Expanders are devices used in orthodontics to widen the upper jaw, or maxilla, to create more space for teeth. They are often used in children and adolescents whose jaws are still growing. The expander is typically made of metal and is attached to the back teeth. It works by applying gentle pressure to the teeth and bones over time. The process of using an expander usually involves turning a small screw in the device, which gradually increases its size. This expansion helps to correct issues like crossbites and can improve overall dental alignment. Treatment duration varies, but it generally lasts several months.