Auxiliary Springs for Crown and Root Movement

2015 ◽  
pp. 210-229
Keyword(s):  
Root Movement

scholarly journals Biomechanical Effects of Torquing on Upper Central Incisor with Thermoplastic Aligner: A Comparative Three-Dimensional Finite Element Study with and Without Auxillaries

2021 ◽  
pp. 030157422097434
Author(s):  
V Sandhya ◽  
AV Arun ◽  
Vinay P Reddy ◽  
S Mahendra ◽  
BS Chandrashekar ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Three Dimensional ◽  
Central Incisor ◽  
Dimensional Finite Element ◽  
Attachment Model ◽  
Three Dimensional Finite Element ◽  
3D Finite Element Method ◽  
Root Movement ◽  
Maxillary Dentition

Background and Objectives: This study was conducted to determine the effective method to torque the incisor with thermoplastic aligner using a three-dimensional (3D) finite element method. Materials and Methods: Three finite element models of maxilla and maxillary dentition were developed. In the first model, thermoplastic aligner without any auxiliaries was used. In the second and third models, thermoplastic aligner with horizontal ellipsoid composite attachment and power ridge were used, respectively. The software used for the study was ANSYS 14.5 FE. A force of 100 g was applied to torque the upper right central incisor. The resultant force transfer, stress distribution, and tooth displacement were evaluated. Results: The overall tooth displacement and stress distribution appeared high in the model with power ridge, whereas the root movement was more in the horizontal ellipsoid composite attachment model. The model without any auxillaries produced least root movement and stress distribution. Conclusion: Horizontal ellipsoid composite attachment achieved better torque of central incisor than the model with power ridge and model without any auxillaries.

Effect of Non-Uniform Blade Root Friction and Sticking on Disk Stresses

2011 ◽  
Author(s):  
Harold R. Simmons ◽  
Vishwas Iyengar
Keyword(s):  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Hold Time ◽  
Creep Damage ◽  
Peak Stress ◽  
Root Surface ◽  
Maximum Speed ◽  
Blade Root ◽  
Turbine Disks ◽  
Root Movement

Stress levels predicted by conventional disk modeling assumptions are lower than expected to cause conventional creep or fatigue damage consistent with slot failures experienced in some compressor and turbine disks. It was suspected that disparate slot to slot friction at the blade root surface will result in sticking of some blade roots as the turbine is shut down while adjacent blades slip; the un-resisted stuck root would pry the steeples apart causing additional bending stress. Testing of a blade root/disk slot pair in a load frame found that the blade root will stick in place as imposed radial loads decrease. Simulation of blade root movement during shutdown indicates peak stress can increase by 20% or more depending on geometric factors. The slot stress only rises above its maximum speed condition on shutdown (at 80% Max Speed in the example case). This brief stress rise will not cause significant creep damage, but can shorten disk life based on low cycle fatigue or hold time fatigue damage.

Three-dimensional monitoring of root movement during orthodontic treatment

2015 ◽  
Vol 147 (1) ◽  
pp. 132-142 ◽  
Author(s):  
Robert J. Lee ◽  
Andre Weissheimer ◽  
John Pham ◽  
Leslie Go ◽  
Luciane Macedo de Menezes ◽  
...  
Keyword(s):  
Orthodontic Treatment ◽  
Three Dimensional ◽  
Root Movement

scholarly journals From 2D to 3D: Construction of a 3D Parametric Model for Detection of Dental Roots Shape and Position from a Panoramic Radiograph—A Preliminary Report

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Laura Mazzotta ◽  
Mauro Cozzani ◽  
Armando Razionale ◽  
Sabrina Mutinelli ◽  
Attilio Castaldo ◽  
...  
Keyword(s):  
Panoramic Radiograph ◽  
Maximum Error ◽  
Parametric Model ◽  
Parametric Models ◽  
Free Form ◽  
Spline Curves ◽  
Accuracy Level ◽  
Root Movement ◽  
Free Form Surfaces ◽  
Movement Simulation

Objectives. To build a 3D parametric model to detect shape and volume of dental roots, from a panoramic radiograph (PAN) of the patient.Materials and Methods. A PAN and a cone beam computed tomography (CBCT) of a patient were acquired. For each tooth, various parameters were considered (coronal and root lengths and widths): these were measured from the CBCT and from the PAN. Measures were compared to evaluate the accuracy level of PAN measurements. By using a CAD software, parametric models of an incisor and of a molar were constructed employing B-spline curves and free-form surfaces. PAN measures of teeth 2.1 and 3.6 were assigned to the parametric models; the same two teeth were segmented from CBCT. The two models were superimposed to assess the accuracy of the parametric model.Results. PAN measures resulted to be accurate and comparable with all other measurements. From model superimposition the maximum error resulted was 1.1 mm on the incisor crown and 2 mm on the molar furcation.Conclusion. This study shows that it is possible to build a 3D parametric model starting from 2D information with a clinically valid accuracy level. This can ultimately lead to a crown-root movement simulation.

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