Orthodontic retention--three methods trialed.

DESIGN: Single centre randomised controlled trial.

INTERVENTION: Patients treated by a single orthodontist were randomised to one of three retention methods: removable vacuum-formed retainer (VFR) covering the palate and the maxillary anterior teeth from canine-to-canine and bonded canine-to-canine retainer in the lower arch (group V-CTC); maxillary VFR combined with stripping of the lower anterior teeth (group V-S); prefabricated positioner covering all erupted teeth in the maxilla and the mandible (group P). All retention appliances were provided within one hour of debonding.

OUTCOME MEASURE: Dental study casts were taken before treatment, at appliance removal and five years or more out of retention. Little's irregularity index, intercanine and intermolar width, arch length and overbite/overjet were recorded.

RESULTS: Twenty-five patients were randomised to each group with 69 completing the two-year retention period (24 in V-CTC group; 23 in V-S group; 22 in P group). Forty-nine patients were available five years post retention (16 in V-CTC group; 17 in V-S group; 16 in P group). No significant differences were found between the groups.

CONCLUSIONS: After five years or more out of retention, the three retention methods had achieved equally favourable clinical results. Thus a maxillary VFR combined with a bonded canine-to-canine retainer in the mandible, a maxillary VFR combined with stripping of the mandibular anterior teeth and a prefabricated positioner can all be recommended.