Related Experiment Video
Updated: Mar 18, 2026
Treatment of Facial Deformities using 3D Planning and Printing of Patient-Specific Implants
Published on: May 23, 2020
A Randomised Controlled Trial Comparing Thermoformed and 3D-Printed Retainers in Young Adults: Evaluation of
Hui Shan Boo1, Norhidayah Nor Zahidah Mohd Tahir2, Aufa Dahlia Bahar3
1Department of Paediatric Dentistry and Orthodontics, Faculty of Dentistry, Universiti Malaya, Lembah Pantai, Kuala Lumpur, 50603, Malaysia. boohuishan@hotmail.com.
Introduction:
To compare post-treatment stability and oral health-related quality of life (OHRQoL) in young adults wearing thermoformed retainers (TFR) versus direct 3D-printed retainers (3DPR) over a six-month part-time retention period.
Materials And Methods:
This single-centre, two-arm parallel randomised controlled trial allocated 30 debonded orthodontic patients (≥ 18 years) to either TFR (Erkodur PETG, 1.0 mm) or 3DPR (NextDent Ortho Flex, 0.75 mm) in a 1:1 ratio. All retainers were worn part-time (8-12 h/day). Digital intraoral scans were obtained at baseline (T0) and six months (T2) using Trios 3, and post-treatment stability was assessed digitally using Little's Irregularity Index, intercanine width, intermolar width, arch length, overjet, and overbite. OHRQoL was evaluated at both time points using the OHIP-14(M) questionnaire. Non-parametric tests were applied following the Shapiro-Wilk assessment, and analyses were conducted using an intention-to-treat approach.
Results:
One dropout in the 3DPR group at T2. At T2, no significant between-group differences were found in Little's Irregularity Index, intercanine width, intermolar width, arch length, or overjet (p > 0.05). Overbite values were statistically higher in the TFR group at T2 (p < 0.05); however, the difference was not clinically significant. Changes in post-treatment stability from T0 to T2 (ΔT2-T0) did not differ significantly between groups (p > 0.05). Total OHIP-14(M) scores improved significantly from T0 to T2 in both groups (TFR p = 0.016; 3DPR p = 0.013), with no significant between-group differences at either time point (p > 0.05). A small but significant difference was observed in the psychological disability domain at T2, with slightly higher scores in the 3DPR group (p = 0.020). No harm was observed.
Conclusions:
TFR and 3DPR demonstrated comparable post-treatment stability and similar improvements in OHRQoL after six months of part-time wear.
Registration:
ClinicalTrials.gov (Identifier NCT05968625).
Protocol:
The protocol was published before trial commencement.
