• The korean journal of orthodontics
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• v.28 no.4 s.69
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• pp.659-668
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• 1998

The purpose of this study was to evaluate the possibility of the decrease of bond strength due to increased thickness of resin base in indirect bracket bonding technique. Metal brackets were bonded to the resin blocks involving bovine lower incisors and the thickness of resin bases was increased by increments of 0.5 mm from 0.0 mm to 2.0 mm. They were divided into two groups, one group is that the thickness of resin base was increased but the loading point from the tooth surface was maintained constantly, the other group is that the loading point from the tooth surface and the resin base thickness were increased concomitantly. The shear bond strength was tested on universal testing machine and the failure patterns were assessed with the adhesive remnant index(ARI). The results were as follows: 1. When the distance from the tooth surface to the loading point was maintained constantly, shear bond strength was increased significantly according to the decrease of distance from the bracket base to the loading point and the increase of resin base thickness. 2. When the distance from the tooth surface to the loading point and the resin base thickness were increased concomitantly, shear bond strength was decreased according to the increase of resin base thickness but significant differences were ignorable. 3. There were no significant differences in ARI scores according to the change in the thickness of resin base. The results of the present study indicated that shear bond strength was not much affected by the thickness of resin base, whereas was decreased according to the increase of distance from bracket base to the loading point.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.99-111
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• 1998

The purpose of this study was to evaluate the positioning errors according to the method of bonding lingual brackets. Dental models of twenty orthodontic patients with malocclusion were selected for this study. The positioning errors were measured on each model that brackets were bonded to. Three different bonding methods were used. For the first method the bracket was bonded intimately to the lingual surface of the model. For the second method, the bracket was bonded intimately to the lingual surface after setting up using articulator. The passive bracketing, bonding the bracket ligated first to ideal archwire, was used after setting up as the last method. The results were as follows: 1. The brackets bonded without setting up showed greater angulation errors in the upper 1st premolar and the lower canine than those in other bonding methods. The brackets bonded without passive bracketing showed greater positioning errors in upper central incisor, lower 1st and End premolars. 2. The brackets bonded without setting up showed greater torque error in lower 2nd premolar than those in other bonding methods. The brackets bonded without passive bracketing showed greater torque errors in all upper teeth, lower 1st and 2nd premolars. 3. The brackets bonded without passive bracketing showed greater rotation errors between upper central incisors, lower central incisors, lower lateral and central incisor, lower canine and lateral incisor. 4. The brackets bonded without setting up showed greater in-out errors between upper canine and lateral incisor than those in other bonding methods. The brackets bonded without passive bracketing showed greater in-out errors between upper central incisors, upper central and lateral incisors, upper 1st and 2nd premolars, lower lateral and central incisors, lower canine and lateral incisor. These results suggest that there is a large amount of positioning error in lingual brackets even by an indirect bonding technique, and it may be reduced by passive bracketing.

• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.259-277
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• 2003

This study was designed to investigate the position of anteroposterior center of resistance for genuine intrusion and the mode of change of the minimum distal force for simultanous intrusion and retraction of the upper and lower incisors according to the increase of labial inclination. For this purpose, we used the three-piece intrusion arch appliance and three-dimensional finite element models of upper and lower incisors. 1. Positions of the center of resistance in upper incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 6m behind the distal surface of the lateral incisor bracket. 2) In $10^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 9mm behind the distal surface of the lateral incisor bracket. 3) In $20^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 12m behind the distal surface of the lateral incisor bracket. 4) In $30^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 16m behind the distal surface of the lateral incisor bracket. 2. Positions of the center of resistance in lower incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 10mm behind the distal surface of the lateral incisor bracket. 2) In $10^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 13m behind the distal surface of the lateral incisor bracket. 3) In $20^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 15m behind the distal surface of the lateral incisor bracket. 4) In $30^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 18m behind the distal surface of the lateral incisor bracket. 3. The patterns of stress distribution were as follows; 1) There were even compressive stresses In and periodontal ligament when intrusion force was applied through determined center of resistance. 2) There were gradual increase of complexity in compressive stress distribution pattern with Increase of the labial inclination when intrusion and retraction force were applied simultaneously. 4. With increase of the labial inclination of the upper and lower incisors, the position of the center of resistance moved posteriorly. And the distal force for pure intrusion was increased until $20^{\circ}$increase of the labial inclination.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1407-1408
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• 2015

현재에는 과거와 달리 표면상 비춰지는 외모의 중요성이 강조되어 치아 교정을 해서 미적 욕구를 충족시키려는 사람들이 증가하고 있다. 특히나 치아를 교정할 때 사용되는 치아교정용 브라켓은 부착되는 위치가 치아 앞면이기 때문에 미관상의 중요성은 치아교정장치 중 가장 크다. 이러한 이유 때문에 미적인 부분을 고려하여 치아색과 유사한 브라켓이 개발되었는데, 이 브라켓은 레진 브라켓이다. 이는 치아 교정에 도움을 주면서 심미성이 우수한 장점이 있지만 음식을 섭취할 때 음식의 색소에 의해 브라켓의 색 변화가 일어난다는 단점이 있다. 본 연구에서는 사람들이 자주 섭취하는 음식이나 음료에 치아교정용 브라켓을 착색시켜 색이 변하는 정도의 차이를 컬러센서를 이용해 측정하였다. 이렇게 측정된 브라켓의 RGB 값은 객관적이고 정량적인 값을 나타낼 수 있다. 이는 브라켓의 변색 뿐만 아니라 치아 미백 치료에도 적용되어 사용될 수 있을 것이다.

• The korean journal of orthodontics
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• v.37 no.4
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• pp.293-304
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• 2007

The purpose of this study was to estimate the fracture resistance of commercially available ceramic brackets to torsional force exerted from arch wires and to evaluate the characteristics of bracket fracture. Methods: Lingual root torque was applied to maxillary central incisor brackets with 0.022-inch slots by means of a $022\;{\times}\;028-inch$ stainless steel arch wire. A custom designed apparatus that attached to an Instron was used to test seven types of ceramic brackets (n = 15). The torque value and torque angle at fracture were measured. In order to evaluate the characteristics of failure, fracture sites and the failure patterns of brackets were examined with a Scanning Electron Microscope. Results: Crystal structure and manufacturing process of ceramic brackets had a significant effect on fracture resistance. Monocrystalline alumina (Inspire) brackets showed significantly greater resistance to torsional force than polycrystalline alumina brackets except InVu. There was no significant difference in fracture resistance during arch wire torsional force between ceramic brackets with metal slots and those without metal slots (p > 0.05). All Clarity brackets partially fractured only at the incisal slot base and the others broke at various locations. Conclusion: The fracture resistance of all the ceramic brackets during arch wire torsion appears to be adequate for clinical use.

• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.401-411
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• 2002

Precise bracket positioning is essential in modem orthodontics. However, there can be alterations in the vertical position of a bracket due to several reasons. The purpose of this study was to evaluate the effect of variations in the vertical bracket position on the crown inclination in Korean patients with normal occlusion. From a larger group of what was considered to be normal occlusions obtained from the Department of Orthodontics, College of Dentistry, Seoul National University, each of the final 10 subjects (6 males and 4 females, with an average age of 22.3 yews) was selected. The dental models of each of the subjects were scanned three-dimensionally by a laser scanner, and measurements drawn from these were made on the scanned dental casts of the subjects were input into the computer program. From this the occlusal plane and the bracket plane were determined. The tooth plane was then constructed to measure the crown inclination on the bracket plane of each tooth. From a practical standpoint, information was obtained on the extent to which the torque of a tooth would be changed as the bracket position was to be moved vertically (in ${\pm}0.5mm,\;{\pm}1.0mm,\;{\pm}1.5mm$) from its ideal position. A one way analysis of the variance (ANOVA) was used to compare each group of the different vertical distances from the bracket plane on a specific tooth. Duncan's multiple comparison test was then performed. There were statistically significant differences in the crown inclination among the groups of different vertical distances for the upper central incisor, upper lateral incisor, upper canine, upper first and second molars, lower first and second premolars, and lower first and second molars (p<0.05). On the upper anterior teeth, upper molars, lower premolars and lower molars, the resultant torque values due to the vertical displacement of the bracket were different depending on the direction of the displacement, occlusal or gingival. This study implies that the torque of these teeth should be handled carefully during the orthodontic treatment. In circumstances in which the bracket must be positioned more gingivally or occlusally due to various reasons, it would be useful to provide the chart of torque alteration of each tooth referred to in this study with its specified bracket prescription.

• The korean journal of orthodontics
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• v.36 no.1 s.114
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• pp.30-44
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• 2006

This study was performed to investigate the location of the ideal bracket positioning plane in lingual orthodontics using the three-dimensional finite element method. Displacement of the anterior teeth were evaluated according to the vertical and the angular movements of the bracket positioning plane. To achieve the ideal movement of anterior teeth in the lingual central plane, the location of the force application point and the amount of the moment applied to the four incisors were evaluated. As the bracket positioning plane was moved parallel toward the incisal edge, uncontrolled tipping and extrusion of the maxillary and the mandibular incisors were increased. But lingual tipping of the crown was decreased in the maxillary and the mandibular canines. As the bracket positioning plane was inclined toward the incisal edge, lingual tipping was increased in the 6 anterior teeth and extrusion of incisors and intrusion of the canine was also increased. As the retraction hook of the canine bracket was elongated, lingual tipping and extrusion of the central incisor and mesial movement and extrusion of the lateral incisor were increased. In the canine, mesial and labial movements of the crown were increased. When the moment was applied to the 4 incisors of the maxillary and the mandibular arch in the lingual central plane, 280 gf-mm in the maxillary central incisor, 500 gf-mm in the maxillary lateral incisor, 170 gf-mm in the mandibular central incisor and 370 gf-mm in the mandibular lateral incisor produced bodily movement of the individual tooth.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.926-928
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• 2011

Material used in aerospace field is exposed in high temperature environments, and the required important factors of material is high strength and low weight. These conditions are satisfying material, as in the titanium alloy has been used mainly. In this paper, Cone shaped brackets that attach to the case, in order to avoid the difficulty of welding position, sheet attached to the brackets welded on, then the way Cone is proposed. Existing methods and proposed method of analysis under the same conditions through thermal stress and structural analysis adequacy of the proposed bracket types were analyzed. The program was used to analysis the ABAQUS/CAE.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.207-215
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• 2005

This study was performed to evaluate clinical practicality of the rebonding method with flowable resin without the removal of the residual resin on the debonded theeth and debonded bracket base after debonding. The samples of the control group (group I) were rebonded with Transbond XT using the usual rebonding method after the residual resin was removed. At experimental group, the brackets were rebonded with Transbond XT(group II) and CharmFil Flow (group III) without removal of residual resin which is the possibility becoming the index (or rebonding to similar position With initial bonding. The Shear bond Strength of the each group was measured. Patterns of bonding failure were evaluated with modified ARI score. and the shear bond strength according to patterns of bonding failure at experimental group was compared. Between the control group $(6.51\pm1.21MPa)$ and the group II rebonded with Transbond XT $(6.30\pm1.01MPa)$ did not have significantly difference in the shear bond strength (p=0.534), and the shear bond strength of group II was Significantly lower 4han the group III rebonded With CharmFil Flow $(7.29\pm1.54 MPa)$ (P=0.009). At control group, there was not large difference if distribution of bending failure pattern. But at experimental group, bond failure did not occur in interface between the resin-enamel. and bond failure between the resin-bracket, within the resin was distributed similarly. There was not significantly difference in the shear bond strength according to patterns of bonding failure at experimental group (P>0.05) The result of this study showed that the method suggested in this study aid flowable resin as rebonding adhesive could be useful in clinically.

• Journal of Periodontal and Implant Science
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• v.28 no.1
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• pp.177-185
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• 1998

Periodontal disease and/or loss of teeth brings pathologic tooth migration that can result in esthetic and occlusal problems. Diastema and general spacing of the teeth, particularly in the anterior segments of the dentition are frequently developed in individuals with advanced periodontal disease. Thus, the overall treatment plan for a patent with advanced periodontal disease often involves periodontal orthodontic combined therapy. Orthodontic treatment in adults with periodontal disease is restricted to tooth alignment with special caution. Indirect bonding can achieve accurate bracket placement. A 38 year old woman with adult periodontitis was treated by periodontal therapy. Subsequently, her diastema was orthodontically corrected by indirect bonding technique. It must be an appropriate case report of periodontal-orthodontic combined therapy.