Orthodontics wires /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call

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Orthodontics wires /certified fixed orthodontic courses by Indian dental academy

  1. 1. ORTHODONTIC WIRES INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2.      ORTHODONTICS WIRES Introduction Terminologies Classification of wires Mechanical properties & clinical application of wires Ideal orthodontic alloy
  3. 3.   Individual wires -Gold wires -Cobalt chromium wires (Elgiloy) -Stainless steel wires -Australian heat treated wires -Nickel Titanium wires (NITI wires) -Beta Titanium wires (TMA wires) -Alpha Titanium wires -Copper Niti wires -Ceramic wires Conclusion
  4. 4. Introduction Those who are enamored of practice without science are like a sailor who goes into a ship without rudder or compass & hence has no certainty where he is going. Practice should always be based upon a secured knowledge of theory.
  5. 5. Terminolgies Mechanics: As an area of study with in the physical sciences, is concerned with the state of rest or motion of bodies, subjected to forces.  Force: Force is defined as an act upon a body that changes or tends to change the state of rest or the motion of that body.  Stress: Displacing force measured across a given area, it is known as stress (force per unit area, pound/sq. inch)  Strain: The change in dimension is called a strain change in length / unit length. Strain could be 1) Plastic 2) Elastic
  6. 6.     Tensile stress: A tensile stress is caused by a load that tends to stretch or elongate a body. It is always accompanied by a tensile strain. Compressive stress: If a body is placed under a load that tends to compress or shorten it. the internal resistance to such a load in called compressive stress. It is accompanied by a compressive strain. Shear stress: A stress that tends to resist a twisting motion or a sliding of one portion of a body over another, is called as shear or shearing stress. The elastic limit of a material is the greatest stress to which a material can be subjected, such that it will return to its original dimensions when the forces are released.
  7. 7.  Proportional limit: If the wire is loaded in tension in small increments until the wire ruptures, without removal of the load each time and if each stress is plotted on a vertical coordinate and the corresponding strain is plotted on the horizontal coordinate a curve is obtained.  Hook’s law: The stress is directly proportional to the strain in elastic deformation.  Yield strength: The yield strength is the stress required to produce the particular offset chosen (plastic strain).
  8. 8.  Modulus of elasticity: If any stress value is equal to or less than the proportional limit is divided by its corresponding strain value, a constant of proportionality will result, this constant of proportionality is known as the modulus of elasticity or Young’s modulus.  The maximal flexibility is defined as the strain that occurs when the material is stressed to its proportional limit.
  9. 9. Stress Elastic Properties Elastic Portion Strain
  10. 10. Elastic Properties Stress Yield strength 0.1% Proportional Limit Elastic Limit Strain
  11. 11. Stress Elastic Properties Ultimate Tensile Strength Fracture Point Strain
  12. 12. Stress Elastic Properties Range Springback Strain
  13. 13. Stress Elastic Properties Resilience Formability Strain
  14. 14. Stress Elastic Properties Modulus of elasticity α Stiffness Springiness α 1 Stiffness Strain .
  15. 15. Wire characteristics of clinical relevance         Springback: Stiffness: Formability: Resiliency: Range: Biocompatible & Environmentally stable. Joinability: Friction:
  16. 16. A rough idea can be obtained clinically as well    Forming an arch wire with the thumb gives an indication of the stiffness of the wire. Flexing the wires between the fingers, without deforming it, is a measure of flexibility Deflecting the ends of an archwire between the thumb and finger gives a measure of resiliency.
  17. 17. Effects of size & shape on elastic properties  Effects of diameter or cross section Strength --- d --- 2d=8 (2d/d)3 springiness --- d --- 2d=1/16 (d/2d)4 Range --- d --- 2d= ½ (d/2d)
  18. 18. Effects of length & attachment Cantilever type supported beam If length is doubled Strength: reduced by ½ Springiness: increased by 8 Increase by doubled. Remains same. Range: increased by 4 times Remains same.
  19. 19. Direction of loading  When a wire is bend so that it permanently deforms & an increase in the bend is desirable it should be done in the original direction of bending & twisting. This is term as the bauschinger effect. Hence the operator should be sure of the last bend made in the wire is in the same direction as the bending produced during its activation.
  20. 20. Fatigue & prevention of fatigue failure Cyclic loading at stress values well below those determined in ultimate strength measurement can produce about failure of a structure. This type of failure is called fatigue. Prevention: 1.prevent minute scratches. 2.Wire should not be marked or notched with file during arch designing. 3.Smooth beaked pliers should be used. 4.Repeated bending at the same spot is to be avoided. 5.Adjustment & bends to be avoided near high stress areas & soldered joints. 
  21. 21. Classification of wires        According to material used Gold archwires Stainless steel archwires Chrom-cobalt archwires Nickel-Titanium archwires  Martensitic  Austenitic  Superelastic  Japanese NiTi  Chinese NiTi  Beta titanium – TMA  Alpha NiTi Copper NiTi Ceramic coated/optiflex archwires
  22. 22. Classification according to cross section    Rounded Rounded rectangular Retangular  Co axial  Twisted  woven
  23. 23. Gold wires     ADA specification Precious metal alloy was used before no.7 1950’s due to its Type I: High precious stability. metal containing Wrought metal is atleast 75% of Au & used in modern Pt dentistry because Type II: Low precious gold in its pure state metal containing is very soft, malleable atleast 65% of Au & & ductile. Pt Not used today due to Composition: Au, Pt, its low yield strength. Pd, Ag, Cu, Ni, Zn
  24. 24. Cobalt chromium nickle alloy    First use as watch springs (Elgiloy) during 1950’s Commercially available as Elgiloy, Rocky mountain orthodontics, Azura & Multiphase. Composition: cobalt- 40%,chromium- 20% nickle- 15%, molybdenum-7%, manganese-2%, carbon- 0.5%, beryllium-0.4%, iron-1.5%
  25. 25. Cobalt chromium nickle alloy  Heat treated before being supplied to the user & are available in several degree of hardness having colour coding Soft:- Blue Ductile:- Yellow Semi resilient:- Green Resilient:- Red Heat treatment increases yield strength & decreases ductility.
  26. 26. Cobalt chromium nickle alloy Physical properties: 1. Tarnish & corrosion resistance is excellent. 2. Hardness, yield strength & tensile strength is comparable to 18-8 stainless steel. 3. Ductility: greater in soft compared to 18-8. lesser in hardened condition.  Mechanical properties: 1. Greater resistance to fatigue & distortion. 2.Non heat treated wires have smaller spring back. 3.Have high modulus of elasticity so its deliver forces more & faster movements occurs of posterior teeth causing loss of anchorage. 
  27. 27. Cobalt chromium nickel alloy 4.Have good formability & can be bent into many configuration relatively easily. 5.Low fusing solder is recommended. 6.Frictional forces between brackets & wires is comparable to stainless steel.  Recent Advances: 1. G & H wire company: can be heat treated in bent areas & easily soldered without annealing. having good ductility, strength, flexibility resistance to fatigue & corrosion & have greater spring back.
  28. 28. Stainless steel wires Steels are iron based alloys that contain less than 1.2% carbon.  When 12 to 30 % chromium is added to iron the alloy is called as stainless steel.  Exist in 3 phases 1.Ferrite (Body centered cubic) structure. This phase is stable upto 912° C 2.Austentic(Face centered cubic) structure. This phase is stable between 912 ° to 1394 °C 
  29. 29. Stainless steel wires 3.Martensite (Body centered tetragonal) struture. If the austenitic alloy is cooled very rapidly it will undergo a spontaneous , diffusionless transformation to a body centered tetragonal structure called martensite. This lattice is highly distorted & strained, resulting in a very hard, strong, brittle alloy.
  30. 30. Stainless steel wires  Ferritic stainless steel: - provides good corrosion resistance. -low cost. -has less strength. -not hardenable by heat treatment. -not readily work hardenable. Hence, finds little application in dentistry.
  31. 31. Stainless steel wires  Martensitic stainless steel: -high strength. -can be heat treated. - decrease corrosion resistance. -decrease ductility. Hence used for surgical & cutting instrument.
  32. 32. Stainless steel wires  Austenitic stainless steel: Most corrosion resistant of the stainless steel. composition: chromium -18% nickel8% carbon- 0.15% AISI 302 is the basic type. Type 304 has similar composition but carbon content is limited to 0.08%,this is the most commonly used type.
  33. 33. Stainless steel wires Austenitic stainless steel is preferable to the ferritic alloys because of: -greater ductility & ability to undergo more cold work without breaking. -substantial strengthening during cold working. -greater ease of welding. - ability to fairly readily overcome sensitization -comparative ease in forming. -disadvantage is it annealing temperature so low fusing silver solder should be used. 
  34. 34. Australian heat treated arch wires   Outstanding properties or characteristics of the Australian wire is its -resiliency, springback after having deflected. Variation in the types of wires is made by fluctuation in the rate at which the wire passes the heat source.
  35. 35. Australian heat treated arch wires Available in the following forms forms colour code 1Regular grade White 2.Regular plus grade Green 3.Special grade Black 4.Special plus Orange 5.Extra special plus Blue 6.Supreme Blue 
  36. 36. Australian heat treated arch wires    Regular grade: lowest grade & easiest to bend. It is used for practice or forming auxiliaries. Regular plus grade: Relatively easy to form ,more resilient than regular grade. Available in sizes 0.014”, 0.016”, 0.018”, 0.020” Special grade: Highly resilient yet can be formed into intricate shapes with little danger of breakage.0.016” is often used for starting arches in many techniques. Available in sizes 0.014”, 0.016”, 0.018”, 0.020”
  37. 37. Australian heat treated arch wires     Special plus grade: used by experienced operators. Hardness & resiliency of 0.016” size are excellent for supporting anchorage. Available in sizes 0.014”, 0.016”, 0.018”, 0.020”, 0.022” Extra special plus grade: This grade is unequaled in resilience. More difficult to bend & subject to fracture. Wire breaks easily if not bend properly, no margin for bending errors. Available in size 0.016” only.
  38. 38. Australian heat treated arch wires   Supreme grade: Also called as premium plus in Australia. Used only in treatment of rotations, alignment & leveling. Though supreme grade exceeds the yield strength of extra special plus it is intended for use in either short sections & where sharp bends are not required. Available in sizes 0.010”, 0.012” & 0.016”
  39. 39. Australian heat treated arch wires   Newer grades of Australian wires: During last 2 decades, 3 more grades have been introduced namely Premium, Premium plus, & supreme ( P, P+ & S ) in an order of increasing yield strength. Properties: greater spring back, greater resiliency, less formability, greater resistance to permanent deformation, more brittle than lower grades. Premium:.008”,.009”,.010”,.011”,.012”,.014”,.016” .018”,.020”
  40. 40. Australian heat treated arch wires Premium plus: . 008”,.009”,.010”,.011”,.012”,.014”,.016”,.018”, Supreme: .008”,.009”,.010”,.011”
  41. 41. Nickel Titanium Alloys    Nitinol was invented in the early 1960’s by William F. Buehler, a research metallurgist at the Naval ordinance. Nitinol: Ni for Nickel and Ti for titanium and nol for Naval ordnance laboratory. Composition: Nickel – 54% Titanium – 44% Cobalt – 02%
  42. 42. Nickel Titanium Alloys The wire has low stiffness in combination with moderately high strength which leads to large elastic deflection or working range.  The alloy has limited formability.  Alloy can exist in various crystallographic forms. At high temperature body centered cubic lattice (BCC) referred to as the austenitic phase.. 
  43. 43. Nickel Titanium Alloys Appropriate cooling induces transformation to a close packed hexagonal martensitic lattice.  This transition can also be induced by stress.  Austenitic NiTi is the high-temperature, low stress form, and martensitic NiTi is the low-temperature, high stress form.  Transformation occurs by a twinning process, which is reversible below the elastic limit. 
  44. 44. Nickel Titanium Alloys   This transition leads to two potential properties shape memory, and super elasticity or pseudoelasticity. Shape memory:     Shape memory refers to the ability of the material to ‘remember’ its original shape after being plastically deformed while in the martensitic form. Hence wire is set into the desired shape and held while undergoing a high temperature heat treatment near 482 ° C. Then cooled and formed into a second shape. Subsequent heating through a lower transition temperature i.e. near mouth temperature leads to returning of the wire to its original shape.
  45. 45. Nickel Titanium Alloys  Inducing the austenitic to martensitic transition by stress can produce superelasticity a phenomenon – NiTi wires. On a stress sufficient to induce the phase transformation there is a significant increase in strength referred to as superelasticity which occurs due to a volumetric change in crystal structure.
  46. 46. Nickel Titanium Alloys    At the completion of the phase transformation, behavior reverts to conventional elastic and plastic strain with increasing stress. Unloading results in reverse transition and recovery. Therefore, NiTi alloy can be produced with either austenitic or martenstic structure with varying degrees of cold work and variations in transition temperature.
  47. 47. Nickel Titanium Alloys    NiTi has low modulus value and larger working range. Less formability and can neither soldered nor welded. Crimpable hooks and stops like cinchback distal to molar buccal tube is recommended. Cinchback is performed by flame annealing which leads to making the wire dead soft and it can be bent into the preferred configuration. Dark blue colour indicates the desired annealing temperature.
  48. 48. Nickel Titanium Alloys  Clinical application:       High springback, flexibility, low constant forces ,shape memory and elasticity are the important and advantageous properties for clinical applications of NiTi. Frictional forces are higher than stainless steel and lower than those with beta-titanium. Uses: Crossbite correction Uprightening impacted canines Opening the bites
  49. 49. Beta-Titanium alloy In 1960 a high temperature of titanium alloy which above 1625 ° F rearranges into a body centered cubic lattice ,referred to as the beta phase, with the addition of elements as molybdenum was developed.  Composition: Titanium- 79% Molybdenum-11% Zirconium-6% Tin- 4% 
  50. 50. Beta-Titanium alloy Also called as TMA wires  Mechanical properties -low modulus of elasticity - modulus of elasticity is twice that nitinol & less than half that of stainless steel. -greater spring back. -good corrosion resistance. - heat treatment is not recommended. -as it is ductile hence loops & bends can be given. 
  51. 51. Alpha Titanium Arch Wire      It is the recent alloy in the family of titanium alloy. Composition: Titanium – 90% Aluminum – 6% Vanadium – 4%   Molecular structure is the alpha phase with a closely packed hexagonal lattice. It possesses fewer slip planes thereby this wire is difficult to deform. Hence it is less ductile than beta-titanium.
  52. 52. Alpha Titanium Arch Wire  Clinical significance: Rectangular wires in the sizes of 0.022” x 0.018” (ribbon mode) or 0.020” x 0.020” (square) are recommended by Mollenhauer for the finishing stage. Alpha titanium combination wire with an anterior ribbon (0.022” x 0.018”) and posterior round (0.018”) sections in second stage of Begg treatment.
  53. 53. Copper-NiTi Arch wire       It was introduced by Rohit Sachdeva and Suhio Mriyasaki in 1994 . Composition: wt % Atomic wt % Titanium 42.99 48.08 Nickel 49.87 45.39 Chromium 0.50 0.96 Copper 5.64 5.57
  54. 54. Copper-NiTi Arch wire     Properties: Copper NiTi generates a more constant force over long activation spans and very small activations as compared to nickel titanium alloys. Copper NiTi more resistant to permanent deformation compared to nickel titanium alloys. Exhibits better spring back characteristics.
  55. 55.  The addition of copper combined with more sophisticated manufacturing and thermal processes make possible the fabrication of four different copper NiTi archwires with precise and consistent transformation temperatures 150 ° C, 270 ° C, 380 ° C and 400 ° C. This enables the clinician to select archwires on a case-specific basis.
  56. 56. Copper-NiTi Arch wire   Classification: Depending on austenitic finish temperatures they are classified into. Type I Af = 15 ° C Type II Af = 27 ° C Type III Af = 35 ° C Type IV Af = 40 ° C
  57. 57. Ceramic Arch Wires  Optiflex archwire: Optiflex is a recent new orthodontic archwire designed by Tallas . It combines unique mechanical properties with a highly esthetic appearance. It is made of clear optical fiber, it comprises of three layers. 1.A silicon dioxide core that provides the force for moving teeth. 2.A silicone resin middle layer that protects the core from moisture and adds strength. 3. A strain resistant nylon outer layer that prevents damage to the wire and further increases its strength.
  58. 58. Ceramic Arch Wires Properties:  Shape: Round or Rectangular  Has wide range of action  Ability to apply light continuous forces  Clinical application: -Sharp bends to be avoided -It is a highly resilient archwire that is especially effective in the alignment of crowded teeth. 
  59. 59. Ceramic Arch Wires    Lee White Wire is tooth coloured, epoxycoated archwire that has superior wear resistance and stability of six to eight weeks. A unique heat treatment bakes on the epoxy coating and makes it possible to offer a wide variety of sizes. The preformed wires are designed in a natural archform
  60. 60. Conclusion    Recent advances in the orthodontic wire alloy has lead to a wide spectrum of wires with varied properties. Hence the orthodontist must make the decision depending upon the clinical situation as to which wire is optimum. An adequate knowledge of the mechanical properties and the clinical applications is a must to aid in making the right decisions.
  61. 61. Effects of Length
  62. 62. Thank you For more details please visit www.indiandentalacademy.com