In this July 31, 2012photo an assistant, left, overlooks as Flavia Soares da Costa has her braces adjusted at the Simetria orthodontic clinic in Rio de Janeiro, Brazil. Not long ago,

 

              In this July  31, 2012photo an assistant, left, overlooks as Flavia Soares da Costa has her braces adjusted at the Simetria orthodontic clinic in Rio de Janeiro, Brazil.  Not long ago,
In this July 31, 2012photo an assistant, left, overlooks as Flavia Soares da Costa has her braces adjusted at the Simetria orthodontic clinic in Rio de Janeiro, Brazil. Not long ago, it would have been all but unthinkable for the majority of Brazilians to undergo pricey dental work but in fact, an estimated 40 million people have joined the ranks of Brazil's middle class between 2003 and 2011, according to the Fundacao Getulio Vargas economic think tank, providing them with greater purchasing power. (AP Photo/Felipe Dana)