Objective: To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion.
Materials And Methods: An in vitro orthodontic force tester (OFT) was used to measure the forces and moments from a typodont where the buccal teeth were translated lingually 0.2 mm to simulate expansion. Hemi-ellipsoid and rectangular attachments with either 0.5 or 1.0 mm thickness were added on upper right first premolar (UR4), second premolar (UR5) and first molar (UR6). Analysis of variance (ANOVA) was used to determine two-way interactions among the factors on the outcomes.
Results: The interactions between group and tooth were significant for all outcomes (p < 0.001). The greatest buccal forces (Fy) were observed with 1 mm rectangular attachment on the UR4 (0.78 ± 0.29 N), with 1 mm hemi-ellipsoid attachment on UR5 (0.28 ± 0.21 N) and with 0.5 mm rectangular attachment on UR6 (1.71 ± 0.18 N). The greatest buccolingual moments (Mx) were obtained with 1 mm rectangular attachment on UR4 (5.61 ± 1.43 Nmm), without any attachments on UR5 (3.33 ± 1.73 Nmm) and with 1 mm hemi-ellipsoid attachment on UR6 (4.18 ± 4.31).
Conclusion: Direct attachment shape and size had a significant effect on the orthodontic forces and moments generated by thermoplastic aligners during simulated expansion. Although loads varied significantly by tooth morphology and its location in the arch, best forces and moments for expansion were obtained with 1 mm rectangular attachments on UR4s, 1 mm hemi-ellipsoid attachments on UR5s and 0.5 mm rectangular attachments on UR6s.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1111/ocr.12865 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The real rotational capacity of the human joints - the muscular and gravitational torques and the foot as a platform.
Acta Bioeng Biomech
September 2024
Jagiellonian University Medical College, Faculty of Medicine, Department of Bioinformatics and Telemedicine, Kraków, Poland.
The purpose was to answer what is the relationship between torques acting on the human body, how does the triceps calf muscle balance the weight of a tilted body and what is the foot's role in the titling body? Two research models were developed. Model 1 - the one-sided lever system consists of a flat bar with, an axis of rotation, used to determine the weight and torque at a given point on it. Model 2 - the two-sided lever system consists of a flat bar imitating a tilted body counteracted by the Achilles tendon, and a platform imitating a foot.
View Article and Find Full Text PDFMolecular Engineering of Amino Acid Crystals with Enhanced Piezoelectric Performance for Biodegradable Sensors.
Angew Chem Int Ed Engl
January 2025
Nanjing University, Department of Physics, 22 Hankou Road, 210093, Nanjing, CHINA.
Amino acid crystals have emerged as promising piezoelectric materials for biodegradable and biocompatible sensors; however, their relatively low piezoelectric coefficients constrain practical applications. Here, we introduce a fluoro-substitution strategy to overcome this limitation and enhance the piezoelectric performance of amino acid crystals. Specifically, we substituted hydrogen atoms on the aromatic rings of L-tryptophan, L-phenylalanine, and N-Cbz-L-phenylalanine with fluorine, resulting in significantly elevated piezoelectric coefficients.
View Article and Find Full Text PDFShear wave elastography reveals passive and active mechanics of triceps surae muscles in vivo: From shear modulus-ankle angle to stress-strain characteristics.
J Appl Physiol (1985)
January 2025
Experimental Biomechanics Group, Institute of Structural Mechanics and Dynamics in Aerospace Engineering, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Germany.
Characterizing individual muscle behavior is crucial for understanding joint function and adaptations to exercise, diseases, or aging. Shear wave elastography (SWE) is a promising tool for measuring the intrinsic material properties of muscle. This study assessed the passive and active shear modulus of the triceps surae muscle group in 14 volunteers (7 females, 25.
View Article and Find Full Text PDFIdentifying the Primary Kinetic Factors Influencing the Anterior-Posterior Center of Mass Displacement in Barbell Squats: A Factor Regression Analysis.
Sensors (Basel)
January 2025
Faculty of Sports Science, Ningbo University, Ningbo 315211, China.
Barbell squats are commonly used in strength training, but the anterior-posterior displacement of the Center of Mass (COM) may impair joint stability and increase injury risk. This study investigates the key factors influencing COM displacement during different squat modes.; Methods: This study recruited 15 male strength training enthusiasts, who performed 60% of their one-repetition maximum (1RM) in the Front Barbell Squat (FBS), High Bar Back Squat (HBBS), and Low Bar Back Squat (LBBS).
View Article and Find Full Text PDFResearch on Lateral Stability Control of Four-Wheel Independent Drive Electric Vehicle Based on State Estimation.
Sensors (Basel)
January 2025
School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
This paper proposes a hierarchical framework-based solution to address the challenges of vehicle state estimation and lateral stability control in four-wheel independent drive electric vehicles. First, based on a three-degrees-of-freedom four-wheel vehicle model combined with the Magic Formula Tire model (MF-T), a hierarchical estimation method is designed. The upper layer employs the Kalman Filter (KF) and Extended Kalman Filter (EKF) to estimate the vertical load of the wheels, while the lower layer utilizes EKF in conjunction with the upper-layer results to further estimate the lateral forces, longitudinal velocity, and lateral velocity, achieving accurate vehicle state estimation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!