Color stability and fluorescence of different orthodontic esthetic archwires

Objective:To evaluate the color stability of six esthetic archwires at different time periods and their fluorescence.Materials and Methods:Samples were evaluated after 7, 14, and 21 days of immersion in staining solution. Color measurements were performed by means of a spectrophotometer according to the Commission Internationale de I''Eclairage L*a*b* system, and color changes (ΔE*) and National Bureau of Standards units were computed. The fluorescence of as-received samples was evaluated by two observers and compared with that of a bovine central incisor. Statistical differences were investigated using analysis of variance and Tukey''s post hoc test.Results:All brands showed statistically significant color change after 21 days (ΔE* from 1.88 to 12.06). The Optis archwire (fiber-reinforced composite) presented the highest color alteration, although staining was observed only near its ends. The Trianeiro archwire (coated nickel-titanium) and the Ortho Organizers archwire (coated stainless steel) presented with less color change. The Optis archwire was the only one that presented with fluorescence similar to that of bovine teeth.Conclusions:All esthetic archwires assessed showed clinically noticeable color change after 21 days in staining solution. The optical properties of currently available esthetic archwires may not yet be ideal.     

Infrared spectroscopy,nano-mechanical properties,and scratch resistance of esthetic orthodontic coated archwires

Objective:To evaluate the material composition, mechanical properties (hardness and elastic modulus), and scratch resistance of the coating of four commercialized esthetic orthodontic archwires.Materials and Methods:The coating composition of esthetic archwires was assessed by Fourier-transform infrared spectroscopy (FTIR). Coating hardness and elastic modulus were analyzed with instrumented nano-indentation tests. Scratch resistance of coatings was evaluated by scratch test. Coating micromorphologic characteristics after scratch tests were observed in a scanning electron microscope. Statistical differences were investigated using analysis of variance and Tukey post hoc test.Results:The FTIR results indicate that all analyzed coatings were markedly characterized by the benzene peak at about 1500 cm⁻¹. The coating hardness and elastic modulus average values ranged from 0.17 to 0.23 GPa and from 5.0 to 7.6 GPa, respectively. Scratch test showed a high coating elasticity after load removal with elastic recoveries >60%, but different failure features could be observed along the scratches.Conclusion:The coatings of esthetic archwires evaluated are probably a composite of polyester and polytetrafluoroethylene. Delamination, crack propagation, and debris generation could be observed along the coating scratches and could influence its durability in the oral environment.     

In vitro biocompatibility of nickel-titanium esthetic orthodontic archwires

Objective:To investigate the cytotoxicity of nickel-titanium (NiTi) esthetic orthodontic archwires with different surface coatings.Materials and Methods:Three fully coated, tooth-colored NiTi wires (BioCosmetic, Titanol Cosmetic, EverWhite), two ion-implanted wires (TMA Purple, Sentalloy High Aesthetic), five uncoated NiTi wires (BioStarter, BioTorque, Titanol Superelastic, Memory Wire Superelastic, and Sentalloy), one β-titanium wire (TMA), and one stainless steel wire (Stainless Steel) were considered for this study. The wire samples were placed at 37°C in airtight test tubes containing Dulbecco’s Modified Eagle’s Medium (0.1 mg/mL) for 1, 7, 14, and 30 days. The cell viability of human gingival fibroblasts (HGFs) cultured with this medium was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by a two-way analysis of variance (α  =  .05).Results:The highest cytotoxic effect was reached on day 30 for all samples. The archwires exhibited a cytotoxicity on HGFs ranging from “none” to “slight,” with the exception of the BioTorque, which resulted in moderate cytotoxicity on day 30. Significant differences were found between esthetic archwires and their uncoated pairs only for BioCosmetic (P  =  .001) and EverWhite (P < .001).Conclusions:Under the experimental conditions, all of the NiTi esthetic archwires resulted in slight cytotoxicity, as did the respective uncoated wires. For this reason their clinical use may be considered to have similar risks to the uncoated archwires.     

In vitro Streptococcus mutans adhesion and biofilm formation on different esthetic orthodontic archwires

ObjectivesTo evaluate the ability of different esthetic archwires to retain oral biofilms in vitro.Materials and MethodsSeven different brands of coated orthodontic archwires were tested: two epoxy coated, two polytetrafluoroethylene coated, two rhodium coated, and one silver plus polymer coated. Conventional uncoated metallic archwires were used as controls. Streptococus mutans adherence to archwires was quantified by colony count following 24 hours of biolfilm growth, and total wire-associated biofilm was measured using a crystal violet staining assay. For both tests, two conditions were used: 0% sucrose and 3% sucrose. For statistical analysis, P < .05 was considered as statistically significant.ResultsFor S. mutans colony forming units per biofilm, there were no statistically significant differences among the various archwires (P = .795 for 0% sucrose; P = .905 for 3% sucrose). Regarding total biofilm formed on archwires in the 3% sucrose condition, there were statistically significant differences in crystal violet staining only for the comparison between Niti Micro Dental White and Copper Ni-Ti wires (P < .05).ConclusionsThe clinical use of esthetic-coated orthodontic wires may be considered to have similar risks as uncoated archwires for biofilm retention.     

In vitro and in vivo biofilm adhesion to esthetic coated arch wires and its correlation with surface roughness

Objective:To evaluate the in vitro ability of esthetic coated rectangular arch wires to retain oral biofilms and in vivo biofilm formation on these wires after 4 and 8 weeks of clinical use and to correlate the findings with the surface roughness of these wires.Materials and Methods:Three brands of esthetic coated nickel-titanium (NiTi) arch wires were selected. Arch wires retrieved after 4 and 8 weeks of intraoral use were obtained from 30 orthodontic patients. Surface roughness (SR) was assessed with an atomic force microscope. In vitro adhesion assays were performed using Streptococcus mutans (MS), Staphylococcus aureus, and Candida albicans. The amount of bacterial adhesion was quantified using the colony-count method. Paired t-test, analysis of variance, post hoc Tukey''s test, and Pearson''s correlation coefficient test were used for statistical analysis at the .05 level of significance.Results:In vitro bacterial adhesion showed significant differences between wires in terms of MS adhesion (P  =  .01). All wires showed significant increases in SR (P  =  .001 after 4 weeks and .007 after 8 weeks) and biofilm adhesion (P  =  .0001 after 4 weeks and .045 after 8 weeks) after intraoral exposure. A significant positive correlation (P  =  .001 after 4 weeks and .05 after 8 weeks) was observed between these two variables in vivo, but the correlation was not significant for in vitro bacterial adhesion.Conclusions:SR and biofilm adhesion increased after intraoral use at all time intervals. There was a positive correlation between SR and biofilm adhesion in vivo only.     

Flexural properties of rectangular nickel-titanium orthodontic wires when used as ribbon archwires

Objective:To compare the flexural properties of rectangular nickel-titanium (Ni-Ti) orthodontic wires in occlusoapical and faciolingual orientations using a standardized test method.Materials and Methods:Twenty-two rectangular Ni-Ti wire groups were tested in occlusoapical (ribbon) orientation: eight conventional Ni-Ti products, five superelastic Ni-Ti products, and nine thermal Ni-Ti products (n = 10 per group). Six products of thermal Ni-Ti wire were tested in faciolingual (edgewise) orientation. A three-point bending test was performed to measure deactivation force at 3.0-, 2.0-, 1.0-, and 0.5-mm deflections of each rectangular wire at 37.0 ± 0.5°C. Analysis of variance and post hoc Student-Newman-Keuls tests were used to compare the mean values of the different groups (α = .05).Results:The ranges of deactivation forces varied greatly with different kinds, sizes, products, and deflections of Ni-Ti wires. One product of conventional and superelastic Ni-Ti wires had steeper force-deflection curves. Four products had similarly shaped flat force-deflection curves, whereas the sixth product had a moderately steep force-deflection curve. Thermal Ni-Ti wires had smaller deactivation forces ranging from 0.773 N (78.8 g) to 2.475 N (252.4 g) between deflections of 1.0 and 0.5 mm, whereas wider ranges of force from 3.371 N (343.7 g) to 9.343 N (952.7 g) were predominantly found among conventional Ni-Ti wires between deflections of 3.0 and 2.0 mm.Conclusions:Clinicians should critically select archwires for use in the occlusoapical orientation not only based on Ni-Ti wire type, size (0.022 × 0.016-in or 0.025 × 0.017-in), and product but also with deactivation deflections from 0.5 and 1.0 mm to obtain light forces in the occlusoapical orientation.     

前牙内收阶段不锈钢方丝摩擦力的变化

目的：研究滑动法前牙内收阶段不锈钢方丝摩擦力的变化.方法：选择GAC、3M、TP、TOMY4种0.019英寸×0.025英寸不锈钢方丝.使用不同时间后的方丝取自恒牙早期拔牙矫治的前牙内收阶段,截取其两侧尖牙远中区域作为检测样本.选择静摩擦系数作为评价方丝摩擦力的指标,使用摩擦力检测仪检测.结果：前牙内收阶段4种不锈钢方丝使用4周、8周、12周、16周及20周期间,静摩擦系数均有所增大,但无统计学意义（P＞0.05）.结论：前牙内收阶段4种不锈钢方丝使用20周期间,摩擦力变化无显著性意义,对支抗控制及牙齿移动效率无明显影响.     

Characterization of the coatings covering esthetic orthodontic archwires and their influence on the bending and frictional properties

Objective:To analyze the coatings covering esthetic orthodontic wires and the influence of such coatings on bending and frictional properties.Materials and Methods:Four commercially available, coated esthetic archwires were evaluated for their cross-sectional dimensions, surface roughness (R_a), nanomechanical properties (nanohardness, nanoelastic modulus), three-point bending, and static frictional force. Matched, noncoated control wires were also assessed.Results:One of the coated wires had a similar inner core dimension and elasticity compared to the noncoated control wire, and no significant differences between their static frictional forces were observed. The other coated wires had significantly smaller inner cores and lower elasticity compared to the noncoated wires, and one of them showed less static frictional force than the noncoated wire, while the other two coated wires had greater static frictional force compared to their noncoated controls. The dimension and elastic modulus of the inner cores were positively correlated (r = 0.640), as were frictional force and total cross-sectional (r = 0.761) or inner core (r = 0.709) dimension, elastic modulus (r = 0.777), nanohardness (r = 0.802), and nanoelastic modulus (r = 0.926). The external surfaces of the coated wires were rougher than those of their matched controls, and the R_a and frictional force were negatively correlated (r = −0.333).Conclusions:Orthodontic coated wires with small inner alloy cores withstand less force than expected and may be unsuitable for establishing sufficient tooth movement. The frictional force of coated wires is influenced by total cross-section diameter, inner core diameter, nanohardness, nanoelastic modulus, and elastic modulus.     

Effects of intraoral aging on surface properties of coated nickel-titanium archwires

Objective:To evaluate the effects of intraoral aging on surface properties of esthetic and conventional nickel-titanium (NiTi) archwires.Materials and Methods:Five NiTi wires were considered for this study (Sentalloy, Sentalloy High Aesthetic, Superelastic Titanium Memory Wire, Esthetic Superelastic Titanium Memory Wire, and EverWhite). For each type of wire, four samples were analyzed as received and after 1 month of clinical use by an atomic force microscope (AFM) and a scanning electronic microscope (SEM). To evaluate sliding resistance, two stainless steel plates with three metallic or three monocrystalline brackets, bonded in passive configuration, were manufactured; four as-received and retrieved samples for every wire were pulled five times at 5 mm/min for 1 minute by means of an Instron 5566, recording the greatest friction value (N). Data were analyzed by one-way analysis of variance and by Student''s t-test.Results:After clinical use, surface roughness increased considerably. The SEM images showed homogeneity for the as-received control wires; however, after clinical use esthetic wires exhibited a heterogeneous surface with craters and bumps. The lowest levels of friction were observed with the as-received Superelastic Titanium Memory Wire on metallic brackets. When tested on ceramic brackets, all the wires exhibited an increase in friction (t-test; P < .05). Furthermore, all the wires, except Sentalloy, showed a statistically significant increase in friction between the as-received and retrieved groups (t-test; P < .05).Conclusion:Clinical use of the orthodontic wires increases their surface roughness and the level of friction.     

不锈钢方丝口腔内应用后表面摩擦力及表面形态变化的研究

Objective The purpose of this study was to investigate the changes of surface frictional forces and surface topography of used-stainles steel(ss) archwires. Method On the testing mandibular model,we measured the static and kinetic friction between the used and unused archwires at different time points and they were examined in the space closure phase. Surface topography of each type archwire was assessed by scanning electron microscope(SEM). Results The surfacial friction of ss archwires used three months are greater than the unused one (P＜0. 05), while much greater than that used after four and five months (P＜0. 01). SEM: The surfacial smooth finish of ss archwires were reduced with the longer time of use, whereas surface roughness were increased. Conclusion The roughness changes on the ss archwires' surfacial structure suggested us to change the archwires in time or increase the anchorage.     

Torsional strength of computer-aided design/computer-aided manufacturing–fabricated esthetic orthodontic brackets

Objective:To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion.Materials and Methods:Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC).Results:The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P < .05). The mean torques at failure ranged from 3467 g.mm for Mark II to 11,902 g.mm for YZ. The mean torsion angles at failure ranged from 15.3° to 40.9°.Conclusion:Zirconia had the highest torsional strength among the tested esthetic brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.     

不锈钢方丝口腔内应用后表面摩擦力及表面形态变化的研究

目的 探讨不锈钢方丝口腔内应用后表面摩擦力及表面形态变化.方法 在粘结托槽的模具上,分别测量口腔内使用前后不锈钢方丝在整体回收前牙时与托槽间产生的表面摩擦力.电镜观察不锈钢方丝使用前后表面形态的变化.结果 不锈钢方丝表面摩擦力使用3个月比未使用的增大,差异有显著性(P＜0.05),4个月、5个月的增加更大,差异有极显著性(P＜0.01).电镜观察,随着使用时间的增加不锈钢方丝表面光洁度降低,粗糙度明显增加.结论 不锈钢方丝随着使用时间的增加表面光洁度降低,摩擦力增加,提示我们矫治过程中应及时更换弓丝,或增加支抗.

Abstract：

Objective The purpose of this study was to investigate the changes of surface frictional forces and surface topography of used-stainles steel(ss) archwires. Method On the testing mandibular model,we measured the static and kinetic friction between the used and unused archwires at different time points and they were examined in the space closure phase. Surface topography of each type archwire was assessed by scanning electron microscope(SEM). Results The surfacial friction of ss archwires used three months are greater than the unused one (P＜0. 05), while much greater than that used after four and five months (P＜0. 01). SEM: The surfacial smooth finish of ss archwires were reduced with the longer time of use, whereas surface roughness were increased. Conclusion The roughness changes on the ss archwires' surfacial structure suggested us to change the archwires in time or increase the anchorage.     

Effect of surface treatment on the mechanical stability of orthodontic miniscrews:: A systematic review with meta-analysis

ObjectivesTo provide collective quantitative evidence about the effect of surface treatments on the mechanical stability of orthodontic miniscrews (MSs).Materials and MethodsThe study was registered in PROSPERO (No. CRD42020209652). The research question was defined according to the PICO (population, intervention, control, and outcomes) format. Various research databases were searched for animal and human studies on effects of surface treatment on the mechanical stability of MSs. Both prospective and retrospective in vivo clinical studies published in English were included. The risk of bias was assessed using SYRCLE''s risk of bias tool for animal studies. The meta-analysis was conducted using RevMan 5.4.ResultsA total of 109 articles were identified; 14 were included in the systematic review, and seven studies with sandblasting, acid etching (SLA) methods of surface treatment were included for meta-analysis. The number of study participants ranged from 6 to 24 (total n = 185), with a mean of 13.2. A total of 949 MSs were used with a mean of 67.8. The overall success rate for surface-treated MSs ranged from 47.9% to 100%. Forest plot of removal torque values showed significantly higher values for SLA surface-treated MSs compared with controls with a standard mean difference of 2.61 (95% confidence interval = 1.49–3.72, I² = 85%). Forest plot of insertion torque showed a standard mean difference of –6.19 (95% confidence interval = –13.63–1.25, I² = 98%, P = .10).ConclusionsSurface treatment of MSs improved primary and secondary stability with good osseointegration at the bone-implant surface. However, significant heterogeneity across the studies included in the meta-analysis made it difficult to draw conclusions.     

Relationship between friction force and orthodontic force at the leveling stage using a coated wire

The relationship between orthodontic force and friction produced from an archwire and brackets affects the sliding of the wire in the leveling stage.

Objective

The purpose of this study was to evaluate the relationship between force and friction in a small esthetic nickel-titanium (Ni-Ti) wire.

Material and Methods

Five esthetic wires (three coated and two plated) and two small, plain Ni-Ti wires (0.012 and 0.014 inches) were used. We performed a three-point bending test according to ISO 15841 and the drawing test with a dental arch model designed with upper linguoversion of the lateral incisor in the arch (displacements of 0.5, 1.0, 2.0 and 3.0 mm), and evaluated the relationship between them.

Results

Unloading bending forces of all wires at displacements of less than 1.0 mm were larger than friction forces, but all friction forces at displacements exceeding 2.0 mm were larger than unloading bending forces. The arch likely expands when displacement from the proximal brackets exceeds 1.0 mm. The friction force of a martensite 0.014-inch Ni-Ti wire was significantly greater than those of the other esthetic and austenitic wires.

Conclusions

A wire with the smallest possible friction force should be used in cases with more than 1.0 mm displacement.     

多种镍钛弓丝应力应变的研究

目的本研究探讨多种 NITI 弓丝在口腔温度下的应力应变,指导临床合理选择弓丝。方法选取9个厂家20年种镍钛弓丝,其中圆丝12种,方丝8种;超弹性弓丝9种,热激活弓丝11种。使用材料力学实验机在35℃±2范围内,进行三点弯曲实验,弓丝跨度为10mm,加载及卸载速度为2mm/s。实验机自动绘制应力应变曲线,进行定性与定量分析。结果弓丝在形变超过3mm 后加载应力下降而卸载力值并无明显变化;相同尺寸情况下,热激活镍钛弓丝与超弹性 NITI 丝相比,并不一会产生更小的卸载力值。本研究中 Dentaurum 的 Tensic 16毫英寸弓丝产生最小的卸载应力(37.03g),其次为非凡的14毫英寸马氏体弓丝(46.33g)。方形 NITI 弓丝较圆丝有较大的滞后。结论镍钛弓丝可以在临床中产生很大的形变同时矫治力变化不大;弓丝的尺寸并不能成为临床弓丝选择的唯一依据,热激活 NITI 弓丝并不一定产生更小的矫治力,但可以提供更方便的临床操作。方 NITI 弓丝在初期纠正旋转拥挤后可以尽早使用。弓丝的选择需要参考其材料力学特性。     

The effect of water storage on the bending properties of esthetic,fiber-reinforced composite orthodontic archwires

Objective:To study the effect of water storage on the bending properties of fiber-reinforced composite archwires and compare it to nickel-titanium (NiTi), stainless steel (SS), and beta-titanium archwires.Materials and Methods:Align A, B, and C and TorQ A and B composite wires from BioMers Products, 0.014-, 0.016, and 0.018-inch, and 0.019 × 0.025-inch NiTi, 0.016-inch SS, and 0.019 × 0.025-inch beta-titanium archwires were tested (n  =  10/type/size/condition). A 20-mm segment was cut from each end of the archwire; one end was then stored in water at 37°C for 30 days, while the other was stored dry. The segments were tested using three-point bending to a maximum deflection of 3.1 mm with force monitored during loading (activation) and unloading (deactivation). Statistical analysis was completed via two-way analysis of variance with wire and condition (dry and water-stored) as factors.Results:In terms of stiffness and force delivery during activation, in general: beta-titanium was > TorQ B > TorQ A > 0.019 × 0.025-inch NiTi and 0.016-inch SS > Align C > 0.018-inch NiTi > Align B > 0.016-inch NiTi > Align A > 0.014-inch NiTi. Water exposure was detrimental to the larger translucent wires (Align B and C, TorQ A and B) because they were more likely to craze during bending, resulting in decreased forces applied at a given deflection. Align A and the alloy wires were not significantly (P > .05) affected by water storage. Overall, the alloy wires possessed more consistent force values compared to the composite wires.Conclusion:Environmental conditions are more likely to affect fiber-reinforced composite archwires compared to alloy wires.     

Alignment efficiency and discomfort of three orthodontic archwire sequences: a randomized clinical trial

Abstract

Aim: To compare the efficiency of orthodontic archwire sequences produced by three manufacturers.

Design: Prospective, randomized clinical trial with three parallel groups.

Setting: Private orthodontic practice in Caloundra, QLD, Australia

Subjects and methods: One hundred and thirty‐two consecutive patients were randomized to one of three archwire sequence groups: (i) 3M Unitek, 0·014?inch Nitinol, 0·017?inch×0·017?inch heat activated Ni–Ti; (ii) GAC international, 0·014?inch Sentalloy, 0·016×0·022?inch Bioforce; and (iii) Ormco corporation, 0·014?inch Damon Copper Ni–Ti, 0·014×0·025?inch Damon Copper Ni–Ti. All patients received 0·018×0·025?inch slot Victory Series^TM brackets.

Outcome measures: Mandibular impressions were taken before the insertion of each archwire. Patients completed discomfort surveys according to a seven‐point Likert Scale at 4?h, 24?h, 3?days and 7?days after the insertion of each archwire. Efficiency was measured by time required to reach the working archwire, mandibular anterior alignment and level of discomfort.

Results: No significant differences were found in the reduction of irregularity between the archwire sequences at any time‐point (T1: P?=?0·12; T2: P?=?0·06; T3: P?=?0·21) or in the time to reach the working archwire (P?=?0·28). No significant differences were found in the overall discomfort scores between the archwire sequences (4?h: P?=?0·30; 24?h: P?=?0·18; 3?days: P?=?0·53; 7?days: P?=?0·47). When the time‐points were analysed individually, the 3M Unitek archwire sequence induced significantly less discomfort than GAC and Ormco archwires 24?h after the insertion of the third archwire (P?=?0·02). This could possibly be attributed to the progression in archwire material and archform.

Conclusions: The archwire sequences were similar in alignment efficiency and overall discomfort. Progression in archwire dimension and archform may contribute to discomfort levels. This study provides clinical justification for three common archwire sequences in 0·018×0·025?inch slot brackets.