A randomized controlled trial comparing retainers in bimaxillary proclination cases

• Main Authors: Maskim, Nurulhuda, Mohd Tahir, Norhidayah @ Nor Zahidah, Wan Hassan, Wan Nurazreena
• Format: Dataset
• Language: English; English; English
• Published: Springer Nature
• Subjects: RK Dentistry
• Online Access: http://eprints.um.edu.my/46314/1/model%20analysis.sav; http://eprints.um.edu.my/46314/2/cephdataBIMAX.sav; http://eprints.um.edu.my/46314/3/OHIP%20dataset.sav; http://eprints.um.edu.my/46314/
• Institution: Universiti Malaya

Background: This randomised prospective clinical study aimed to determine the most suitable retention protocol to maintain the stability of bimaxillary proclination cases treated by four premolars extraction and fixed appliances. In this prospective, parallel, single-centre, single-blinded, control trial with a 1:1:1 allocation ratio, block randomization using an online randomiser was used to allocate twenty-seven participants into three groups; fixed bonded retention (FBR), vacuum-formed retention (VFR), and dual retention (DR) comprising both fixed bonded and vacuum-formed retainers. Participants were assigned a blinding code for data entry. Data were collected every three months from debond (T0) for 12 months (T4). The primary outcome measures were changes in soft and dental tissue parameters measured on manually traced lateral cephalograms. Secondary outcome measures were intra-arch changes, measured on dental casts, and Oral Health-Related Quality of Life (OHRQoL), assessed using the modified Malaysian short version Oral Health Impact Profile-14 (OHIP-14[M]) questionnaire. Data was analysed by repeated measures analysis of variance. This trial was registered with Clinicaltrial.gov (NCT04578704). Results: At T4, the upper lip, lower lip and upper incisors moved anteriorly by a mean difference (MD) of 1.63 mm (SD 3.7), 0.48 mm (SD 1.1), and 0.54 mm (SD 0.97), respectively. The upper and lower incisor angulations also increased (p < 0.05) by 0.96 degree (SD 2.1) and 1.11 degree (SD 2.63), respectively, while the interincisal angle reduced significantly by 0.56 degree (SD 1.23). At T4, only the change in upper incisor inclination (UII) showed significant differences between groups (η2 = 0.296; p = 0.015). Post-hoc comparisons found both FBR and VFR groups had proclined more than the DR group (UII, MD 3.33 degrees; 95% CI 0.46, 6.21; p = 0.019; and UII, MD 3.22 degrees; 95% CI 0.35, 6.09; p = 0.024, respectively). The OHIP-14[M] score showed no differences between groups. Conclusions: In a long term 12-months observation period, fixed bonded retainers, vacuum-formed retainers, and combination of both these retainers are acceptable to maintain orthodontically treated bimaxillary proclination. In terms of relapse in the upper incisor inclination, dual retention is preferred as it prevents proclination more than either single form of retainers.