Clinical Effectiveness of Bonded Versus Vacuum-formed Retainers

Clinical Effectiveness of Bonded Versus Vacuum-formed Retainers After 12 Months: A Randomized Controlled Trial

The purpose of the study was to compare the clinical effectiveness of bonded versus vacuum-formed retainers regarding their retention capacity; periodontal health; survival rates; and patients' perception after 12 months of removal of fixed appliances.

The null hypotheses considered that there was no differences between the retainers in relation to the aspects evaluated.

This single-center randomized controlled trial was performed at the Department of Orthodontics, Bauru Dental School, University of São Paulo, Brazil.

A total of 50 patients completing orthodontic treatment were recruited. The patients were prospectively and randomly allocated into two groups. The first group consisted of 25 patients with canine-to-canine V-bend bonded retainers; while the second group comprised 25 patients with vacuum-formed retainers. In both groups, the same retainers were installed in the maxillary and mandibular arches.

Patients were evaluated at deboning (T0), after 3 months (T1), 6 months (T2), and 12 months (T3). In each appointment, digital models were obtained and the other clinical variables were evaluated. The primary and secondary outcomes were compared between retainers in the time-points evaluated.

Inclusion Criteria:

• Patients with the proper completion of orthodontic treatment and correction of the initial malocclusion.
• Acceptable oral hygiene (assessed through clinical examination).
• Presence of all teeth up to the second molars.
• Clinically acceptable teeth alignment.

Exclusion Criteria:

• Patients with any systemic condition that may have an influence on periodontal health.
• Patients with facial deformities.
• Initial malocclusion that required extreme corrections, large transverse expansions or orthognathic surgery.
• History of periodontal diseases.