Tooth movement is a natural process whether a person has had orthodontic treatment or not.  There is more susceptibility to this movement once the braces are removed and a greater potential for relapse, therefore retainers should be placed very soon after debanding the appliances.  There are three main types of retainers commonly used.

1. Hawley retainer

Hawley retainer is a traditional retainer that has been used since the 1920s.  The retainer is designed mainly with an acrylic plate inside and a metal wire outside.  The teeth are held passively within these two components.  Hawley retainer is removable, adjustable, and hygienic.  The retainer does not cover the teeth making them settle into their final occlusion easily during retention.  Hawley retainer, however, is less esthetic (due to the metal wires) and requires compliance by patient to be effective.  If not worn as indicated, teeth could relapse.

2. Essix retainer

Essix retainer is made from thin plastic material (similar to Invisalign aligner).  A plastic sheet is molded over the plaster model by a vacuum suction machine after pre-softened with heat.  These custom formed plastic trays cover the entire dentition to restrict teeth from shifting.  Essix retainers are nearly invisible and can be used as trays for teeth whitening or as a night guard to protect teeth from grinding.  The major drawback is durability.  The plastic tends to deform over time from use and therefore replacement may be needed every couple of years.

3. Fixed (bonded) retainer

Fixed retainer is formed by bonding a metal wire behind the teeth (usually lower front teeth).  It prevents teeth from moving as they are "glued" on the wire.  The fixed retainer is not always indicated for the upper teeth because it tends to interfere with the bite (the lower incisors may bite on the wire).  Compliance is not an issue with this retainer as it is bonded to the teeth.  The major drawback, however,  is oral hygiene care.  Bonded wires make flossing less easy and cause plaque to build up readily.

4. Instructions for retainer use

(1) The retainers should be used all of the time for the first three months after braces are removed.  After three months of full time use, you may gradually transition to night time use.  Six months after, you should be able to wear your retainers only at night during sleep.

(2) You don't have to wear your retainers while eating; remove your retainers before meals.

(3) The retainers should be cleaned every day with tooth brush and tooth paste to prevent plaque build-up.  Also, the retainers should be cleaned with denture cleaner tablet (e.g. Efferdent or Polydent) approximately three times a week.

(4) Be sure to store your retainers in your retainer case whenever you are not using them.

(5) When dining out in a restaurant, make sure you don't wrap your retainer with napkin and leave aside.  You will forget and lose them.

(6) Pets like to chew on retainers; be sure to keep your retainers from your pets.

(7) Do not put your retainer in hot water.  It will become distorted as it is made of plastic.