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Randomized Controlled Trial
. 2011 May;81(3):404-9.
doi: 10.2319/072610-437.1. Epub 2011 Jan 24.

A retrospective randomized double-blind comparison study of the effectiveness of Hawley vs vacuum-formed retainers

Stephen Barlin  1 , Roland Smith, Ray Reed, Jonathan Sandy, Anthony John Ireland
Affiliations
Randomized Controlled Trial

A retrospective randomized double-blind comparison study of the effectiveness of Hawley vs vacuum-formed retainers

Stephen Barlin et al. Angle Orthod. 2011 May.

Abstract

Objective: To compare Hawley with vacuum-formed retainers.

Materials and methods: Eighty-two patients who had received treatment with upper and lower fixed appliances were randomly assigned either a Hawley or a vacuum-formed retainer. Study models were fabricated for each patient on day of debond and 2 months, 6 months, and 12 months after debond. Using a specially constructed pantograph, four variables were measured for each set of models at each of these time periods. These were upper and lower intermolar widths, intercanine widths, arch length, and a modified Little's index of irregularity. Method error was determined by repeating the measurements on 10 sets of models.

Results: For each of the variables under test and at each of the four time periods, there were no statistically significant differences (α = .05) between each of the two retainers, vacuum-formed and Hawley.

Conclusion: The degree of relapse that is likely to occur following a course of fixed appliance therapy is unlikely to be affected by the choice of retainer, vacuum-formed or Hawley. Therefore, when deciding on the type of retainer to be fitted following fixed appliance therapy, other factors such as cost may play a more significant role.

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Figures

Figure 1
Figure 1
The pantograph. (A) Measuring microscope. (B) Measuring table. (C) Recording paper. (D) Pantograph arm. (E) Pen recorder.
Figure 2
Figure 2
Lin's concordance correlation coefficient plot used to assess the repeatability and method error for the measurement of upper intercanine width (mm).
See this image and copyright information in PMC

Comment in

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