Jennifer Hudson

Jennifer Hudson's Oscar-winning smile. Photo: Getty Images for ACMA

When Jennifer Hudson won an Oscar for her debut performance as Effie White in "Dreamgirls," the star flashed a smile that was punctuated by a gap in her front teeth.

And according to Hudson's cosmetic dentist, New York's Dr. Debra Glassman, she wanted a perfect smile to match her bright, new trophy.

"The joke was, she won an Oscar, and she wanted an Oscar-winning smile," Glassman tells StyleList. "There was pressure after her Oscar win, but the real pressure to do something about her teeth came when she signed a cosmetic contract," adds Glassman.

The contract -- a two-year deal with Avon to rep the brand's products -- came to an end this year. But Hudson is busy gearing up to play Nelson Mandela's wife, Winnie, in a movie based on the former South African first lady's unofficial biography, "Winnie Mandela: A Life."

Thanks to extensive dental bonding and whitening, the 28-year-old actress/songstress is ready to show off her smile.

And according to Dr. Glassman -- who also does a lot of Invisalign work on her clients -- the benefits of straight teeth are more than just aesthetic value.

"Once your teeth are straight, you can keep them cleaner. Plaque doesn't get caught in as many places, and it's much easier to brush and floss and prevent cavities," he says.

A case of clear Invisalign straightening treatments (for about nine months use) will set you back about $5500 to $6300. Partial jobs are also very common, and cost nearly $3500.

"You'll start seeing a change in about six weeks. And the celebrities love that they can take out the Invisalign liners if they need to themselves for events and shoots," says Dr. Glassman.

Getting a celeb-worthy smile sounds great, but for some stars front gaps and teeth imperfection are just fine.