Retention: type, duration and need forcommon guidelines. A survey of NorwegianorthodontistsVaska Vandevska-Radunovic, Lisen Espeland, Arild StenvikDepartment of Orthodontics, University of Oslo
Fig. 1. Vacuum pressed retainerFig. 2. Fixed 33-43 retainerMaintenance of the orthodontictreatment result and prevention ofrelapse require the use of some type ofretention appliances (Figs. 1 and 2).However, among orthodontists, there isno agreement about the type, durationor follow-up of a common retentionprotocol.Surveys conducted in Australia/NewZealand, the Netherlands, the UnitedKingdom, and the United States showcertain similarities between the countrieswhen it comes to the type of maxillaryand mandibular retention devices, butshow disagreements when it comes toduration of retention, follow-up and needfor common guidelines
AIMS:1. To survey retention protocols among orthodontists inNorway and compare the results with similar studies in othercountries2. To examine the perceived need for common guidelinesrelated to retention type, duration and follow-up
Materials and MethodsA postal questionnaire with addressed, pre-stamped return envelops were sent to allorthodontists listed by the Norwegian Association of Orthodontists (NAO). The finalversion of the questionnaire consisted of 14 questions, grouped as follows :1. Background of the participants: gender, years in practice as aspecialist, number of days/week in practice, place where specialitywas obtained2. The most commonly used type of retainers3. Duration of retention and scheduling of follow-up appointments4. Information provided to the patients5. Factors influencing the choice of and/or changes in retentionprotocols6. Manufacturing of orthodontic retention devicesAt the end, the participants were asked if they felt there is a need for commonguidelines regarding retention procedures. Space was also provided for additionalcomments if desired.
ResultsSample characteristicsOf the 193 questionnaires that weremailed, 150 forms were completed andreturned (77.7%).Forty-six (30.7%) orthodontists were womenand 104 (69.3%) were men. The majorityobtained their speciality training inNorway (58.1% in Oslo and 33.1% inBergen), while 8.8% were educatedabroad (not specified).As for the number of years in orthodonticpractice, 58.7% worked >20 years, and41.3% worked <20 years in practice.Most of the orthodontists worked 5days/week (47.9%), 32.6% worked 4days/week, whilst the remaining 19.5%worked 3 days or less per weekRetention proceduresAll orthodontists used some form forretention.The most commonly used retainer in theupper jaw was a combination of fixed andremovable retainer, followed by a clearthermoplastic retainer only, and a Hawleyretainer (Fig. 3a).In the lower jaw, a fixed retainer bonded to allanterior teeth was most common (Fig.3b). Inter-maxillary retention (activatorsor positioners) was used by less than 20%of the orthodontists.
Lower jawFixed retainerbonded to caninesonlyFixed retainerbonded to allanterior teethOther form forretention66.422.611bUpper jawHawley retainerThermoplasticretainerFixed retainerFixed+removableretainer40.618.632.48.8aFig. 3. Percentage of the most commonly used retainers in the upper (a) andin the lower (b) jaw.
Tables 1 to 3 summarize the results concerning theduration of retention (Table 1) and factors influencing thechoice of retention (Tables 2 and 3).
Retention time % orthodontistsUpper jaw Lower jaw< 2 years 15 22-3 years 34.7 10.23-5 years 23.7 27.9> 5 years 18.4 41.5permanently 8.2 18.4Table 1. Duration of retention in the upper and lower jaw
Factors % orthodontistsOriginal malocclusion 95.2Oral hygiene 49.7End result 54.4Patient’s motivation 33.3Patient’s age 43.5Periodontal health 34.0Wisdom teeth 23.1Oral habits 27.9Tooth morphology 8.2Table 2. Factors influencing the choice of a certain retainer type
Factor % of orthodontistsSpecialty training 27.7Clinical experience 57.4Literature 3.5Courses 5.0Colleagues 6.4Table 3. Factors influencing the decision for the retention protocol in use
Female orthodontists were significantly more in favor of having commonguidelines than males . They also differed in their choice of retainer inthe upper jaw, as they used a combination of fixed and a removableretainer significantly more often than their male colleagues (p<0.05).The length of clinical experience had a significant effect on the choice ofretention appliance in the lower jaw. Orthodontists working >20 years inpractice more commonly used retainers bonded to canines only, whilethose working <20 years preferred retainers bonded to all anterior teeth.
Conclusions1. The most commonly used retention appliances in Norwayare fixed retainers in the mandible, and a combination of afixed and a removable retainer in the maxilla.2. The choice of retention devices is similar to those reportedin the other surveys. There are, however, disparities relatedto duration of retention, follow-up regimens and theperceived need for common retention guidelines.3. Retainers in the mandible are kept much longer than in themaxilla, and most often more than 5 years.4. Half of the orthodontists desire common retentionguidelines, women being significantly predominant.