ABSTRACT

Objectives

To compare relapse and failure rates of computer-aided design/computer-aided manufacturing (CAD/CAM) and standard fixed retainers.

Materials and Methods

This single-center, single-blinded, prospective randomized clinical trial included 46 patients who completed active orthodontic treatment and complied with retention visits. The patients were randomly assigned to three groups: CAD/CAM group with multistranded stainless steel wires (CAD/CAM, n = 16), Lab group with the same multistranded wires (lab, n = 16), and control group with stainless steel Ortho-FlexTech wires (traditional, n = 14). Intraoral scans were obtained at placement of fixed retainers (T1), 3-month visit (T2), and 6-month visit (T3) and measured for intercanine width and Little's Irregularity Index. Failures were recorded.

Results

The CAD/CAM group experienced less intercanine width decrease than the traditional group at 3 months (mean difference, 0.83 ± 0.16 mm; 95% confidence interval [CI], 0.44–1.22; P < .001) and 6 months (mean difference, 1.23 ± 0.40 mm; 95% CI, 0.19–2.27; P < .05). The CAD/CAM group experienced less increase in Little's Irregularity Index compared with the lab group within 3 months (mean difference, 0.81 ± 0.27 mm; 95% CI, 0.12–1.49; P < .05). Failures from greatest to least were experienced by the lab group (43.8%), the CAD/CAM group (25%), and the traditional group (14.3%).

Conclusions

Within 6 months of bonding fixed retainers, CAD/CAM fixed retainers showed less relapse than lab-based and traditional chairside retainers and less failures than lab-based retainers.

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Author notes

a

Resident, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.

b

Associate Professor, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.

c

Professor and Department Chair, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.