Treatment of Complications after Unintentional Tooth Displacement by Active Bonded Retainers

Maintenance after orthodontic treatment is often mistaken for stability of the post-treatment status. As stated by Oppenheim in 1934, "Retention is the most difficult problem in orthodontia; in fact, it is the problem". Bonded lingual retainers, which have become a standard part of retention protocol due to the relapse tendency of lower-incisor irregularity, have been shown to be effective in maintaining the alignment of the mandibular anterior region. Nevertheless, such retainers can loosen without being noticed or even be unintentionally activated, resulting in undesirable tooth displacement.