When Robert first went in to get his braces put on, his lateral incisors weren't in yet. That's the tooth in between the front tooth and the canine tooth.
There was a big enough gap between his front two teeth that there just wasn't space for them to come down. (His upper jaw was also too narrow, making things a bit tighter in there.) So after a "spreader" of sorts in the roof of his mouth for a month or so -- pulling apart the suture there -- his upper jaw now aligns with the bottom. They also had a spring put in to force the space between the front and canine teeth open allowing room for those lateral incisors.
Eventually the space opened up and the wee teeth popped out. So now, more brackets needed to be put on.
Here's Robert getting prepped. The teeth have to be uber-dry for the adhesive to stick onto the teeth, so they spread the lips away and suction off their surfaces.
Voila! Two more brackets were glued on.
Then they have to cure the glue and harden it up so the brackets don't move around when they attach the new wire.
So, no more springs are necessary! Yeah! They were inconvenient at first when Robert was getting used to the whole braces thing. If anything went wrong and we had to call the doctor after hours, it was always because a spring disconnected and his wire was hanging loose and poking him.
So now he's just a regular dude with braces and no extra appliances attached.