Research shows that Hawley retainers are not effective for preventing incisor irregularity relapse. Hawley retainers also affect speech, especially the d, s, t, and i sounds, however as they are often only worn at night time, this concern may not be so prevalent. Research shows that participants that wear Hawley retainers report being more embarrassed about the appliance than wearing vacuum formed retainers and they found Hawley retainers more difficult to wear. However, if the patient has concerns with regards to the visible metal wire, a clear polyethylene bow can be used to enhance aesthetics.