Yellow teeth indicate an addiction to smoking cigarettes, drinking coffee, or swishing with butter. I can't believe it's not toothpaste with today's Groupon: for $169, you get a 90-minute in-house Boost Teeth-whitening treatment at Merry Dental Care Center in Eden Prairie (a $470 value).

Merry Dental Care Center's team of enamel advocates restores confidence in discolored gumstones using the Opalescence Boost whitening system designed to vanquish stains. Over the span of 90 minutes, a trained technician swaddles teeth in a hydrogen-peroxide-based gel that blanches smiles without the use of light, which can make teeth as sensitive as Big Bird during hunting season. The gel's carefully mixed solution also contains potassium nitrate and fluoride, as well as ingredients that purge ivory food destroyers of blemishes caused by coffee drinking or cigarette smoking.

Results vary based on dental history and oral habits.