Feiou Lin, Hao Sun, Zhenyu Ni, Minling Zheng, Linjie Yao

Retention is an important component of orthodontic treatment; however, poor compliance with retainer use is often encountered, especially in adolescents. The purpose of this study was to prove the hypothesis that verbal instructions combined with images showing the severe consequences of poor compliance can increase retainer use. This study was a randomized controlled trial. The sample was recruited from Wenzhou, People's Republic of China, between February 2013 and May 2014, and 326 participants were randomized into three groups. Patients and parents in Group A (n=106) were given routine retainer wear instructions only; in Group B (n=111), images illustrating the severe consequences of poor compliance with Hawley retainer use were shown to patients, combined with routine instructions; and in Group C (n=109), images illustrating the severe consequences of poor compliance with Hawley retainer use were shown to patients and parents, combined with routine instructions. Three months after debonding, questionnaires were used to investigate daily wear time and the reasons for poor compliance. Differences in means between the groups were tested by one-way analysis of variance. The mean daily wear time in Group C (15.09±4.13 hours) was significantly greater than in Group A (12.37±4.58 hours, P<0.01) or Group B (13.50±4.22 hours, P<0.05); the mean daily wear time in Group B was greater than in Group A, but was not significant (P=0.67). Reasons for nonusage were forgetting to wear the retainer (51%) and finding the retainer bothersome to frequently insert and remove (42%). Verbal instructions combined with images showing the severe consequences of poor compliance can increase retainer use. Parents play an important role in compliance with retainer use in adolescent patients.