One of the protagonist's girfriends is played by Cristiana Capotondi, who had real lingual braces when the movie was shot.
No relevance to the plot, but they do show up in a scene:

https://dereferer.me/?https://dereferer.me/?http://www.imagebam.com/image/159ca4529890667
https://dereferer.me/?https://dereferer.me/?http://www.imagebam.com/image/86b771529890709