White teeth are a personal adornment that research has shown pays dividends socially.  A 2012 study showed that both men and women are attracted to whiter smiles.  Another study showed its participants with white teeth had a better chance of landing a job position and receiving a higher salary offer than those with yellower teeth.  It would appear a little vanity pays the bills.  

The Type of Staining Matters

Our teeth become discolored from extrinsic and intrinsic stains.  First, extrinsic stains coat the surface of our teeth and are caused by pigmented foods and drinks — think red wine and brown liquids like teas and soft drinks.  Tobacco also is a major contributor to discoloration (and that’s just one of many reasons to avoid it).  Because extrinsic stains adhere to the outside of your teeth, they can be removed mechanically with a tooth brush and a whitening toothpaste*.  Electric toothbrushes, such as Philips Sonicare can remove them more efficiently.  A professional cleaning at our office can also remove extrinsic stains.

A second type of stain is intrinsic stain, which occur below the surface of the tooth. Most commonly, intrinsic stains come from those same pigments from foods and drinks work their way within the enamel and dentin layers.  Also, as we age our dentin naturally yellows and our teeth undergo wear of the enamel, allowing the more colored dentin to show through.  Other intrinsic stains occur while the teeth are forming, from excessive fluoride (causing dark yellow or white stain) in water sources, or from the use of the drug tetracycline (producing dark grey stain).  Teeth can also become discolored from metal fillings, decay, or after impact trauma.  Because intrinsic stains  are within our teeth, they cannot be brushed or polished away.  Instead a whitening agent must be used.  

The active ingredient in ADA approved whitening products is either carbamide peroxide or hydrogen peroxide.  

Over the counter strips have shortcomings.  Their concentration of peroxide in the strip is typically less than what a professional can provide, requiring more time and the purchase of more strips to achieve a similar shade change.  Store bought strips usually do not cover enough teeth.  Smile as big as you can in a mirror and the average person will see all the way to their first molars. Over the counter strips do not extend past the canines for most patients, leaving several teeth that show up in your smile untreated and discolored.  Finally, those strips do not adapt well enough to get into the crevices between the teeth.  Our teeth are not perfectly flat.  Their surfaces round as they approach their neighbors and gums.  If peroxide is unable to contact these areas, one is left with teeth that look yellow around the edges.

Walking bleach

*A quick word on whitening toothpastes.  In our practice we find an increase in sensitivity for patients using these dentifrices.  There is also concern being raised about the these the abrasiveness of these pastes contributing to tooth wear at the gum line.  For this reason we recommend whitening pastes for occasional use or using a safer abrasive, like baking soda that can be found in Arm and Hammer pastes.