Interpretations
orthodontic
REGRESSION, MINOR, LITTLE
It was evident that even if the anterior teeth were retained for 2 years, small short-term changes occurred during the retention period and, of course, during the 1-year post-retention period. The initial benefits from the bonded retainer 13–23 in group A during the retention period were equalised after removing the retention appliance. This finding contrasts with the assumption that most relapse occurs during the first years after debonding the orthodontic appliance. However, when the bonded retention appliance was removed after 2 years, there were some immediate changes, particularly in group A. Unfortunately, no predictors for the increase in irregularity could be identified. Since the sample size was not calculated with multiple regression analysis in mind and the changes were minor, this trial might have too little power for this type of analysis.Anyway, the knowledge from this trial about changes during the first post-retention year is essential and hypothesis-generating for further investigations of post-treatment stability. In the 1980s and 1990s, 1 to 3 years retention periods were considered adequate. Then, the 20-year follow-up published by Little However, among our patients´ parents, we frequently meet those who did not need lifelong retention. Even if treated decades ago with only a few years with retention, we still find almost perfectly aligned teeth. Thus, long-term retention should be recommended only for those who need it. In this context, it seems promising that the total increase in irregularity shown for all three groups in this trial was minor. Nevertheless, when advising the patient on further use of the retention or not, it is necessary to listen to the patient´s demand and inform about the risk of changes of the maxillary anterior teeth alignment.