in one new episode of season 3, Kristin Kreuk as Lana Lang gets a retainer and is so embarrassed that she doesn't want her friends to see her wearing it, at the end of the episode, chloe sees her wearing it and tells her that she looks cute with her retainer. At the end, she smiles to clark and removes her retainer before kissing him!
many great shots, Kristin Kreuk looks really sexy with a retainer, I will post the pics and a video of her removing her retainer !

http://www.imdb.com/title/tt0279600/

yes it seems to be true, I found an extract of the script on the web:
"Lana! I won't laugh! Come on, please?" Chloe heard Clark say as she walked towards the Torch office one morning.

  "Hey guys, what's going on?" Chloe asked as she took in Clark standing in front of Lana and Lana standing with her arms firmly across her chest and her jaw clenched so tight that Chloe could see her jawline from the doorway.

  "Today's Lana's big day, remember?" Clark said, looking at Chloe, then turning back to face Chloe.

  "Oh! I forgot! Let me see, Lana!" Chloe grinned widly as she entered the office and dropped her bookbag in the chair in front of her computer, then joined Clark standing across from Lana.

  "No." Lana said simply.

  "Why not?" Chloe questioned.

  "She's thinks I'm going to laugh at her." Clark sighed.

  "I know he won't! I got them to!" Chloe said in Clark's defence.

  "You won't laugh either?" Lana asked Chloe.

  "Never." Chloe said, flashing Lana a huge grin.

  "Ok, but don't tell Whitney...he hasn't seen me yet." Lana sighed, letting her arms fall to her sides and looked straight at Clark and Chloe, smiling broadly The morning sun streaming in through the windows glinted brightly off her...braces.

Whitney left the series in the second season, that ist right.
But it is not unusual as we all know that obviously dead persons come
back to life in this kind of tv series.
Maybe the older among us remember the return of Bobby Ewing in Dallas !

http://www.fernsehserien.de/index.php?serie=3808

Dieses Rätsel schein ja bis heute nicht gelöst worden zu sein. Haltet Ihr diese Meldung trotzdem für authentisch?

@claude
did you watch all episodes of session 1,2,3 ? did you also see other sessions from smallville later?