Bright white teeth make smiles contagious, causing citywide epidemics that disrupt funerals, staring contests, and period Civil War-era photo shoots. Spread the sparkly germ of happiness with today's Groupon: for $149, you get a Zoom! teeth-whitening treatment at Smiles by Design (a $735 value).

Smiles by Design’s trained technicians administer a grin inducing Zoom! whitening treatment during a quick, roughly 45-minute procedure that yields immediate results. Lips and gums are tucked under a cozy, protective cover before a clinician applies Zoom!-specific whitening gel over teeth, coaxing stains out into the open and allowing Zoom!'s special light to vanquish fang discoloration. According to Zoom!, recipients of the treatment can expect an average of eight shades of improvement, which is 10 times the whitening power of a milk bath, or twice as effective as spraying teeth with Sun-In.