Destang DL, Kerr WJS Eur J Orthod 2003; 25: 65–69

To compare these different regimes, 2 consultant orthodontists using them were selected from a Scottish survey. Group 1 was of 20 patients in retention with a Hawley appliance 3 months full time and 3 months nights only. Group 2 had 18 patients with a similar retainer for respective periods of 6 months each.

Subjects were aged 11–19 yrs at start of treatment, and limited to Classes I or II malocclusion with anterior maxillary crowding or contact point displacement. All subjects were first treated with pre-adjusted edgewise mechanics using Roth prescription brackets, and retention co-operation was judged similar in both groups.

Measurement up to 3 months post-retention showed incisor irregularity relapse to be greater in Group 1 (7 patients > 3 mm), with no changes in inter-canine and inter-molar width or arch length. The authors suggest that 1 year's retention is clinically beneficial.