Related Experiment Video
Updated: Jun 30, 2026
Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires
Published on: July 24, 2018
Effect of Bonding Height on Force-Moment Generation in Orthodontic Fixed Lingual Retainers: An In Vitro Study
Francesca Thaden1, Linus Hötzel1, Benedikt Dotzer1
1Department of Orthodontics and Dentofacial Orthopedics, LMU University Hospital, LMU Munich, Munich, Germany.
Objectives:
To investigate the effect of different bonding heights on force-moment generation in orthodontic fixed lingual retainers under loading in a biomechanical setup.
Materials And Methods:
Three commercially available lingual retainers were evaluated: two conventionally fabricated stainless-steel retainers (R1, R2) and one CAD/CAM-manufactured nickel-titanium retainer (R3). Using a biomechanical test setup, vertical forces and labiolingual moments were recorded and applied in three dimensions in response to a standardized vertical displacement of 0.3 mm. The effect of three standardized bonding heights (incisal, middle, and gingival thirds of the clinical crown) was assessed.
Results:
Both forces and moments increased with vertical loading. Statistically significant differences were observed among retainer materials, whereas bonding height did not significantly affect the outcomes. At 0.3 mm vertical displacement, the lowest force and moment were recorded for R1 bonded incisally (0.59 ± 0.37 N; 3.48 ± 0.37 Nmm), and the highest for R3 at mid-crown bonding height (1.40 ± 0.13 N; 8.70 ± 1.19 Nmm).
Conclusions:
Retainer type was found to have a greater influence on force and moment development than bonding height. Multistranded stainless-steel retainers may be more susceptible to deformation under occlusal loading. Further studies are required to determine the clinical relevance of bonding height in fixed lingual retainers.
