Wires in orthodontics /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
00919248678078

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Wires in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. WIRES IN ORTHODONTICS www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. CONTENTS     INTRODUCTION PHASES OF ARCHWIRE DEVELOPMENT WROUGHT METAL ALLOYS BASIC MECHANICAL PROPERTIES      WIRE CHARACTERISTICS OF CLINICAL RELEVANCE GOLD ALLOYS STAINLESS STEEL Multistranded wires Australian Arch wires www.indiandentalacademy.com
  4. 4. INTRODUCTION www.indiandentalacademy.com
  5. 5. CONTENTS       CHROME- COBALT ALLOYS TITANIUM ALLOYS Alpha Titanium alloy Beta Titanium alloy Nickel Titanium alloys COMBINATION WIRES    ESTHETIC ARCH WIRES COMPARISON OF ARCHWIRES IN ORTHODONTIC APPLICATIONS CONCLUSION www.indiandentalacademy.com
  6. 6. PHASES OF ARCHWIRE DEVELOPMENT (Evans and Durning - BJO 1996) METHOD OF FORCE DELIVERY MATERIALS USED CONCEPT PHASE I Variation in archwire dimension Stainless steel, Gold VARIABLE CROSSSECTIONAL ORTHODONTICS PHASE II Variation in archwire material but same dimension Beta Titanium, Nickel Titanium, Stainless Steel, Cobalt chromium VARIABLE MODULUS ORTHODONTICS PHASE III Variation in archwire properties (super elasticity) Superelastic Nickel Titanium PHASE IV Variation in structural composition of wire material Thermally activated Nickel Titanium PHASE V Variation in archwire material composition / structure Graded thermally active Nickel Titanium www.indiandentalacademy.com VARIABLE TRANSFORMATION TEMPERATURE ORTHODONTICS
  7. 7. WROUGHT METAL ALLOYS       Formation of wrought alloy wires : Melting Formation of ingot Rolling (Turk’s head apparatus) Drawing Wrought alloy properties and micro structure differ from the same alloy when cast. www.indiandentalacademy.com
  8. 8.    Force systems of orthodontic wires are determined by:  appliance design and  wire composition  Proportional to Elastic modulus (E) Low forces biologically desirable Large elastic deflection / working range depending on PL, YS and E www.indiandentalacademy.com
  9. 9. Other important properties:  Ductility  Joinability : soldering, welding  Corrosion resistance  Cost factor  www.indiandentalacademy.com
  10. 10. BASIC MECHANICAL PROPERTIES STRESS Force per unit area within a structure subjected to an external force or pressure. COMPRESSIVE STRESS Ratio of compressive force to cross sectional area perpendicular to the axis of applied force  www.indiandentalacademy.com
  11. 11. TENSILE STRESS Ratio of tensile force to the original cross sectional area perpendicular to the direction of applied force.  SHEAR STRESS Ratio of force to the original cross sectional area parallel to the direction of the force applied  FLEXURAL STRESS / BENDING STRESS Force per unit area of a material subjected to flexural loading  www.indiandentalacademy.com
  12. 12. STRAIN Change in length per unit initial length.  PROPORTIONAL LIMIT Maximum stress at which stress is proportional to strain and above which plastic deformation occurs  WORKING RANGE Maximum amount of elastic strain that an orthodontic wire can sustain before it plastically deforms  www.indiandentalacademy.com
  13. 13. YIELD STRENGTH The stress at which a test specimen exhibits a specific amount of plastic strain  MODULUS OF ELASTICITY / YOUNG’S MODULUS (E) Ratio of elastic stress to elastic strain. It represents relative stiffness of the material.  www.indiandentalacademy.com
  14. 14. FLEXIBILTIY Is a measure of the amount to which a wire can be strained without undergoing plastic deformation. Maximum flexibility is defined as the flexural strain that occurs when the material is stressed to its proportional limit.  www.indiandentalacademy.com
  15. 15. RESILIENCE A relative amount of stored energy per unit volume released on unloading of a test specimen.  PERMANENT / PLASTIC DEFORMATION If a material is deformed by a stress at a point above the proportional limit then plastic or permanent deformation occurs.  www.indiandentalacademy.com
  16. 16. DUCTILITY Relative ability of a material to deform plastically under a tensile stress before it fractures  www.indiandentalacademy.com
  17. 17. COLD WORKING / STRAIN HARDENING / WORK HARDENING It is the mechanical manipulation (plastic deformation) of wire at room temperature. - Stressing beyond PL to cause permanent deformation - Hardness increases - Ductility decreases - Dislocation of grains, altering their shape (spaghetti) - Modulus of elasticity remains unchanged  www.indiandentalacademy.com
  18. 18. ANNEALING Controlled heating and cooling process designed to produce desired properties in a metal. The annealing process is intended to soften metals, to increase their plastic deformation potential, to stabilize shape and increase machinability.  www.indiandentalacademy.com
  19. 19. 3 STAGES OF ANNEALING  Recovery Properties of cold worked metal begin to disappear. Residual stresses of cold worked metal (warping) disappear Temperature used is lower than that used for recrystallization Stress relief heat treatment of orthodontic wires reduces risk of fracture  www.indiandentalacademy.com
  20. 20.  Recrystallization - Significant changes in microstructure Deformed grains replaced by new strain-free grains Original soft and ductile properties return Recrystallization occurs only if metal has been sufficiently cold worked www.indiandentalacademy.com
  21. 21.  - Grain growth Grain size increases after recrystallization Depends on the severity of cold working www.indiandentalacademy.com
  22. 22.  1. - HEAT TREATMENT Solution heat treatment / softening heat treatment casting placed in an electric furnace – 700 degrees C for 10 mins and then quenched Tensile strength, hardness, proportional limit reduced Ductility increased www.indiandentalacademy.com
  23. 23. 2. - - Age hardening/ hardening heat treatment soaking or aging the casting at a specific temperature for a definite time before it is water quenched 200 and 450 degrees C depending on composition usually 15 – 30 mins YS, PL, MoR increases, ductility decreases www.indiandentalacademy.com
  24. 24. SLIP PLANES Application of shearing stresses tend to cause lateral displacement of 2 adjacent planes of atoms with respect to each other  www.indiandentalacademy.com
  25. 25. SLIP PLANES www.indiandentalacademy.com
  26. 26. GRAINS A microscopic single crystal in the microstructure of a metallic material  GRAIN BOUNDARY It is the area where crystals meet. It is the area of mismatch in which atoms are irregularly spaced creating a weaker non crystalline structure. Decreases mechanical strength and increases corrosion  LATTICE A space lattice is defined as any arrangement of atoms in space in which every atom is situated similarly to every other atom as a result of primary or secondary bonds  www.indiandentalacademy.com
  27. 27.  FCC www.indiandentalacademy.com
  28. 28.  BCC www.indiandentalacademy.com
  29. 29. WIRE CHARACTERISTICS OF CLINICAL IMPORTANCE (Kapila and Sachdeva AJO 1989)  - SPRINGBACK Working range Maximum elastic deflection Maximum flexibility Range of activation Range of deflection Ratio of YS to (E) It is a measure of how far a wire can be deflected without causing permanent deformation www.indiandentalacademy.com
  30. 30. LOAD-DEFLECTION RATE Force magnitude delivered by an appliance and is proportional to the modulus of elasticity  FORMABILITY Ability to bend a wire into loops, coils and stops wihout fracturing the wire  www.indiandentalacademy.com
  31. 31. BIOCOMATIBILITY Includes resistance to corrosion and tissue tolerance to elements present in the wire  JOINABILITY The ability to attach auxillaries by welding or soldering when incorporating modifications to the appliance  www.indiandentalacademy.com
  32. 32. FRICTION The preferred wire material for moving a tooth relative to the wire would be one that produces the least amount of friction at the bracket  www.indiandentalacademy.com
  33. 33. GOLD ALLOYS Popular till 1940’s  Noble metal  Type IV commonly used  Composition: Gold 55-65% Platinum 5-10% Palladium 5-10% Copper 11-18% Nickel 1-2%  www.indiandentalacademy.com
  34. 34. Advantages: Inert metal High corrosion resistance Good formability  Disdavantages Low YS and (E) Limited springback High cost  www.indiandentalacademy.com
  35. 35. STAINLESS STEELS Accidentally discovered a few years before FWW  Strauss and Eduard Maurrer  Entered dentistry in 1919 – Hauptmeyer – Krupp’s Dental Polyclinic (‘Wipla’)  Used as orthodontic wire in 1929  www.indiandentalacademy.com
  36. 36. CARBON STEELS Binary alloy of Fe and C (<2.1%) 3 types 1. Ferrite – BCC- stable upto 912 deg C 2. Austenite – FCC stable b/w 912-1394 deg C 3. Martensite – BCT  www.indiandentalacademy.com
  37. 37.  Classification of Stainless Steels (AISI): Austenitic stainless steel (300 series) Type 302, 304, 316L (implants) commonly used FCC structure stable at very high temp above 912 degrees Cr b/w 13-25% - PASSIVATING EFFECT C reduced to prevent SENSTIZATION - STABILIZATION 1. www.indiandentalacademy.com
  38. 38. 2. 3. - Ferritic stainless steel (400 series) BCC microstructure Cannot be hardened by heat treatment Not readily work hardenable Martensitic stainless steel (400 series) Less corrosion resistant Used for surgical and cutting instruments www.indiandentalacademy.com
  39. 39.  - DUPLEX STAINLESS STEEL Consists of micro-structure with both Austenitic and Ferritic grains Contains Mo and Cr with low Ni content Improved toughness and ductility www.indiandentalacademy.com
  40. 40.  - MECHANICAL PROPERTIES High yield strength and high modulus of elasticity Yield strength Elastic Modulus Springback Goldberg + Burstone 275 x 103 25,000 x 103 11.0 Kusy et al 227 x 103 28,000 x 103 8.1 www.indiandentalacademy.com
  41. 41. - High load-deflection rate Low springback High stiffness increases resistance to deformation Cold working increases strength but reduces ductility Stress relief heat tratment www.indiandentalacademy.com
  42. 42. - Annealing can cause recrystallization ADVANTAGES: Greater springback than gold Excellent formability Higher yield strength Moderate cost Low levels of bracket/wire friction (Garner et al, Kusy et al, kapila) www.indiandentalacademy.com
  43. 43. DISADVANTAGES:  Springback lesser than Ti based alloys  Not as resilient as B-Ti or Nitinol  High forces are produced that dissipates over longer periods of time - www.indiandentalacademy.com
  44. 44. MULTI-STRANDED/BRAIDED WIRES - Flexible - Sustain large deflections - Apply lower forces when deflected - Good working range Can be used during initial levelling aligning - PSEUDO-VARIABLE MODULUS MATERIAL www.indiandentalacademy.com 
  45. 45. ROUND .0155” .0175” .0195” .0215” RECTANGULAR .016 x .022 .017 x .025 .018 x .025 .019 x .025 SQUARE .016 x .016 www.indiandentalacademy.com
  46. 46.  Wires used during initial levelling and aligning should be:  Flexible – low stiffness Good working range Sustain large deflections Apply low forces when deflected High strength to withstand masticatory stresses     www.indiandentalacademy.com
  47. 47. STUDIES  Kusy & Stevens (Angle Orthod. 1987) - Viable alternative to the new NiTi alloys which are slightly expensive Studied the mechanical properties of triple stranded S.S. wires and compared them with TMA and Nitinol Wire dimensions used - .0150 .0175 .0195 .0215 www.indiandentalacademy.com
  48. 48. - - .015 triple stranded wire had a greater working range but delivered very light forces than Nitinol / TMA .0195 triple stranded wire same stiffness as that of .016 NiTi However Ti alloys were Stronger – reduced distortion over longer spans www.indiandentalacademy.com
  49. 49. Evans, Jones & Newcombe (AJO.DO 1998) - Compared 3 commonly used orthodontic archwires: - .016 x .022 medium force NiTi - .016 x .022 graded force NiTi - .0155 multistranded S.S. Results: no significant difference in aligning capability b/w the 3 archwires  www.indiandentalacademy.com
  50. 50. PRODUCT CATALOGUE ORMCO Force 9 (braided) Respond (multistranded) D-Rect (braided) www.indiandentalacademy.com Triple flex (triple stranded)
  51. 51. GAC International Wildcat Tricat Pentacat Quadcat Multibraided www.indiandentalacademy.com Hexacat
  52. 52. American orthodontics – Twist (triple stranded) CO-Ax (five strand) Straight woven (eight- stranded rectangular wire) Dentaurum – Dentaflex Triple strand (round & rectangular) Six strand Co-axial Eight strand (braided, rectangular) www.indiandentalacademy.com
  53. 53. Leone - Twist (straight and preformed round & rectangular) Flex (straight and preformed round) Unitek - HI-T II Twist Flex (silver soldered) Unitek braided wire (8 strand) Unitek Coxial TP Orthodontics – CoAx, Pre-Cut CoAx (central core wire www.indiandentalacademy.com with 5 outer strands
  54. 54.      AUSTRALIAN ARCHWIRES A.J. Wilcock – 1940’s Begg technique PROPERTIES: Ultra-high tensile strength Highly resilient Zero stress relaxation Highly resistant to deformation www.indiandentalacademy.com
  55. 55.  - Available in Grades (in order of resilience): Regular Regular plus Special Special Plus www.indiandentalacademy.com
  56. 56.  - Higher grades were developed later over the last 25 years: Premium Premium plus Supreme www.indiandentalacademy.com
  57. 57.  - TP ORTHODONTICS: Standard grade – white label Standard plus grade – green label Premier grade – black label Premier plus grade – orange label www.indiandentalacademy.com
  58. 58.  - JCO 1988 interview of A.J. Wilcock Jr. by P.C. Kesling Wire should always be straightened to improve resilience Higher grades are succeptible to fracture therefore decreased formability Lower grade wires exhibit better formability and are more ductile www.indiandentalacademy.com
  59. 59.  - - Straightening processes: SPINNER STRAIGHTENING (Bauschinger effect) PULSE STRAIGHTENING www.indiandentalacademy.com
  60. 60. Pulse straightened – straight lengths www.indiandentalacademy.com
  61. 61.  PROTOCOL FOR BENDING AUSTRALIAN WIRE www.indiandentalacademy.com
  62. 62.  PROTOCOL FOR BENDING AUSTRALIAN WIRE www.indiandentalacademy.com
  63. 63. RECENT ADVANCES IN STAINLESS STEEL: - Avoidance of Ni due to its allergic potential - Mn used as alternative MEZANIUM – SCHEU DENTAL NONINIUM – DENTAURUM Ni FREE – FORESTADENT NoNi – PYRAMID ORTHODONTICS  www.indiandentalacademy.com
  64. 64. CHROME COBALT ALLOYS Cobalt based alloy  Elgin watch company (1950’s) - ELGILOY  COMPOSITION: COBALT 40% Cr 20% Ni 15% Mo 7% Mn 2 % C 0.15% Be 0.4% Fe 15% www.indiandentalacademy.com 
  65. 65.        TYPES: Blue Elgiloy (soft) Softest Can be bent easily with fingers or pliers Can be welded at low temperatures Recommended for considerable bending, soldering or welding Excellent for edgewise arches, lingual arches, retainers and removables Heat treatment increases resistance to deformation www.indiandentalacademy.com
  66. 66. Yellow Elgiloy (ductile)  Relatively ductile  More resilient than blue elgiloy  Heat treatment increases its resilience and springback  Green Elgiloy (semi-resilient)  More resilient than yellow and can be shaped with pliers before heat treatment  www.indiandentalacademy.com
  67. 67.       Red Elgiloy (resilient) Most resilient High spring qualities Careful manipulation with pliers as it withstands only minimal working Heat treatment makes it extremely resilient – not recommended All adjustments to be made before heat treatment www.indiandentalacademy.com
  68. 68.   - Non heated elgiloy wires have smaller springback compared to stainless steel of similar sizes except for Red Elgiloy Heat treatment or precipitation hardening 482 degrees celsius for 7-12 minutes in a dental furnace Properties similar to stainless steel after heat treatment Higher temp can cause annealing. So use of temperature indication paste recommended. www.indiandentalacademy.com
  69. 69.  - Advantages: Greater resistance to fatigue and distortion Longer function as a resilient spring Better corrosion resistance High modulus of elasticity delivers twice the force of B-Ti and 4 times the force of Nitinol www.indiandentalacademy.com
  70. 70. Exhibits good formability before heat treatment and better springback properties after heat treatment  Disadvantage: Loss in yield strength and tensile strength if annealed. So weld and solder with caution.  www.indiandentalacademy.com
  71. 71. Applications of Elgiloy PENTA-MORPHIC ARCH FORMS – Dr. RICKETTS Yellow Elgiloy – heat treated to maintain arch form and resilience www.indiandentalacademy.com
  72. 72. RICKETTS UTILITY ARCH - Blue Elgiloy (.016 x .016), unheat treated; designed to be used without heat treating www.indiandentalacademy.com
  73. 73. Elgiloy Preformed natural arches Elgiloy Preformed ideal arches www.indiandentalacademy.com
  74. 74. Maxillary anterior torquing retractor Double delta space closure arch levellerRicketts www.indiandentalacademy.com Double delta space closure arch levellerRicketts
  75. 75. Bioprogressive Auxillaries - Ricketts www.indiandentalacademy.com
  76. 76. RETAINERS MANDIBULAR LINGUAL RETAINER HAWLEY RETAINER www.indiandentalacademy.com
  77. 77. PRODUCTS: ROCKY MOUNTAIN – Elgiloy ORMCO – Azurloy DENTAURUM – Remaloy UNITEK – Blue Flexiloy (16x16, 16x22, 18x25, 19x25) LEONE Leoloy (blue & yellow)  www.indiandentalacademy.com
  78. 78. TITANIUM ALLOYS  ALPHA TITANIUM  BETA TITANIUM  NICKEL TITANIUM www.indiandentalacademy.com
  79. 79. ALPHA TITANIUM        Developed by A.J. Wilcock Jr. (JCO 1988) Pure titanium exists in 2 forms: Alpha Titanium (below 885 deg C) Beta Titanium (above 885 deg C) Crystallographic lattice arrangement differs in both types Alpha Ti – closely packed hexagonal Beta Ti – BCC lattice arrangement www.indiandentalacademy.com
  80. 80. Alpha Ti manufactured by feedback centerless grinding technique  COMPOSITION: Ti – 88.9 % Al – 7.86 % Vanadium – 4.05 %  www.indiandentalacademy.com
  81. 81. RECTANGULAR SQUARE www.indiandentalacademy.com COMBINATION
  82. 82. PROPERTIES: Less ductile than Beta Ti because it has fewer slip planes due to its closely packed hexagonal configuration.  At oral temp (37 deg C) it has a tendency to harden by absorbing intraoral free hydrogen ions to form Ti hydride therefore becoming brittle  www.indiandentalacademy.com
  83. 83. NICKEL TITANIUM ALLOY        Stoichiometric binary alloy of Ni and Ti HISTORY Developed by William F. Buehler – research metallurgist in the late 1950’s Naval Ordinance Laboratory, Silver Springs, Maryland  Naval Surface Weapons Centre Accidental discovery Studying metals with SME for the US Navy Polaris reentry vehicle’s nose cone  space research programme. Nitinol  Nickel Titanium Naval Ordinance Laboratory www.indiandentalacademy.com
  84. 84. 1971 – introduced to orthodontics by George Andreasen and marketed by Unitek Corporation as Nitinol™  Nitinol – Ni 50% and Ti 50%  www.indiandentalacademy.com
  85. 85.          Key properties of Nitinol alloys include: Large forces that can be generated due to the shape memory effect Excellent damping properties below the transition temperature Excellent corrosion resistance Nonmagnetic High fatigue strength Moderate impact resistance Moderate heat resistance Biocompatible www.indiandentalacademy.com
  86. 86.            Applications Aerospace and naval applications - Nitinol fluid fittings or coupling have are being used in military aircraft and naval craft. Medical Applications - Tweezers for removing foreign objects via small incisions, anchors for tendon fixation and stents for cardiovascular applications Dentistry - Orthodontic wires, which no not need to be retightened and adjusted Safety devices - Safety valves/actuators to control water temperature and fire sprinklers Other uses include: Spectacle frames Household appliances and deep fryers Vibration control in the form of engine mounts and actuators for buildings Fasteners, seals, connectors and clamps Mobile telephone antennaes www.indiandentalacademy.com
  87. 87. Manufacturing Process      Nickel and titanium are manufactured into Nickel Titanium alloy by a process of VACCUM INDUCTION MELTING or VACCUM ARC MELTING in a furnace. Several remelts are required to improve homogenity Powdered alloy  hot pressed to form wires Final shape  drawing or rolling Predetermined shapes e.g. archform obtained by heating the alloy in moulds at 500 deg C www.indiandentalacademy.com
  88. 88. Glossary and Properties of Nickel Titanium alloys     - NiTi exhibits POLYMORPHISM  ALLOTROPY NiTi can exist in 2 crystalline structures: Austenitic NiTi (A NiTi) BCC lattice structure High temperature Martensitic NiTi (M NiTi) Closely packed hexagonal lattice, less symmetrical Low temperature phase www.indiandentalacademy.com
  89. 89.       AUSTENITIC NiTi High temp phase Rigid and stiffer Symmetrical Uniform structure – allows sound waves to pass thru it easily Less dense       MARTENSITIC NiTi Low temp phase Flexible Less symmetrical Boundaries between regions with different orientation reduce vibrations which muffle the sound More dense www.indiandentalacademy.com
  90. 90.      STABILIZED NiTi / Nitinol (Martensitic Niti) Introduced to orthodontics by Dr George Andreasen in 1971 who realised its Shape Memory potential However the SME effect could not be exploited because it was suppressed during cold working Low stiffness compared to austenitic NiTi Low force per unit deactivation delivering light continuous forces www.indiandentalacademy.com
  91. 91. Martensitic NiTi with fixed composition at room temperature  Incapable of demonstrating changes  Elastic properties due to inherently stable structure  Springy wire  Poor formability  www.indiandentalacademy.com
  92. 92.       AUSTENITIC NiTi Introduced in 1980’s Chinese NiTi – 1985, reported by Burstone and developed by Tien Hua Cheng and associates at General Research Institute for non ferrous metals, Beijing Japanese NiTi – 1986 reported by Miura et al, Furukawa Electric Company Ltd (1978). Active austenitic alloys  form SIM or stress induced martensite Superelasticity www.indiandentalacademy.com
  93. 93.    ACTIVE NiTi Fixed composition Capable of undergoing changes in its crystal structure when stress/temp is applied Active Austenitic stress stress Austenitic Martensitic Austenitic Active Martensitic cold hot Austenitic Martensitic Austenitic www.indiandentalacademy.com
  94. 94. SHAPE MEMORY  Andreasen and Morrow have explained it as the capability of the NiTi wire to return to a previously manufactured shape when it is heated through its TTR  www.indiandentalacademy.com
  95. 95. SHAPE MEMORY NiTi (predetermined shape  archform) cooled heat Deformed (martensitic) www.indiandentalacademy.com
  96. 96. SUPER ELASTICITY / PSEUDOELASTICITY  Ability to withstand elastic deformation to very high degree when compared to other alloys and return to its original shape without undergoing plastic deformation  www.indiandentalacademy.com
  97. 97.      THERMODYNAMIC PROPERTY Refers to the ability of an archwire to return to its intended shape once heated through its transition temperature. TRANSITION TEMP RANGE It is the temperature at which martensitic NiTi is converted to austenitic NiTi To be of clinical value thermodynamic archwires should have a transition temperature close to mouth temperature www.indiandentalacademy.com
  98. 98. TWINNING www.indiandentalacademy.com
  99. 99. MARTENSITIC PHASE TRANSFORMATION www.indiandentalacademy.com
  100. 100. Cell structure during Martensitic Phase Transformation twinning De-twinning www.indiandentalacademy.com
  101. 101. POLAR BEAR WIRE CHILLER www.indiandentalacademy.com
  102. 102. HYSTERESIS     Transformation from austenite to martensite do not take place at the same temperature This difference is known as hysteresis Range for most NiTi alloys is 40 – 60 deg C Non linear stress/strain curve where the loading curve differs from the unloading curve www.indiandentalacademy.com
  103. 103. HYSTERESIS CURVE www.indiandentalacademy.com
  104. 104. FLATTER LOAD DEFLECTION CURVE FOR A- NiTi GREATER SPRINGBACK THAN M- NiTi www.indiandentalacademy.com
  105. 105. Over a considerable range of deflection, the force produced by A-NiTi hardly varies  Therefore an initial archwire would exert about the same force whether it is deflected a relatively small or large distance.  www.indiandentalacademy.com
  106. 106. STRESS-STRAIN CURVE FOR SUPERELASTICITY www.indiandentalacademy.com
  107. 107. LOADING AND UNLOADING CURVE FOR A-NiTi www.indiandentalacademy.com
  108. 108. ACTIVATION-REACTIVATION TO UNLOADING FORCE CHARACTERISTICS www.indiandentalacademy.com
  109. 109. SHAPE MEMORY SUPER ELASTICITY MECHANICAL OR THERMALLY STRESS INDUCED INDUCED AT ORAL TEMP MARTENSITIC PHASE TRANSFORMATION AUSTENITIC  MARTENSITIC  AUSTENITIC www.indiandentalacademy.com
  110. 110.     It is difficult to bend A-NiTi wires because they do not udergo plastic deformation easily. But it can be shaped and properties altered if their temp is elevated The superelastic properties of only a section of a wire can be changed by heat Rx The properties of A-Niti have quickly made it the preferred material for ortho applications where a long range of activation with relatively constant force is needed. www.indiandentalacademy.com
  111. 111. COPPER NiTi        Introduced in 1994 by Dr. Rohit Sachdeva Quarternary alloy Nickel Titanium Copper Chromium New generation NiTi with both superelastic and shape memory properties www.indiandentalacademy.com
  112. 112.     Advantages of Cu-NiTi over traditional NiTi alloys: More resistant to permanent deformation and exhibits better springback Smaller loading force for the same degree of deformation More consistent forces which are active longer within the optimal tooth moving range www.indiandentalacademy.com
  113. 113.      Presence of Cu helps to : Lower the stress required to deform martensitic phase Decreases hysteresis therefore it does not lose its recovery load Enhances thermal reactive properties of NiTi Creates a consistent unloading force which closely approximates loading forces www.indiandentalacademy.com
  114. 114.     Uses both stress induced and temperature dependent martensitic transformation To exploit superelasticity to its fullest potential the working temp of the ortho appliance should be greater than the Af temp Differential between Af temp and mouth temp determines the force generated Af temp can be controlled by altering the composition, thermomechanical treatment and manufacturing process www.indiandentalacademy.com
  115. 115.    - Classified into 4 types based on the Af temp: Type I – Af 15 deg C not used frequently as it generates very high forces clinical indications are few Type II – Af 27 deg C generates higher forces when compared to Types III and IV in patients with average or higher pain threshold normal periodontal health where rapid tooth movt is required and the force system generated is constant www.indiandentalacademy.com
  116. 116.  - Type III – Af 35 deg C generatesforces in mid range patients with low to normal pain threshold periodontium is normal to slightly compromised when relatively low forces are desired www.indiandentalacademy.com
  117. 117.  - Type IV – Af 40 deg C generate tooth moving forces only when mouth temp exceeds 40 deg C for patients who are very sensitive to pain compromised periodontal health for patients who have long intervals between appointments or poor co-operation www.indiandentalacademy.com
  118. 118.  - ADVANTAGES: constant and sustained unloading forces decreased hysteresis  equal activation and deactivation forces provides precise transformation temp easier to engage into the slot  20% less loading force than NiTi decrease of force is less than NiTi alloys therefore it continues to work as teeth near their intended positions www.indiandentalacademy.com
  119. 119. GRADED THERMODYNAMIC NICKEL TITANIUM ARCHWIRES       Bioforce Sentalloy GAC International Unique property of variable transformation temperature within the same archwire Graded force delivery within the same aligning archwire Lighter forces of 80g anteriorly Heavier force of 300g posteriorly www.indiandentalacademy.com
  120. 120. MEDICAL AND OTHER APPLICATIONS OF NiTi Brain spatulas Surgical Tissue spreaders Laser cut tubings and sheets Coronary probes www.indiandentalacademy.com
  121. 121. NiTi Products - ORMCO NiTi Reverse curve NiTi - Turbo  - www.indiandentalacademy.com - A+ Align wire Align SE 200 Align XF
  122. 122.  - 3M Unitek Nitinol (stabilised martensitic) Nitinol SE Nitinol Heat Activated www.indiandentalacademy.com
  123. 123.  - Rocky Mountain Orthodontics Orthonol ( stabilised martensitic) Orthonol Super Elastic Nickel-Titanium Orthonol Reverse Vector Thermanol (heat activated NiTi) www.indiandentalacademy.com
  124. 124.  - Masel Orthodontics Elastinol Bendible Masel Alloy Onyx Ultra www.indiandentalacademy.com
  125. 125.  - GAC International Sentalloy Neosentalloy Bioforce Sentalloy Retranol Sentalloy open and closed coil springs www.indiandentalacademy.com
  126. 126. Thank you www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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