The goal of orthodontic retention is to increase the stability of the dentition after orthodontic treatment. Studies have shown that 40% to 90% of orthodontic patients have unacceptable dental alignment 10 years after treatment. Various methods of retention are in use today. Three main types of retainers used in the United States are Hawley, vacuum-formed, and fixed retainers.

The first of the 2 phases of retention is called the retention phase. In this phase, the final alignment of the dentition is maintained as the associated soft tissues remodel at a rate above the baseline. The length of this remodeling process varies among different associated tissue types. Reorganization of the periodontal ligament occurs over a 3 to 4 month period. The gingival collagen-fiber network takes 4 to 6 months to remodel, and the elastic supracrestal fibers remain deviated for more than 7 months. It is generally accepted that this phase is completed within a year of debonding.

The second phase of retention, called the postretention phase, begins when increased remodeling of the supporting tissues after orthodontic treatment is complete and lasts the rest of the patient’s life. During this extended period of time, teeth are subjected to variable muscular forces acting on the periodontium with associated modeling and remodeling. The goal of the postretention phase is to maintain the alignment of the dentition regardless of changing forces. It is generally accepted that patients need to wear retainers for less time per day during the postretention phase compared with the retention phase.

A Cochrane Review of orthodontic retention reported that, “There are insufficient data on which to base our clinical practices on retention present . . . Given that the vast majority of orthodontic patients undergo a phase of retention, this vital area of orthodontic research should be given priority in the near future.”

Little research has been published that addresses patient compliance with orthodontic retainers. An Australian study in 2005 concluded that there is a strong positive relationship between maxillary retainer compliance and patient-reported appliance comfort.

A survey conducted at the University of Kentucky in 2008 evaluated patient compliance with orthodontic retainers. The authors found that the patient’s age, sex, amount of time since debonding, understanding of proper compliance, and retainer type all significantly influenced patient compliance. It was also found that patients were more compliant with vacuum-formed retainers than Hawley retainers initially after debonding. However, compliance decreased at a much faster rate with vacuum-formed retainers than with Hawley retainers. As a result, patients were more compliant overall with Hawley retainers than with vacuum-formed retainers. Finally, this study found that very few patients wore their retainers as instructed at 5 years after debonding.

A review of the literature yielded 3 studies that evaluated retention protocols in Australia and New Zealand, the United Kingdom, and the Netherlands. Preferred methods of retention varied among the providers in these countries. Orthodontists in Australia and New Zealand preferred vacuum-formed retainers for the maxillary arch and fixed retention for the mandibular arch. Private practices in the United Kingdom preferred a combination of vacuum-formed retainers and fixed retention. Orthodontists in the Netherlands preferred fixed retention for both arches. The wide variations in the data of these studies support the position of the Cochrane review that practice guidelines are needed for orthodontic retention.

Keim et al conducted surveys regarding orthodontic trends over the past 25 years in the United States. They found that between 1986 and 2008 there was an increase in the use of vacuum-formed and fixed retainers as the preferred retainer types. During this same time period, they also found a corresponding decrease in the use of Hawley retainers. These authors reported an increase in lifelong retention protocols among US orthodontists during this time period.

A recent study by Valiathan and Hughes surveyed 2000 members of the American Association of Orthodontists (AAO) in the United States regarding orthodontic retention; they received 658 responses. The survey asked for the orthodontists’ most popular retention modality for each arch. Just over 58% of respondents preferred the Hawley retainer for the maxillary arch, and 40.2% preferred the fixed lingual retainer for the mandibular arch. Commentary responding to this study in the American Journal of Orthodontics and Dentofacial Orthopedics suggested that it would be of interest to determine “why orthodontists retain as they do.” Specifically, the reader feedback called for the study of a possible relationship among practicing orthodontists between their preferred retention protocols and their decisions on extractions.

The purpose of this study was to identify the general retention protocols used by US orthodontists via a census survey. Multiple variables were tested for possible associations, including type and duration of instructed retainer wear, practice of phase 1 treatment, and extraction rate. An additional goal was to identify how these protocols have changed over the past 5 years and how they might continue to change over the next 5 years.