• Geomechanics and Engineering
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• v.36 no.1
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• pp.71-81
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• 2024

This study analyzes the pull-out behavior of tunnel-type anchorage under various joint conditions, including joint direction, spacing, and position, using a finite element analysis. The validity of the numerical model was evaluated by comparing the results with a small-scaled model test, and the results of the numerical analysis and the small-scaled model test agree very well. The parametric study evaluated the quantitative effects of each influencing factor, such as joint direction, spacing, and position, on the behavior of tunnel-type anchorage using pull-out resistance-displacement curves. The study found that joint direction had a significant effect on the behavior of tunnel-type anchorage, and the pull-out resistance decreased as the displacement level increased from 0.002L to 0.006L (L: anchorage length). It was confirmed that the reduction in pull-out resistance increased as the number of joints in contact with the anchorage body increased and the spacing between the joints decreased. The pull-out behavior of tunnel-type anchorage was thus shown to be significantly influenced by the position and spacing of the rock joints. In addition, it is found that the number of joints through which the anchorage passes, the wider the area where the plastic point occurs, which leads to a decrease in the resistance of the anchorage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.247-255
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• 2021

The Ulsan anchorage has not secured a sufficient area than the anchorage demand, and the criteria for objective evaluation are not clearly defined. In this study, a general formula to solve the problems of the current anchorage density and occupancy concept was derived, and new adequacy evaluation criteria were proposed. The proposed criteria were applied to the Ulsan E anchorage to evaluate the suitability of the anchorage. The anchorage density and occupancy of the E1 anchorage were 129 % and 122 %, respectively, showing that both evaluation techniques exceeded 100 %, requiring anchorage expansion according to the evaluation criteria. A plan to expand the anchorage was reviewed considering the traffic pattern and the distance from the pilot boarding point. Therefore, a plan to open 35˚ on a sector at the end of the Ulsan No. 1 fairway was developed, and its suitability was verified. Base on the verification results, there was a part of the overlap between the extended area and the traffic track on the south of the E3 anchorage, but the possibility of affecting the marine traffic was minimal. In addition, it was confirmed that anchorage adequacy was achieved.

• Journal of Korean Dental Science
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• v.3 no.1
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• pp.5-10
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• 2010

This study sought to compare the amounts of posterior anchorage loss during the en masse retraction of the upper anterior teeth between orthodontic mini-implant (OMI) and conventional anchorage reinforcement (CAR) such as headgear and/or transpalatal arch. The subjects were 52 adult female patients treated with sliding mechanics (MBT brackets, .022" slot, .019X.025" stainless steel wire, 3M-Unitek, Monrovia, CA, USA). They were allocated into Group 1 (N=24, Class I malocclusion (CI), upper and lower first premolar (UP1LP1) extraction, and CAR), Group 2 (N=15, Cl, UP1LP1 extraction and OMI), and Group 3 (N=13, Class II division 1 malocclusion, upper first and lower second premolar extraction, and OMI). Lateral cephalograms were taken before (T0) and after treatment (T1). A total of 11 anchorage variables were measured. Analysis of variance was used for statistical analysis. There was no significant difference in treatment duration and anchorage variables at T0 among the three groups. Groups 2 and 3 showed significantly larger retraction of the upper incisor edge (U1E-sag, 9.3mm:7.3mm, P<.05) and less posterior anchorage loss (U6M-sag, 0.7~0.9mm:2mm, P<.05; U6A-sag, 0.5mm:2mm, P<.01) than Group 1. The ratio of retraction amount of the upper incisor edge per 1 of anchorage loss in the upper molar made for the significant difference between Groups 1 and 2 (4.6mm:7.0mm, P<.05). Group 3 showed a relatively distal inclination of the upper molar (P<.05) and the intrusion of the upper incisor and first molar (U1E-ver, P<.05; U6F-ver, P<.05) compared to Groups 1 and 2. Although OMI could not shorten the treatment duration, it could provide better maximum posterior anchorage than CAR.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.1
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• pp.39-46
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• 2018

In this paper, an unbonded post-tensioning anchorage for a single-stranded wire that allows more efficient stress distribution in the post-tensioned anchorage zone was developed by using a finite element analysis using a commercial program. The stress analysis was carried out using a 3D model in the anchorage zone of the concrete member using the developed anchorage. The result of analysis ensured that the developed anchorage reduced the maximum bursting stress in anchorage zone compared to the case of existing anchorage and the location where maximum bursting stress also occurred closer to the anchorage. Bursting force was calculated using AASHTO, modified $M{\ddot{o}}rsch$ and Stone. As a result, it was concluded that an effective reinforcement design of the anchorage zone can be designed by modified $M{\ddot{o}}rsch$.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.699-706
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• 1999

Anchorage plays an important role in orthodontic treatment. Endosseous implants may be considered adequate firm anchorage. However, clinicians have hesitated to use endosseous implants as orthodontic anchorage because of limited implantation space, high cost, and long waiting period before osseointegration occurs. Recently, some clinicians have tried to use titanium miniscrews and microscrews in treatment due to their many advantages such as ease of insertion and removal, low cost, immediate loading, and the ability to place microscrews in any area of alveolar bone. The author treated a case with skeletal cortical anchorage using titanium microscrew implants. During six months of orthodontic force application from skeletal cortical anchorage, the author could get 4 mm bodily retraction and intrusion of upper anterior teeth. The most outstanding result was a 1.5 mm posterior refraction of the upper posterior teeth. The titanium microscrew implants had remained firm and stable throughout treatment. These results indicate that skeletal cortical anchorage might be a very good option.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.249-255
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• 2002

Recently, Skeletal Anchorage System (SAS) has been focused clinically with the view point that it could provide the absolute intraoral anchorage. First, it began to be used for the patient of orthognathic surgery who had difficulty in taking intermaxillary fixation due to multiple loss of teeth. And then, its uses have been extended to many cases, the control of bone segments after orthognathic surgery, stable anchorage in orthodontic treatment, and anchorage for temporary prosthesis and so on. SAS has been developed as dental implants technique has been developed and also called in several names; mini-screw anchorage, micro-screw anchorage, mini-implant anchorage, micro-implant anchorage (MIA), and orthosystem implant etc. Now many clinicians use SAS, but the anatomical knowledges for the installed depth of intraosseous screws are totally dependent on general experiences. So we try to study for the cortical thickness of maxilla and mandible in Korean adults without any pathologic conditions with the use of Computed Tomography at the representative sites for the screw installation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.398-404
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• 2014

The criteria of operating anchorage and the unit of anchorage capacity have not been unified and the different terms have been used in same matters in each regulations related to the anchorages provided in major domestic ports. The competent authorities and vessels which are going to use anchorages are confused due to those situations. This paper suggests the schemes to unify criteria of operating anchorage, the unit of anchorage capacity and terms used in same matters through reviewing the anchorage operating regulations provided in major domestic ports. In addition, this paper suggests that the principles of anchorage naming, the unit of anchorage capacity and the number of vessels that can be accommodated should be established at the next revision of regulations through reviewing the status of anchorages in major foreign ports to minimize the confusion on operating anchorages.

• The korean journal of orthodontics
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• v.49 no.5
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• pp.279-285
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• 2019

Objective: This study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance. Methods: Patients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome. Results: Thirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater. Conclusions: In comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

• The Journal of the Korean dental association
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• v.52 no.9
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• pp.532-540
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• 2014

In contemporary orthodontic treatment skeletal temporary anchorage devices (TADs) are routinely used as an anchorage reinforcement to provide improved anchorage control with reduced requirement for patient's compliance. For past few decades, various types of TADs have been explored and their clinical application has been expanded. Therefore, the purpose of this article is to present three major types of orthodontic skeletal anchorage devices and discuss their rationale, clinical procedure, insertion site, and potential complications as well as their management.

• Smart Structures and Systems
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• v.15 no.2
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• pp.375-393
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• 2015

In this study, local dynamic characteristics of mountable PZT interfaces are numerically analyzed to verify their feasibility on impedance monitoring of the prestress-loss in tendon anchorage subsystems. Firstly, a prestressed tendon-anchorage system with mountable PZT interfaces is described. Two types of mountable interfaces which are different in geometric and boundary conditions are designed for impedance monitoring in the tendon-anchorage subsystems. Secondly, laboratory experiments are performed to evaluate the impedance monitoring via the two mountable PZT interfaces placed on the tendon-anchorage under the variation of prestress forces. Impedance features such as frequency-shifts and root-mean-square-deviations are quantified for the two PZT interfaces. Finally, local dynamic characteristics of the two PZT interfaces are numerically analyzed to verify their performances on impedance monitoring at the tendon-anchorage system. For the two PZT interfaces, the relationships between structural parameters and local vibration responses are examined by modal sensitivity analyses.