Default Encryption process 100% complete, but went wrong

note: I started the encryption process without produce any back up

After lunched, the process took 2 hours. Once the process reached the 100% the phone restarted and asked me the password. I entered it and then an android robot showed up for just a moment. After that the screen went black and the bootup animation showed up again. The fact is that the animation runs for just 2 seconds and then the screen remains black (even if the phone seems to be powered on).

I just tried deleting the wipe cache with no results. I also found the issue was experienced before by other users.
Is there a way to recover the data?

thanks