whats being put too sleep like may get it for dental work, any advice also when put under whats it like _________?

If you're asleep how would you know?

You'll never know until you wake up and then you still won't know because you'll have nothing to remember...:)   

I've been put under many times - twice for dental work.  Each time it was "instantaneous".  The anesthesiologist comes in and asked me to count backwards from 99.  By the time I reached 96 the procedure was over.  Although the procedure may have taken hours, it was if I had never never lost conscientiousness.  The grogginess afterwards is like being in a fog, but after 12-24 hours (most of which is spent in bed asleep), you're back to feeling like you always do.  

If I ever am put to sleep for dental work it won't be quick.  First bone replacement has to take place then later the dental work.  It will be a process.