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Dirk Wiechmann Volker Rummel Andrea Thalheim Jean-Stefane Simon Lital Wiechmann 《American journal of orthodontics and dentofacial orthopedics》2003,124(5):593-599
After 20 months of clinical testing and more than 600 bonded arches, brief interim conclusions can be drawn on treatment with a new lingual bracket system, one that differs fundamentally from conventional appliances in both design and manufacture. The demand for maximum individuality is met by using state-of-the-art computer-aided design/computer-aided manufacturing technology to fuse the 2 normally separate processes of bracket fabrication and bracket positioning. Both the brackets and the pertinent archwires are customized. Additional advantages of the system include direct and thus simplified rebonding in the event of bracket loss, more precise finishing, and enhanced patient comfort. 相似文献
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Clarice Nishio Andréa Fonseca Jardim da Motta Carlos Nelson Elias José Nelson Mucha 《American journal of orthodontics and dentofacial orthopedics》2004,125(1):56-64
The aim of this study was to evaluate the frictional force between orthodontic brackets and archwires. The differences in magnitude of the frictional forces generated by ceramic brackets, ceramic brackets with metal reinforced slot, and stainless steel brackets in combination with stainless steel, nickel-titanium, and beta-titanium orthodontic archwires were investigated. Brackets and wire were tested with tip angulations of 0 degrees and 10 degrees. Friction testing was done with the Emic DL 10000 testing machine (S?o José do Rio Preto, PR, Brazil), and the wires were pulled from the slot brackets with a speed of 0.5 cm/min for 2 minutes. The ligation force between the bracket and the wire was 200 g. According to the data obtained, the brackets had frictional force values that were statistically significant in this progressive order: stainless steel bracket, ceramic bracket with a metal reinforced slot, and traditional ceramic bracket with a ceramic slot. The beta-titanium wire showed the highest statistically significant frictional force value, followed by the nickel-titanium and the stainless steel archwires, in decreasing order. The frictional force values were directly proportional to the angulation increase between the bracket and the wire. 相似文献
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OBJECTIVES: In orthodontic therapy, different materials are used and subjected to a damp oral environment, which can modify their properties. In order to evaluate the biocompatibility of metallic and non-metallic orthodontic appliances their in vitro cytotoxicity has been measured. METHODS: Twenty-eight new and nine clinically used materials, including brackets, molar bands and archwires were used. The metallic materials were made of stainless steel, gold-plated steel, pure titanium, nickel-titanium, titanium-molybdenum and silver-based soldering alloy. The non-metallic materials were in polycarbonates and ceramics. After a release period of the material in the culture medium (0.1 mg/ml) for 3 and 14 days, the viability of fibroblasts L929 cultivated with this medium was compared to negative control with MTT assay. RESULTS: The results showed the non-cytotoxicity of the materials. The metallic and non-metallic materials were similar in terms of cytotoxicity. The cytotoxicity of clinically used samples was equivalent to that of the same non-used samples, except a cytotoxic sample, at 14 days, corresponding to a soldered and clinically used molar band. The 3 day results were different from the 14 day results in six cases out of 37. SIGNIFICANCE: In spite of the presence of one cytotoxic sample, the orthodontic materials can be considered as non cytotoxic. However, the practitioner should pay attention to the composition and the polish of soldering silver-based alloys containing copper and zinc in order to limit cytotoxic ion release. The cytotoxicity of the used sample related to ion release might be related to some clinical sub-acute effects related with orthodontic materials, thus a long term release period may be suitable to evaluate in vitro the sub-acute clinical effects of alloys. 相似文献
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Tahereh Hosseinzadeh Nik Tabassom Hooshmand Habibeh Farazdaghi Arash Mehrabi Elham S Emadian Razavi 《Progress in orthodontics》2013,14(1):48
Background
The purpose of this study was to assess the surface characterization and frictional resistance between stainless steel brackets and two types of orthodontic wires made of stainless steel and nickel-titanium alloys after immersion in a chlorhexidine-containing prophylactic agent.Methods
Stainless steel orthodontic brackets with either stainless steel (SS) or heat-activated nickel-titanium (Ni-Ti) wires were immersed in a 0.2% chlorhexidine and an artificial saliva environment for 1.5 h. The frictional force was measured on a universal testing machine with a crosshead speed of 10 mm/min over a 5-mm of archwire. The surface morphology of bracket slots and surface roughness of archwires after immersion in chlorhexidine were also characterized using a scanning electron microscope (SEM) and an atomic force microscope (AFM), respectively.Results
There was no significant difference in the frictional resistance values between SS and Ni-Ti wires immersed in either chlorhexidine or artificial saliva. The frictional resistance values for the SS and Ni-Ti wires immersed in 0.2% chlorhexidine solution were not significantly different from that inartificial saliva. No significant difference in the average surface roughness for both wires before (as-received) and after immersion in either chlorhexidine or artificial saliva was observed.Conclusions
One-and-half-hour immersion in 0.2% chlorhexidine mouthrinse did not have significant influence on the archwires surface roughness or the frictional resistance between stainless steel orthodontic brackets and archwires made of SS and Ni-Ti. Based on these results, chlorhexidine-containing mouthrinses may be prescribed as non-destructive prophylactic agents on materials evaluated in the present study for orthodontic patients. 相似文献9.
正畸托槽与弓丝的摩擦力研究进展 总被引:4,自引:2,他引:4
随着滑动机制在固定矫治中的普遍应用,托槽与弓丝相对运动产生的摩擦力就显得尤为重要。摩擦力越大,牙移位的实际矫治力比例就越小,进而影响矫治效果。所以,为减小摩擦阻力,获得最有效的牙移位与最适的生物组织反应,国内外许多学者对正畸托槽与弓丝的摩擦力进行了大量的研究,本文就正畸托槽与弓丝摩擦力的研究进展作一综述。 相似文献
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Friction between archwires and labial brackets has received considerable attention; however, information on the frictional behaviour of commercially available lingual brackets is limited. The aim of this study was to investigate the frictional resistance resulting from a combination of lingual orthodontic brackets (7th Generation, STb, Magic, and In-Ovation L) and stainless steel archwires at 0, 5, and 10 degrees of second-order angulation. Each bracket type (n = 30) was tested with three different sizes of archwires. Static and kinetic frictional forces were evaluated with a universal testing machine. Statistical analysis of the data was performed with non-parametric Kruskal-Wallis and Dunn's multiple comparison tests. All tested brackets showed higher frictional forces as the wire size and second-order angulation increased. The lowest friction was found with In-Ovation L brackets and 0.016 inch archwires at 0 degrees angulation, and the greatest friction with a combination of STb brackets and 0.017 × 0.025 inch archwires at 10 degrees angulation. For all combinations, Magic and In-Ovation L brackets showed lower frictional resistance when compared with 7th Generation and STb brackets. The slot width (occluso-gingival dimension) of the brackets, measured using the optics of a microhardness machine, showed that all brackets were oversized and that Magic brackets had the largest slot width. Surface roughness of the brackets investigated using atomic force microscopy and scanning electron microscopy, demonstrated that the 7th Generation brackets had the greatest surface roughness. 相似文献
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The friction and wear patterns of orthodontic brackets and archwires in the dry state 总被引:3,自引:0,他引:3
D. J. Michelberger DDS MSca Reg L. Eadie PhDb M. Gary Faulkner PhDc Kenneth E. Glover DDS MScd Narasimha G. Prasad PhDe Paul W. Major DDS MScf 《American journal of orthodontics and dentofacial orthopedics》2000,118(6):662-674
Frictional resistance at the bracket-archwire interface has been demonstrated to impede tooth movement when sliding mechanics are used. Thus, the coefficients of friction of titanium and stainless steel brackets used in conjunction with stainless and ion-implanted beta-titanium archwires were investigated using a single contact interface between the brackets and archwires. The wear patterns between the brackets and the.016- in flat archwire surfaces were also examined using scanning electron microscopy and energy dispersive x-ray analysis. Stainless steel brackets tested with. 016-in flat stainless steel wire surfaces recorded the lowest coefficient of static friction mean (0.289), whereas titanium brackets paired with.016-in flat ion-implanted beta-titanium wire surfaces produced the highest mean (0.767). Stainless steel brackets had significantly (P <.05) lower coefficients of friction than titanium brackets for all wires except.020-in round stainless steel wires. Ion-implanted beta-titanium wires generally had significantly larger coefficients of friction than stainless steel wires. The increased friction of the titanium and ion-implanted beta-titanium alloys is also reflected in the severity of their wear patterns. An inverse relationship between friction and archwire surface dimension was generally found for ion-implanted beta-titanium wires. Round stainless steel wires demonstrated lower coefficients of kinetic friction than the flat stainless steel wire surfaces. 相似文献
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目的:探究人工唾液条件下不同时间,几种直丝托槽与弓丝在后牙段的动摩擦力状况.方法:在人工唾液条件下,4个时间段:0、15、30、45 d,使用Instron万能材料力学实验机,模拟弓丝在后牙段滑动,按正交设计测试4种直丝托槽与4种弓丝组合在后牙段的动摩擦力.结果:3M MBT托槽的动摩擦力最小,0.48mm×0.64哪方丝的动摩擦力最大,0.46 mm圆丝的动摩擦力最小.弓丝、托槽组合在人工唾液条件下作用15 d动摩擦力最大、30 d动摩擦力最小.结论:0.46 mm圆丝的动摩擦力最小;人工唾液作用30 d动摩擦力最小;3M MBT托槽比较适合于滑动法关闭问隙. 相似文献
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A comparative study of frictional forces between orthodontic brackets and arch wires 总被引:6,自引:0,他引:6
James R. Bednar DDS MS Gary W. Gruendeman DDS James L. Sandrik PhD 《American journal of orthodontics and dentofacial orthopedics》1991,100(6):513-522
An in vitro study of simulated canine retraction was undertaken to evaluate the difference in frictional resistance between stainless steel arch wires and steel and ceramic brackets with elastomeric, steel, and self-ligation. Each bracket slot was 0.018 x 0.025 inch. The arch wires used were 0.014-inch, 0.016-inch, 0.018-inch, 0.016 x 0.016-inch, and 0.016 x 0.22-inch stainless steel. A testing apparatus was designed to attempt to simulate the clinical situation in which teeth tip slightly while they slide along the arch wire. Under these testing conditions, the self-ligating steel bracket did not demonstrate less friction than the elastic or steel-ligated stainless steel brackets. For most wire sizes, elastomer-ligated ceramic brackets demonstrated the greatest friction when compared with other bracket/ligation technique combinations. The clinical significance of this study becomes apparent when stainless steel brackets are used on the posterior teeth and ceramic brackets are used on the anterior teeth. If sliding mechanics are used, the anterior teeth may be more resistant to movement than the posterior teeth because of the greater friction of the ceramic brackets. This could result in more posterior anchorage loss than would be expected if only one type of bracket were used. 相似文献
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The viscoelastic behaviour of prototype composite orthodontic archwires was evaluated using a bend stress relaxation test. Archwires having 10 different volume fractions of reinforcement were subjected to constant bending radii in a water bath at 37 degrees C for time periods of up to 90 days. The wires were subsequently released and left unconstrained for the same testing conditions. Creep-induced changes in the unconstrained bending radii of the wires were measured at specific times during both phases (stress relaxation and recovery) of the test. The statistical analysis showed that stress relaxation behaviour was strongly correlated with the archwire reinforcement level. The final relaxation varied, with decreasing reinforcement, from 2 to 8 per cent. Archwire recovery was not correlated with reinforcement level, and revealed a final viscous loss of only 1 per cent. The relaxed elastic moduli in bending of the composite wires were similar to the elastic moduli in bending of several conventional orthodontic archwire materials. Losses that were associated with the viscoelastic behaviour varied with decreasing reinforcement level from 1.2 to 1.7 GPa. Because these modulus losses were minimal, each archwire retained sufficient resilience to be applicable to the early and intermediate stages of orthodontic treatment. 相似文献
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A 23-year-old female patient with lip protrusion and crowding received lingual orthodontic treatment with multi-slotted brackets and preformed straight archwires. After 5 months of alignment and leveling, anterior retraction was performed for 21 months. Final detailing took five months. The appliances were removed 31 months after the start of treatment. With these multi-slotted lingual brackets, treatment progressed in the simplest and most effective way and board-standard finishes were achieved. Furthermore, the use of preformed lingual straight archwires (PLSWs) allowed much more convenient treatment application. 相似文献
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