Superelastic Nickel-titanium Wires Research Articles

Initial arch wires used in orthodontic treatment with fixed appliances.

Initial arch wires used in orthodontic treatment with fixed appliances.

Uprighting horizontally impacted third molars by super-elastic nickel-titanium wire in patients with an extracted first molar.

Protracting lower second molars and uprighting horizontally impacted third molars is a significant orthodontic challenge in patients who require the extraction of severely decayed first molars. Here, we describe the use of biomechanics to upright 90°-tilted lower third molars following second molar protraction. Herein, we introduce a technique for uprighting the lower third molars by (1) the placement of superelastic nickel titanium archwires, (2) bonding, and (3) repositioning of a buccal tube in a tilted position to compensate for the efficiency of Ni-Ti (nickel-titanium) wire. The treatment mechanics used for our two cases showed that even severely impacted third molars can be uprighted by routine continuous straight-wire techniques. This technique proved to be a simple, efficient and reliable treatment option for uprighting horizontally impacted third molars.

Effectiveness of laser-engineered copper-nickel titanium versus superelastic nickel-titanium aligning archwires: A randomized clinical trial.

: To compare the effectiveness of laser-engineered copper-nickel titanium (SmartArch) and superelastic nickel-titanium (SENT) archwires in aligning teeth and inducing root resorption and pain experienced by patients. : Two-arm parallel groups with a 1:1 allocation ratio were used. The participants were patients aged 11.5 years and older with 5-9 mm of mandibular anterior crowding who were indicated for non-extraction treatment. The primary outcome was alignment effectiveness, assessed using Little's irregularity index (LII) over 16 weeks with a single wire (0.016-inch) in the SmartArch group and 2 wires (0.014- and 0.018-inch) in the SENT group (8 weeks each). Secondary outcomes included root resorption evaluated by pre- and post-intervention periapical radiographs and pain levels recorded by the participants during the first week. : A total of 40 participants were randomly allocated into 2 groups; 33 completed the study and were analyzed (16 in the SmartArch group and 17 in the SENT group, aged 16.97 ± 4.05 years). The total LII decrease for the SmartArch and SENT groups was 5.63 mm and 5.29 mm, respectively, which was neither statistically nor clinically significant. Root resorption was not significantly different between the groups. The difference in pain levels was not statistically significant for the first 5 days following wire placement; however, there was a significant difference favoring the SENT group in the final 2 days. : SmartArch and SENT archwires were similarly effective during the alignment phase of orthodontic treatment. Root resorption should be observed throughout the treatment with either wire. SmartArch wires demonstrated higher pain perception than SENT wires.

Properties of Superelastic Nickel-Titanium Wires after Clinical Use.

The aim of the present study was to describe and determine changes in the superelastic properties of NiTi archwires after clinical use and sterilization. Ten archwires from five different manufacturers (GAC, 3M, ODS, GC, FOR) were cut into two segments and evaluated using a three-point bending test in accordance with ISO 14841:2006. The center of each segment was deflected to 3.1 mm and then unloaded to 0 N to obtain a load-deflection curve. Deflection at the end of the plateau and forces at 3, 2, 1 and 0.5 mm on the unloading curve were recorded. Plateau slopes were calculated at 2, 1 and 0.5 mm of deflection. Data obtained were statistically analyzed to determine differences (p < 0.001). Results showed that the degree of superelasticity and exerted forces differed significantly among brand groups. After three months of clinical use, FOR released a greater force for a longer activation period. GC, EURO and FOR archwires seemed to lose their mechanical properties. GC wires released more force than other brand wires after clinical use. Regarding superelasticity after sterilization, GAC, 3M and FOR wires recovered their properties, while EURO archwires lost more.

Loads of continuous mechanics for uprighting the second molar on the second molar and premolar

This paper aims to evaluate the effect of tube height on uprighting a mandibular second molar with a continuous arch, specifically the main effects on the molar tube and the side effects on the second premolar bracket. Slot brackets (0.18-in) and tubes were passively bonded from the left second molar to the right second premolar of the patient's cast and fixed to an orthodontic force tester. A mesially tipped second molar along with its tube was positioned at 5 different heights in relation to the bracket slots of the remaining appliance: 2 mm below (group -2), 1 mm below (group -1), leveled (group 0), 1 mm above (group 1) and 2 mm above (group 2). Each group had 10 different 0.016 × 0.022-in superelastic nickel-titanium wires tied one at a time to the appliance to register the vertical forces (Fz) and tipping moments (Mx) produced at the molar tube and the premolar bracket, statistically. Analysis of variance was used to identify differences of load among the groups for wire response to the position of the tube in relation to the other brackets' slots. As the molar tube was positioned more occlusally, Fz and Mx decreased at the molar tube from 1.31 N to 0.75 N and 13.98 N.mm to 11.84 N.mm, respectively, whereas at the premolar bracket, Fz and Mx decreased from 1.52 N to 0.88 N and 8.77 N.mm to 1.05 N.mm, respectively. In all groups, the load system at the molar tube (the main effects) registered a distal tipping moment and an extrusive force, whereas at the premolar bracket, the load system (side effects) included a distal tipping moment and an intrusive force. As the tube moved occlusally, the extrusive force and the uprighting moment decreased, along with the side effects at the premolar bracket. Attempting to bond the molar tube more occlusally (within reasonable intraoral dimensions) when trying to upright a molar does not appear to be sufficient to keep a molar from extruding.

Treatment of Class II malocclusion with the improved superelastic nickel-titanium alloy wire and long hooks for mandibular molar protraction

• Two patients were treated with extraction of the mandibular second premolars. • We used superelastic nickel-titanium alloy wires as working wires. • The use of nickel-titanium wires and long hooks worked to mesialize the molar bodily. The mandibular first molar must be carefully moved to prevent mesial tipping and extrusion in case extraction of the mandibular second premolar is required to achieve the desired goals. The nickel-titanium alloy has unique mechanical properties, including superelasticity and shape memory, leading to the generation of continuous light forces that may be more biologically compatible than intermittent strong forces. However, it provides poor root control because of its low stiffness. We herein have experienced the patients with Angle Class II malocclusion that uses the improved superelastic nickel-titanium wire (ISW) and long hooks to achieve bodily movement of the mandibular first molar. The 0.022 × 0.028-in slot preadjusted edgewise appliances and 0.020 × 0.025-in ISWs as the working archwire were used. We pinched the crimpable long hooks on the rectangular ISW and applied 100-150 g of contractile force between the fixed long hooks and bracket hooks of the mandibular first molars to activate the system with ligature wire lacing. The mandibular molars were uprighted and mesially moved; panoramic radiographs did not indicate severe root resorption. These experiences suggest that this method involving the combined use of the ISW and long hooks may be one of the useful methods for closing spaces by facilitating the uprighting and mesial movement of the molars in treating Class II malocclusion.

A clinical comparison of the effectiveness of two types of orthodontic aligning archwire materials: a multicentre randomized clinical trial.

To compare the heat-activated nickel titanium (HANT) with superelastic nickel-titanium (SENT) archwires in terms of their effectiveness of aligning teeth, possibility of inducing root resorption, and perception of pain. Orthodontic patients aged 12 years or over with mandibular anterior crowding of 3-6 mm, who required treatment without extractions were randomly allocated (a simple non-stratified randomization) to the HANT and SENT archwires groups with a 1:1 allocation ratio. The archwire sequence in both groups was 0.014-inch and 0.016-inch, respectively. Each archwire was placed for 4 weeks. The outcome measures included the amount of crowding assessed blindly using Little's irregularity index (LII), apical root resorption, and pain perception. The effectiveness of alignment was tested using 2 × 2 mixed factorial analysis of variance (ANOVA) model, while root resorption and pain perception were tested by the Mann-Whitney U-test and Wilcoxon signed-rank test (P < 0.05). Thirty-four patients were randomized and recruited from four centres, of those 31 were analysed (15 participants for the HANT and 16 for the SENT groups) with an overall mean age of 19.13 ± 5.73 years. The total reduction in the LII was 2.69 mm and 2.74 mm for the HANT and SENT groups, respectively. This did not reach the level of statistical (P = 0.809) or clinical significance. Similarly, root resorption and pain perception showed non-significant difference between groups. However, there was a slight increase in root resorption with the SENT group. A long-term evaluation of root resorption is required. Both HANT and SENT archwires were equally effective in the aligning stage of orthodontic treatment. Root resorption with SENT wires should be monitored throughout treatment. The trial was registered with ClinicalTrials.gov on 18 September 2019, registration number: NCT04090931.

Comparison of the load-deflection characteristics of 0.012″ heat-activated, superelastic and bent superelastic nickel titanium wires

PurposeTo compare the characteristics and load-deflection graphs of 0.012″ heat-activated NiTi, superelastic NiTi and bent (bends placed at 1, 2 and 3mm) superelastic NiTi wires, focusing on force at 0.5mm after deactivation after deflection by 1, 2, 3 and 4mm. Materials and methodsThree-bracket bending tests using a 10N load cell with 1mm/min crosshead speed and 8mm span were performed at 37°C. Three groups of wires, 0.012″ heat-activated NiTi wires (HANT), superelastic NiTi wires (S), and superelastic NiTi wires with bends placed at 1, 2 and 3mm (SB1, SB2 and SB3, respectively) were deflected by 1, 2, 3 and 4mm. Deactivation forces (N) at 0.5mm after deactivation were compared using ANOVA. ResultsBent NiTi wires produced lighter forces than superelastic and heat-activated NiTi wires (P<0.05). Superelastic and heat-activated NiTi wires had linear load-deflection graphs at 1mm deflection. No bent NiTi wires had linear load deflection graphs; hysteresis was observed after 2, 3 and 4mm deflection in all NiTi groups. Increasing the number of bends and deflection appeared to inactivate NiTi wires. ConclusionsAfter any deflection, all bent NiTi wires produce lighter forces at 0.5mm after deactivation than superelastic NiTi and heat-activated NiTi wires. This study indicates bending a NiTi wire close to a displaced tooth with up to 1mm deflection can produce an active light deactivation force to level severely displaced teeth.

THE DIFFERENCE OF SURFACE MORPHOLOGY AND CHEMICAL COMPOSITION OF SUPER-ELASTIC NICKEL TITANIUM ORTHODONTIC WIRES BEFORE AND AFTER IN ARTIFICIAL SALIVA SUBMERSION

Objective: In order to Investigate the difference of morphology and composition of Super-elastic Nickel Titanium wire before and after submersed in artificial saliva with normal pH (pH 6:50) and acidic pH (pH 3.75). Material and method: Super-elastic Nickel Titanium wire were divided into 2 groups. Each group consisted of 3 samples submerged in 150 ml of artificial saliva for 28 days. The first group was Super-elastic Nickel Titanium wire submersed in artificial saliva with normal pH (pH 6.50) while the second group was submersed in artificial saliva with acidic pH (pH 3.75). Wire surface morphology was Analysed using Scanning Electron Microscope (SEM) while the wire composition was Analysed using Energy Dispersive X-ray Spectroscopy (EDS. Result: Scanning Electron Microscope revealed a significant difference of surface morphology of super-elastic nickel titanium before and after submersed in artificial saliva between normal pH (pH 6.0) and acidic pH (pH 3.75). SEM investigation Showed a fibrous microstructure on the surface of superelastic nickel titanium before submersed in artificial saliva and became rough and showed many form of pitting or crevice corrosion after submersed in artificial saliva for 28 days. The chemical compositions in surface morphology were analysed using EDS Also showing a different result. The major compositions of super-elastic nickel titanium wire were the C, N, Ni and Ti and after submersed in artificial saliva for 28 days has made any additional elements O, Al, Si, P, Cl, Ca, K and Fe. Conclusion: the surface morphology of nickel titanium surface rugosity greater SEM Showed and presence of many forms of pitting or crevice corrosion after submersed in artificial saliva with normal pH and acidic pH. The major surface composition of a super-elastic nickel titanium before submersed in artificial saliva were the C, N, Ni and Ti and as a major composition of super-elastic nickel titanium before and after submersed in artificial saliva with normal pH (pH 6.0) and acidic pH (pH 3.75 ).

A Systematic review on aligning efficiency of superelastic NITI: in comparison with conventional NITI and multistranded stainless steel archwires

Background: The initial leveling and aligning phase of orthodontic treatment involve the use of nickel titanium wires. The nickel titanium wires exhibit unique properties like shape memory and superelasticity. In the beginning, conventional nitinol wires were used, which lacked the superelastic property. Nowadays, superelastic nickel titanium wires are being used commonly. This systematic review aims to evaluate the efficiency of Superelastic NITi in the initial alignment of orthodontic treatment in comparison with conventional NiTi and multistranded stainless steel archwires by measuring the amount of decrowding and the time taken for decrowding.Method: A systematic literature search was performed on Pubmed, Cochrane, Google scholar &amp; Lilacs.Result: Thirty four studies were identified by the search and ten studies satisfied the inclusion criteria and one study was excluded after abstract reading. Finally nine articles were included for quality assessment.Conclusion: This systematic review concluded that there was no significant differences in the aligning efficiency of superelastic NiTi in comparison with conventional NiTi and multistranded stainless steel wires.Â

Residents' journal review

Residents' journal review

Ceramic brackets and low friction : A possible synergy in patients requiring multiple MRI scanning.

To investigate any advantages of low friction biomechanics in orthodontic patients with fixed appliances without producing metal artifacts during magnetic resonance imaging (MRI). Frictional resistance generated by bracket-wire-ligature systems was analyzed via an experimental model that reproduced upper canine misalignment. Each sample was tested 10 consecutive times in a dry state; a total of 160 tests were carried out. We documented the frictional forces generated by a 0.012- and 0.014-inch superelastic nickel-titanium wire (SENT) with ceramic self-ligating brackets (SLB) with metal insert and ceramic monocrystalline brackets with nonconventional elastic ligatures (NCEL) in conjunction with various degrees of canine misalignment (1.5, 3.0, 4.5, and 6.0mm). Comparisons between the frictional forces released by the two different bracket-wire-ligature systems were made by conducting 3-way analysis of variance (ANOVA) with Tukey HSD pairwise test (P<0.005). We observed no clinically relevant difference between the frictional forces released by ceramic SLB and ceramic brackets in conjunction with a 0.012- and 0.014-inch SENT. Statistically significant differences were apparent with a 0.012-inch SENT at 4.5 and 6.0mm of canine misalignment, where the SLB revealed higher frictional forces. Ceramic brackets with NCEL revealed frictional forces similar to those generated in conjunction with ceramic SLB, thereby helping to avoid metal artifacts in case of expected necessary MRI during orthodontic treatment with fixed appliances.

Force deflection comparison of various heat-activated superelastic nickel-titanium archwires: An in-vitro study

Objectives: To evaluate the load - deflections, compare superelasticity ratios and evaluate mechanical hysteresis for 5 commercial types of heat-activated superelastic orthodontic arch wires in a customized design of 3-point bend test maintained at a temperature of 37°C. Materials and Methods: The 3-point bending test was executed and provided values for the modulus of elasticity in bending, flexural stress, flexural strain and the flexural stress-strain response of the material. Results: Austenitic nickel-titanium (A-NiTi) exhibited constant forces but over a lesser range of deflection whereas heat-activated, superelastic nickel-titanium (NiTi) wires exhibited lower forces over a larger range of deflection. Conclusions: Heat-activated NiTi wires exhibited lower forces over a larger range of deflection, with the exception of one brand. In addition, they exhibit better superelastic ratios and a higher mechanical hysteresis than A-NiTi. A-NiTi exhibited constant forces but over a lesser range of deflection.

Residents' journal review

Residents' journal review

Frictional resistance in monocrystalline ceramic brackets with conventional and nonconventional elastomeric ligatures

BackgroundThe objective of this study was to compare the frictional forces generated by three types of monocrystalline ceramic brackets coupled with conventional elastomeric ligatures (CEL) and nonconventional elastomeric ligatures (NCEL) during the alignment of apically displaced teeth at the maxillary arch.MethodsAll tests (a total of 480 tests) were carried out in a dry state on a universal testing machine with a testing model consisting of three 0.022-in. monocrystalline ceramic preadjusted brackets (from the maxillary right second premolar through the right central incisor). The canine bracket was bonded to a sliding bar that allowed for different vertical positions. The frictional forces generated by a 0.012- and 0.014-in. superelastic nickel titanium wire (SENT) with conventional and nonconventional ligatures at various amounts of canine misalignment (1.5, 3.0, 4.5, and 6.0 mm) were recorded. Comparisons between the different types of bracket-wire-ligature systems were carried out by means of analysis of variance on ranks with Tukey's post hoc test (P < 0.05).ResultsNo significant differences were assessed among the three types of monocrystalline brackets with NCEL when coupled with 0.012-in. SENT. Radiance brackets with NCEL coupled with 0.014-in. SENT showed significantly greater frictional force than Inspire Ice brackets and Pure brackets with NCEL. A significantly greater amount of frictional force was generated with CEL when compared with NCEL for all the tested variables, with the exception of the Pure brackets with 0.012-in. SENT at 1.5 and 3.0 mm of canine misalignment where similar frictional forces were found.ConclusionsNonconventional elastomeric ligatures are able to reduce friction in monocrystalline ceramic brackets.

A Simple Therapeutic Approach to Pincer Nail Deformity Using a Memory Alloy: Measurement of Response

Pincer nail deformity (PND) is a dystrophy characterized by transverse overcurvature of the nail plate that may cause intractable pain and decrease the quality of life of patients. To evaluated the efficacy of a superelastic nickel-titanium (SE NiTi) wire for the treatment of PND using transverse curvature improvement and subjective assessment of pain relief during and after the treatment. SE NiTi wire was implanted over the distal tip of the nail for the treatment of PND in 43 patients (28 female, 15 male), with a total of 73 digits receiving treatment. Evaluations of improvement included measuring changes in transverse curvature of the nail and subjective assessment of pain relief throughout the follow-up period. In all patients, treatment of the pincer nail with implantation of SE NiTi wire achieved satisfactory results. Significant improvement (p<.05) of the transverse overcurvature of the nail was seen in all patients at 2months, and relief of pain was determined in 100% of cases throughout our follow-up period. This simple SE NiTi wire insertion method is noninvasive and inexpensive, leaves no cosmetic disfigurement, and leads to excellent therapeutic results. Patients achieved great satisfaction. Thus, this technique should be considered the first line of treatment in the correction of mild to moderate PND.

Effect of Artificial Salvia on Force Values of Two Types of Nickel Titanium Ortho-dontic Arch Wires

Aims: To study the effect of artificial saliva and time interval on the amount of force values of nitinol and superelastic NiTi wires. Materials and Methods: Two types of orthodontic wires chosen for the study nitinol and superelastic NiTi wires of a guage of 0.016 inch in diameter (Dentaurum, Germany). Specimens of the wires were divided in to two groups ;the control group(dry condition) contained the wires as - received condition and experimental groups for the study of the force value of wires which subjected to artificial saliva for three time incubation periods (3 days, 7 days, 28 days) . At end of each incubation periods ,the wire specimens were tested for the effect of artificial saliva on force values of the wire. The measurement of force values of arch wires done with a universal tensile testing ma-chine ,the force values of specimens were evaluated with the help of three point bending test. The re-sults were subjected to the descriptive statistics and to the ANOVA and Duncan’s Multiple Range Analysis Tests to detect the amount of changes among these groups . Result: The findings of the present study showed that the control group of nitinol wires had the highest rate of force value with significant difference (P≤ 0.05) with experimental groups, while the experimental group after 28 days gave rise to the lowest one with significant difference (P≤ 0.05) from other groups. For the superelastic nickel titanium the result showed that the control group had the highest rate of force value while the experimental group after 28 days gave rise to the lowest one with significant difference (P≤ 0.05) from control and non significant difference (P> 0.05) with the experimental groups after 3 days and 7 days. Conclusion: The nitinol wires showed a continuous change in force values with increase time in ar-tificial saliva, so this required reactivating or changing the wire at a certain interval of use. While force values of the superelastic nickel titanium wires decreased after 3 days interval and remained constant after that .

Mechanical Properties of Controlled Memory and Superelastic Nickel-Titanium Wires Used in the Manufacture of Rotary Endodontic Instruments

IntroductionThe aim of this study was to investigate the structure and mechanical properties of newly developed controlled memory (CM) nickel-titanium wires used in the manufacture of rotary endodontic instruments. MethodsThe composition and the phase transformation behavior of both types of wires were examined by x-ray energy dispersive spectroscopy and differential scanning calorimetry, respectively. Conventional superelastic (SE) nickel-titanium wire was used as a control. The mechanical properties of the wires at selected temperatures (room temperature, 37°C, and 60°C) were evaluated with tensile, cyclic tensile, and cantilever bending tests by using an Instron 3365 universal testing machine. The data of austenitic transformation finishing temperature (Af) were analyzed statistically by using 1-way analysis of variance test at a significance level of P < .05. ResultsThe raw CM wires contained a nickel content of 50.7% ± 0.5% and possessed a relatively higher Af than SE wires (P < .05). The critical plateau stress and ultimate tensile strength of the CM wires were lower than they were for the SE wires, but the maximum strain before fracture of the CM wires (58.4% ± 7.5% to 84.7% ± 6.8%) was more than 3 times higher than it was for SE wires (16.7% ± 3.8% to 27.5% ± 5.4%). The maximum strain of the CM wires with a diameter of 1.22 mm tested at room temperature (23°C ± 2°C) was up to 84% ± 6.4%. CM wires were not SE at either room temperature or 37°C; however, they exhibited superelasticity when heated to 60°C. ConclusionsThe raw CM wires exhibited different phase transformation behavior and mechanical properties when compared with SE wires, attributing to the special heat treatment history of CM wires. This study suggested greater flexibility of endodontic instruments manufactured with CM wires than similar instruments made of conventional SE wires.

Orthodontic forces released by low-friction versus conventional systems during alignment of apically or buccally malposed teeth

The aim of the present study was to analyse the forces released by passive stainless steel self-ligating brackets (SLBs) and by a non-conventional elastomeric ligature-bracket system on conventional brackets ([slide ligatures on conventional brackets (SLCB)]) when compared with conventional elastomeric ligatures on conventional brackets (CLCB) during the alignment of apically or buccally malposed teeth in the maxillary arch. An experimental model consisting of five brackets was used to assess the forces released by the three different bracket-ligature systems with 0.012-inch super-elastic (SE) nickel-titanium (NiTi) wires in the presence of different amounts of apical or buccal canine misalignment of the canine (ranging from 1.5 to 6 mm). The forces released by each wire/bracket/ligature combination with the three different amounts of apical or buccal canine misalignment were tested 20 times. Comparisons between the different types of wire/bracket/ligature systems were carried out by means of analysis of variance on ranks with Dunnett's post hoc test (P < 0.05). No difference in the amount of force released in presence of a misalignment of 1.5 mm was recorded among the three systems. At 3 mm of apical misalignment a significantly greater amount of orthodontic force was released by SLB or SLCB when compared with CLCB, while no significant differences were found among the three systems at 3 mm of buccal canine displacement. When correction of a large amount of misalignment (6 mm) was attempted, a noticeable amount of force for alignment was still generated by the passive SLB and SLCB systems while no force was released in presence of CLCB.

Mechanical properties of coated superelastic archwires in conventional and self-ligating orthodontic brackets

Coated archwires have been introduced to improve esthetics during orthodontic treatment. Our aim was to investigate the mechanical properties of coated superelastic archwires compared with conventional superelastic archwires with conventional and self-ligating brackets. Four types of orthodontic archwires were investigated, 2 superelastic nickel-titanium and 2 coated Ultraesthetic archwires in 0.016-in and 0.018 x 0.025-in dimensions (all from G&H Wire, Greenwood, Ind). To achieve the same nominal size, the coated archwire is constructed from a smaller archwire that, when coated, reaches the nominal dimensions stated for the archwire. Conventional edgewise Orthos and Damon 2 self-ligating brackets (both from Ormco, Orange, Calif) were used with each wire. All specimens were tested in a universal testing machine in a 3-point bending test at a speed of 1 mm per minute and deflected for 2 mm. Loading and unloading forces were recorded and load-deflection curves plotted. Coated superelastic wires produced statistically significantly lower forces in loading and unloading when compared with the superelastic nickel-titanium wires at most archwire deflections (P <0.01). For nickel-titanium wires, loading values ranged from 189 to 1202 g, whereas the respective values for coated wires were 124 to 772 g. For all wires, an increase in size resulted in an increase in force. Interactions between wire type (coated or uncoated) and bracket type were observed. Ultraesthetic coated archwires produced lower force values in loading and unloading compared with uncoated wires of same nominal size. The Damon 2 self-ligating bracket system produced lower force values in loading and unloading. The lowest forces were generated by the combination of Ultraesthetic coated archwires and Damon 2 self-ligating brackets.