Nickel Titanium Alloys / orthodontic courses by Indian dental academy
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Transcript of Nickel Titanium Alloys / orthodontic courses by Indian dental academy
NICKEL-TITANIUM NICKEL-TITANIUM ALLOYSALLOYS
& &
NEWER ORTHODONTIC NEWER ORTHODONTIC WIRESWIRES INDIAN DENTAL INDIAN DENTAL ACADEMYACADEMY Leader in continuing dental education www.indiandentalacademy.comwww.indiandentalacademy.co
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NICKEL TITANIUM WIRES “ To obtain fairly rapid tooth
movement, HYALINISED ZONES were to be avoided or kept to a minimum.” - REITAN
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NICKEL TITANIUM WIRES Ideally orthodontic wires are designed to move
teeth with light, continuous forces.
Stainless steel Co-cr alloys Beta titanium Nickel titanium
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NICKEL TITANIUM ALLOYS Conventional - Nitinol
Superelastic - Pseudoelastic – Japanese NiTi -Thermoelastic – Cu NiTi
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TITANIUM Titanium was discovered by GREGOR ( England 1790 ) BOTHE et al implanted titanium in lab. animals (1940)
A light weight metal Atomic weight – 47.9 Non magnetic
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TITANIUM Corrosion resistant Biocompatibility High strength Ductility
Two phages Alpha Beta
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TITANIUM Alpha phase – Hexagonal unit cells At room temperature
Beta phase – Body centered cubic cells At temperatures above 16200F or 8820C
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TITANIUM Alpha type – ALPHA TITANIUM (A.J. Wilcock)
Beta type – Beta II or ORMCO’ TMA Titanium-Niobium wires
Both alpha & beta phases – Ti-Al-Fe & Ti-Al-V
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TITANIUM SUPERIOR CORROSION RESISTANCE A thin complex film Tio2 gives Ti affinity, a self
adherence that may cause friction.
Titanium is not esthetic
Lacer aided depositions Implantation of nitrogen ( IONGUARD )
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NICKEL-TITANIUM ALLOYS 2 forms of NiTi alloys
1. Martensite - Body centered cubic/tetragonal lattice
2. Austenite – Face centered (close packed hexagonal)
‘R’ phase – Rhombohedral
“SMART MATERIALS”www.indiandentalacademy.co
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NICKEL-TITANIUM TRANSITION TEMPERATURE RANGE
TTR above the body temperature renders the alloy austenitic which is more rigid
TTR below the body temperature renders it martensitic that is super elastic
Austenite wires - 2% of the strain range Martensitic wires - 8%.
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NICKEL-TITANIUM HYSTERESIS
The range for most binary alloys is 400 – 600
Above the TTR the alloy is fully austenitic (Af),by lowering the temperature martensite will form (Ms)
The temperature at which all the austenite is converted to martensite is designated as martensite finish (Mf)
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PROPERTY AUSTENITE AUSTENITE
YIELD STRENGTH 560 MPa 100 MPa
ELASTIC MODULUS
75 GPa 28 GPa
NICKEL-TITANIUM
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MARTENSITIC TRANSFORMATIONADDDITIONS and IMPURITIES Third metal can lower the TTR to as low as –
3300F or lower the Hysteresis
Thermally activated alloys contain third metal (Cu,Co)
Small amounts of Al, Zr, Cr, or Fe will improve the strength of the martensitic form
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NICKEL-TITANIUM Smaller atoms such as oxygen, nitrogen, and
carbon can not substitute for larger ones,but disrupt the matrices
Ti4Ni2O4 inclusion, which lowers the alloy elasticity (memory changes) interstitial oxygen causes NiTi alloys to become susceptible to corrosion
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MECHANICAL PROPERTIES Pseudoelasticity and thermoelasticity of nickel
titanium alloys: A clinically oriented review.Part I:Temparature transitional changes
– SANTORO et al (AJODO June 2001)
SHAPE MEMORY PSEUDOELASICITY SUPERELASTICITY
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NICKEL-TITANIUM ALLOYS The crystal structure of the alloy will be
confirmed by means of RADIOGRAPHIC DEFRACTION or DIFFERENCIAL SCANNING CALORIMETRY
STUDY OF RESISTIVITY
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NICKEL-TITANIUM ALLOYS SHAPE MEMORY
‘The ability of material to remember its original shape after being plastically deformed’
A certain shape is set at elevated temperatures (above the TTR).When the alloy is cooled below the TTR, it can be plastically deformed but when it is heated again the original shape is restored.
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NICKEL-TITANIUM ALLOYS THERMOELASTICITYThrough deflection and repeated temperature
cycles the wire in the austenitic phase is able to memorise the preformed shape
Ex; An orthodontic archform
By lowering the temperature the alloy is transformed into martensite and becomes pliable and easily deformed
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NICKEL-TITANIUM ALLOYS PSEUDO ELASTICITY A small percentage of martensite ( Intermediate Phase R ) is present in the grain
structure.
Under the conditions of stress “Stress induced martensite ( SIM ) ” will be formed.
A LOCALISED STRESS RELATED SUPERELASTIC PHENOMENON
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NICKEL-TITANIUM ALLOYS SIM is unstable In orthodontic clinical applications, SIM forms
where the wire is tied to brackets on malalligned teeth so that the wire becomes pliable in deflected areas.
In those areas the wire will be super elastic untill tooth movement occurs.
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NICKEL-TITANIUM ALLOYS SUPERELASTICITY
The stress value remains fairly constant up to a certain point of wire deformation. At the same time deformation rebounds, the stress value remains again constant.
It is determined by the typical crystallographic characteristics of NiTi
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NICKEL-TITANIUM ALLOYS STRESS-STRAIN CURVE
A-B shows elastic deformation of the austenitic phase B is the stress at which martensite will form C-D elastic deformation of martensite
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NICKEL-TITANIUM ALLOYS The unique force deflection curve for A-NiTi wire
occurs because of a phase transition in grain structure from austenite to martensite , in response not to a temperature change but to applied force.
This transformation is a mechanical analogue to the thermally induced shape memory effect.
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NICKEL-TITANIUM ALLOYS CLASSIFICATION
NiTi orthodontic wires are generally classified as
NON SUPER ELASTIC ( M –NiTi ) Nitinol SUPER ELASTIC ( A-NiTi ) Japanese NiTi ( Sentinol )
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NICKEL-TITANIUM ALLOYS WATERS ( 1992 ) divided the compounds into 3 groups
based on their TTRs 1) Group I – Alloys with TTR between room temperature and
body temperature. ( Mart active alloys )
2) Group II - TTR below room temperature. (austenitic)
3) GROUP III – Alloys with TTR close to body temperature which by virtue of the shape memory effect spring back to their original shape when activated by body heat.
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NICKEL-TITANIUM ALLOYS III) EVANS and DURNING introduced a even more
comprehensive classification of orthodontic alloys dividing into 5 groups.
1) Phase 1 – Including alloys like gold and ss. 2) Phase II – Stabilised 3) Phase III – Super elastic active austhentic 4) Phase IV – Thermodynamic active
martensitic 5) Phase V - Graded thermodynamic.
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NITINOL Laboratory and clinical Analysis Of Nitinol Wire - G F. Andreasen, R E. Morrow ( AJO Feb
1978 )
Introduction of stainless steel wire appliances. (1930- 1940) Nitional ( Early 1960s) - William.F.Buehler, a
research metallurgist at the Naval Ordinance Laboratory in Silver Springs, Maryland
( Now called the Naval Surface Weapons Center ). www.indiandentalacademy.co
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NITINOL Ni – Nickel Ti – Titanium Nol - Naval ordinance laboratory
It was marketed by Unitek Clinical use of Nitinol wire started in May
1972 by G.F.ANDREASEN et al.
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NITINOL SHAPE MEMORY WIRE
Nitinol has the characteristic of being able to return to a previously manufactured shape when it is heated to a transition temperature range.
ELASTIC ORTHODONTIC WIRE Compared with stainless steel Nitinol wire has an out standing elasticity which is useful for orthodontic applications.
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NITINOL In orthodontic applications
1 . Requires fewer arch wire changes. 2 . Requires less chair time. 3 . Shortens the time required to accomplish
the rotations and leveling 4 . Produces less patient discomfort.
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NITINOL PHYSICAL PROPERTIES.
Material property Nitinol Stainless steel
Alloy Nickel, Titanium Iron, Chrome,Nickel
Ultimate strength 230,000 to 250,000p.s.i
280,000 to 300,000p.s.i
Modulus of elasticity
4.8 x106 p.s.i 28.5 x 106 p.s.i
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NITINOL BEND TEST A series of bend and torsion test have been
performed in accordance with the new ADA Specification
no.32 on orthodontic wires .
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NITINOL TORSION TEST A comparison between nitinol and stainless steel
wires.
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NITINOL STORED ENERGY COMPARISONS Stored energy of Nitinol wire is significantly
greater than an equivalent SS wire.this comparison was based upon the wires being bent 90 degrees
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NITINOLCLINICAL APPLICATIONS Class I ,II,III malocclusions in both extraction
and non extraction cases
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NITINOL The most important benefits from Nitinol wire
are realised when a rectangular wire is inserted early in the treatment.
Simultaneous rotation, leveling, tipping,and torquing can be accomplished earlier with a resilient rectangular wire,
Cross bite correction
Uprighting impacted canines Opening the bite
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NITINOL LIMITATIONS 1.Nitinol cannot be bent with sharp – cornered
instruments.
2. It will readily break when bent over a sharp edge.
3.The bending of loops or omega bends are not recommended. ( especially closing loops ).
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NITINOL 4 . Nitinol cannot be soldered or successfully
welded to it self with out annealing the wire, because the bending of tie- back hooks entails a high risk of failure.
5 . Cinch – backs distal to the buccal tubes are easily accomplished by flame annealing .Care should be taken not to over heat the wire.
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JAPANESE NITI The super - elastic property of the Japanese
NiTi alloy wire for use in orthodontics. - Fujio Miura et al ( AJODO July 1986 ) In 1978 Furukawa electric co.ltd of
Japan produced a new type of alloy 1. High spring back. 2. Shape memory. 3. Super elasticity.
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JAPANESE NITI TESTS 1. Examination of mechanical property of the wire. 1. Tensile test 2. Bending test
2. Measurements of the influence of specific treatment
on the wire. www.indiandentalacademy.co
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JAPANESE NITI 1. Tensile test
Tensile testing was performedfirst because it is the most acceptable method.
Co-Cr-Ni, Nitinol , Ss and Japanese NiTi.
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JAPANESE NITI Bending test 3 point bending test was conducted in a
specially designed situation similar to the conditions involved in moving teeth in the oral cavity.
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JAPANESE NITI Measurement of the influence of special
heat treatment on the wire. A comparative analysis was conducted for this
property before and after being subjected to heat using a .016 inch Japanese NiTi alloy wire.
Nitrate salt bath . 2000 c , 3000c, 4000c, 5000c, and 6000c. 5, 10, 60, and 120 min. 20 different variations.
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JAPANESE NITI RESULTS
The effects of temperature were negligible up to 5000c .
Super elasticity can be influenced by temperature and time.
It is possible to modify the amount of orthodontic force in an individualised segment of the arch wire.
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CLINICAL IMPLICATIONS0.016” medium preformed arch wire was tied
into thelateral incisor and canine bracket.
INITIAL
TWO MONTHS LATER
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CLINICAL IMPLICATIONS NITI COIL SPRINGS TOOTH MOVEMENT RANGE- 0.5 mm per week . Force range 75 to 100 gms. NiTi coil springs . The concept of NiTi coil springs was
suggested in 1975. 1. Open coil springs. 2. Closed coil springs.
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CLINICAL IMPLICATIONS STUDIES ON THE JAPANESE NiTi ALLOY COIL SPRINGS -F.Miura et al ( AJODO AUGUST 1988 )
study conducted to evaluate the efficiency and mechanical properties of closed & open coils as well as stainless steel coil springs.
10 mm Closed coil springs- tensile test .50 mm Open coil spring- compression test.
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CLINICAL IMPLICATIONS FACTORS THAT AFFECT THE MECHANICAL
PROPERTIES OF SPRINGS.
1. Diameter of the wires super elastic activity. 2. Size of the lumen 1/ super elastic activity. 3. Martensite transformation temperature super
elastic activity. 4. Pitch of the open coil spring – when it is changed
from fine to coarse, the load value of super elastic activity remains same but range increases.
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CLINICAL IMPLICATIONS MOLAR DISTALIZATION WITH SUPER ELASTIC
NiTi WIRE. - R.LOCATLLI et al ( JCO 1992 MAY ) . 100gms neosentalloy wire . Markings 1. Distal wing of first pre molar bracket. 2. 5 to 7mm distal to the anterior opening of the molar tube. 3. Between the lateral incisors and canines.
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CLINICAL IMPLICATIONS Crimp a stop to the wire at each mark
Insert the wire into the molar tube until the stop abuts the tube
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CLINICAL IMPLICATIONS NICKEL TITANIUM DOUBLE LOOP SYSTEM - GIANCOTTI ( JCO APRIL 1998 )
After second molar erupts 80g Neosentalloy arch wire 2 sectional arch wires
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CLINICAL IMPLICATIONSNew application of superelastic NiTi rectangular
wires F.Miura, Mogi, Y.Okamoto ( JCO sept 1990 )
FINISHING WIRES NEOSENTALLOY can be used in the initial phases It has 3 dimensional tooth control.
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CLINICAL IMPLICATIONSFACTORS CONTROLLING FORCE LEVEL
HEAT TREATMENT – Changes force levels,and memory properties
COMPOSITION OF THE ALLOY – Lowering the ratio of the nickel decrease the force level
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CLINICAL IMPLICATIONS INDIVIDUALISED PRESURGICAL ARCH FORMS - MIURA et al
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CLINICAL IMPLICATIONS ADVANTAGES
Provides 3 dimensional control Effective in surgical orthodontic cases Eliminates need to change arch wires frequently
DISADVANTAGES Bracket friction will be more when large wires
are used
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BIOEFFICIENT THERAPY ANTHONY.D.VIAZIS ( JCO Sept 1995 )
Superelasticity –Llight constant force levels
Shape memory – Easy arch wire placement
REFRIGERENT SPRAY – ENDO ICE
CLINICAL IMPLICATIONS
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CLINICAL IMPLICATIONSWIRE SELECTION Wire flexibility will be more in vertical direction than horizontal direction
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CLINICAL IMPLICATIONS ORIGINAL SUPERELASTIC WIRES ( ROUND SENTALLOY
) Light, medium, & heavy force levels RECTANGULAR NEOSENTALLOY I generation: 1OOg, 200g, & 300g force levels II generation: 80g force in the central incisor region(alignment) 320g force in the molar region (posterior leveling)
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CLINICAL IMPLICATIONS BIOFORCE IONGUARD WIRES
3-micron nitrogen coating that is produced by ion bombardment of the wire surface.
Reduce 1.Friction 2. Breakage 3.Release of nickel into the mouth .
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COPPER NiTi VARIABLE TRANSFORMATION
TEMPERATURE ORTHODONTICS - ROHIT C. L. SACHDEVA.
“Variable cross sectional orthodontics”.
“Variable modulus concept”
- BURSTONE
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COPPER NiTi “VARIABLE TRANSFORMATION
TEMPERATURE THERMO MECHANICS”
Stress induced martensite
Martensite transformation is also temperature dependent
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COPPER NiTi
AUSTENITIC FINISH TEMPERATURE ( Af ) should be lesser then body temperature.This difference determines the force generated by nickel titanium alloys.
Af can be controlled by affecting the composition , thermo mechanical treatment &manufacturing process of the alloy.
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COPPER NiTi COPPER NiTi Introduced by Rohit sachdeva It has the advantage of generating more
constant forces than any other super elastic nickel titanium alloys.
More resistant to deformation.
Smaller mechanical hysteresis
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COPPER NiTi QUATERNARY METAL – Nickel, Titanium, Copper, Chromium
CLASSIFICATION
Type I Af – 150 c Type II Af - 270 c Type III Af - 350c Type IV Af - 400c
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COPPER NiTi Type II wire 1. Generates the highest forces .
2. Average or higher pain threshold.
3. Normal periodontal health.
4. Rapid tooth movement is required.www.indiandentalacademy.co
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COPPER NiTi TYPE III WIRE
1. Low to normal pain threshold.
2. Slightly compromised periodontium.
3. When relatively low forces are desired.
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COPPER NiTi IV TYPE IV WIRE
1. Intermittent forces . 2. Patients who are sensitive to pain. 3. Compromised periodontal conditions. 4. Patients co operation is very less. 5. Beneficial as an initial rectangular wire
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COPPER NiTi OPTIMAL TOOTH MOVEMENT FORCE.
The ideal arch wire would not exhibit any hysteresis, thus providing equal loading ( engaging ) & unloading ( tooth driving forces ).
Copper enhances thermal reactive properties and creates a consistent unloading force.
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COPPER NiTi Earlier shape memory wires have partially met
these goals. eg : a partially corrected rotation .
A major cause of this deficiency is the hysteresis that severly limits the working range of super elastic arch wires.
Difficulty in setting constant TT while manufacturing .
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COPPER NiTi ADVANTAGES OF COPPER NiTi ALLOYS OVER
OTHER NiTi WIRES 1. Smaller loading force for the same degree of
deformation.( 20% less ) 2. Reduced hysteresis makes to exert consistent
tooth movement and reduced trauma. 3. Consistent TT has ensured consistency of
force from batch to batch of arch wires results in affective tooth movement.
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CHINESE NITI WIRE CHINESE NiTi wire - A new orthodontic wire - C. J. BURSTONE ( AJO JUNE 1985 )
Dr. TIEN HUA CHENG et al at the General Research Institute for Non- Ferrous Metals in Beijing China
( Late 1980s ).
Chinese NiTi wire has much lower transitional temperature than NiTi wire.
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CHINESE NITI WIRE CANTILEVER APPARATUS
0.016 SS, Nitinol and A-NiTiwere submitted to a flexuraltest
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CHINESE NITI WIRE 3 Characteristics
1. The spring back.
2. Stiffness
3. Maximum movement.
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CHINESE NITI WIRE SPRING BACK The range of action of the wire.
For 800 activation SS – 160
Nitinol – 520
Chinese NiTi - 730
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CHINESE NITI WIRE STIFFNESS
The force or movementproduced for each unit Activation
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CHINESE NITI WIRE The magnitude of force increases if the wire is
retied into a bracket.
1500
1000
500
0 20 40 60 80www.indiandentalacademy.com
CHINESE NITI WIRE THE MAXIMUM MOVEMENT..
WIRE MOVEMENT SPRING BACK
%RECOVERY
SS 3,067 16 20
NITINOL 2,112 52 65
NITI 1,233 73 91
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CHINESE NITI WIRE TIME DEPENDANT CHANGES.The wires remained tied between 3 brackets for
periods of 1 minute,1 hour and 72 hours.
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CHINESE NITI WIRE CLINICAL SIGNIFICANCE
1. Applicable in situations where large deflections are required.
2. When tooth are badly malpositoned.. 3. Nitinol wire deformation is not time
dependent 4.Middle range of deactivation forces are
useful in designing an appliance with constant forces.
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Effects Of Cold Disinfectants On The Mechanical Properties And The Surface Topography Of Nickel Titanium Arch Wires.
- J.E.BUCKTHAL & R.P.KUSY ( AJODO 1988 )
1. High cost 2. Super elasticity
Heat sterilisation is the most reliable method of destroying pathogens.
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Nitinol is susceptible to a pitting type of corrosion attack.
Sterilant solutions; 1. 2% acidic gluteraldehyde ( Banicide ) 2. Chlorine dioxide ( Exspor 4:1:1 ) Disinfectant solution; 3. Iodophor ( Wescodyne ) Wires tested; 12 Straight 1 inch length of
rectangular 0.017 X 0.025” Nitinol and Titanol
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4 GROUPS; 0 ( Control ) 1 ( Group 1 ) 2 ( Group 2 ) 3 ( Group 3 )
BEND, TENSILE and LASER SPECTROSCOPY
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SUMMERY No significant changes were detected . The results supported the use of cold
disinfectant procedures.
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NICKEL HYPERSENSITIVITY REACTION Strong biologic sensitizer
SYMPTOMS; Contact dermatitis contact stomatitis Angular chelitis Severe gingivitis Mild erythema with or without edema
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Nickel hyper sensitivity reaction before, during, and after orthodontic therapy.
-G.R.P.JANSON et al ( AJODO JUNE 1998 )
.170 patients of both sexes were examined . 3 groups A - Before B - During C - After 5% Nickel Sulfate in white petrolium
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RESULTS
Orthodontic treatment with SS does not induce a nickel hypersensitivity reaction.
Frequency in females is 4 times more than in males
Association between personal history of allergic reaction & nickel hypersensitivity
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BETA - TITANIUMBeta titanium: A new orthodontic alloy C.J.BURSTONE& A.J.GOLDBERG ( AJO Feb
1980) ORMCO CORPORATION 3 characteristics 1. Spring back - High 2. Stiffness - Low 3. Formability - High www.indiandentalacademy.co
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BETA - TITANIUM Beta titanium was introduced by Dr. CHARLES
BURSTONE and JON GOLDBERG in the university of CONNECTICUT ( Early 1980s )
Composition Titanium - 73.5% Molybdenum - 11.5% Zirconium - 6% Tin - 4.5 %
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BETA - TITANIUM At temperatures below 16250F –
hexagonalClosed packed crystal form.
Yield strength - 55 X 103 p.s.i Modulus of elasticity - 15.5 X 106 p.s.i Spring back - YS = 0.35 X 10–2
E SS - 1.1 X 10–2
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BETA - TITANIUM At temperatures above 16250 F pure titanium rearranges
into body centered cubic lattice - BETA PHASE
BETA STABILISED ALLOYS ( molybdenum or columbium )
Yield strength – 1,70,000 p.s.i Modulus of elasticity – 9,400.000 p.s.i YS/E -1.8X10-2
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BETA - TITANIUMTEST FOR SPRING BACK
TINIUS OLSEN STIFFNESS TESTER ¼ inch span of wire A. Straight wires B. Wires with 350 bend C. Wires which are over bent to 900 and then
bent back to 350
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BETA - TITANIUM MODE STAINLESS
STEEL BETA TITANIUM
PERCENT INCREASE
A 16.0 32.8 105%
B 16.5
31.3 90%
C 17.5 37.3 113%
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BETA - TITANIUM ADVANTAGES:
Low stiffness Good formability High spring back Weldable Ductile Corrosion resistance
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BETA - TITANIUM CLINICAL IMPLICATIONS
Ideal edgewise arches can be deflected twice than SS
allows greater range of action and useful for • Initial tooth alignment • Finishing arches Forces - 0.4% of SS
Eg; 0.018 x 0.025 TMA = 0.014 x 0.020 SSwww.indiandentalacademy.com
BETA - TITANIUM CLINICAL IMPLICATIONS Highly ductile Tieback loops Complicated bends
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BETA - TITANIUMWelding of TMA wire - C.J.BURSTONE ( JCO Sept 1987 )
5 basic principles; 1. Proper positioning 2. Minimum voltage 3. Small contact area 4. Single short pulse 5. Pressure
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Improper welding
Low voltage - The parts may delaminate
High voltage - Wire become brittle Cracks Melting
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CLINICAL IMPLICATIONSPASSIVE APPLICATIONS
ACTIVE APPLICATIONS
SPACE CLOSURE
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ALPHA TITANIUM - WILCOCK company TITANIUM - 90% ALUMINIUM - 6% VANADIUM – 4%
Close packed hexagonal lattice ALPHA stabilising elements – Aluminum, Gallium,
Germanium, Carbon, Oxygen and Nitrogen
‘ NEAR ALPHA ALLOY ’www.indiandentalacademy.co
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ALPHA TITANIUM PROPERTIES; Heat treated to improve strength Satisfactory creep properties – Finishing &
breaking arches wire becomes hard in the oral environment
due to hydrogen absorption TITANIUM HYDRIDE Less ductile – one slip plane Nickel free
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TITANIUM-NIOBIUM A new finishing wire alloy M. Dalstra et al ( COR 2000 July )
Nickel free Titanium alloy (SYBRON DENTAL SPECIALITIES. CALIFORNIA )
Ti - 82% Ti - 74% Mo - 15% ( or) Nb - 13% Nb - 3% Zr - 13%
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TITANIUM-NIOBIUM PROPERTIES Easy to bend, fomability is less than TMA When lower forces are used than TMA Stiffness – ¾ of SS, - ¼ of TMA Load deflection rate is lower than TMA Yield strength is lower than SS
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TITANIUM-NIOBIUM ADVANTAGES;
Substitute for SS No leaching of nickel
CLINICAL IMPLICATIONS; Finishing wire with multiple bends Fixed retainers ( Biocompatible )
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COMPOSITE WIRESThe future of orthodontic materials ROBERT.P.KUSY (AJODO Jan
1998) Metals Polymers Ceramics Advantages are realised Disadvantages are minimised
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METAL-CERAMIC METAL-
POLYMER
CERAMIC- COMPOSIRE
POLYMERS
METALS
CERAMICS
SEMICONDUCTORS
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COMPOSITE WIRESIn orthodontics composite prototypes of arch wires, ligatures,
brackets - S-2 glass fibers ( ceramic ) - Acrylic resins ( polymer )
Esthetically pleasing because they tend to transmit
the colour of host teeth Strong & Springy
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COMPOSITE WIRES PULTRUSION The process of manufacturing components of
continuous lengths & a constant cross sectional shape
Eg; Arch wires
Bundles of continuous fibers are impregnated with a polymeric resin pulled through a sizing die
Then passed through a curing die that imparts a
precise shape ( Electro magnetic radiation ) www.indiandentalacademy.co
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COMPOSITE WIRESThe characteristics of the arch wires can be
changed by - PULTRUSION
Round Rectangular Ligature wires – Polyethylene fiber + Acrylic
resin 2 ½ times stronger than SS Lose most of their tying force in less than 3 hrswww.indiandentalacademy.co
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Comparison of unidirectional fiber reinforced polymeric composites to NITI alloys in bending
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COMPOSITE WIRES
ADVANTAGES;
patients with allergic reactions with nickel Esthetic than previous wires Better strength & springiness
DISADVANTAGES; Shape can not be changed www.indiandentalacademy.co
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COMPOSITE WIRESOPTIFLEX WIRES A composite ceramic fiber-plastic-nylon
( ORMCO )
Dr.TALASS
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COMPOSITE WIRES Structure – Clear optical fiber made of 3 Layers
A. Silicon dioxide core - ForceB. Silicon resin middle layer - Protection from moistureC. Nylon layer - Prevents from damage www.indiandentalacademy.co
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COMPOSITE WIRES The wire can be ROUND or RECTANGULAR
• Wide range of action • Light continuous force • Sharp bend must be avoided• Highly resilient - Effective in the alignment
of crowded teeth
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TIMOLIUM WIRES Improved titanium wires
1. FRICTION 2. RESISTANCE TO BREAKAGE 1. FRICTION Smooth surface texture
Less friction
Accelerate treatment time
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TIMOLIUM WIRES 2. RESISTANCE TO BREAKAGE
Surface defects
Yield strength
Compressive strength
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BETA –III WIRES Introduced by RAVINDRA NANDA Bendable High force Low deflection rate Co-efficient of friction is more Nickel free titanium wire with memory Ideal for multilooping, cantilever, utility
arches
First choice of wire for finishing stages where tip & torque corrections fully accomplished during initial stages.www.indiandentalacademy.co
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NICKEL TITANIUM PALATAL EXPANDERCORRECTION OF POSTERIOR CROSS BITES - Skeletal expansion - Dental expansion The goal of palatal expansion is to maximise
skeletal movement and minimise dental movement.
EXPANSION APPLIANCES - Rapid palatal expansion appliances - Slow expansion appliances
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NICKEL TITANIUM PALATAL EXPANDERRAPID PALATAL EXPANSION APPLIANCES ( RPE) - Produce large forces at the suture site over a short period.
Conventional RPE appliances 1. Uncomfortable 2. Require patient co- operation 3. Laborious 4. Inefficient because of the intermittent nature of
their force application
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NICKEL TITANIUM PALATAL EXPANDER Slow expansion appliances
- Light , continuous forces - Best physiologic changes ( Both
orthopedic and orthodontic ) - Produce a widening rather than an actual
separation of the suture.
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NICKEL TITANIUM PALATAL EXPANDER NICKEL TITANIUM PALATAL EXPANDER W.V.ARNDT ( JCO 1993 )
Tandem loop, nickel titanium , temperature activated palatal expander.
- Light continuous pressure on the mid palatal suture .
( Simultaneous uprighting , rotating , and distalising
the maxillary first molars ) www.indiandentalacademy.co
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NICKEL TITANIUM PALATAL EXPANDER
THE ACTION OF THE APPLIANCE
- A consequence of nickel titanium’ s shape memory and transition temperature effects.
The nickel titanium expander has a transition temperature of 940 F.
Below TTR – Metal is flexible Above TTR – Metal stiffen
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8 Different intermolar widths ( 26mm – 47mm )
Forces ranging from 180 – 300gms 26 – 32mm - Softer wires that produce lower
force levels for younger patients 3mm will be added for overcorrection
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A comparison of dental and dento- alveolar changes between rapid palatal expansion and nickel titanium expansion appliances.
- C. CIAMBOTTI et al ( AJODO JAN 2001 )
The objectives;To compare – Amount of mid palatal suture separation - Alveolar process tipping - Maxillary first molar tipping - Maxillary first molar rotation - Palatal depth changes
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Mixed or early permanent dentition.
12 patients treated with RPE appliances ( 6 males, 6 females with an average age of 11.1 yrs )
Duration 127 days
13 patients treated with NiTi palatal expansion appliances. ( 3 males, 10 females with an average of 9.4 yrs )
Duration 153 days
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RPE APPLIANCE – A tooth borne appliance
Mid palatal jack screw Activation 0.5mm, 2 times per day Expansion – Occlusal aspect of lingual cusp
of maxillary first molar contacted the occlusal aspect of buccal cusp of mandibular first molar.
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NiTi EXPANDER
A tandem loop temperature activated appliance ( GAC International ) designed by ARNDT
The proper size was selected by measuring the
inter molar width and then adding 3 to 4mm Tetrafluoroethane refrigerant
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RESULTS 1. Palatal width change - RPE group is 28 % - In NiTi group 16 %. 2. Buccal tipping of the alveolar
process - RPE group – 5.080. - NiTi group – 6.610
3. Molar rotation - RPE group 1.580
- NiTi group 26.610 www.indiandentalacademy.co
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4. Radiographic evidence shows that mid palatal suture separation is less obvious in the NiTi group than RPE group.
5. No correlation between age and amount of dento- alveolar expansion.
6. RPE appliance widened the palate more reliably, NiTi appliance tipped the molars buccally.
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A review of contemporary arch wires: Their properties and characteristics
- ROBERT KUSY ( AO JUNE 1997 )
CHARACTERSTICS OF THE IDEAL ARCH WIRE Ideally archwires are designed to move
teeth with light continuous forces
No one wire is best for all stages
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CRITERIA OF ANIDEAL ARCH WIRE
Esthetic
Good range
PoorBiohost
Tough
GoodSpring back
Lowfriction
Weldable
Springy
Formable
Biocompatible
Resilient
Strong
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APPLYING ARCH WIRES
During initial stages - great range and light forces VARIABLE CROSS SECTION ORTHODONTICS - Multistranded stainless steel wire
Variable modulus orthodontics - NiTi alloy wire
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Intermediate stages of treatment
Beta titanium alloys Larger sizes of Nitinol
( under sized stainless steel wire if sliding mechanics are required )
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FINAL STAGES OF TREATMENT
More arch stability and less tooth movements
- Large gauges of beta titanium or - Stainless steel wires
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A comparative study of metallurgical and working properties of two new titanium based alloy wires (TiMolium and Beta III ) with the earlier introduced titanium wires ( TMA ), and also alpha titanium wires
- Jiku Abraham TiMolium – T.P.Orthodontics Beta III - Ortho organizers TMA - Ormco corp. Alpha Titanium – A.J. WILLCOCK
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Straight rectangular wires
GROUP I 4 wires in 16”x 22” dimensionGROUP II 4 wires in 17”x 25” dimensionGROUP III 4 wires in 19”x 25” dimension
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Properties studied are 1. Yield, tensile strength & elastic modulus2. Maximum load via 3-point bending test3. Frictional resistance4. Welding characteristics 5. Stress relaxation6. Working range / spring back7. Surface topography8. Micro hardness9. Elemental analysis
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INSTRON MODEL NO.1193 Expr. Setup for Yield strength & ultimate tensile
strength
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Manufacturers claim that; TiMolium is superior to TMA wires in the
following; 1. Friction and surface smoothness 2. Compressive strength 3. Yield strength & breakage resistance
Beta III is bendable , high force low deflection, nickel free arch wire with memory.
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Results of the study showed that The coefficient of friction, surface
smoothness,yield strength & ultimate tensile strength of TiMolium was superior to that of TMA .
However TMA has low load deflection rate and high spring back than TiMolium .
Yield strength of Beta III was lower than TMA and TiMolium
Formability is good but resiliency is low. www.indiandentalacademy.co
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CLINICAL IMPLICATIONS OF THIS STUDY;
1. Correction of crowding or alignment of teeth -
TMA > Beta III
2. Intrusion - TMA shows a better stress relaxation TMA > TiMolium .
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3. Space closure
Sliding mechanics - TiMolium shows lowest values of coefficient of
friction in both static as well as kinetic friction. TiMolium > Alpha titanium
Frictionless mechanics – Formability - Beta III > TMA > TiMolium Resilience - TiMolium > TMA > Beta III
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WELDABILITY
TiMolium > Beta III
FINISHING STAGES
Incomplete tip, torque correction Beta III > TMA > TiMolium
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