One day while doing some research for one of his college courses in the library, he noticed a section of books about human evolution and it occurred to him to see whether they had any information about why white teeth were so important in the first place. According to evolutionary biologists, human beings, just like other animals, evolved natural preferences in sexual selection that cause us to be attracted to one another on the basis of physical features that are indicators of good physical health and genetic material (Margulis & Sagan, 2000; Zuk, 2002). More specifically, features such as well-formed white teeth provide visual cues of good health and immunity systems because the production of healthy enamel requires good health and sufficient caloric resources. Therefore, in addition to providing evidence of good health, white teeth also suggest greater access to food resources.

During early human evolutionary periods, access to food resources would have been one of the principal factors considered by females in sexual selection because they depended on the male who fathered their children to be good providers for their children (Margulis & Sagan, 2000; Zuk, 2002). Moreover, in modern times, white teeth (and straight teeth rather than crooked teeth) provide a visual indication of professional success and access to financial resources since wealthier men are more likely to be able to afford good dental care or cosmetic dentistry whereas missing teeth or crooked teeth or discolored teeth might suggest that someone is less financially well-off (Ackerman, 1999). Mike realized that white teeth were much more important than he ever realized.

Identification of the Problem and its Solution

The more Mike came to understand about why good teeth mattered so much to women the more important it became to him to find out why his teeth were so discolored and why neither of the teeth whitening products he tried had...

Mike decided to mention it the next time he saw his dentist. His dentist took one look at his teeth and asked Mike whether he had ever taken tetracycline or another antibiotic for an extended period of time as a child. Mike responded that he had been on tetracycline for several years in high school and that it had been prescribed by his dermatologist for acne. The dentist then explained that this is why the over-the-counter teeth whiteners failed to do anything for him. According to his dentist, tetracycline and certain other antibiotics can cause teeth to change color "intrinsically" which means from the inside out (Lee, 2009). Over-the-counter teeth whitening products can only change the color of teeth that are discolored "extrinsically" such as by becoming stained by cigarette smoke or coffee or wine (Lee, 2009).
The dentist explained that, unfortunately, the only way to change the color of Mike's teeth would be through dental laser surgery, veneers, or bonding, all of which were considerably more expensive than the treatments available for teeth discolored only superficially (Lee, 2009). Mike decided not to commit to any of those procedures immediately but in light of what he learned about why healthy-looking teeth make such a difference socially, he decided to plan to begin saving his money for that very purpose.