One of the most important aspects in orthodontic treatment is retention. Orthodontic treatment results are potentially unstable and therefore, retention is necessary for three reasons.
The three reasons are as follows:
- The gingival and periodontal tissues are affected by orthodontic tooth movement and require time for reorganization when the appliances are removed.
- Changes produced by growth may alter the orthodontic treatment results.
- The teeth may be in inherently unstable position after the treatment, so that soft tissue pressures constantly produce a relapse tendency.
The tendency of the teeth to move back from post-treatment to the pretreatment position is relapse. Orthodontists have long since been aware of the fact that teeth that have been moved in or through the bone by mechanical appliances have a tendency to return to their former position.
Retention in relation to orthodontics can be defined as the holding of teeth in ideal esthetic and functional positions. The type of retentive measures and the duration of their use are determined by how many teeth have been moved and how far, the occlusion and age of the patient, the cause of a particular malocclusion, the rapidity of correction, the length of cusps and health of tissues involved.
Retention planning is divided into three categories depending on the type of treatment instituted:
- Limited retention.
- No retention.
- Prolonged or permanent retention.
Many appliance types have been used for the retention of post-treatment tooth position. The first appliances proposed were bonded or banded fixed appliances, then removable retainers were advocated. Most recently the uses of bonded fixed retainers have been introduced:
- The retainers can be classified into removable, fixed or a combination of both. The fixed retainer provides a greater degree of support and control than a removable retainer.
- A fixed retainer is commonly bonded to the lingual of the lower anterior teeth following a fixed appliance treatment, while a removable retainer remains the retainer of choice for the maxillary arch.
The purpose of this book was to obtain detailed information about retention, stability, relapse and mainly on various type of retainers used in orthodontics.