There could be a number of factors. Try going to your Settings app and "forget" your WiFi network. Then, have the iPad find it again so you can use it. Or, try to reset your wireless router (essentially, unplug the router, leave it off for a bit then plug it back in). Or, although you just did a restore, maybe try the restart or reboot options. To do that (apologies if you know how):
Restart: Hold down the power button until the power off slider appears. Slide it off. When the iPad finishes shutting down, hold down the power button again until the Apple logo appears.
If that doesn't help, try this last step...
Reset: Hold both the power and home buttons until the screen goes dark and the Apple logo then appears (the slide to unlock screen may or may not appear). Once the logo appears, release the buttons. After a time, your homescreen will appear. Please note that it may take some time for the Apple logo to appear or for your homescreen to appear (or both). This is normal. Eventually, the homescreen will appear.
That's all I can think of at the moment. So, give those a try and hopefully someone else will come along who might have another idea.
Marilyn