Force-Controlled Biomechanical Simulation of Orthodontic Tooth Movement with Torque Archwires Using HOSEA (Hexapod for Orthodontic Simulation, Evaluation and Analysis)

Abstract

This study aimed to investigate the dynamic behavior of different torque archwires for fixed orthodontic treatment using an automated, force-controlled biomechanical simulation system. A novel biomechanical simulation system (HOSEA) was used to simulate dynamic tooth movements and measure torque expression of four different archwire groups: 0.017″ x 0.025″ torque segmented archwires (TSA) with 30° torque bending, 0.018″ x 0.025″ TSA with 45° torque bending, 0.017″ x 0.025″ stainless steel (SS) archwires with 30° torque bending and 0.018″ x 0.025″ SS with 30° torque bending (n = 10/group) used with 0.022″ self-ligating brackets. The Kruskal–Wallis test was used for statistical analysis (p < 0.050). The 0.018″ x 0.025″ SS archwires produced the highest initial rotational torque moment (My) of −9.835 Nmm. The reduction in rotational moment per degree (My/Ry) was significantly lower for TSA compared to SS archwires (p < 0.001). TSA 0.018″ x 0.025″ was the only group in which all archwires induced a min. 10° rotation in the simulation. Collateral forces and moments, especially Fx, Fz and Mx, occurred during torque application. The measured forces and moments were within a suitable range for the application of palatal root torque to incisors for the 0.018″ x 0.025″ archwires. The 0.018″ x 0.025″ TSA reliably achieved at least 10° incisal rotation without reactivation.

Investigation of Forces and Moments during Orthodontic Tooth Intrusion Using Robot Orthodontic Measurement and Simulation System (ROSS)

“…After an initial drop, the slope of the force, as well as the moment curves, presented a rather linear progression (Figure 2). The initial drop for the first movement interval (0.5 mm) is a typical irregularity, as found in other biomechanical simulation setups [46]. Moreover, the superimposed best-fit straight lines suggest a rather linear correlation between the force, moment, and intrusion distance, which is only applicable to a limited degree.…”

Biomechanical Simulation of Orthodontic En-Bloc Retraction Comparing Compound Technique and Sliding Mechanics Using a HOSEA Robotic Device

“…For the investigation of orthodontic en-bloc retraction, an established biomechanical test stand, HOSEA, was applied with a modified maxillary model [25]. The maxillary model was virtually prepared using the software OnyxCeph 3TM (Version 3.2.185; Image Instruments GmbH, Chemnitz, Germany).…”

“…Robotic force-controlled biomechanical test stands allow the investigation of the behavior of actual orthodontic appliances without the influence of subjectively determined parameters or measurement points [24]. HOSEA is a novel biomechanical test system based on a hexapod platform with parallel kinematics that is autonomously moved by a force-controlled algorithm designed for the investigation of complex multiaxial motion sequences in orthodontics [25]. The algorithm processes the measured forces and moments of the applied mechanics and calculates the resulting movements as a function of feedback parameters.…”

In vitro study examines posterior torque impact on 3D mechanics of anterior teeth in clear aligner treatment

“…Its corrective force is transmitted through the deformation of the archwire, from the brackets on the buccal or lingual surface to the orthodontic teeth. Due to the presence of a gap angle between the archwire and the brackets, and the force application point at the resistance center of the teeth on the buccal or lingual side, fixed orthodontic appliances often result in suboptimal control of the teeth [ 1 ]. In contrast, removable clear aligners, due to their full coverage of the tooth surface, result in more uniform force distribution across all tooth surfaces, closer to the resistance center of the teeth [ 2 ].…”