Some of the Kenyan tribes have preserved their traditional dress, culture, and pastoralist lifestyle. They have remained with simple diets relying on staples of rice, potatoes, and milk. They have avoided and also have little taste for western foods like soda, cookies, crackers, and other sweets. I find from a dental perspective that these patients have aesthetic, naturally white smiles, with little decay or stain.
Back in the states home bleaching trays, in-office zoom whitening, and other products like Crest Whitening Strips are becoming very popular to establish a whiter smile. Our composite (tooth colored filling materials) typically come in shades A-D and 1-4. Maybe when you have been at the dentist you have heard the dentist and assistant going back and forth, "I think she's a B-2, no look at the cervical she is really a C-3." Aren't we kind to categorize you by the shade of your teeth? Anyway, because of the whitening products new shades of composites like extra-light, and extra-extra light have been developed to restore anterior whitened teeth to achieve an appropriate shade match.
In Kenya we often have the opposite problem. We simply need some darker composite shades. Say a Z-4, as you can see in the restoration to the right (different patient from the full face picture). Many patients are not to blame for their brown teeth (quite honestly some don't care. Of which I can understand as they have bigger fish to fry in their daily life like putting dinner on the table tonight) . The brown intrinsic staining and pitting of teeth is often due to dental fluorosis caused by excessive fluoride in the water here along the Great Rift Valley.
But if their is a company out their making some new composite shades for the developing world please send them our way