• The Journal of the Korean dental association
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• v.11 no.2
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• pp.123-129
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• 1973

The authors measured orthodontic force using the orthodontic materials of the Rocky Mountain Products Company. The results were as follows : ① Use latex of wide diameter in long distance, and when the latex of wide diameter activated by four or five times, we obtained a optimal force. ② The authors obtained canine retractions with sectional arch. Activation of sectional arch began at 1mm and had to do not activations of 3mm more. ③ The leveling started from .014 green round wire and finished to. 0.16" green Elgiloy round wire. Permit only a mild force in ideal arch form, in rectangular wire. ④ Fundamentaly, elastic thread obtained maximum force by activating as two times. ⑤ Coil spring obtained more heavy force from short distance than long distance.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.198-203
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• 2004

In these days, the orthodontic surgery including lingual orthodontics has attracted a person' attention due to its functional and esthetic appreciation. The delivery of the optimal orthodontic treatment is greatly influenced by clinician' ability to predict and control the tooth movement by applying force system to dentition. The skeletal anchorage system with the miniscrew has been used recently in the lingual orthodontics to assist the anchorage control. Precise understanding of the force system produced from the various orthodontic appliances is necessary. However, the qualitative and quantitative effect of the miniscrew has not been identified well. In this paper, three dimensional finite element analysis is introduced on the lingual orthodontics to investigate the effect of anterior retraction force on the miniscrew and transpalatal arch wire. The purpose of this study is to determine the location of the miniscrew and the point of force application of the anchorage system in the lingual orthodontics. The analysis results indicate the efficient position of the miniscrew and the transpalatal arch wire in the lingual orthodontics.

• Restorative Dentistry and Endodontics
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• v.39 no.3
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• pp.226-229
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• 2014

Orthodontic extrusion is usually performed by means of a fixed orthodontic appliance that utilizes arch wire attached to adjacent teeth and transfers the desired force by elastic from the wire to the root. However, clinicians often encounter cases where the bonding required for tooth traction is not possible because the adjacent teeth have been restored with ceramic or veneer. The purpose of this case report is to describe a modified orthodontic extrusion appliance that is useful when conventional orthodontic treatment is not possible. The modified appliance was fabricated using an artificial tooth, clear plastic sheeting, and a braided fiber-reinforced composite strip that covered adjacent teeth without bonding. It satisfied the esthetic and functional needs of the patient and established the optimal biologic width.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1237-1244
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• 2004

The orthodontic surgery including lingual orthodontics has recently attracted a person's attention due to its functional and esthetic appreciation. The skeletal anchorage with the miniscrew is newly adopted in the lingual orthodontics to assist the upholding ability. The appliciation needs to understand the mechanism of the orthodontic appliance and its related orthodontic correction for optimal orthodontic treatment. There is, however, few information about the qualitative and quantitative effect of the orthodontic appliance with the miniscrew has not been well identified. In this paper, three dimensional finite element analysis is introduced to the lingual orthodontics in order to investigate the effect of the anterior retraction force on the miniscrew and transpalatal arch wire. The analysis determines the adequate location of the miniscrew and the point of force application of the anchorage system in the lingual orthodontics. The analysis results demonstrate the effect of the position of the miniscrew and the transpalatal arch wire on the lingual orthodontics.

• The korean journal of orthodontics
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• v.46 no.4
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• pp.228-241
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• 2016

Objective: Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Methods: Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor ${\kappa}B$ ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. Results: On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. Conclusions: These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR.

• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.3
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• pp.180-190
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• 2019

Patients who have a moderate periodontitis with pathologic tooth migration of maxillary incisors, it is necessary not only periodontal treatment for reduce periodontal inflammation, but also orthodontic treatment to teeth repositioning. For orthodontic treatment, it is necessary to apply less force and careful considerations of the center of resistance of the tooth and optimal force of tooth movement. At this time, the segmental arch applied only to the target teeth, is more effective and predictable, because applied force and direction can be controlled. In addition, to design the orthodontic appliance that can prevent the unwanted tooth movement that used as an anchorage is important. In recent years, various types of skeletal anchorage system have been used for preventing loss of the anchorage. We reported the patient who had extruded maxillary central incisor due to pathologic tooth migration, treated by a successful periodontal-orthodontic multidisciplinary treatment using an orthodontic appliance designed to apply less traumatic force and reduce an anchorage loss.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.27-32
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• 2022

There has always been a demand for orthodontic treatment. Orthodontic treatment allows tooth to be arranged by flexible arch wire fixed with tooth-attached brackets. Arch wire generate constant pressure to tooth brackets which moves the teeth to proper place. When the bracket transmits force, the braced wing of the bracket may deform. Deformed tie wing will lead to lost tension of elastic ligature. Then, lacking grip between tie wing and ligature might delay the tooth movement. Furthermore, tooth brackets used for orthodontic treatment make contact with in direct oral surface and this cause feeling of irritation that comes from height of tooth braces. This study suggests an optimal teethe bracket design to make up for inconvenience by shorten the height of bracket and complement the shape of bracket to reduce strain rate using finite element analysis. As a result, new optimal design of teethe bracket indicates lower strain rate of the bracket wing and takes good effects of shorten body height in terms of convenience.

• The korean journal of orthodontics
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• v.18 no.1 s.25
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• pp.25-53
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• 1988

Retraction of canines represents a fundamental stage in a considerable number of orthodontic treatment. Correct position of the canine after retraction is most important for function, stability, and esthetics. The purpose of this study was to investigate the stress in the periodontal tissue at the initial phase during canine retraction using various types of sectional retraction springs, by finite element method. Three dimensional model of tooth, periodontal ligament, bone and eight springs were simulated and tested. The following results were obtained. 1. In sectional retraction springs, increasing number of helix and the closed loop in preference to the open loop provided an decrease in horizontal force. Without angulating the arms of spring, the T-loop revealed the highest Moment-to-force ratio. 2. The Moment-to-force ratio raised by angulating mesial and distal arms of spring, but very large horizontal force was applied to canine. 3. When optimal force and optimal moment was applied to canine, the stress induced was homogeneous and the difference of stress value from cervix to the apex was little.

• The korean journal of orthodontics
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• v.48 no.1
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• pp.3-10
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• 2018

Objective: The purpose of this study was to predict the optimal bending angles of a running loop for bodily protraction of the mandibular first molars and to clarify the mechanics of molar tipping and rotation. Methods: A three-dimensional finite element model was developed for predicting tooth movement, and a mechanical model based on the beam theory was constructed for clarifying force systems. Results: When a running loop without bends was used, the molar tipped mesially by $9.6^{\circ}$ and rotated counterclockwise by $5.4^{\circ}$. These angles were almost similar to those predicted by the beam theory. When the amount of tip-back and toe-in angles were $11.5^{\circ}$ and $9.9^{\circ}$, respectively, bodily movement of the molar was achieved. When the bend angles were increased to $14.2^{\circ}$ and $18.7^{\circ}$, the molar tipped distally by $4.9^{\circ}$ and rotated clockwise by $1.5^{\circ}$. Conclusions: Bodily movement of a mandibular first molar was achieved during protraction by controlling the tip-back and toe-in angles with the use of a running loop. The beam theory was effective for understanding the mechanics of molar tipping and rotation, as well as for predicting the optimal bending angles.

• The korean journal of orthodontics
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• v.24 no.1 s.44
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• pp.87-94
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• 1994

The purpose of this study was to evaluate the torque effect of othodontic wires. Ten types of orthodontic wires (five types of materials, two types of cross-sectional dimensions) were selected. Each group of ire type was constituted with five specimens. These specimens were tested on the universal testing machine(Instron) with specially-designed jig. The torque-twist curve of each wire was obtained and the results were analyzed statistically. The results were as follows. 1. 0.017'$\times$ 0.025' wire showed more torque effect than 0.016'$\times$ 0.022' wire at the same twist. 2.Torque effect was the greatest in stainless steel and the least in Nitinol. 3.The maximum amount of torque was the greatest in heat-treated Blue Elgiloy and the least in Nitinol.