Braces made of metal or porcelain and are attached to your teeth. Metal wires and rubber bands are then used to provide a force to help the teeth move into into the correct position.
Aligners are made of plastic and are custom made to fit your teeth. Each aligner moves the teeth step by step towards the final position. Small bumps of composite resin (tooth coloured filling material) are attached to various teeth to help the aligner grip the tooth so it can be moved correctly.