• 대한치과교정학회지
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• 제50권6호
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• pp.401-406
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• 2020

Objective: To investigate and compare the slot sizes and parallelism of metal injection molding (MIM) and computerized numerical control (CNC) brackets. Methods: The following four MIM bracket series with 0.022-inch (in) slots were selected for investigation: Di MIM mini Twin (Ortho Organizers), Mini Diamond Roth (Ormco), Gemini MBT (3M Unitek), and Formula R Roth (Tomy). The following four CNC bracket series with 0.022-in slots were selected for investigation: Econoline MBT (Adenta), Legend mini MBT (GC Orthodontics), Crown mini MBT (Adenta), and Evolve MBT (DB Orthodontics). The slot dimensions were measured using an optical microscope (XTCam-D310M; Mitutoyo) with a resolution of 1 ㎛. The results were statistically analyzed using one-way analysis of variance and the Tukey post-hoc test with a significance level of 0.05. Results: The results indicated that all the investigated slot sizes were oversized with respect to the manufacturers' specifications (0.022 in). Among the eight bracket series, the Di MIM bracket (MIM) was the most oversized by 10.4%, whereas the Evolve bracket (CNC) was the least oversized by 2.6%. The slots in seven of the bracket series had divergent walls instead of parallel ones. The Evolve bracket alone had parallel slot walls. Conclusions: Regardless of the manufacturing method, all the slot sizes of the brackets investigated in this study were significantly oversized; most of the slot walls were nonparallel, except for those of the Evolve bracket. This study could not establish that the CNC method was more accurate than the MIM method in manufacturing bracket slots.

• 대한치과기공학회지
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• 제33권1호
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• pp.47-54
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• 2011

Purpose: To investigate shear bonding strength between dental zirconia ceramics with different surface treatment and metal bracket. Methods: Zirconia ceramics(LAVA, 3M ESPE, USA) were divided to 4 groups according to their surface treatment; no surface treatment(G1), sand blasting(G2), silane coating(G3), and sand blasting+silane coating(G4). Specimens were bonded to metal bracket using resin bond($Transbond^{TM}XT$, 3M Unitek, USA). Shear bond strength was measured using universal test machine(3366 INSTRON. U.S.A) with cross head speed of 1 mm/min. Microstructural investigation for fracture surface was performed after shear test. Results: Shear bonding strengths of single surface treatment groups (G2 and G3) were higher than no treatment group(G1). Combined Treatment Group (G4) showed the highest shear bond strength of 9.15MPa. Microstructural observation shows that higher shear bonding strength was obtained when debonding was occurred at metal bracket/resin interface rather than zirconia ceramic/resin interface. Conclusion: Surface treatment of zirconia is necessary to obtain higher bonding strength. Combined treatment can be more effective when surface the surfaces are kept clean and homogeneous.

• 대한치과교정학회지
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• 제21권3호
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• pp.543-560
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• 1991

Practitioners are aware of the presence of friction between bracket system and archwire during sliding movement of teeth. Clinically a mesiodistally applied force must exceed the frictional force to produce a tooth movement. The objective of this study were to determine, on a dry condition, changes in magnitude of friction with respect to load, 3rd order inclination (Torque), archwire materials and ligature type. Three wire alloys (Stainless Steel, TMA, NiTi) in two wire sizes (.016, .016x, .022 inch) were examined respect to two bracket system (Straight, Standard), and two ligature type (Metal, Plastic ligature) at three levels of load (100g, 150g, 200g). The results were as follows; 1. Frictional resistance was found to increase with increasing load for S.S., TMA, NiTi. 2. The straight bracket system was exhibited more frictional force than standard bracket system for .016x, .022 S.S. tightly ligated metal ligature. But, torque difference did not increase friction for loose metal ligature & plastic ligature. 3. Regardless of the ligature type, torque and load, stainless steel wire sliding against stainless steel exhibited the lowest friction, and TMA sliding against stainless steel exhibited the highest friction. 4. The loose stainless steel ligature generated lower frictional resistance than plastic ligature in all experimental groups. 5. The following factors affected friction in decreasing order; wire material ligature type, and load.

• 대한치과교정학회지
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• 제37권5호
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• pp.376-385
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• 2007

고정성 장치를 이용한 교정 치료는 심미적 개선이 주목적 중 하나이나, 금속재 브라켓은 치료기간 동안 비심미적으로 보이는 단점이 있다. 이러한 이유로 치아색과 유사한 심미적 브라켓이 선호되었으나 호선과의 마찰저항이 금속재 브라켓보다 큰 것으로 알려져 있다. 본 연구는 최근 개발된 심미적 브라켓의 일종인 인산칼슘재 브라켓의 마찰저항을 측정하고 기존 금속재 브라켓과 금속슬롯 삽입형 도재 브라켓과의 마찰저항의 차이를 구명(究明)해 보고자 하였다. 실험군으로서 인산칼슘 재질의 Hyaline II (Tomy, Tokyo, Japan) 브라켓을, 대조군으로서 metal slot이 삽입된 도자기 재질인 Clarity (3M Unitek, Monrovia, CA, USA) 브라켓과 스테인레스 스틸 금속재 브라켓인 Kosaka (Tomy, Tokyo, Japan) 브라켓을 사용하고, $0.019\;{\times}\;0.025$ 인치 스테인레스 스틸 강선 (3M Unitek, Monrovia, CA, USA)을 이용하며 결찰재는 합성고무링 (Ormco, Glendora, CA, USA)을 사용하였다. 치아의 생리학적 환경을 재현하기 위해 모의 생물학적 모형을 고안하였으며 이에 강선을 삽입하여 load cell (Push & pull gauge, RX-2 AIKOH, Osaka, Japan)로 분당 5 mm로 견인하며 만능시험기(Instron4467, Instron, Norwood, MA, USA)로 마찰저항을 측정하였다. 실험결과, 실험군인 인산칼슘 재질 브라켓의 마찰저항은 대조군인 금속슬롯 삽입형 도재 브라켓 보다 작고 (p < 0.01) 금속재 브라켓의 마찰저항보다 크게 나타나 (p < 0.05), 인산칼슘재 브라켓은 심미적 측면에서 금속재 브라켓을, 효율적 측면에서 금속슬롯 삽입형 도재 브라켓을 대체하여 사용 가능함을 시사하였다.

• 대한치과교정학회지
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• 제36권3호
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• pp.207-217
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• 2006

사회 문화적 발달과 함께 심미적 요구가 증가되면서 교정 환자 수의 증가와 함께 교정 치료 중의 심미성에 대한 요구도 늘어나고 있다. 치료 중 심미성을 증진시키기 위한 목적으로 세라믹 브라켓이 개발되어 널리 사용되고 있으나 세라믹 자체의 취성(brittleness), 대합치의 마모뿐만 아니라, 임상적으로 높은 마찰 저항이 그 문제점으로 지적되고 있다. 본 연구는 세라믹 브라켓의 마찰 저항을 알아보고 그 개선방안을 찾는데 지침이 되고자 하는 목적으로 시행하였다. 연구 재료로는 마찰 저항을 줄이기 위해 금속 슬롯이 삽입된 다결정 세라믹 브라켓과 금속 슬롯이 삽우되지 않은 단결정 세라믹 브라켓과 금속 브라켓을 이용하였으며, $.019{\times}.025$ 스테인리스 와이어를 브라켓 슬롯에 대해 $0^{\circ},\;10^{\circ}$의 각도를 부여하여 만능시험기상에서 이동시켜 그때의 정적, 동적 마찰력을 측정하였다. 연구 결과, 전체적인 평균 마찰력은 금속 브라켓, 금속 슬롯이 삽입된 다결정 세라믹 브라켓, 단결정 세라믹 브라켓 순으로 증가하였다. 브라켓 슬롯과 와이어 사이의 각도가 $0^{\circ}$일 때가 $10^{\circ}$일 때에 비해서 낮은 마찰 저항을 보였으며, 브라켓 슬롯과 와이어 사이의 각도가 $10^{\circ}$일 때 단결정 세라믹 브라켓의 동적, 정적 마찰 저항은 금속 브라켓이나 금속 슬롯이 삽입된 다결정 세라믹 브라켓에 비해 유의성 있게 크게 나타났다 (p<0.05). 본 연구를 통해서 금속 브라켓에 비해 세라믹 브라켓, 특히 금속 슬롯이 삽입되지 않은 단결정 세라믹 브라켓의 마찰 저항이 높은 것을 확인할 수 있었으며, 브라켓 슬롯과 와이어간의 각도가 증가하면 마찰 저항도 커지는 것을 확인할 수 있었다. 따라서 마찰력을 줄이기 위한 세라믹 브라켓의 개발과 함께 교정 치료 시 과도한 치관 경사를 막음으로써 마찰 저항을 줄이고 심미성을 유지하면서 치료의 효율을 높이도록 해야할 것이다.

• Journal of Korean Dental Science
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• 제4권2호
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• pp.46-51
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• 2011

Purpose: For aesthetic reasons, composite resin brackets are widely used. However, related studies are rare. This pilot study sought to compare the stress distributions in two commercially available composite resin brackets with metal slot. Materials and Methods: Two commercially available resin brackets -- full-metal slot resin bracket (fSRB) and partial-metal slot resin bracket (pSRB) with straight wire appliance dimension of $0.022{\times}0.028$ in -- were selected. In each bracket, 3-dimensional finite element models were constructed, and stress level was evaluated using finite element analysis. By loading the tipping force and torsion moment, which are similar to those applied by the stainless steel rectangular wire ($0.019{\times}0.025$ -in), stress distributions were calculated, and von Mises stress values were obtained. Results: In pSRB and fSRB, the stress value of the torque moment was much higher than that of the tipping force. The pSRB showed higher stress value than fSRB in both tipping force and torque moment because of the difference in size and configuration of the metal frame inserted into the slot. More stress was also found to be concentrated on the slot area than the wing area in fSRB. Conclusion: The slot form of fSRB was found to be more resistant to the stress of tipping and torque than the slot form of pSRB. In addition, the slot areas -- rather than the wing areas -- of the bracket showed breakage susceptibility. Therefore, resistance to the torque moment on the slot area should be considered in bracket design.

• 대한치과교정학회지
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• 제35권2호
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• pp.116-126
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• 2005

본 연구는 고정성 장치를 이용한 교정 치료에서 브라켓과 교정용 호선 사이의 활주 이동 동안 발생하는 마찰력에 디자인과 재질이 다른 각각의 브라켓과 여러 종류의 호선 다양한 브라켓-호선 각도 등이 어떤 영향을 미치는가를 알아보기 위하여 4종의 브라켓 (stainless steel twin 브라켓인 Gemini, 좁은 근원심 폭경과 single bracket의 디자인이 포함된 Mini Uni-Twin. metal-reinforced 세라믹 브라켓인 Clarity. 세라믹 브라켓인 Transcend)을 사용하고, 3종의 교정용 호선(0.015"$0.010\times0.022"$ stainless steel 호선, 0.010" Nitinol)을 이용하여 브라켓-호선 각도를 각각 $0^{\circ},\; 3^{\circ}8^{\circ},\; 9^{\circ}$로 조절하면서 실험한 결과, Gemini는 유의하게 가장 낮은 정지, 운동 마찰력을 보였으며 (P<0.001). Clarity는 $0^{\circ}$의 브라켓-호선 각도에서 Transcend는 $5^{\circ}와\;9^{\circ}$의 각도에서 유의하게 가장 높은 정지, 운동 마찰력을 보였고 (P<0.001) $0.016{\times}0.022"$ stainless steel 각형 호선은 유의하게 가장 높은 정지, 운동 마찰력을 보였으며 (P<0.01). 0.016" stainless steel 원형 호선은 $0^{\circ}와\;3^{\circ}$의 브라켓-호선 각도에서 (P<0.01), 0.016" Nitinol은 $8^{\circ}와\;9^{\circ}$의 각도에서 (P<0.001) 유의하게 가장 낮은 정지. 운동 마찰력을 보였고 브라켓-호선 각도가 증가함에 따라 유의하게 정지, 운동 마찰력도 증가하였다 (P<0.001)

• 대한치과교정학회지
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• 제45권6호
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• pp.299-307
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• 2015

Objective: The aims of this study were to compare the shear bond strength between orthodontic metal brackets and glazed zirconia using different types of primer before applying resin cement and to determine which primer was more effective. Methods: Zirconia blocks were milled and embedded in acrylic resin and randomly assigned to one of four groups: nonglazed zirconia with sandblasting and zirconia primer (NZ); glazed zirconia with sandblasting, etching, and zirconia primer (GZ); glazed zirconia with sandblasting, etching, and porcelain primer (GP); and glazed zirconia with sandblasting, etching, zirconia primer, and porcelain primer (GZP). A stainless steel metal bracket was bonded to each target surface with resin cement, and all specimens underwent thermal cycling. The shear bond strength of the specimens was measured by a universal testing machine. A scanning electron microscope, three-dimensional optical surface-profiler, and stereoscopic microscope were used to image the zirconia surfaces. The data were analyzed with one-way analyses of variance and the Fisher exact test. Results: Group GZ showed significantly lower shear bond strength than did the other groups. No statistically significant differences were found among groups NZ, GP, and GZP. All specimens in group GZ showed adhesive failure between the zirconia and resin cement. In groups NZ and GP, bonding failed at the interface between the resin cement and bracket base or showed complex adhesive and cohesive failure. Conclusions: Porcelain primer is the more appropriate choice for bonding a metal bracket to the surface of a full-contour glazed zirconia crown with resin cement.

• 대한치과교정학회지
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• 제51권4호
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• pp.270-281
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• 2021

Objective: The aim of this in vitro study was to evaluate the changes in friction between orthodontic brackets and archwires coated with aluminum oxide (Al₂O₃), titanium nitride (TiN), or chromium nitride (CrN). In addition, the resistance of the coatings to intraoral conditions was evaluated. Methods: Stainless steel canine brackets, 0.016-inch round nickel-titanium archwires, and 0.019 × 0.025-inch stainless steel archwires were coated with Al₂O₃, TiN, and CrN using radio frequency magnetron sputtering. The coated materials were examined using scanning electron microscopy, an X-ray diffractometer, atomic force microscopy, and surface profilometry. In addition, the samples were subjected to thermal cycling and in vitro brushing tests, and the effects of the simulated intraoral conditions on the coating structure were evaluated. Results: Coating of the metal bracket as well as nickel-titanium archwire with Al₂O₃ reduced the coefficients of friction (CoFs) for the bracket-archwire combination (p < 0.01). When the bracket and stainless steel archwire were coated with Al₂O₃ and TiN, the CoFs were significantly lower (0.207 and 0.372, respectively) than that recorded when this bracket-archwire combination was left uncoated (0.552; p < 0.01). The friction, thermal, and brushing tests did not deteriorate the overall quality of the Al₂O₃ coatings; however, some small areas of peeling were evident for the TiN coatings, whereas comparatively larger areas of peeling were observed for the CrN coatings. Conclusions: Our findings suggest that the CoFs for metal bracket-archwire combinations used in orthodontic treatment can be decreased by coating with Al₂O₃ and TiN thin films.

• 대한치과교정학회지
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• 제44권3호
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• pp.105-112
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• 2014

Objective: The purpose of this study was to evaluate the effects of three different surface conditioning methods on the shear bond strength (SBS) of metal brackets bonded directly to gold alloy with chemically cured resin. Methods: Two hundred ten type III gold alloy specimens were randomly divided into six groups according to the combination of three different surface conditioning methods (aluminum oxide sandblasting only, application of a metal primer after aluminum oxide sandblasting, silica coating and silanation) and thermocycling (with thermocycling, without thermocycling). After performing surface conditioning of specimens in accordance with each experimental condition, metal brackets were bonded to all specimens using a chemically cured resin. The SBS was measured at the moment of bracket debonding, and the resin remnants on the specimen surface were evaluated using the adhesive remnant index. Results: Application of metal primer after aluminum oxide sandblasting yielded a higher bond strength than that with aluminum oxide sandblasting alone (p < 0.001), and silica coating and silanation yielded a higher bond strength than that with metal primer after aluminum oxide sandblasting (p < 0.001). There was no significant change in SBS after thermocycling in all groups. Conclusions: With silica coating and silanation, clinically satisfactory bond strength can be attained when metal brackets are directly bonded to gold alloys using a chemically cured resin.