Archwires In Orthodontics.pptx

ORTHODONTIC MATERIAL :ARCHWIRES
By
Samkit Bothra

CONTENTS
INTRODUCTION
HISTORY OF ARCHWIRES
PROPERTIES
DESIRABLE PROPERTIES OF ORTHODONTIC ARCHWIRES
CLASSIFICATION OF ARCHWIRES
WIRE ALLOYS:
GOLD ALLOYS
STAINLESS STEEL
COBALT CHROMIUM NICKEL ALLOY
NICKEL TITANIUM ALLOYS
BETA TITANIUM
NEWER ARCHWIRES
AESTHETIC ARCHWIRES
CLINICAL SELECTION OF ORTHODONTIC ARCHWIRES
REFERENCES

INTRODUCTION
The art of orthodontics involves correction of the position of
teeth and the relation of craniofacial structures. Teeth are moved
by the use of forces and moments, which are delivered through
the use of various types of wires.
In fixed appliance, wires are used in the shape of arch called as
arch wires
Arch wire is basic active components of fixed appliance system.
The concept of arch wire came into being during the time of
E.H.Angle

Can be divided into the following phases:-
 Material Scarcity, Abundance of Ideas (1750-1930)
 Abundance of materials , Refinement of Procedures (1930 – 1975)
 The beginning of Selectivity (1975 to the present)

MATERIAL SCARCITY, ABUNDANCE OF IDEAS(1750-1930)
 During this period, very few materials were available for the orthodontist.
 Before Angle, dentists used to have noble metals and their alloys for orthodontic
appliances of the time.
 The metals used were Gold, platinum, iridium and silver alloys. Although they had
good corrosion resistance, and acceptable esthetics, they lacked the flexibility and
tensile strength needed for complex machining.

Then, Angle (1887) introduced German silver (a type of brass) into orthodontics.
Angle used various proportions of the metals in German silver around the
composition of Neusilber brass (Cu 65%, Ni 14%, Zn 21%), as well as applying
various degrees of cold work.
Thus he was able to obtain German silver of different properties – rigid for jack
screws, elastic enough for expansion arches, or malleable enough to make bands.

Later on in this era, stainless steel was introduced by Wilkinson in 1929. This was
the alloy which, later on, truly replaced noble metals and brasses in orthodontic
appliance construction.

ABUNDANCE OF MATERIALS, REFINEMENT OF PROCEDURES (1930 – 1975)
 Increase in number of materials being produced due to improvement in metallurgy and
organic chemistry.
 1940’s :-
 With the substantial rise in the cost of gold, Austenitic stainless steel began
to replace gold.
 In early 1940’s Begg partner with Wilcock to make resilient orthodontic wires –
AUSTRALIAN STAINLESS STEELS.

In 1960s :-
 Cobalt –Chromium alloys were introduced. Their physical properties were very similar to
stainless steel. However they had the advantage that they could be supplied in softer and more
formable state that could be hardened by heat treatment.
 The Elgin watch company developed this alloy as a spring in their watches. This was later
marketed by Rocky Mountain Orthodontics as Elgiloy.
In 1962 :-
 Buehler discovers Nitinol at Naval Ordinance laboratory.
In 1970 :-
 Andreasen brought this intermetallic composition of 50% Ni and 50% Ti to orthodontics.
 Unitek company licensed the patent (1974) and offered a stabilized martensitic alloy that
doesn’t exhibit shape memory effect under the name NITINOL.

THE BEGINNING OF SELECTIVITY (1975 TO THE PRESENT)
In 1977 :
Beta titanium was introduced to orthodontic profession by C.J Burstone and Jon
Goldberg.
In 1980’s :
Mr. A.J Wilcock produce a Ultra high tensile stainless steel round wires – The SUPREME
GRADE.

In mid 80’s -
 Burstone reported of an alloy, Chinese NiTi
Miura et al reported on Japanese NiTi, an alloy developed in Japan.
 Both of these alloys i.e Chinese NiTi and Japanese NiTi are active austenitic alloys that
form Stress Induced Martensite (SIM)
 Mr. A.J Wilcock Jr. develops much harder Alpha Titanium archwires.
In 1990’s :
 Neo-Sentalloy is introduced as a true active martensitic alloy.
 Optiflex a new Orthodontic archwire – developed by M.F Talass.
In 1994 :-
 Copper NiTi, a new quaternary alloy containing Ni, Ti, Cu and Cr was invented by
Dr. Rohit Sachdeva and Miyasaki

In 2000 :-
 Titanium Niobium – an innovative new arch wire designed for precision tooth to tooth
finishing reported by Dalstra et al.
 Additional progress in orthodontic arch wire materials including composite “plastic” wires
is being made.
In 2008:-
Fibrocomposite wires by biomers

PROPERTIES OF ORTHODONTIC WIRES
• Various properties of wires can be derived from the stress-strain graph.

STRESS :-
When a force acts on a body tending to produce deformation, a resistance
is developed to this external force application. The INTERNAL reaction is
equal in intensity and opposite in direction to the applied external force and
is called stress.
Stress ( ‫)م‬ = Force/Area
Commonly expressed as Pascal

COMPLEX STRESS:
A single type of pure stress does not occur in a wire. Although, while applying one type of
force, for example tensile, we only see a stretching of the material, actually all three types of
stress exist. A decrease in the diameter represents the compressive stress. And the two
perpendicular movements ( in length &  in diameter occurring together) represent shear
stress.

STRAIN:
Change of shape (deformation) of a material when subjected to stress. Strain is measured in
units of length such as inches/millimeters.
• By definition strain is change in length per unit area.
STRAIN=l/L

Strain Elastic
Plastic
Each type of stress is capable of producing a corresponding deformation in a body.
· Tensile stress produces tensile strain.
· Compressive stress produces compressive strain.
· Shear stress produces shear strain.

Strain
Stress
Elastic limit
ELASTIC LIMITS:
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.

Strain
Stress
Elastic Limit
Proportional Limit
The point on the graph at which a permanent deformation is first observed is called the proportional limit.
Since the proportional limit (stress P) is the greatest stress possible, it may be defined as the greatest
stress which may be produced in a material such that the stress is directly proportional to the
strain.
PROPORTIONAL LIMIT

Strain
Stress
Elastic Limit
Proportional Limit
Yield strength
0.1%
Experimentally, it is very difficult to measure the first point at which a deformation occurs. Hence, a
particular “offset” is chosen.
YIELD STRENGTH

Strain
Stress Ultimate Tensile
Strength
Fracture Point
Yield strength
The maximum force that the wire can withstand, before it fractures, is the ultimate tensile strength.

MODULUS OF ELASTICITY:
• If any stress value equal or less than the proportional limit is divided by its corresponding
strain value, a constant of proportionality will result, this constant is called as Modulus of
elasticity.
• Since modulus of elasticity is the ratio of stress to strain it shows that the less is the strain for
a given stress the greater will be its modulus
• Modulus of elasticity = Stress/Strain
• The unit for modulus of elasticity is force per unit area (Mpa or psi)

Strain
Stress
Slope α Stiffness
Stiffness α 1 .
Springiness
If the modulus of elasticity of a material is high, i.e. the slope is steep, a large amount of force will be
required to cause a deformation in the wire. This means, that the wire is stiff.
Stiffness is proportional to the slope of the graph in the elastic portion. The reciprocal of stiffness, is
springiness.
Stiffness = 1 .
Springiness

FLEXIBILITY:
• When a material can be bent considerably with small stress, then the material is known as
flexible.
• Maximal Flexibility is defined as the strain which occurs when the material is stressed
beyond its proportional limit.
• Max. flexibility = Proportional limit
Modulus of elasticity

TOUGHNESS –
It can be defined as the force required to fracture a material.
It can be measured as the total area under the stress – strain graph.
BRITTLENESS –
Considered to be the opposite of toughness. A brittle material, is elastic, but
cannot undergo plastic deformation. Brittle materials are apt to fracture at or
near its proportional limit.

FATIGUE –
Repeated cyclic stress of a magnitude below the fracture point of a wire can
result in fracture. This is called fatigue.
RANGE
• The distance that the wire bends elastically, before permanent deformation, is called the
range. This can be calculated as the distance on the x-axis up to the proportional limit.
• The greater the range and springback, the more the wire can be activated.

Ultimate tensile Strength = Stiffness x Range
Strain
Stress
Range Springback

Strain
Stress
Resilience Formability
RESILIENCY
When a wire is stretched, the space between the atoms increases. Within the elastic limit, there is an
attractive force between the atoms. So, the stretching causes some amount of energy to be stored within
the wire. This property is known as resilience.

FORMABILITY
Formability is the amount of permanent deformation that the wire can withstand without
breaking. Hence it is an indication of the ability of the wire to take the shape of a spring, arch-
wire, etc.
Stress
Resilience Formability Strain

DUCTILITY:
• It is the ability of the material to withstand permanent deformation under tensile load without
rupture. It depends on the tensile strength and plasticity.
MALLEABILITY:
• Is the ability of the material to withstand permanent deformation under compression, without
rupture. It increases with increase in temperature.

DESIRABLE PROPERTIES OF ORTHODONTIC WIRES:
The ideal properties for an orthodontic purpose according to Proffit are:
• High strength.
• Low stiffness.
• High range.
• High formability.

CLASSIFICATION
composition
Gold alloys
Stainless
steel
Cobalt
chromium
Nickel
titanium
Martensitic
Austenitic
Beta
titanium
Ceramic
coated
Cross section
round
rectangle
square
multistranded

“Noble metal alloys”
COMPOSITION :-
gold 56%
copper 14%
silver 25%
palladium 4%
other Zn, Sn, In, Fe, Ga,
Gold Copper Silver palladium, platinum nickel zinc
Age
Hardening
To counter the
color of copper
↑ The
fusion
temp.
↑ Strength & tarnish resist.

Extreme formability
Strength can be increased
by heat treatment as well
as cold working
Low Modulus of Elasticity
Good joinability
Excellent biocompatibility
Low yield strength
Low springback
High cost
Only the Crozat appliance is still
occasionally made from gold following
original design of early 1900s
ADVANTAGES DISADVANTAGES
USES

 Most widely used and accepted material in orthodontics .
 Stainless steel today is used to make arch wires, ligature wires, band material,
brackets and buccal tubes.
 Steels are iron bases alloys that contain less than 1.2% carbon.

iron chromium nickel carbon
Stabilizes homogenous mass
and corrosion resistant
austenitic phase at low
temperature
Passivating effect by
forming strongly
adherent layer of
chromium oxide
(Cr2O3) on surface.
Provides
strength and
hardness
COMPOSITION
Chromium (11-26%)– Not only does
chromium improve the corrosion
resistance of steel, it also stabilizes the
BCC ferrite phase.
Nickel(0-22%) – At lower temperatures,
nickel stabilizes the crystal into a
homogenous and corrosion –
resistant austenitic phase. So do
copper, manganese and nitrogen.
Carbon (0.08-1.2%)– provides strength,
but reduces the corrosion resistance.
This occurs by a process called
sensitization.

TYPE
(Space lattice)
CHROMIUM NICKEL CARBON
Ferritic (BCC) 11.5 – 27 0 0.20 max.
Austenitic (FCC) 16 –26 7 – 22 0.25 max.
Martensitic (BCT) 11.5 – 17 0 – 2.5 0.15 – 1.20
BALANCE is Iron
DIFFERENT CLASSES OF STEEL EVOLVE FROM THREE POSSIBLE
LATTICE ARRANGEMENT OF IRON

FERRITIC STAINLESS STEELS – AISI 400 SERIES
· Provide good corrosion resistance at a low cost provided that high strength is not required.
· Not readily work hardenable.
· Finds little application in dentistry.
MARTENSITIC STAINLESS STEELS – AISI 400 SERIES
· High strength and hardness.
· Less corrosion resistant and less ductile.
Used for surgical and cutting instruments

AUSTENITIC STAINLESS STEEL – AISI 300 SERIES
Most commonly used for orthodontic materials. Most corrosion resistant of the stainless
steels.
AISI 302
Three Types AISI 304
AISI 316 L
18% Chromium.
AISI 302 8% Nickel.
0.15% Carbon.
Balance iron

THE AUSTENITIC STEELS ARE GENERALLY MORE PREFERABLE :-
• Greater ductility and ability to undergo more cold work without breaking.
• Substantial strengthening during cold work. Cold work is the only way to strengthen
austenitic steel .
• Easy to weld
• Can overcome sensitization
• Comparative ease in forming.
Ferrite + cementite
Austenite
Martensite
TEMPERING HEATING
QUENCHING
This process results in
↓ hardness
↑ toughness

CORROSION RESISTANCE:
PASSIVATION: A thin transparent but tough and impervious oxide layer forms passive layer
on surface of alloy when it is subjected to oxidizing atmosphere such as room air.
Causes of Corrosion of Stainless Steel:
◦ Any surface roughness or unevenness.
◦ Incorporation of bits of Carbon steel or similar metal in its surf
◦ Soldered joints
SENSITIZATION:
18–8 stainless steel may loose its resistance to corrosion if it is heated b/w 4000 C-9000 C.
The reason for decrease in corrosion resistance is Precipitation of Chromium Carbide (Cr3 C) at
the grain boundaries which is most rapid at 650

CLINICAL IMPLICATION OF STAINLESS STEEL
• In the 1st stage of alignment and leveling as an option to NiTi wires; S.S. can be used. If
S.S. is used, multistranded wires or loops to increase springiness can be used.
• For alignment smallest diameter wire with adequate strength is preferred. When multiple
strands of same diameter wire are used, strength increases, springiness relatively
unaffected.
• S.S. wire also finds application in 2nd stage i.e. closing extraction spaces.
• A closing loop made of S.S. wire generate closing force as well as appropriate moments to
bring root apices together at extraction site.
• Finally the typical finishing archwire is either 18  25(0.18 slot) or 21 X 25 (0.22 slot) steel.
These wires are flexible enough to engage narrow brackets even if moderate degree of
tipping has occurred and it will generate the necessary root paralleling forces.

AUSTRALIAN STAINLESS STEEL WIRES
• Dr. P.R. Begg with an Australian Metallurgist Mr. A.J.Wilcock, developed a more
tensile wire material which was thin enough to distribute optimal tooth moving for
long periods, over long distances with minimal loss in the intensity of force.

Different grades of Australian wires formerly used( on the basis of Resiliency):
• At that time, late 1950s, the grades available were –
• Regular white
• Regular plus Green
• Special Black
• Special plus Orange
in increasing order of tensile strength

1) REGULAR GRADE:
• Lowest grade
• Easiest to bend
• Used for practice or forming auxiliaries
• Can be used for archform distortion is not a problem and bite opening is not
required.
• Available in sizes 0.012”, 0.014”, 0.016”, 0.018”, 0.020”.
2) REGULAR PLUS GRADE
• Relatively easy to form, more resilient than regular grade
• Used for making auxilaries and arch form when more pressure and resistance to
deformation is desired.
• Available in sizes 0.014”, 0.016”, 0.018”, 0.020”.

3) SPECIAL GRADE
• Highly resilient yet can be formed into intricate shaped with little danger of breakage.
• The 0.016” is often used for starting arches in many techniques.
• Available in sizes 0.014”, 0.016”, 0.018”, 0.020.
4) SPECIAL PLUS GRADE
• Routinely used by experienced operators
• Hardness and resilience of 0.016” are excellent for supporting anchorage and reducing
deep overbite.
• Available in sizes 0.014”, 0.016”, 0.018”, 0.020”, 0.022”.

RECENT ADVANCES IN AUSTRALIAN STAINLESS STEEL WIRES
A.J Wilcock scientific and Engineering Company. Announced new series of wire
grades and sizes.
The fundamental difference for the superior properties for these new wires is use of
new manufacturing process called PULSE STRAIGHTENING
.NEWER WILCOCK WIRES
• Newer grade of wires came to market with superior properties with advent in
manufacturing process
• they are-
1.PREMIUM - PURPLE
2.PREMIUM PLUS – GOLD
3.SUPREME - BEIGE

PREMIUM GRADE
They are more difficult to bend, occasional breakage to be expected.
They are efficient to open the bite.
PREMIUM PLUS
The 0.014 premium plus wire is used in high angle cases to prevent undue molar extrusion
and due to less diameter do not produce much force and has an intrusion effect which is
favorable in such cases.
SUPREME
Supreme grade wires are used to unravel crowding of anterior Teeth.
They have resistance and yield diameter near to NI-TI wires and cost wise they are more
economic.

BRAIDED AND TWISTED WIRES
 Very small diameter s.s wire can be braided or twisted together by the manufacturer to form
wires for clinical orthodontics.
 Separate strands may be as small as 0.005 or 0.010, comprised of five or seven wrapped
around a central wire of same diameter.
 It affords extreme flexibility and delivers extremely light forces, full engagement of the arch
wire at an early stage.
 Used at the beginning of the treatment to align labiolingually displaced or rotated anterior
teeth.

They are available in both round and rectangular shape.
 Different type of multi-stranded wires are available
 Triple stranded – 3 wires twisted
 Coaxial – 6 wires wrapped around a core wire
 Braded – 8 strand rectangular wire.

ELGILOY
• In 1950s Elgin watch company was developing a complex alloy whose primary
ingredients were cobalt, chromium Iron and Nickel.
• These alloys were originally developed for use as watch springs (Elgiloy) but their
properties are also excellent for orthodontic purpose.

• Elgiloy had a very attractive property of having its strength and formability modified by heat
treatment.
• Before heat treatment, the alloy is highly formable, and can be easily shaped.
• Once it is given the desired shape, and formability is no longer needed, it is heat treated.
• The strength of the alloy increases and the formability decreases.
• Heat treated at 482oc for 7 to 12 mins
• Precipitation hardening
•  ultimate tensile strength of the alloy, without hampering the resilience.
• After heat treatment, elgiloy had elastic properties similar to steel.

BLUE YELLOW GREEN RED
◦ ◦.
MANUFACTURED IN FOUR TEMPERS IN INCREASING ORDER OF RESILIENCE
Ductile
◦More resilient
◦Available in
Round
Square
Rectangular
-Most resilient of elgiloy
wires,
-High spring qualities
-Withstands only
minimal work hardening
-Heat treatment makes
it extremely resilient.
◦It comes in round shape
only.
◦More resilient
than yellow
elgiloy
◦can be shaped
with pliers before
heat treatment.
◦It comes in round
wires only
This wire is soft.
◦Bent easily with
fingers and pliers.
◦can be soldered
◦can be welded
with low heat
treatment
◦Available in
Round
Square
Rectangular

CLINICAL IMPLICATION
The advantage of Co-Cr wire over S.S. includes greater resistance to fatigue and distortion and longer function
as a resilient spring.
The high modulus of elasticity of Co-Cr and S.S. wires suggest that they deliver twice the force of -titanium and
4 times the force of Nitinol wires for equal amount of activation.
Co-Cr wires have good formability and can be bent into many configurations relatively easily. Caution should be
exercised when soldering attachments to these wires, since high temperature cause annealing with resultant loss
in yield and tensile strength, low fusing solder is recommended.
This wire is good for :
loop systems
utility arches
overlay intrusions / base arches.
lingual / palatal bars
quad helix

NICKEL TITANIUM
WIRES
• NiTi was invented in 1962 by William F. Beuhler, a research metallurgist at
Naval Ordnance Laboratory in Silver Springs, Maryland, now called the Naval
Surface Weapons center.
• The name is an acronym derived from the elements which comprise the alloy,
• ‘Ni' for nickel,
• ‘Ti' for titanium
• ‘Nol' for Naval Ordnance Laboratory.
• This alloy is introduced in the year 1971 by George Andreason to the
orthodontic profession.

COMPOSITION AND PHYSICAL PROPERTIES
• Nickel – 54%
• Titanium – 44%
• Cobalt – 2%
2 forms of NiTi alloys
1. Martensite - Body centered cubic/tetragonal lattice
2. Austenite – Face centered (close packed hexagonal)
nickel titanium

• NiTi wire may be classified as:-
 Martensitic stabilized alloys
 Martensitic active alloys
 Austenitic active alloys
Martensitic stabilized alloys
 Not posses shape memory and superelasticity
 Proffit refers to these alloys as M-NiTi’s.
 Cold working of the wire creates stabilized martensitic structure

Martensitic active alloys
 Employ thermoelastic effect to achieve shape memory
 Eg – Neo Sentalloy and copper NiTi
Austenitic active alloys
 They undergo stress induced Martensitic transformation when activated
 These alloys display superelastic behaviour
 The reverse transformation from Martensitic back to Austenite take place during unloading
or deactivation.
 Eg – Japanese NiTi

• At high temperature – BCC lattice is stable, cooling FCC martensitic lattice. This
transition can also be induced by application of stress.
• This characteristic of austenitic to martensitic transition result in two unique features:
• Shape memory
• Superelasticity

USEFUL PROPERTIES OF NiTi
SHAPE MEMORY
SUPERELASTICITY
SHAPE MEMORY WIRE
• Most orthodontists are aware of nitinol because of unique property of ‘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.
• It has characteristic of being able to return to a previously manufactured shape when it is heated
through a transition temperature range (TTR).
• To use this property the wire must 1st be set into the desired shape and maintained at a
elevated temperature.

 After the wire has cooled to room temperature it can be plastically deformed.
 But when heated again the original shape is restored. This property, called
THERMOELASTICITY.
 But proved difficult to exploit in orthodontic applications.
 The cobalt content is used to control the lower transition temperature with can be near mouth
temperature 370C.
 After considerable experiment , Nitinol was marketed in the late 1970s for orthodontic use in
stabilized martensitic form, with no application of phase transition effects .
 Nitinol is exceptionally springy and quite strong but with poor formability
 Other martensitic alloys later marketed have similar strength and springiness to nitinol but
better formability
 Commercially available - M-NiTi .
 In late 1980’s new Niti wire with an active austenitic grain structure appeared.
 They exibit the other remarkable property called Superelasticity

SUPERELASTICITY:
• Superelasticity means the ability of the wire to exert the same force whether it is deflected a
relatively small or a large distance.
• This unique force deflection curve for A-Niti wire occurs because of a phase transition in grain
structure from austenite to martensitic form
• This can be produced by stress, not by temperature difference and is called stress induced
martensitic transformation
• Some currently available wires are almost dead soft at room temp and becomes elastic at
mouth temp , which can make them to place initially but the exceptional range that goes with
superelasticity is obtainable only if a stress-induced transformation also occurs.

• In general Nickel-Titanium wires have relatively low modulus values and large working
range, the wires are difficult to form, can neither be soldered nor welded.
• Since hooks can not be bent or attached to nitionol, crimpable hooks and stops are
recommended for use.
• Cinchback distal to molar buccal tube can be obtained by flame annealing the end of the
wire. A dark blue colour indicates the desired annealing temperature.
• The most important benefit from Nitinol wire is realized when a rectangular wire is inserted
early in treatment. Simultaneous rotation, leveling, tipping and torquing can be accomplished
early with a resilient rectangular wire like Nitinol.
• Wire / bracket frictional forces with Nitinol wire are higher than S.S. but lower than -
Titanium.

• NiTi can be successfully used in treatment of
• Crossbite correction
• Uprighting impacted canines
• Opening the bite
• Nitinol wires can be used in Class I, II, III malocclusion in both extraction and non-extraction
cases.
• In selecting cases that benefit most from the use of nitinol wire, the primary criteria are the
amount of malalignment of teeth from ideal arch form.

CHINESE NITI
• This alloy has unique characteristics and offers significant potential in the design of
orthodontic appliances.
• It has low TTR than Nitinol its history of little work hardening in a parent phase which is
austenitic yield mechanical properties that differ significantly from Nitinol.
• Because of this high range of action and spring back chinese Ni-Ti is applied when large
deflections are required.
• It has springback that is 4.4 times more compared to stainless steel and 1.6 times that of
nitinol.
• Stiffness of this wire is 73% that of S.S and 36% that of nitinol.
• These wires are highly suitable if low stiffness is required and large deflections are needed.

JAPANESE NITI
• It posses excellent spring back ,shape memory ,super elasticity.
• It delivered a constant force over an extended portion of deactivation range and less likely to
under go permanent deformation.
• It generates a physiological tooth movement because of relatively constant force delivered
for a long period of time during the deactivation of the wire
• This super elasticity can be produced by stress and not by temp. difference
• Heat treatment at 500 deg centigrade for 5 minutes produced optimum super elasticity

Titanium has been used as structural metal since 1952.
In 1977, Burstone and Goldberg introduced it to orthodontics.
At temperature above 16250 F pure titanium  BCC lattice (-phase).
+ molybdenum, columbium, a titanium based alloy  -stabilized titanium.
Distinctive features of this wire include –
good springback
low force delivery levels
good formability
weldability.

PROPERTIES
 The low modulus allows low forces even for large deflection.
 High springback
 Modulus of elasticity of -titanium is twice that of nitinol and less than one half that of S.S.
 Formability of -titanium wire is similar to S.S. however titanium can not be bent over as
sharp a radius as S.S.
 -titanium can be joined by welding and has good corrosion resistance.

High springback
High formability
Low Modulus of Elasticity
Low load deflection rate
Low stiffness
Environmentally stable
Excellent corrosion resistance
Can be joined by electrical
resistance welding
More friction than stainless steel
or chrome-cobalt alloys.
Become brittle on overheating.
OnlyTMA can be welded toTMA,
it is not possible to weldTMA to
stainless steel.
ADVANTAGES DISADVANTAGES

CLINICAL IMPLICATUONS:
• As a finishing wire - because it delivers force values less than half that of stainless steel.
• Ideal edgewise arches fabricated of titanium have sufficient superiority over S.S.
• They can be deflected approximately twice as far without permanent deformation thus greater
range of action for initial tooth alignment or finishing arches.
• -titanium is ductile, which allows for placement of tie-back loops or complicated bends.
Springback properties are not lost during bending applications.

ALPHA TITANIUM ALLOY
• Developed in 1988, by Mr. A.J. Wilcock Jr. of Australia, they are pure titanium in alpha
phase.
• Composition
• Titanium - 90%
• Aluminium - 6%
• vanadium - 4%

Wire Type Springback Stiffness Formability
Stored
Energy
Friction
Biocompatibility
&
Environmental
Stability
Jointability
Stainless Steel Low High Good Low Low Good
Solderable &
Weldable
Multi-
stranded
High Low Poor High
Not
Known
Good
Solderable &
Weldable
Cobalt
Chromium
Low High Good Low
Low to
Moderate
Good
Solderable
Weldable
Beta-
Titanium
Average Average Good Average High Good Weldable
Nickel-
Titanium
High Low Poor High
Low to
Moderate
Good
Not
Joinable
CLINICAL SELECTION

COPPER NiTi
Introduced by Rohit Sachdeva and Sychio Miyasaki in 1994.
• Due to the incorporation of Copper these wires have better defined thermal Properties than NiTi
and show Better control over tooth movement.
• The addition of copper to the alloy decreases theTransition temperature range approximating the
intraoralTemperature.This helps in easy activation and deactivation of the wires

DEPENDING ON AUSTENITIC FINISHTEMPTHEY ARE CLASSIFIED INTO
Type I Af – 150 c
Type II Af - 270 c
Type III Af - 350c
Type IV Af - 400c
It is the differential between Af temperature and mouth temperature that determines the force
generated by nickel titanium alloys. Understanding the factors that can influence the
thermomechanical characteristics of nickel titanium has enabled to develop this new quaternary
alloy.

• Type I is not used for clinical application due to high force levels.
• Type II produces highest force and in indicated in normal patients.
• Type III is indicated in patients with low to normal threshold of pain and also in
periodontically compromised patients.
• Type IV produces lowest level of force and are good in patients highly sensitive to pain.

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
effective tooth movement.

• In 1993, Hanson combined the mechanical advantages of multistranded cables with the
material properties of superelastic wires to create a superelastic nickel titanium coaxial wire.
• This wire, called Supercable, comprises seven individual strands that are woven together in
a long, gentle spiral to maximize flexibility and minimize force delivery.
JCO 1998 ,BY- JEFF BERGER
SUPERCABLE

TITANIUM-NIOBIUM
A new finishing wire alloy
Michel Dalstra et al ( COR 2000 July ) investigated this newly introduced wire.
• Nickel free Titanium alloy
• Ti- nb is soft and easy to form and has similar working range of stainless steel.
• Bends can be made easily in this wire and also avoids excessive force levels of a steel wire.
• The low spring back and high formability of the titanium-niobium arch wire allows creation of
finishing bends.

DUAL FLEX ARCH WIRES
• Type 1:
• The Dual flex arch has its anterior segment made up of 0.016" titanol. It is a Nickel Titanium
alloy manufactured by Lancer pacific, the posterior segment is made up of 0.016" Stainless
Steel thus combining anterior and posterior segments of different stiffness.
• Cast ball hooks are provided at the junction of the two segments just mesial to the cuspids.
• The flexibility of Titanol anterior segment greatly simplifies bracket engagement in the crowded
anterior teeth while the rigidity of stainless steel posterior segment controls rotation movements,
prevents tipping from elastic traction and permit bite opening.
• It is ideal for lingual appliance where anterior interbracket width is greatly reduced.

Type 2:
• Dual flex arch wire is of 0.016" x 0.022" rectangular Titanol wires in the anterior and 0.018"
Stainless Steel posterior segmental wire.
• It is useful in retraction of anterior teeth to upright position, where it does not need all of
extraction spaces.
• Engagement of rectangular anterior titanol segment in the bracket slots impedes movement of
the anterior teeth while closing remaining extraction space by mesial movement of posterior
teeth.

TRI FORCE ARCH WIRE
• It has been pre programmed to deliver the right amount of force for each area of the mouth.
Strongest to more deeply rooted molars, medium at the bicuspids and gentle at the anteriors.
• It is an Austenitic wire delivering force constantly. It prevents dumping of molars and unwanted
rotation of premolar and gentle force to anterior teeth causing no discomfort.
• It gives three dimensional control early in the treatment.

ESTHETIC ARCHWIRES
• One promising approach towards achieving an esthetic arch wire is the use of composites.
• Which can be composed of ceramic fibers that are embedded in a linear or crosslinked
polymeric matrix.

JCO,1992 BY- M.F.TALASS
It is a new orthodontic wire designed by M.F.TALASS
It has high esthetic apperance with unique mechanical properties. (manufactured by ORMCO)
It is made of clear optical fiber, it comprises 3 layers
1. A silicon dioxide core that provides the force for moving teeth.
2. A silicon resin middle layer that protects the core from moisture and adds strength.
3. A stain-resistant nylon outer layer that prevents damage to the wire and further increases its
strength.
The wire can be either round or rectangular and is manufactured in various sizes.
OPTIFLEX

ADVANTAGES OF OPTIFLEX
 Esthetic orthodontic arch wire.
 Stain resistant.
 Deliver light continuous force.
 Very flexible.
 Superior mechanical properties.

When using optiflex, certain precautions should be undertaken
 Optiflex arch wires must be tied into the bracket with elastomeric ligatures. Metal
ligatures should never be used since they fracture the glass core.
 Sharp bend similar to those placed in metal arch wire should never be attempt with
optiflex. These bends will immediately fracture the core.
 rough diet should be avoided
 Do not “cinch back” optiflex.

 Marsenol is a tooth colored nickel titanium wire manufactured by glenroe technologies.
 It is E.T.E. coated nickel titanium. (Elastomeric poly tetra florethylene emulsion).
 Marsenol exhibits all same working characteristics of an uncoated super elastic nickel
titanium wire.
 The coating adhesive to the wire remains flexible.
 The wire delivers constant forces over long periods activation and is fracture resistant.
MARSENOL

LEE WHITE WIRE
• Lee white wire, manufactured by Lee pharmaceuticals
• Is resilient stainless steel or nickel titanium arch wire bonded to a tooth colored Epoxy
coating,
• Suitable for use with ceramic and plastic.
• The epoxy is completely opaque and does not chip, peel, stain or discolors.

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.

IN SEARCH OFTHE IDEAL ARCHWIRE

REFERENCES :
• Contemporary orthodontics 4th edition – proffit
• Orthodontics current principals and techniques- graber vanarsdall
• Orthodontic materials – brantely
• A future of orthodontic material – a long term view – kusy
• Kapila & Sachdeva. Mechanical properties and clinical applications of orthodontic wires.
AJO 89;96:100-109.
• Anusavice K J; Phillips, science of dental materials; W B Saunders Company; 1996; 10th
edition, 33-75; 619-655.

Kusy & Greenberg. Effects of composition and cress section on the elastic properties of
orthodontic wires. Angle Orthod 1981;51:325-341
Burstone. Variable modulus orthodontics. AJO 81; 80:1-16
Kusy. A review of contemporary archwires: Their properties and characteristics. Angle
orthodontist 97;67:197-208
Stannard, Gau, Hanna. Comparative friction of orthodontic wires under dry and wet
conditions. AJO 86;89:485-491
Arthur J Wilcock. JCO interviews. JCO 1988;22:484-489
Arthur Wilcock. Applied materials engineering for orthodontic wires. Aust. Orthod J.
1989;11:22-29.

Archwires In Orthodontics.pptx

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