The present study aims to assess the effectiveness of three different retention schemes used to maintain tooth position after orthodontic treatment with fixed orthodontic appliances (stability) and to evaluate possible association between retention scheme and gingival recessions on the lingual surfaces of the lower anterior teeth seen for up to 5 years post-treatment. Moreover the possible association between primary relapse tendency and long term occlusal stability will be evaluated.

This is a randomized, controlled, single-center, equivalence trial with three parallel groups and an allocation ratio of 1:1:1, that aims to investigate the effectiveness of 3 orthodontic retention schemes on post-treatment mandibular arch stability and gingival recession.

Inclusion Criteria:

• Both sexes
• Age between 10 and 16 years
• At the finishing stage of orthodontic treatment, programmed for debonding
• Class I to Class II molar relationship before the beginning of orthodontic treatment
• Non-extraction treatment plan with fixed straight-wire appliances
• Space deficiencies and irregularity of no more than 6mm in the maxillary/ mandibular arch (Irregularity Index)

Exclusion Criteria:

• No missing teeth, impacted teeth or other dental anomalies
• No congenital anomalies/ syndromes