Date of Award

7-7-2026

Thesis Type

PhD

Document Type

Thesis

Divisions

Faculty of Dentistry

Department

Department of Orthodontics, Paediatric and Special Care Dentistry

Institution

Universiti Malaya

Abstract

Precise bracket placement is crucial for fixed orthodontics, as errors in tip, torque, or position can cause multidimensional malocclusions. Although pre-adjusted appliances reduce wire bending, accurate initial positioning along the facial axis of the clinical crown (FACC) remains crucial. While dental loupes are well established in other dental fields for visualisation, evidence in orthodontics specially for bracket bonding, remains limited and inconsistent. This study aims to assess the impact of dental loupes on the accuracy of bracket positioning along the FACC, contrasted with non-loupe techniques, to compare the bonding procedure duration and to compare the post-alignment of the anterior teeth. This study was a two-arm parallel, prospective, single-centre, single-blinded randomised clinical trial involving 18 patients randomly divided into two groups: i) loupe group (L), and ii) non-loupe group (NL), all in a 1:1 ratio. A block randomisation technique with fixed block sizes (6:6:6) was employed without stratification. The gold standard was generated by scanning the teeth of both arches in all 18 patients using an intraoral scanner (iTero Element 2®). Scans were saved as STL files and used to fabricate physical models via 3D printing for extraoral bracket placement. Experienced orthodontists placed brackets on the 18 printed models which were re-scanned to establish the gold-standard bracket positioning (T1). A standardised bond-up protocol was applied to both groups, with bracket placement performed using a universal bracket holder and a Michigan Williams periodontal probe for positioning. The loupe group utilised Zumax DFK 3× magnification at a 42 cm working distance. Data collection involved intraoral scanning immediately after bracket placement (T2) and upon the achievement of passive alignment (T3). Outcomes measured were mean linear deviations in mesio-distal (MD) and occlusogingival (OG) dimensions, mean angular deviation in mesio-distal angulation (MDang), measured via Medit Design®, bonding time and Little’s Irregularity Index (LII). Reliability was assessed with ICC; comparisons used independent t-tests and Mann- Whitney U tests for T1 vs T2 bracket positions, and Fisher’s Exact Test for T3 alignment. Significance set at p < 0.05. Baseline characteristics were comparable. The NL group showed a distal MD bias, while the L group exhibited more balanced deviations. Both groups demonstrated a greater OG tendency in the mandibular region than the maxilla. Only a few tooth-specific differences reached significance versus the gold standard (ULPM OG p = 0.017; LR2 and LRPM MD p < 0.05; UR2 MDang p = 0.027). Bonding time was shorter in the NL group (42.9 ± 5.6 min) than in the L group (47.5 ± 3.1 min). Post-alignment LII did not differ significantly between groups and was similar across arches. In conclusion, dental loupes did not confer a clear advantage in bracket positioning during the initial alignment phase. Any accuracy gains appeared limited to isolated teeth and did not translate into a meaningful reduction in overall malalignment, while bonding time was modestly longer. Potential benefits may emerge later during finishing, where enhanced visualisation could reduce repositioning or wire bending. Routine loupe use for initial positioning may not be warranted without targeted training or selective application.

Initial

khm

Additional Information

Thesis (PhD) – Faculty of Dentistry, Universiti Malaya, 2026.

Download

Available for download on Friday, July 07, 2028

Share

COinS