• The korean journal of orthodontics
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• v.31 no.4 s.87
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• pp.459-465
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• 2001

The purpose of this study was to evaluate the feasibility of the combined use of paste resin with sealant as an adhesive of the indirect bonding. The resin bases made of light-cured resin were bonded to the bovine incisors at a distance of 0.0, 0.2 or 0.4 mm using the sealant only or the mixture of sealant and paste resin. Bond strength of each group was measured using universal testing machine. The results were as follows : 1. The bond strength was reduced in both groups as the distance between enamel surface and resin base increased. 2. The bond strength showed no statistical difference between two groups in case the distance between enamel surface and resin base was 0.0 mm. 3. In case the distance between enamel surface and resin base was 0.2 or 0.4 mm, the sealant with paste resin group showed significantly higher bond strength than the sealant only group. The results of the present study indicate that the use of paste resin with sealant may be desirable as an adhesive in indirect bonding, particularly in case a gap is suspected between enamel surface and resin base.

• 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.28 no.2 s.67
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• pp.277-284
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• 1998

The purpose of this study was to evaluate the propriety of making use of the light-cured resin base in indirect bracket bonding technique by study of shear bond strength and failure patterns according to the material of resin base. Metal brackets were bonded to the stone models of specimens involving bovine lower incisor with chemical-cured(Excel), light-cured(Light-Bond) and thermal-cured(Therma-Cure) resin. They were transferred to the specimens and bonded using sealant. The shear bond strength was tested on Instron. After bracket removal, the bracket base was examined and assessed with the adhesive remnant index(ARI). The results were as follows : 1. No significant differences in shear bond strength were found among the three groups (P>0.05). 2. No significant differences in ARI score were found among the three groups (P>0.05). The above results suggest that light-cured resin base in addition to chemical-cured and thermal-cured resin bases is useful in the indirect bonding technique.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.191-199
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• 2005

This study was experienced in order to obtain the shear bond strength of orthodontic bracket adhesives under the blood contamination that can be occurred during the procedure of bracket bonding under window opening surgery. As a result of this study, shear bond strength of all glass ionomer groups were lower than resin cement groups. However, the strength of uncontaminated and post-contaminated group of glass ionomer was strong enough to perform an orthodontic forced eruption. This study revealed that during a window opening surgery, glass ionomer without etching procedure is available in order to bond a bracket if surface of teeth is not pre-contaminated by blood before the adhesive application. Both simple procedure and less adhesives remnant after bonding failure could make light-cured glass ionomer cement the ultimate choice for racket bonding.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.195-204
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• 2008

Orthodontic brackets often need to be bonded to porcelain such as porcelain fused to metal crowns and porcelain jacket crowns. The purpose of this study was to evaluate the clinical usability of direct bonding system on porcelain teeth by measuring shear bond strength according to various conditions and observing adhesive failure patterns. The specimens, 20 maxillary premolars and 80 porcelain teeth that were produced by duplication of the labial surface of a maxillary first premolar were used and randomly divided into four groups of twenty teeth each. The 5 different preparation procedures tested: (1) application of 37% phosphoric acid on natural teeth, (2) sandblasting on porcelain surfaces, (3) sandblasting and application of 9.6% hydrofluoric acid on porcelain surfaces, (4) sandblasting and application of silane on porcelain surface, (5) sandblasting and application of 9.6% hydrofluoric acid and silane on porcelain surfaces. The metal brackets were bonded with Transbond $XT^{(R)}$ bonding material. The shear bond strength was tested by the micro universal testing machine(Kyung-Sung, Korea) and the amount of residual adhesive on the tooth surface after debonding was examined by stereoscope and assessed with an adhesive remnant index. The results of this study suggest that the direct bonding system on porcelain teeth with sandblasting, HF and porcelain primer is clinically useful.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.3
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• pp.264-273
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• 2022

Due to the development of properties of adhesive materials currently used in dentistry, the bonding ability between the brackets and the tooth enamel has been greatly improved. In general, in situations where cooperation can be obtained, adhesion of the orthodontic bracket through the conventional three-step process can show excellent bonding strength. However, if it is difficult to expect patient cooperation, as in the pediatric dentistry area, or if moisture isolation is not properly performed, the binding strength that does not reach the expected effect. As a result, various products that simplify the process for adhesion are being developed. The aim of this study was to evaluate and compare the shear bonding strength between the conventional 3-step adhesion system, self-etching primer system and one-step adhesion system that reduces the priming process. A total of 60 human maxillary, mandibular premolars were prepared. Group I (control group) were followed conventional 3-step bonding process. Group II were conditioned with self-etching primer. Group III were etched with 37% phosphoric acid and brackets were bonded with self-priming adhesive. The resultant shear bond strength of each group was measured and an adhesive remnant index (ARI) was recorded. The mean shear bond strength of group I, II, III were 14.69 MPa, 11.21 MPa and 12.21 MPa respectively. Significant differences could only be found between group I, II and group I, III (p < 0.05). The ARI indicated no significant difference among all groups.

• The korean journal of orthodontics
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• v.36 no.2 s.115
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• pp.125-135
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• 2006

The purpose of this study was to measure and compare the level of frictional resistance generated from three currently used ceramic brackets; 1, Crystaline $V^{(R)}$, Tomy International Inc., Tokyo, Japan; 2, $Clarity^{(R)}$, 3M Unitek, Monrovia, CA, USA; 3, $Inspire^{(R)}$, Ormco, Orange, CA, USA; with composite resin brackets, Spirit, Ormco, Orange, CA, USA; and conventional stainless steel brackets, Kosaka, Tomy International Inc., Tokyo, Japan used as controls. In this experiment, the resistance to sliding was studied as a function of four angulations $(0^{\circ},\;5^{\circ},\;10^{\circ}\;and\;15^{\circ})$ using 2 different orthodontic wire alloys: stainless steel (stainless steel, SDS Ormco, Orange, CA, USA), and beta-titanium (TMA, SDS Ormco, Orange, CA, USA). After mounting the 22 mil brackets to the fixture and $.019{\times}.025$ wires ligated with elastic ligatures, the arch wires were slid through the brackets at 5mm/min in the dry state at $34^{\circ}C$. Silica-insert ceramic brackets generated a significantly lower frictional force than did other ceramic brackets, similar to that of stainless steel brackets. Beta-titanium archwires had higher frictional resistance than did stainless steel, and all the brackets showed higher static and kinetic frictional force as the angulation increased. When the angulation exceeded $5^{\circ}$, the active configuration emerged and frictional force quickly increased by 2.5 to 4.5-fold. The order of frictional force of the different wire-bracket couples transposed as the angle increased. The silica-insert ceramic bracket is a valuable alternative to conventional stainless steel brackets for patients with esthetic demands.

• The korean journal of orthodontics
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• v.28 no.6 s.71
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• pp.947-954
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• 1998

The purpose of this study was to compare shear bonding strengths and debonding patterns of the ceramic brackets attached on the crystal which were grown on the enamel surface of a tooth with different concentrations of lithium sulphate-contained polyacrylic acid in different application times. Four kinds of concentrations of mixed solutions were made and applied to the enamel surface on extracted human premolars. The solutions were made by adding 0.3M or 0.6M of lithium sulfate to $50\%\;or\;65\%$ of polyacrylic acid with 0.3M sulfuric acid. The solutions were applied for 30 or 60 seconds. After bonding, a universal testing machine was used to measure the shear bond strength, and then observations were made of debonding patterns through the stereoscope. And the enamel surface was observed through the scanning electron microscope to examine the pattern of crystal growth and debonding. The results were as follows: 1. Shear bond strength in the enamel surface treated with $50\%$ polyacrylic acid was higher than that with $65\%$ polyacrylic acid. 2. There were no statistical differences in shear bond strength according to concentration of lithium sulfate and application time of solutions . 3. Enamel surface was almost free of resin debris after debonding. 4. Enamel surface treated with $50\%$ polyacrylic acid showed higher density of crystal growth than that with $65\%$ polyacrylic acid under scanning electron microscope.

• The korean journal of orthodontics
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• v.30 no.5 s.82
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• pp.613-623
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• 2000

The purpose of this study was to amount of the frictional forces with the brackets and wires, ligation methods, dry/wet, offsets, interbracket distances, velocity and to compare them each other by different conditions. This study tested 0.018'x0.025' slot sized 8 types of orthodontic bracket systems and 0.016', 0.016'x0.022' sized stainless steel, NiTi, Cu-NiTi orthodontic wires. One cuspid bracket were positioned on the slide glass and archwire was engaged into bracket and ligated with elastomeric modules. The values of frictional forces were measured with the instron universal testing machine. The results were as follows; 1. Polycrystalline ceramic bracket had the highest mean frictional forces and followed and by ceramic reinforced plastic bracket, metal bracket, plastic bracket with metal slot, monocrystalline ceramic bracket, single bracket, self-ligating bracket, friction free bracket in descending order. The self-ligating bracket showed low frictional forces in the round wires and high frictional forces in the rectangular wires. 2. Stainless steel wires had the least frictional forces and followed by NiTi, Cu-NiTi wires in descending order. Round wires had lower frictional forces then that of rectangular wires. 3. The stainless steel ligation method had significantly greater mean frictional forces them the elastomeric module ligation method. 4. Artificial saliva statistically increased the frictional forces in stainless steel wire, NiTi wire and Cu-NiTi wire. 5. There was a statistically significant difference with offset change 6. There was no statistically significant difference with interbracket distance in stainless steel wires but a significant difference in NiTi wires as the interbracket was decreased. 7 There was no statistically significant difference with velocity change. From the above findings, self-ligating bracket, stainless steel wires and the elastomeric module ligation method might be effective than any other materials to reduce the frictional forces in the orthodontic treatment and can be correlated to clinical situations seen in orthodontic patient care.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.91-96
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• 2020

For the anchor bolts and brackets that fix the stone wall, which is an external finishing material, it is necessary to maintain the performance required for the mechanical structure from the initial design stage and secure high durability. For this, the design and safety evaluation in consideration of the load conditions are necessary, so the structural analysis applying the finite element analysis technique was performed as a method to verify durability. As a result of structural analysis for various shapes for optimal design, a reinforcing structure was added to alleviate the maximum stress generated at the rear part of the bracket in contact with the bolt. In addition, a reinforcing plate was additionally attached to the bracket to relieve the stress concentration of the L-shaped bracket to make the stress distribution uniform, so that the safety factor satisfies the standard conditions. In addition, the fatigue life analysis by cyclic load was performed, and the fatigue safety factor was analyzed. As a result, the durability was obtained.