Styles and Middleton have beaten off competition from stars including David Beckham, Tom Daley, Cheryl Cole and Tulisa, reported Digital Spy online.
At the other end of the lists, which were conducted by Pearly's, Jeremy Clarkson and Towie stars Chloe Simms and Joey Essex were voted as having the worst teeth.
Pearly's founder Liz Ridley said, "Badly discoloured teeth are a complete turn off. It's not a surprise a heavy smoker like Jeremy Clarkson came top while those who took part in our survey obviously think Chloe Simms has had too much done.
"White teeth tend to give a much younger appearance because they look fresh and smart - and their pearly white teeth remain the focus. A person with a dazzling smile is sure to look more confident and full of life, than somebody with yellow, damaged teeth that look dull and unkempt."
Kate Middleton also found herself at the top of another poll recently - she was voted as the celebrity with the best nose.
While the Duchess has sparked a boom in requests for her nose at cosmetic surgery offices, Styles's sparklers have prompted a 500 per cent boom in young men sourcing teeth whitening.