Mechanical testing and finite element analysis of orthodontic teardrop loop

Coimbra, Maria Elisa Rodrigues; Penedo, Norman Duque; Gouvêa, Jayme Pereira de; Elias, Carlos Nelson; Araújo, Mônica Tirre de Souza; Coelho, Paulo G.

doi:10.1016/j.ajodo.2007.07.017

Cited by 22 publications

(19 citation statements)

References 5 publications

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“…This is associated with the longer wire in the inter-bracket space, which promotes both increase in activation amplitude of the loop and reduction of the amount of HF produced. 11,13,15,16,17 Therefore, it was also found that the HF and L/D ratio released by the loops made of SS and BT were greatly influenced by the presence of the helix, resulting in reduction of the mean magnitude of HF by approximately 21% for the SS teardrop-shaped loop, and by 17% for the BT teardrop-shaped loop.…”

Section: Discussionmentioning

confidence: 95%

Mechanical evaluation of space closure loops in Orthodontics

Rodrigues¹,

Mikami²,

Filho³

et al. 2011

Braz. oral res.

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This study evaluated the mechanical performance of teardropshaped loops and teardrop-shaped loops with helix used in orthodontic space closure. Sixty retraction loops made with 0.019" x 0.025" stainless steel (SS) and beta-titanium (BT) wires were used. They were attached to a testing machine to measure the magnitudes of the sagittal force and the load-deflection ratio necessary for 1 mm, 2 mm and 3 mm activation. The results demonstrated that the BT alloy presented significantly smaller mean values (p < 0.01) of sagittal force and load-deflection than the SS alloy. The loop with the highest mean value of sagittal force and load-deflection was the teardrop-shaped loop (p < 0.01). Differences were observed in the mean values of sagittal force and load-deflection among activations, and the highest mean value was found in the activation of 3 mm, while the smallest mean value was evident in the activation of 1 mm (p < 0.01). It could be concluded that the metallic alloy used and the presence of a helix in configuration of the loops may have a strong influence on the sagittal force produced and on the load-deflection ratio; the teardrop-shaped loops and teardrop-shaped loops with helix in BT presented the release of lighter forces; the teardrop-shaped loop in SS generated a high load-deflection ratio, providing high magnitudes of horizontal force during its deactivation.

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Section: Discussionmentioning

confidence: 95%

Mechanical evaluation of space closure loops in Orthodontics

Rodrigues¹,

Mikami²,

Filho³

et al. 2011

Braz. oral res.

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“…Finite element analysis used in this study is eminently suited for accurately calculating and optimizing complex loops. 9,10 We used this method to systematically analyze forces and moments at the ends of a ubiquitous type of closing loop. Before discussing the results, it is important to note that forces and moments encountered clinically may differ from the pure loop force system we calculated because they may contain out-of-plane curvature effects or the wire play of a 0.016 3 0.022-inch wire in 0.018 3 0.025-inch bracket slots.…”

Section: Discussionmentioning

confidence: 99%

T-loop force system with and without vertical step using finite element analysis

Techalertpaisarn

Versluis

2015

The Angle Orthodontist

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“…The finite element (FE) method was commonly used to analyze the locations of CR in previous studies 2,[12][13][14][15][16] because of its unique ability to deal with completed biostructures in the clinic. [17][18][19] However, the FE method requires special training and is time consuming, which makes it impractical for use in the clinic.…”

Section: Introductionmentioning

confidence: 99%

Estimating the location of the center of resistance of canines

Jiang

Kula

Chen

2015

The Angle Orthodontist

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Objective: To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image. Materials and Methods: The maxillary cone-beam computed tomography (CBCT) scans of 18 patients were used. Finite element (FE) models of the canines and their surrounding tissues were built based on their CBCT scans to calculate the locations of CR. Root length, centroid of the contact surface (CCS), and centroid of projection of the contact surface (CPCS) were also obtained from the images. The CCS and CPCS locations were projected on the tooth's long axis, which were represented as percentages of the root length measured from the root's apex. Results: Using the FE results as the standards, the errors of using CCS or CPCS to estimate CR were calculated. The average location of CR calculated using the FE method was 60.2% measured from the root's apex in the MD direction and 58.4% in the BL direction. The location of the CCS was 60.9%. The difference in CR was 0.7% in the MD direction and 2.5% in the BL direction. The location of CPCS was 60.2% in the MD direction and 59.1% in the BL direction, which resulted in a 0.1% and 0.8% difference with the reference CR, respectively. The average difference of CR in the MD and BL directions was small but statistically significant (P , .05). Conclusion: The locations of the CR of a human canine in the MD and BL directions can be estimated by finding the CPCSs in those directions. (Angle Orthod. 2016;86:365-371.)

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Mechanical testing and finite element analysis of orthodontic teardrop loop

Cited by 22 publications

References 5 publications

Mechanical evaluation of space closure loops in Orthodontics

Mechanical evaluation of space closure loops in Orthodontics

T-loop force system with and without vertical step using finite element analysis

Estimating the location of the center of resistance of canines

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