital or developmental enamel defects (amelogenesis imperfecta, dentinogenesis imperfecta) or patients with deep stains caused by medications (tetracycline stains). In the first situation, the enamel grows to have a structure or thickness other than normal and will not whiten. In the second situation, think of the enamel sponge being as hard as a rock and stained all throughout. There is not a good way to soak, and squeeze the stain out of the rock hard sponge. The diagnosis is a key for success and this may explain some of the horrific stories some of you have mentioned.

Q: How to brush and what to use?

A: This is such a broad topic, but I will try to filter it through what has been discussed before on the topic of thinning enamel. The enamel may only get thinner if there are chemicals involved (erosion), if there is mechanical rubbing of surface (abrasion), if there is mechanical tooth on tooth contact (attrition) or mechanical “bending of enamel” resulting in cracks (abfraction). It is often found that all three are present in patients with thin enamel. Lowered pH, in other words, an acidic environment contributes to the fast decalcification of the enamel surface. As enamel becomes decalcified, abrasive forces become very destructive and result in the loss and thinning of the outer layer of the tooth. It is a myth that the hard and medium tooth brushes will cause abrasion of enamel. In the study by Dzakovich in the mid 2000’s, it was found that it is not the brush but the tooth paste that is an abrasive agent. Tooth paste contains silica, sand.  If you are trying to prevent enamel abrasion, use very little toothpaste, use tooth pastes with very fine particles of silica or resort to some old fashion techniques such as soap. After all, this is how our ancestors kept the teeth clean.

Q: Are Veneers worth it? Or should you just go with Dental Implants?

A: Veneers can be used in situations when the patient is aesthetically concerned about the appearance but has, otherwise, generally healthy teeth. Veneers are not indicated for teeth with a history of root canal treatment, large fillings, or teeth with damaged or underdeveloped enamel. Veneers are thin layers made of ceramic (or plastic, like discounted veneers, careful there) that are glued onto the surface of a prepared tooth. In most cases, teeth need to be prepared by reducing the front surface to allow for an improved replacement of the enamel layer. In an ideal situation, though quite rare, teeth are small to begin with and all that needs to be done is to roughen the tooth surface, create enamel replacements, and then bond the veneers in place.

How well veneers stay on the tooth without popping off depends on the bonding of the ceramic veneer to the tooth. Successful bonding depends on the type of ceramic, the strength of the glue, but most importantly, the amount and the quality of enamel left on the tooth. The two main indications of poor veneer performance occur if the enamel is thin or damaged. When this is the case, bonding strength may be compromised and then I would recommend crowns to restore form and function.

I’ll say it again, veneers can be a great choice for patients who have aesthetic concerns for their, generally, healthy teeth. Although some people may consider this a cosmetic treatment, that assumption is incorrect. While “cosmetic” refers to something that may be unimportant or easy, that is not the case for veneers. To be specific, veneers are an aesthetic procedure that requires a precise, technical, and scientific approach in order to be successful. If you are considering veneers, it is highly recommended that you seek out an experienced prosthodontist that can accurately evaluate whether your teeth are suitable for veneers. A prosthodontist specializes in the aesthetic reconstruction of teeth, implant dentistry, and the replacement of teeth. Prosthodontists are the only dental specialists trained in putting on veneers. They are your best bet to get the most out of your financial investment, and feel confident that your beautiful smile was designed with quality and longevity. (For more information on Prosthodontists, please see the “Who’s Who in Dentistry” blog)

If you have any questions or comments regarding this blog, please post in the comments below. Don’t forget to mention any other topics you would like to see covered!

Also, if you are located in the Midwest, specifically the Chicago or Milwaukee area, please feel free to contact me or my office. Your first consultation is free! We have expert Prosthodontists and General Dentists who are more than happy to help you with all of your dental needs. We look forward to hearing from you soon!