To compare relapse and failure rates of computer-aided design/computer-aided manufacturing (CAD/CAM) and standard fixed retainers.
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.
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%).
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.
Resident, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.
Associate Professor, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.
Professor and Department Chair, Department of Orthodontics, Saint Louis University, Saint Louis, Mo, USA.