Orthodontic retainers are custom-made devices, usually made of wires or clear plastic that holds teeth in position after surgery or any method of realigning teeth. Once a phase of orthodontic treatment has been completed to straighten teeth, there remains a lifelong risk of relapse (a tendency for teeth to return to their original position) due to a number of factors: recoil of periodontal fibres, pressure from surrounding soft tissues, the occlusion and patient’s continued growth and development. By using retainers to hold the teeth in their new position for a length of time, the surrounding periodontal fibres adapt to changes in the bone which can help minimize any changes to the final tooth position after the completion of orthodontic treatment. Retainers may also be used to treat overjets. Removable retainers include Hawley, Vacuum-formed, Begg and Barrer. They provide orthodontic retention when worn and they can be taken in and out of the mouth. They can be worn part-time or full-time if required or as advised by the orthodontist. In comparison to fixed retainers, removable retainers are easier to clean. The best-known removable retainer is the Hawley retainer, which consists of a metal wire that typically surrounds the six anterior teeth and keeps them in place. Hawley retainers are one of the oldest types of removable retainers. Named for its inventor, Dr. Charles A. Hawley, the labial wire, or Hawley bow, incorporates 2 omega loops for adjustment. It is anchored in an acrylic baseplate that sits in the palate (roof of the mouth). They are made from metal wire running along the outside of the teeth. There are many adaptations possible with Hawley retainers. The advantage of this type of retainer is that the metal wires can be adjusted to finish treatment and continue minor movement of the anterior teeth as needed. It also benefits from being robust and rigid, easy to construct and allows prosthetic tooth/teeth to be added onto with metal stops placed mesial and distal to the prosthetic teeth to prevent any relapse. To help fix rotations; acrylic facing can be added to the labial bow and a bite plane added to maintain the result of deep overbite correction. Also, to control the position of the canine, reverse U-loop can be employed. Additionally, to avoid occlusal interferences, the labial bow can be soldered to the cribs. The main disadvantages of this type of retainer is its inferior aesthetics, interference with speech, risk of fracture and inferior retention of lower incisors in comparison to vacuum-formed retainers. Recently, a more aesthetic version of the Hawley retainer has been developed. For this alternative, the front metal wire is replaced with a clear wire called the ASTICS. This retainer is intended to be adjustable similarly to the traditional Hawley retainer, which is not practical with vacuum-formed retainers. 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.

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Regards,
Catherine
Journal Co-Ordinator
Journal of Orthodontics and Endodontics