I am using iOS 7.0.4 and since the upgrade, I no longer have the airplay function/icon!!! HELP!

I am using iOS 7.0.4 and since the upgrade, I no longer have the airplay function or icon on my iPad. I want to use the AppleTV with the iPad in my classroom, but the Airplay icon is gone from the Controll. Can anyone help me to fix this PLEASE? I have updated the software on the AppleTV, and both the AppleTV and iPad are on the same network. I also restarted the router! Still no icon for the Airplay.