TMA Wires Research Articles

In Vitro Effect Of Fluoride Prophylactic Agents On Titanium Molybdenum Alloy And Stainless Steel Orthodontic Wires – Scanning Electron Microscope Study

Background: TMA (Titanium-molybdenum) and SS (Stainless steel) wires are most commonly availed for orthodontic treatment. Meanwhile, patients are encouraged to employ mouthwashes containing fluoride to maintain their oral hygiene. Objective: To assess the effect of different fluoride prophylactic agents on TMA and SS wires for specific time periods namely 10 minutes, 1 hour, 24 hours. Material and Methods: The sample comprised TMA and SS wires immersed in agents such as Artificial saliva (pH = 6.8), Acidulated phosphate fluoride gel 1.23% and Stannous fluoride 0.4% to evaluate surface changes incorporated. 180 cut wires were used in this study; out of which half were SS and the other half were TMA wires. These wires were immersed for 10 minutes, 1 hour and 24 hours in each agent. Scanning electron microscope was also utilized to analyze the surface alterations. Results: The roughness of these wires increased after immersing in prophylactic agents. An increase in the surface roughness was found with SS wires in stannous fluoridesolution and APF gel on immersion at 10 minutes, 1 hour, and 24 hours’ time intervals with p-value being significant at 24 hour time in stannous fluoride. Conclusion: Orthodontists must avoid the contact of orthodontic wires containing titanium protective coating with prophylactic agents. Bangladesh Journal of Medical Science Vol.22 (Special Issue) 2023 p.47-51

Evaluation of surface-modified orthodontic wires by different concentration and dipping duration of titanium oxide (TiO2) nanoparticles.

To evaluate in-vitro surface characteristics and frictional properties of orthodontic stainless steel and beta-titanium archwires after surface modification with different concentrations and coating time of titanium oxide (TiO2) nanoparticles by Sol-gel dip coating method. The experiment was carried out with 4 different concentrations (1:2, 1:4, 1:6, and 1:8) and three different dipping durations (24 hours, 48 hours, and 72 hours) over ten main test groups of SS and TMA archwires with uncoated wires acting as control in both dry and wet conditions. Phase analysis and surface characterization of TiO2 was analyzed by X-ray Diffractometry, surface evaluation with the help of scanning electron microscopy (SEM), and frictional characteristics were evaluated. Among all the concentrations 1:6 ratio with 48 hours of dipping duration showed better surface characteristics. A statistically significant difference in frictional coefficient was observed in both SS and TMA wires than their respective controls (p = 0.001). Intragroup comparison among SS and TMA groups showed that groups with 1:6 ratio and 48 hours dipping duration had least frictional coefficient in both dry and wet conditions (p = 0.001). Intergroup comparison between SS and TMA showed that SS group had significantly reduced friction than TMA (p = 0.001) except in few groups. TiO2 nanoparticle with a concentration ratio of 1:6 and 48 hours dipping duration is recommended for surface modification of orthodontic archwires.

Effects of pendulum appliance versus clear aligners in the vertical dimension during Class II malocclusion treatment: a randomized prospective clinical trial

BackgroundThe aim of the present study was to compare the effects on vertical dentoskeletal dimension produced by Pendulum appliance and Clear Aligners in patients with Class II malocclusion.Trial designThis is a prospective two-arm parallel group randomized clinical trial with 1:1 allocation ratio.MethodsThe Pendulum Group (PG) consisted of 20 patients (15F, 5 M) with a mean age of 17.2 ± 4.3 years. The Clear Aligners Group (CAG) comprised 20 patients (13F, 7 M) with a mean age of 17.2 ± 3.2 years. Distalization’s protocol in PG involved the activation of TMA wires till the achievement of Class I molar relationship. A protocol of sequential distalization was applied in the CAG. For each subject lateral cephalograms have been analyzed before treatment (T1) and at the end of the therapy (T2). Descriptive statistics and statistical between-group comparisons (PG vs CAG) were calculated for the craniofacial starting forms at T1 and for the T2–T1 changes. Statistical between-group comparisons for the T2–T1 changes were performed with independent samples t-tests (P < 0.05).ResultsThe PG showed significantly greater increases in SN^GoGn° when compared with CAG (+ 2.1 and − 0.3 degrees, respectively). Clockwise rotation of the occlusal plane with significantly greater increase of SN^POccl angle was observed in PG (+ 2.8 degrees) when compared with CAG (− 4.2 degrees).The PG revealed a significant increase in the N-Me variable with a mean change of + 4.4 mm compared to the CAG with mean values of − 1.2 mm. The PG showed an increase in the ArGo^GoMe angle (+ 0.7° degrees) compared to the CAG (− 3.4° degrees). The PG showed significantly greater increases in both maxillary and mandibular first molar to palatal plane (+ 1.3 and + 2.1 mm, respectively) when compared with CAG (− 0.9 and − 0.2 mm, respectively).ConclusionsUpper molar distalization with clear aligners represents a valid alternative to non-extraction treatment of Class II malocclusion, reducing the extrusion of maxillary first molars and improving the management of the occlusal plane and vertical dimension.Trial registration: ClinicalTrials.gov, NCT05298280. Registered 28 March 2022—Retrospectively registered, https://clinicaltrials.gov.

Detailed study to evaluate and compare the change in the modulus of elasticity and yield strength during the loading and unloading phase for five different orthodontic wires as a result of exposure to prophylactic fluoride agents and GC tooth mousse wit

Direct bonding and de-bonding procedures during orthodontic treatment lead to areas of enamel demineralization around brackets. During the etching procedures some of the extra area also gets etched and may remain exposed for plaque accumulation resulting in demineralization and white spot lesions around the brackets. To prevent this we use Ortho brush, Chlorhexidine mouth rinses, Fluoride mouth rinses and recently available GC Tooth mousse. However, they may cause corrosion and discoloration of Orthodontic wires1.Mechanical properties of the wire like Yield strength and Modulus of elasticity affects the performance of wire inside the oral cavity. Surface topography of archwire is one of the factors which influence the mechanical properties. Orthodontic mechanotherapy encompasses the use of several arch wires during various stages of treatment. Stainless steel, Nickel titanium and TMA wires are the ones predominately used. In this study we are trying to evaluate and compare the mechanical properties of Nickel titanium, Copper nickel titanium, β Titanium, Stainless steel and Australian 0.016" stainless steel wires immersed in FLUROVIL gel, PHOSFLUR mouth rinse and GC Tooth mousse with those immersed in Distilled water.

Effect of zirconium oxide nano-coating on frictional resistance of orthodontic wires.

Objectives:Minimizing the frictional force between orthodontic wire and brackets is imperative to safely obtain a more favorable result by applying lower loads. Several methods have been proposed for this purpose such as changing the wire shape/size, changing the bracket design, and coating wires with different materials. This study aimed to assess the effect of zirconium oxide (ZrO2) nano-coating on frictional resistance of three types of orthodontic wires.Materials and Methods:This in vitro, experimental study evaluated 42 pieces of nickel-titanium (NiTi), stainless steel (SS), and beta-titanium (TMA) orthodontic wires, and 42 maxillary canine brackets. The samples were divided into six groups with and without ZrO2 nano-coating. The nano-coating was applied on the wires using the sol-gel technique. The presence of ZrO2 nano-coating was evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The surface roughness of the samples was evaluated using atomic force microscopy (AFM). The brackets and wire had a 5° angle relative to each other. The static and kinetic friction of the samples were evaluated in the presence of artificial saliva and occlusogingival movements in a universal testing machine. Data were analyzed by the Shapiro–Wilk's test, one-way ANOVA, Kruskal–Walli's test, Mann–Whitney U test, independent t-test, and Tukey's test.Results:ZrO2 nano-coating was only observed on TMA wires. The surface roughness of coated NiTi and SS wires had no significant difference from that of non-coated wires (P > 0.05). However, this difference was significant for TMA wires with and without the coating (P < 0.05). The static and kinetic friction were not significantly different between wires with and without coating (P > 0.05).Conclusions:ZrO2 nano-coating could only be applied on TMA wires, and had no significant efficacy for reduction of static or kinetic friction of TMA wires.

Torque Comparison Between Two Passive Self-Ligating Brackets with Respect to Interbracket Wire Dimensions and Types: A Finite Element Analysis

Objective: This study aimed to analyze the expression of torque between 2 passive self-ligating brackets by simulating different clinical situations using finite element analysis. Material and Methods: Two passive self-ligating brackets, that is, Damon Q (Ormco, Glendora, California) and Smart Clip (3M Unitek, Monrovia, California), were 3D modeled using micro-computed tomography. ANSYS V14.5 software was used for analysis. Archwire and bracket interactions were simulated to measure torque expression by changing wire alloys (stainless steel [SS] and titanium molybdenum [TMA]) and interbracket dimensions. Results: Damon Q brackets generated higher torque values compared to Smart Clip brackets with both SS and TMA wires. Damon Q brackets generated the highest torquing moment of 25.72 Nmm and 7.45 Nmm, while Smart Clip brackets generated 22.25 Nmm and 7.31 Nmm with 0.019 × 0.025″ SS and TMA wires, respectively, at an interbracket distance of 12 mm. Torquing moments decreased for Damon Q and Smart Clip brackets when wire length increased from 12 mm to 16 mm. Conclusion: Damon Q with 0.019 × 0.025″wires exhibited superior torquing characteristics as compared to Smart Clip brackets with similar archwires.

Expression of Torque and Its Effect on Various Biological Structures Caused by Varying Archwire Material: A 3D FEM Study

Objective: Studying torque expression and biomechanical effects of various wires on giving palatal root torque, using finite element (FE) method (FEM). Conclusion: TMA wires are most favourable for torquing, in terms of torque expression and susceptibility to root resorption. Materials and Method: Geometric model of maxillary right central incisor was developed, using computed tomography (CT) scan. 0.022" × 0.028" Standard edgewise brackets and 10-mm-long stainless steel (SS), titanium molybdenum (TMA) and titanium niobium (TiNb) archwires of dimension 0.019" × 0.025" were modeled and a palatal root torque of 25 degrees was applied on all wires. The angular displacement of the crown and root and nodal displacement at the incisal edge and root apex in y and z axis were analyzed along with stresses on periodontal ligament (PDL), bone, cementum, enamel, and bracket. Results: Buccal crown and palatal root movement was seen, which was maximum for SS and least for TMA. Angular displacement was also highest for SS. Compressive stresses were concentrated at the bucco-cervical and linguo-apical regions in the PDL, cementum, and bone and tensile stresses were concentrated in the linguo-cervical regions. In the enamel, the bracket attachment site showed maximum stresses, and slot base showed higher values of stresses than wings. All stress values were highest for SS and least for TMA.

An In Vitro Evaluation of Frictional Characteristics of Labial and Lingual Self-ligating Brackets with Various Archwire Alloys

Background: An understanding of bracket slot–archwire interface is imperative for biomechanical effectiveness in orthodontic sliding mechanics and hence the aim of the study is to evaluate frictional properties of lingual self-ligating brackets comparing with conventional lingual and labial self-ligating brackets using three different archwire alloys in various environments. Materials and Methods: This in vitro study compared the frictional force of labial and lingual self-ligating and conventional lingual brackets with stainless steel, TMA, and Cr-Co alloy archwires of 0.017” × 0.025” dimension in dry and wet conditions. Frictional forces were evaluated in a simulated half arch fixed appliance using a testing machine. Static and kinetic friction were measured and analyzed by one-way analysis of variance (ANNOVA) test and post hoc Duncan multiple range test. The effects of brackets and archwires in dry and wet conditions were analyzed by three-way variance (ANNOVA) test. Result: The maximum frictional forces were observed with labial self-ligating brackets followed by lingual conventional brackets and the least by lingual self-ligating brackets. Of all the wires tested, TMA wires had the maximum frictional forces followed by Co-Cr and stainless steel. In both conditions, the values were non-significant with all bracket–wire combinations except with Co-Cr and TMA wires. Conclusions: Varied amount of frictional force was shown by the brackets and wires with highest by labial self-ligating bracket, followed by lingual conventional and lingual self-ligating brackets. TMA wires experienced higher friction followed by Co-Cr and stainless steel with minimum friction.

Evaluation of Surface Roughness and Microbial Biofilm Adhesion of Different Orthodontic Arch-wires

Objectives: To assess the capability of different orthodontic arch-wires to retain oral biofilm and to correlate the adhesion to surface roughness of the wires. Methods: Four types of orthodontic arch- wires were used for the study, Nickel-titanium (NiTi), Copper nickel-titanium (Cu-NiTi) , Beta Titanium (TMA ) & Beta III Titanium (CNA) new arch wires and 4 weeks after intraoral usage, were examined for Surface roughness (SR) using an atomic force microscope (AFM). Adhesion of Streptococcus mutans (MS), Staphylococcus aureus (SA), and Candida albicans (CA) were performed using colony count method. Statistically, the following tests were done: analysis of variance, Pearson correlation coefficient test, post hoc Tukey test. Results: The four wire types showed significant increases in SR (P˂ 0.05) after 4 weeks of intra-oral usage, TMA wires recorded the highest roughness values while the lowest ones were for NiTi wires. Bacterial adhesion was detected on all wires, ANOVA showed significant differences between the wires concerning MS, SA and CA adhesion. A significant positive correlation (P=.001) was observed between bacterial adhesion and surface roughness after intra-oral exposure. Conclusions: SR of the wires increased after intra-oral use and there was a positive correlation with the biofilm adhesion.

Evaluation and comparison of surface characteristics of commercially available TMA wires using scanning electron microscopy and optical profilometer.

The aim of this study was to evaluate and compare the surface characteristics of colored titanium molybdenum alloy archwires (purple-coated TMA and honey dew-coated TMA) and the regular titanium molybdenum alloy archwires. The experiment comprised three groups, Group I - regular TMA archwires, Group II - purple-coated TMA archwires, Group III - honey dew-coated TMA wires involving 21 samples each. The surface characteristics were assessed using scanning electron microscopy and optical profilometer. The results were statistically analyzed using analysis of variance wherein Group I regular TMA wires exhibited a root mean square value of 148.071 nm and a standard deviation of 9.0027 nm followed by group II (purple-coated TMA wires) which showed a root mean square value of 84.095 nm with a standard deviation of 2.6005 nm, while group III (honey dew-coated TMA wires) was found to have a root mean square value of 71.681 nm with a standard deviation of 1.4645 nm on subjecting to optical profilometry. The surface roughness is higher for regular TMA wire exhibiting superior characteristic of color-coated TMA wires, especially honey dew-coated TMA wires over the regular and purple-coated TMA wires. This property of the archwires details regarding its application in both sliding and frictionless mechanics in retraction phase of fixed orthodontic treatment.

Evaluating the Amount of Tooth Movement and Root Resorption during Canine Retraction with Friction versus Frictionless Mechanics Using Cone Beam Computed Tomography.

BACKGROUND:The current study was carried out to compare the amount of tooth movement during canine retraction comparing two different retraction mechanics; friction mechanics represented by a NiTi closed coil spring versus frictionless mechanics represented by T - loop, and their effect on root resorption using Cone Beam Computed Tomography (CBCT).METHOD:Ten patients were selected in a split-mouth study design that had a malocclusion that necessitates the extraction of maxillary first premolars and retraction of maxillary canines. The right maxillary canines were retracted using T - loops fabricated from 0.017 X 0.025 TMA wires. The left maxillary canines received NiTi coil spring with 150 gm of retraction force. Pre retraction and post retraction Cone Beam Computed Tomography were taken to evaluate the amount of tooth movement and root resorption using three-dimensional planes.RESULTS:T - loop side showed statistically significant higher mean anteroposterior measurement than NiTi coil spring side, indicating a lower amount of canine movement pre and post a canine retraction. Concerning the root resorption, there was no statistically significant change in the mean measurements of canine root length post retraction.CONCLUSION:The NiTi coil spring side showed more distal movement more than the T-loop side. Both retraction mechanics with controlled retraction force, do not cause root resorption.

The effect of food simulating liquids on the static frictional forces and corrosion activity of different types of orthodontic wires

ObjectivesThe purpose of this study was to investigate the effect of some food stimulating liquids (FSLs) on the static frictional forces and corrosion activity of different orthodontic archwire materials. MethodsStainless steel (SS), β-titanium (TMA), and nickel titanium (NiTi) archwires were stored in heptane, citric acid, and ethanol each. Every storage combination group consisted of 12 wires. The static frictional forces between the SS brackets and each of the three types of orthodontic wires were measured as received, after 2 weeks and after 4 weeks storage in each FSL. The corrosion activity of the wires in citric acid and ethanol were measured. ResultsFor SS wires, citric acid and ethanol 4-week storage showed the highest statistically significant static friction values. For the TMA and NiTi wires, 4-week storage in citric acid showed higher statistically significant static friction values compared with no storage. Citric acid showed the highest corrosion activity for the three types of orthodontic wires. SS showed the highest corrosion activity in both citric acid and ethanol. ConclusionsFour-week storage in citric acid had the highest deleterious effect, as it significantly increased the static frictional force values of SS, TMA, and NiTi archwires. SS has the highest corrosion activity and thus its frictional force values are affected by 4-week storage in both citric acid and ethanol.

Evaluating the Surface Characteristics of Stainless Steel, TMA, Timolium, and Titanium-niobium Wires: An in vivo Scanning Electron Microscope Study.

Recent metallurgical research and advancement in material science has benefited orthodontists in the selection of an appropriate wire size and alloy type, which is necessary to provide an optimum and predictable treatment results. The purpose of the study was to clinically evaluate and compare the surface characteristics of 16 x 22 stainless steel, Titanium molybdenum alloy, timolium, and titanium-niobium before and after placing them in a patient's mouth for 3 months using a scanning electron microscope (SEM). The total sample size was 40, which were divided into four groups (group 1 - stainless steel wires, 10 samples, group 2 - TMA wires, 10 samples, group 3 - timolium wires, 10 samples, and group 4 - titanium-niobium wires, 10 samples), and these were further subdivided into 5 each. The first subgroup of five samples was placed in the patient's mouth and was evaluated under SEM, and another subgroup of five samples was directly subjected to the SEM. Scanning electron microscopic evaluation of surface characteristics of unused 16 x 22 rectangular stainless steel wire under 500 x magnification showed an overall smooth surface. Stainless steel wire samples placed in the patient's mouth showed black hazy patches, which may be interoperated as areas of stress. TMA unused wires showed multiple small voids of areas and small craters with fewer elevated regions. The TMA wire samples placed in the patient's mouth showed black hazy patches and prominent ridges, making the wire rougher. Timolium unused archwires showed heavy roughness and voids, whereas wires tested in the patient's mouth showed homogeneous distribution of deep cracks and craters. Unused titanium-niobium archwires showed uniform prominent striations and ridges with occasional voids, whereas wires used in the patient's mouth showed prominent huge voids that could be interpreted as maximum stress areas. Stainless steel (group 1) used and unused wires showed smooth surface characteristics when compared with all the other three groups followed by timolium, which was superior to titanium-niobium wires and TMA wires. Timolium wires are superior to titanium-niobium wires and TMA wires.

Comparative Evaluation of Frictional Properties, Load Deflection Rate and Surface Characteristics of Different Coloured TMA Archwires - An Invitro Study.

During tooth movement the success of sliding mechanics is dependent upon various factors which include frictional resistance at bracket-archwire interface, surface roughness of archwire materials and elastic properties of archwires. Ion implantation techniques reduce the frictional force and allow better tooth movement clinically. The main objective of this study was to evaluate and compare the frictional properties, load deflection rate and surface characteristics of Honey dew and Purple coloured (Ion implanted) TMA wires with uncoated TMA wires. Fifteen archwire samples were divided into three groups comprising of five samples in each group namely, Group I - Uncoated TMA wires (Control), Group II - Purple coloured TMA wires and Group III- Honey dew TMA wires. Friction and load deflection rate testing were performed with the Instron Universal testing machine and the surface characteristics of the wires were evaluated before and after sliding using Scanning Electron Microscope. The mean frictional characteristics and surface roughness for Honey dew TMA wires was lesser than Purple coloured TMA wires which was statistically significant. Both the coloured TMA wires showed low frictional characteristics and less surface roughness than uncoated TMA wires (the control). The mean load deflection rate was low for both coloured ion implanted TMA wires when compared to uncoated TMA wires which was statistically significant. Coloured ion implanted TMA wires, especially Honey dew TMA wires have low friction, low load deflection rate and improved surface finish. Hence they can be used in frictionless as well as sliding mechanics, where uncoated TMA wires are inefficient.

Comparison of the Amount of Maxillary Canine Retraction, with T-Loops, using TMA and Stainless Steel Wires: A Clinical Study

Comparison of the Amount of Maxillary Canine Retraction, with T-Loops, using TMA and Stainless Steel Wires: A Clinical Study

Profile of the orthodontist practicing in the State of São Paulo - Part 2

The choice of brackets, bands and wires is a very important aspect of orthodontic treatment. Stainless steel prevailed for a long time, but new alloys and resources have emerged to diversify the orthodontic wire mechanics. This study aimed to investigate the profile and materials used by orthodontists practicing in the State of São Paulo, Brazil. A questionnaire was sent to 2,414 specialists in Orthodontics and Dentofacial Orthopedics registered with the Regional Board of Dentistry of São Paulo State (CRO-SP). To assess the association between qualitative variables, the Chi-square association test was employed at 5% significance level. Five hundred and ninety-three (24.65%) questionnaires were completed and sent back. Efficiency was the key reason given by the professionals for choosing a particular material. The majority showed a preference for metal brackets (98%), followed by ceramics (32%) and polycarbonate (7.8%). The most widely used brackets had 0.022 x 0.028-in slots (73.2%). Regarding orthodontic wires, 88.2% employed round steel wires and conventional round NiTi wires, while 52.6% used round heat-activated NiTi and 46.5% rectangular TMA wires. Elastics (92.9%) were the most widely used method to tie the orthodontic archwire to the bracket. In this survey, the orthodontists claimed that efficiency was the major motivator for choosing orthodontic materials. Conventional brackets tied with conventional elastic ligatures are still the most used by the professionals. Among steel and conventional Nitinol wires, round wires ranked first. The use of resources recently available to Brazilian orthodontists, such as self-ligating brackets and mini-implants, was not significant.

A comparative assessment of torque generated by lingual and conventional brackets

The aim of this study was to assess the effect of bracket type on the labiopalatal moments generated by lingual and conventional brackets. Incognito™ lingual brackets (3M Unitek), STb™ lingual brackets (Light Lingual System; ORMCO), In-Ovation L lingual brackets (DENTSPLY GAC), and conventional 0.018 inch slot brackets (Gemini; 3M Unitek) were bonded on identical maxillary acrylic resin models with levelled and aligned teeth. Each model was mounted on the orthodontic measurement and simulation system and 10 0.0175 × 0.0175 TMA wires were used for each bracket type. The wire was ligated with elastomerics into the Incognito, STb, and conventional brackets and each measurement was repeated once after religation. A 15 degrees buccal root torque (+15 degrees) and then a 15 degrees palatal root torque (-15 degrees) were gradually applied to the right central incisor bracket. After each activation, the bracket returned to its initial position and the moments in the sagittal plane were recorded during these rotations of the bracket. One-way analysis of variance with post hoc multiple comparisons (Tukey test at 0.05 error rate) was conducted to assess the effect on bracket type on the generated moments. The magnitude of maximum moment at +15 degrees ranged 8.8, 8.2, 7.1, and 5.8 Nmm for the Incognito, STb, conventional Gemini, and the In-Ovation L brackets, respectively; similar values were recorded at -15 degrees: 8.6, 8.1, 7.0, and 5.7 Nmm, respectively. The recorded differences of maximum moments were statistically significant, except between the Incognito and STb brackets. Additionally, the torque angles were evaluated at which the crown torque fell well below the minimum levels of 5.0 Nmm, as well as the moment/torque ratio at the last part of the activation/deactivation curve, between 10 and 15 degrees. The lowest torque expression was observed at the self-ligating lingual brackets, followed by the conventional brackets. The Incognito and STb lingual brackets generated the highest moments.

Effect of sodium bicarbonate air abrasive polishing on resistance to sliding during tooth alignment and leveling: An in vitro study

Abstract Objective: The aim of this in vitro study was to evaluate the Resistance to Sliding (RS) provided by metallic brackets and 3 types of orthodontic wires (TMA, SS and NiTi), before and after the use of sodium bicarbonate airborne particle abrasion, in an experimental model with 3 non leveled brackets. Materials and Methods: The bicarbonate airborne abrasion was applied perpendicularly to the bracket slots at a distance of 2 mm, for 5 seconds (T2) and 10 seconds (T3) on each bracket slot. In a universal testing machine, the wires were pulled through a set of 3 non leveled brackets at a cross head speed of 50 mm/min for a distance of 10 mm, and static and kinetic friction readings were registered at T1 (no airborne abrasion), T2 and T3. Results: For all tested wires, a significant RS increase between T1 and T3 (P&lt;0.001) was seen. For SS and TMA wires, there was a statistically significant RS increase between T1 and T2 (P&lt;0.001). Between T2 and T3, RS increase was significant for TMA (P&lt;0.001) and NiTiwires (P&lt;0.05). Conclusions: Sodium bicarbonate air abrasive polishing during orthodontic treatment is not recommended, once this procedure promoted a significant RS increase between the metallic brackets and all the three types of wires tested.

Evaluation of Rotation, Tipping and Extrusion During Canine Retraction by Sliding Mechanics Using Different Arch Wires.

Aims: To evaluate the amount of rotation, tipping and extrusion using different wires and to Estimate the difference in the amount of tipping, rotation and extrusion between Stainless steel and Teflon ligature in different wires. Materials and Methods: The standardizing criteria were all Typodont teeth situated in well–aligned, covered and immobilized by the acrylic bite except canine; The available space for canine sliding was (14 mm) measured by digital vernia. Elastic chain exerting 180 gm of force on canine measured carefully by tension gauge. In both vertical and horizontal direction a photographs that were taken for Typodont using digital camera. The angle between bite plane extension bar and Canine extension bar were (90o) measured by protractor directly on the photograph. Preformed band with its attachments, ready made stainless steel, composite coated and TMA arch wires all were (0.018×0.025) with the use of stainless steel and Teflon ligature, Standard titanium spring 11 mm length, Typodont components, within six types of connection the two types of ligation material had been applied to the three different wires then the 1st premolar space tend to be closed by distal canine displacement then the resultant rotation, tipping and extrusion were measured. Statistical Descriptive analysis: One–way and, Two–ways Analysis of Variance were done to detect the variability between methods and which is the best. Results: Three important results showed in the study: First, canine sliding over the composite coated arch wire with the use of stainless steel ligature gave rise to significant decrease in rotation, tipping and extrusion when compared with other methods. Second, stainless steel ligature when compared with Teflon ligature of the same corresponding method gave rise to a significant decrease in the degree of rotation tipping and extrusion. Third, Composite coated arch wires showed lowest degree of rotation then followed by TMA arch wires ordinarily this is due to their rough surface. The largest rotation seen in the stainless steel arch wire this is due to its smooth surface texture, and the same thing for the tipping of the composite coated wires that gave rise to the lowest degree of tipping followed by the stainless steel wires, these result possibly due to their stiffness then higher tipping seen at TMA wires ordinarily a result of their flexibility this sequence were the same for both types of ligations. Conclusions: Best method of space closure is the use of either composite coated arch wire or stainless steel arch wire with stainless steel ligature that give us highest resistance to tipping, lowest extrusion and relatively little rotation when compared with other methods.

Mechanical properties of several nickel-titanium alloy wires in three-point bending tests

The purpose of this study was to clarify the mechanical properties of 42 brands of nickel-titanium alloy orthodontic wires from 9 manufacturers by conducting three-point bending tests under uniform testing conditions. Manufacturers included A-Company, Hoya Medical, Lancer, Ormco, Rocky Mountain, Sankin, Tomy (GAC), TP, and 3M/Unitek. Cobalt-chrome, and titanium-molybdenum alloy wires were also tested as a reference for comparison of force levels. All reported data were recorded during the unloading process to simulate the force that a wire exerts on a tooth as it is moved into the dental arch from a position of malocclusion. The following results were obtained for the nickel-titanium wires tested. (1) Among the 0.016 inch round wires tested under a maximum deflection of 1.5 mm, the difference between the smallest (Copper nickel-titanium 35) and the largest (Aline) load values was 136 g. For the 0.016 × 0.022 inch rectangular wires tested, the difference between the smallest (Copper nickel-titanium 40) and the largest (Aline) load values was 337 g. (2) The change in load between 1.5 and 0.5 mm of deflection was examined to clarify the superelastic properties of the wires tested. For the 0.016 inch wires, 17 wire brands produced a load difference of less than 100 g, and two brands produced a difference of at least 100 g (Aline and Titanal = 100 g). For the 0.016 × 0.022 inch wires, 15 brands produced a load difference of less than 100 g, and eight brands produced a difference of over 100 g. The smallest and largest load differences were 3 g (Copper nickel-titanium 35) and 200 g (Aline). (3) The majority of the samples with a smaller load difference between deflections of 1.5 mm and 0.5 mm in the unloading process were found among super-elastic wires, while samples with a larger load difference were predominantly found among work-hardened wires. Compared with cobalt-chrome and TMA wires, nickel-titanium alloy wires exert significantly less force. However, the amount of force varies greatly from brand to brand. Consequently, when using nickel-titanium alloy wires, brands must be selected carefully by taking into consideration the severity of the malocclusion and the stage of orthodontic treatment in each case. It is the intent of this study to offer clinicians an unbiased guide for the selection of appropriate nickel-titanium alloy wires. (Am J Orthod Dentofacial Orthop 1999;115:390-5)