The reliability of bonded lingual retainers.

BACKGROUND

Bonded lingual retainers have become increasingly popular, but there is little information on their long-term reliability.

OBJECTIVES

The aims of this retrospective study were to investigate the reliability of bonded upper and lower lingual retainers and the factors contributing to their failure.

METHODS

The study group were 149 patients who returned between 2002 and 2005 with failed upper and/or lower fixed lingual retainers. Approximately 230 patients were debonded each year and approximately 1150 patients were covered annually by a 5-year guarantee of replacement or repair of failed retainers. The retainers were made from 0.018 inch round stainless steel heat-treated orthodontic wire. The upper retainers had loops opposite the embrasures and the lower retainers had loops between the lateral incisors and canines. The following details were recorded: teeth involved, patient gender, the likely cause of any damage and the time taken for each repair.

RESULTS

Between 35 and 40 patients required repair/replacement of their retainers each year. Multiple bond failures occurred in approximately 9 per cent of these patients. Male patients had twice the fracture rate of female patients. Extra-oral trauma was the most frequent cause of failure followed by intra-oral trauma, operator error and wire fracture. The central incisors in both arches were the most frequent sites of failure. Single tooth repairs required approximately 12 minutes of the orthodontist's chair-side time.

CONCLUSIONS

Bonded lingual retainers are a reliable form of retention after orthodontic treatment.