If you're talking about the types of retainers, you should know there are three main types. The first and best-known retainer is the Hawley retainer. This is the piece of acrylic with wires that most people know about. It's removable, so a lot of patients like it. Next up in removable retainers, we have the Essix type. If you're a patient who wore Invisalign clear aligners or any other type of clear aligner trays, you'll know what we mean when we say these retainers are just like Invisalign or Spark aligners. Finally, you have fixed retainers, which are metal wires cemented to the back of your teeth to prevent any unwanted dental movements.