Dental materials

2. CONTENTS
DEFINITION
HOW WROUGHT METAL ALLOYS ARE MADE?
USES
PROPERTIES
DEFORMATION OF METALS
CARBON STEEL
GOLD ALLOYS

3.  STAINLESS STEEL
TITANIUM ALLOYS
CHROMIUM – COBALT ALLOYS
AJ WILCOCK WIRES
CONCLUSION

4. • Wrought: Beaten to shape.
• Alloys: A metal made by combining two or
more metallic elements to give greater
strength or resistance to corrosion

5. • What are wrought metal
alloys?
These are cold worked metals that
are plastically deformed to bring
about a change in shape of structure
and their mechanical properties.

6. How wrought alloys are made?
Mechanical
work
Heat
treatment
Wrought
alloy

7. How wrought metal alloys are made?
Cast alloys
Series of dies
Intermdiate heat treatment
Round wires

8. Where all they are used?

9. ORTHODONTIC WIRES
ORTHODONTIC
BRACKETS
PRE-FABRICATED CROWNS

10. PARTIAL DENTURE CLASP
ENDODONTIC FILES
SURGICAL INSTRUMENTS

11. PROPERTIES
• Strength
• Stiffness
• Springback
• Resilience
• Formability
• Malleability
• Ductility
• Joinability
• Biocompatibility

12. STRESS
STRAIN
ELASTIC POINT
THE RATIO OF STRESS
TO STRAIN N THE
LINEAR PORTION OF
THE CURVE IS CALLED
YOUNG’S MODULUS
ELASTIC LIMIT

13. STRESS
STRAIN
THE
DEFORMATION
MOST USED IS
0.2%
YIELD STRENGTH
YIELD POINT

14. STRESS
STRAIN
ULTIMATE TENSILE
SRENGTH

15. STRESS
STRAIN
SPRING BACK
POINT OF ARBITARY
CLINICAL LOADING

16. STRESS
STRAIN
RESILENCE

17. STRESS
STRAIN
FORMABILITY
YIELD
POINT
FRACTURE POINT

18. MALLEABILITY
• The material's ability to form a thin sheet by
hammering or rolling.

19. DUCTILITY
• The material's ability to be stretched into a
wire.

20. BIOCOMPATIBILITY
• Resistant to corrosion.

21. JOINABILITY
Ease of auxillary attatchment soldering or welding

22. Stress-strain curve

23. DEFORMATION OF METALS
 LATTICE IMPERFECTIONS
 DISLOCATIONS
 STRAIN HARDENING
 FRACTURE

24. CRYSTALIZATION
OF METALS
RANDOM
GROWTH
LATTICE POINTS
ARE VACCANT OR
OVER CROWDED
LATTICE IMPERFECTIONS

25. Lattice imperfections are classified as:
POINT DEFECTS
LINE DEFECTS

26. POINT DEFECTS
Vacancy – a vacant lattice site
Divacancy/ Trivacancy – two or
more missing atoms
Interstitial – extra atom
present in space lattice

27. Vacancies are also known as “Equilibrium defects”.
This is necessary for the process of diffusion of
metals

28. DISLOCATIONS
Edge dislocation - lattice is regular except for the
one plane of atoms that is discontinuous, forming
“dislocation line” at the edge of the half plane.

29. • Edge dislocation
• Continuous shear stress
application
• Dislocation reaches edge
of the crystal & disappears
• Leaves ONE UNIT of slip at
the crystal surface

30. SLIP PLANE

31. Dislocations
are not equilibrium defects
it requires significant energy
Slip plane –
plane along which a dislocation moves

32. STRAIN HARDENING/ WORK HARDENING
• DEFORMATION AT ROOM TEMPERATURE

33. Dislocations tend to
buildup at grain
boundaries
Atomic slip occurs on
other intersecting slip
planes
Point defects increase
& entire grain
becomes distorted
Greater stress is
required to produce
further slip
Metal becomes
stronger, Harder and
less Ductile
Further increase in cold work metal FRACTURE

34. • Consequences of strain hardening
• Surface hardness
• Yield Strength
• Ultimate tensile
strength
•Ductility
• Resistance to
corrosion of the metal

35. ANNEALING
• Controlled heating and cooling process designed to
produce desired properties in a metal.
• Annealing takes place in 3 successive stages
Recovery
Recrystallization
Grain growth

37. RECOVERY
• Cold worked properties begin
to disappear.
• Slight decrease in tensile
strength.
• No change in ductility.
• No changes in microscopic
structure.

38. • Recrystallization
The old grains are
replaced by new set of
grains.
The material attains its
original soft and ductile
condition.
The fibrous structure is
transformed to small
grains.

39. • Grain growth
Phenomenon occurs only in wrought metals
Grain size range from fine to coarse
Fine grain structure if annealed further,
grains begin to grow
Large grains consume smaller grains
Grain growth process does not progress
indefinitely to form single crystal
Rather, an ultimate coarse grain structure
is formed

40. CARBON STEELS
• Iron-based alloys usually containing 1.2% Carbon
• Based on 3 possible lattice arrangements of iron,
different classes of steels are:
oFerrite
oAustenite
oMartensite

41. Ferrite
 Body centered cubic (BCC)
 Pure iron at room temperature
 Phase is stable in temperature as high as 912C
 Carbon has very low solubility in ferrite

42. Austenite
• Face centered cubic (FCC)
• Stable form of iron at temperature between 912C &
1394C
• Maximum carbon solubility is 2.1% by weight.

43. Martensite
• Body centered tetragonal crystal structure.
• Produced by quenching of austenite to undergo
spontaneous, diffusionless transformation.
• This is a very strong brittle and hard alloy.
• The formation of martensite is actually a
strengthening mechanism of carbon steel.

44. • Lattice is highly distorted & strained resulting in an
extremely hard, strong, brittle alloy-MARTENSITE
MARTENSITE decomposes to form FERRITE & CARBIDE
Accelerated by heat treatment process called
TEMPERING
Reduces hardness but increases toughness

45. WROUGHT GOLD ALLOYS

46. HISTORY

47. GOLD WIRES WRAPPED AROUND THE NECK OF
ADJACENT TEETH.
The Use of Gold in Dentistry AN HISTORICAL OVERVIEW. PART I
J. A. Donaldson British Dental Association Museum, London, U.K.

48. DENTAL APPLICATIONS OF GOLD ALLOYS
CONSTRUCTION OF REMOVABLE PARTIAL DENTURE
CLASP.
FABRICATION OF ORTHODONTIC APPLIANCES.
AS RETENTION PINS FOR RESTORATION.

49. • Type 5 and Type 10 dental gold alloys are used
as orthodontic wires.
Gold in Dentistry: Alloys, Uses and Performance
Helmut Knosp, Consultant, Pforzheim, Germany Richard J Holliday, World Gold
Council, London, UK Christopher W. Corti, World Gold Council, London, UK

51. PLATINUM-GOLD-PALLADIUM WIRES (P-G-P)
• Composition:
– Platinum: 40%-50%
– Gold: 25%-30%
– Palladium: 25%-30%
• They possess,
1) High fusion temperature & high recrystallization
temperature.
2) Meet composition requirements for ADA type I
gold wire.

52. PALLADIUM-SILVER-COPPER WIRES (P-S-C)
Composition:
Palladium: 42%-44%
Silver: 38%-41%
Copper: 16%-17%
Platinum: 0%-1%
P-S-C wires are neither Type I nor Type II gold
wires, but their mechanical properties meet
the requirements for ADA Type I or II gold wire

53. EFFECT OF CONSTITUENTS OF GOLD
ALLOYS
PLATINIUM –
• Bluish white metal.
• Hardness similar to copper.
• Higher melting point ( 1772°C) than porcelain.
• Coefficient of thermal expansion close to porcelain.
• Lighten the color of yellow gold based alloys
• Common constituent in precision prosthetic
attachments.

54. PALLADIUM
• White metal darker than platinum
• Density little more than half that of Pt and Au
• Absorbs hydrogen gas when heated
• Not used in pure state in dentistry
• Whitens yellow gold based alloys.

55. SILVER(Ag)
• Malleable, ductile; white metal.
• Stronger and harder than gold, softer than
copper.
• Absorbs oxygen in molten state and difficult to
cast
• Forms series of solid solutions with palladium
and gold .
• Neutralizes reddish color of alloys containing
copper

56. COPPER:
• Contributes the ability
to age harden.
IRIDIUM:
• Grain refiners
• Improves mechanical
properties and
uniformity of properties
within alloy
• Extremely high melting
point of Ir - 2410°C and
Ru - 2310°C – serve as
nucleating centers

57. NICKEL :
• strengthenerofalloybut
itreducesductility.
• largequantityofNitends
toreduce tarnish
resistance&changealloy
responsetoage
hardening.
ZINC :
• added as a scavenger agent
to obtain oxide-free ingots

58. TREATMENT OF GOLD ALLOYS
• Softening heat treatment/homogenizing-
Solution heat treatment.
• Hardening heat treatment-Age hardening.

59. Softening Heat Treatment
• Increases ductility .
• reduces tensile strength ,proportional limit and
hardness.

60. HARDENING HEAT TREATMENT
• Increases strength, proportional limit, and hardness,
but decreases ductility.
• Copper present in gold alloy helps in this process.

61. STAINLESS STEEL ALLOYS

62. HISTORY
• First developed accidently by Harry Brearley in
Sheffield, England.

63.  He tested this steel with nitric
acid ,lemon juice and tested
under microscope and found that
his alloys were highly resistant,
and immediately recognised the
potential for his steel within the
cutlery industry.
 He named it as ‘Rustless Steel’,
but Stuart, dubbed it ‘Stainless
Steel’ after testing the material in
a vinegar solution, and the name
stuck

64. • Stainless steel entered dentistry in 1919, introduced
at Krupp’s dental poly clinic in Germany by F. Haupt
Meyer.
• In 1930 Angle used it to make ligature wires.

65. • Manufacturing of stainless steel
MELTING
INGOT
FORMATION
ROLLING DRAWING

66. MELTING
The selection and melting of the components of alloys
influence the physical properties of wire .

67. Composition (as per AISI)
TYPE Cr Ni C Mn Si P S
302 17-19 8-10 0.15 2 1 0.045 0.03
304 18-20 8-12 0.08 2 1 0.045 0.03
416 12-14 - 0.15 1.25 1 0.06 0.15

68. • the molten metal is poured into
the mold.
• A non uniform chunk of metal is
produced.
• The mechanical properties of the
ingot is controlled by its granular
structure.
• When the ingot is cooled, grains
forms at once.
• These growing crystals are
surrounded each another.
Ingot
formation
INGOT — colony
of irregularly
shaped grains of
different
materials.

69. The pouring and cooling process affect
porosity.
When ingot cools the inner mass hardens
later, inside the outside hardened shell,
which results in additional vacuum voids.

70. ROLLING

71. • First mechanical step in process.
• Ingot is rolled in series of rollers to reduce its diameter.
•. Now the wire is actually an "distorted ingot".
• The squeezing and rolling of ingot alters the shape and
arrangement of the crystals
• The metal is annealed by heating into high temperature,
which relives the internal stress formed by rolling.
• On cooling ,it resembles an original casting.
• Rolling will cause the elongation crystals into an finger like
process, closely meshed with each other.
• Hardness/ brittleness increases as the grain positions and
arrangements are altered

72. DRAWING
The wire is reduced to its
final size by drawing.
This is a more precise
process in which the wire is
pulled through a small hole
in a die.
Before it is reduced to
orthodontic size a wire is drawn
through many series of dies and
annealed several times along
the way to relieve work
hardening.

74. • The wires used in orthodontics are generally
American Iron and Steel Institute {AISI} types 302
and 304 austenitic stainless steels. These alloys are
known as “18-8” Stainless steels, so designated
because of the percentages of chromium and nickel
in the alloy.
IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-
ISSN: 2279-0861.Volume 14, Issue 1 Ver. I (Jan. 2015), PP 47-50

75. Properties of stainless steel
• When 12-30% chromium is added to steel it forms
STAINLESS STEEL.
• Yield strength - 1100-15000Mpa.
• The modulus of elasticity - 160 to 180 GPa.
• PASSIVATION- property of SS to resist tarnish and
corrosion.
IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-
ISSN: 2279-0861.Volume 14, Issue 1 Ver. I (Jan. 2015), PP 47-50

77. • Sensitization
CORROSION RESISTANCE OF STAINLESS STEEL
18-8 STAINLESS
STEEL LOSES ITS
RESISTANCE TO
CORROSION.
DUE TO PRECIPITATION OF CHROMIUM
CARBIDE AT GRAIN BOUNDARIES. (650C)
Reduce the carbon content.
Precipitate carbide along slip planes.
METHODS TO
REDUCE

78. • STABILIZATION
A method employed
where introduction of
some element that
precipitates as carbide
in preference to
chromium
TITANIUM is used approx 6
times Carbon content for
stabilization

79. Ferritic
Martensitic
Austensitic
S
T
A
I
N
L
E
S
S
S
T
E
E
L

80. Ferritic stainless steel
• It has BCC structure
• Composition:
Chromium - 11.5% to 27%
Carbon – 0.2%
Nickel – 0%
• Properties:
– Provide good corrosion resistance.
– Not hardenable by heat treatment because
temperature change induces no phase change in solid
state.
– Not readily work hardenable.
– Little application in DENTISTRY.

81. Martensitic stainless steel
• BCT structure.
• Composition:
Chromium – 11.5% to 17%
Nickel – 0% to 2.5%
Carbon – 0.15% to 1.2%
• Properties:
– Can be heat treated
– Has less corrosion resistance than other types of
stainless steels
• Used for surgical and cutting instruments

82. Austenitic stainless steel
• FCC structure.
• AISI 302 series
• Most corrosion resistant metal.
• Used for orthodontic wires,endodontic instruments,
crowns in pediatric dentistry.

83. Austenite
18-8 stainless steel used in orthodontic
stainless steel wires and brackets
AISI 302(basic alloy)
17-19% chromium
8-10%nickel
0.15% carbon
AISI 304
18-20%chromium
8-12%nickel
0.08% carbon

84. • AISI 316 L
L – low carbon content, 0.03%
10-14% Nickel
2-3% molybdenum
16-18% chromium
- used to make implants
AISI-type
is currently used for bracket
manufacturing
Variations in surface characteristics and corrosion behaviour of metal brackets and wires
in different electrolyte solution.sChia-Tze Kao, Tsui-Hsien Huang,Europen jounal of
orthodontics volume 33 issue 5,page 555-560

85. Comparing Austenitic over Ferritic stainless
steel
Austenitic stainless steel has:
• -Greater ductility & ability to undergo
more cold work without fracturing
• -Substantial strengthening during cold
working
• -Greater ease of welding
• -Ability to overcome sensitization
• -Comparative ease in forming
-Less critical
grain growth

86. Duplex steels SAF2205
• Both austenite and ferrite grains
• Increased toughness and ductility
than Ferritic steels
• Twice the yield strength of austenitic
steels
• High corrosion resistance
• Lower nickel content
By Dr. Claude Matasa
ORTHODONTIC BIOMATERIALS
Properties, risks and prevention
Due to its low
content in nickel,
the steel has been
preferred for the
manufacture of
one-piece
brackets by
CEOSA, Madrid
(Bioline® & Low
nickel”®)

87. Precipitation hardened steels [pH steels] [600 series]
[630/17-4] [631/17-7]
 Certain elements as chromium,copper,etc added
to steel tends to precipitate and increase the
hardness on heat treatment. –aging treatment-
decrease corrosion resistance.
 The strength is very high.
 Used to make mini-brackets.(due to high tensile
strength( PH17-4)
 Edge lock brackets(17-7 ormco)

88. Cobalt containing alloys
Used both for wires and brackets. Contain a large
proportion of nickel.
Manganese containing steels
Known as austenizing element, manganese acts by
interstitially solubilizing the real austenizing element
nitrogen thus replacing nickel
Types [500 series]
501 and 502 are low chromium [4-6%] steel not used
for orthodontic appliance

89. Titaniumalloys
Nickel titanium
(NiTi)
β- titanium
α- titanium
Titanium
niobium
Timolium
Beta III

90. NICKEL TITANIUM ALLOYS

91. History
• The term nitinol is derived from its composition and
its place of discovery (Nickel Titanium-Naval
Ordnance Laboratory).
• William J. Buehler along with Frederick Wang,
discovered its properties during research at the Naval
Ordnance Laboratory in 1959.

92. Composition:
Nickel – 54%
Titanium – 44%
Cobalt- 2% or less
Nitinol alloy can exist in various crystallographic
forms:
Austenitic phase – BCC lattice, exists at high
temperatures & stable form
Martensitic phase – Close packed Hexagonal lattice,
exists at room temperature

94. Austenitic NiTi
Chinese
NiTi(1985)
Japanese
NiTi(1986)
Cu
NiTi(1994)

95. • A-NiTi is difficult to bend as they do not
undergo plastic deformation easily
• Can be shaped if temperature

96. • Superelastic properties of only a section of a wire can
be changed by heat.
• Properties of A-NiTi have quickly made it the
preferred material for orthodontic appliances.

97. MARTENSITIC NiTi
Dr GEORGE ANDERSON (1971)
SHAPE MEMORY COULD
NOT BE EXPLOITED
• STIFFNESS
• FORCE PER DEACTIVATION
• FORMABILITY

98. The cooling/heating cycle shows thermal hyteresis

99. The relative concentration of two phases in the alloy
will determine the relative stiffness of the wire and the
amount of force delivered.

100. • In metals that crystalize in HCP , deformation occurs
by Twinning.
This twinning is responsible for Shape memory and
super elastic properties of metals.

101. Shape memory effect
Superelasticity – phenomenon where austenite to
martensite transition is induced by stress .
Achieved by 1st establishing a
shape at temp erature near 482°C
cooled & formed into a 2nd shape
and heat treated through a low
transition temperature
wire will return to its original shape
COBALT content is used to control
the lower transition temperature
(approx 37°C mouth temperature)

102. SHAPE MEMORY
THERMALLY INDUCED
AT ORAL TEMPERATURE
SUPER ELASTICITY
MECHANICAL OR
STRESS INDUCED
MARTENSITIC PHASE TRANSFORMATION
AUSTENITIC MARTENSITIC AUSTENITIC

103. Key properties of Nitinol alloys include:
• Large forces that can be generated.
• Excellent damping properties below the transition
temperature.
• Excellent corrosion resistance.
• Nonmagnetic.
• High fatigue strength.
• Moderate impact resistance.
• Moderate heat resistance.
• Biocompatible.

104. Advantages
I. Fewer arch wire changes
II. Less chair side time
III. Less patient discomfort

105. Uses of NITINOL
DENTISTRY:
ORTHODONTIC WIRES
ENDODONTIC FILES

106. • MEDICAL APPLICATION:
ANCHORS FOR TENDON FIXATION.
STENTS FOR CARDIOVASCULAR
APPLICATION

107. • AEROSPACE AND NAVAL APPLICATION:
• ACTUATOR TO CONTROL WATER:

108. Miura F, Mogi M, Ohura Y, Hamanaka H.: The super- property of the Japanese NiTi alloy wire for
use in orthodontics. Am J Orthod Dentofac Orthop 1986; 90: 1-10.
Recent advances in NiTi wires
• Bioforce sentalloy
• Nitrogen coated archwires
• Nitinol total control

109. Nitinol Total Control
• Developed by TODD A.THAYER.
• Superelastic nickel titanium alloy to deliver light,
continuous forces over a desired treatment range
with bend ability required to account for variations in
tooth morphology,archform and bracket
prescriptions.

110. COPPER NiTi
Introduced in 1994 by Dr. Rohit
Sachdeva.
Quartenary alloy
• Nickel
• Titanium
• Copper
• Chromium
Has both superelastic and shape
memory properties.

111. • Advantages of Cu-NiTi over traditional NiTi
alloys:
More
resistant to
permanent
deformation
and better
springback
Smaller
loading
force for
same
degree of
deformation
More
consistent
forces which
are active
longer within
the optimal
tooth
moving
range

112. • Presence of copper helps to:
• Stress required to
deform martensitic
phase
• Hysteresis
Thermal
reactive
properties of
NiTi
Creates a consistent unloading force
which closely approximates loading
forces.

113. MARTENSITIC
TRANSFORMATION
STRESS INDUCED TEMPERATURE DEPENDENT

114. • To exploit superelasticity to its fullest potential the
working temperature of the orthodontic appliance >
austensitic finish temperature.
• Difference between austensitic and mouth
temperature determines the force generated.
• Austensitic temperature
1.COMPOSITION 2.THERMOMECHANICAL TREATMENT
3.MANUFACTURING PROCESS

115. AUSTENSITIC
FINISH
TEMPERATURE
TYPE I TYPE II TYPE III TYPE IV

116. • TYPE I:
NOT FREQUENTLY USED AS IT
GENERATES VERY HIGH FORCES.
Af
15C

117. • TYPE II:
• > FORCES WHEN COMPARED TO TYPE III AND
TYPE IV.
• AVERAGE OR HIGHER PAIN THRESHOLD
PATIENTS.
• NORMAL PERIODONTAL HEALTH
• RAPID TOOTH MOVEMENT.
• FORCE GENERATED IS CONSTANY
Af
27C

118. • TYPE III:
• GENERATES FORCES IN MILD RANGE.
• LOW TO NORMAL THRESHOLD PATIENTS.
• NORMAL TO SLIGHTLY COMPROMISED
PERIODONTIUM.
Af
35C

119. • TYPE IV:
• GENERATE TOOTH MOVING FORCES ONLY
WHEN MOUTH TEMP ERATURE>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
Af
40C

120. • ADVANTAGES:
• Constant and
sustained
unloading
forces.
• hysteresis –
equal actvation
and
deactivation
forces.
• Provides prescise
transformation
temperature.
• Easier to engage in a
slot
• Decrease of force is
less than NiTi hence
it continues to work
as teeth near their
intended positions.

121. β-TITANIUM
• Termed as Titanium-Molybdenum Alloys
(TMA)
Dr. CHARLES BURSTONE AND
JON GOLDBERG

122. • Composition:
– Titanium – 77.8%
– Molybdenum – 11.3%
– Zirconium – 6.6%
– Tin – 4.3%

123. • Mechanical properties of beta-titanium alloys
ELASTIC MODULUS • SPRINGBACK.
• YIELD STRENGTH TO
ELASTIC MODULUS RATIO.
• COLD WORKED.
• DUCTILITY
GOOD FORMABILITY COMPARED TO AUSTENSITIC STAINLESS
STEEL
• CORROSION RESISTANCE.
• ENVIRONMENTAL STABILITY.
HEAT TREATMENT

124. ONLY ORTHODONTIC WIRE POSSESSING
TRUE WELDABILITY

125. Welding properties of beta-titanium alloys
 Clinically satisfactory joints can be made
by welding.
 Weld made with insufficient heat fails at
the interface between the wires.
 Overheating may cause a failure adjacent
to the welded joint.

126. Advantages of Beta-titanium over Stainless steel
• Beta-titanium replaced stainless steel for certain uses,
as stainless steel had dominated orthodontics since the
1960s.
• It has strength/modulus of elasticity ratios almost
twice those of 18-8 austenitic stainless steel, larger
elastic deflections in springs, and reduced force per
unit displacement, 2.2 times below those of stainless
steel appliances.
JON GOLDBERG* and CHARLES J. BURSTONE+ Department of Restorative Dentistry,*
Department of Orthodontics+, The University of Connecticut Health Center, Farmington,
Connecticut 06032, and Institute of Materials Science,*+ Storrs, Connecticut 06268

127. INITIAL TOOTH ALIGNMENT
• CLINICAL USE
FINISHING ARCHES
K-SIR ARCH
PENDULUM APPLIANCE

128. TITANIUM-NIOBIUM
• Composition :
Titanium- 82%
Molybdenum-15%
Niobium- 3%
Nickel free
alloy.

129. PROPERTIES
• Easy to bend.
• Formability < TMA
Load deflection
• Yield strength < SS.
• Stiffness ¼ of SS.
• Indicated when lower forces than those
exerted by TMA are needed.

130. ADVANTAGES
• No leaching of Nickel.
• Biocompatible.

131. CLINICAL IMPLICATIONS
• Finishing wire with multiple bends
• Fixed retainers

132. TIMOLIUM TITANIUM WIRE
Timolium archwires combine
• Flexibility
• Continuous force NICKEL TITANIUM
• Springback
• High stiffness
• Bendability STAINLESS STEEL

133. • Easier to bend and shape
• Can be welded.
• Loops and bends can be made without breakage.

134. CLINICAL IMPLICATIONS
During initial treatment it is excellent for:
• space closure
• tooth alignment
• levelling and bite opening.
Total control during detailing makes Timolium the
wire of choice during the final treatment phase.

135. β-III WIRES
Introduced by Dr.RAVINDRA
NANDA
 Bendable
 High force
 Low deflection rate
 Co-efficient of friction is more

136. • 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

137. ΑLPHA- TITANIUM
The composition of α-titanium include
• 88.9% titanium,
• 7.86% Aluminum
• 4.05% Vanadium.
The elastic modulus and yield strength
• 110 GPa and 40 MPa respectively
Aluminum, carbon, oxygen and nitrogen, stabilize the
a-titanium structure. That is, they raise the
temperature for transformation to β-titanium.

138. • Hexagonal lattice possesses fewer slip planes making
it less ductile than ß-titanium.
• The wires are soft enough for initial gentle action on
teeth in spite of large wire dimension .
• They seem to harden and become brittle with
passage of time in the mouth, possibly due to the
absorption of hydrogen and formation of titanium
hydrides.

139. COBALT-CHROMIUM NICKEL ALLOY

140. • Cobalt – 40%
• Chromium – 20%
• Nickel – 15%
• Molybdenum – 7%
• Manganese – 2%
• Carbon – 0.016%
• Beryllium – 0.04%
• Iron – 15.8%
Composition:

141. • Also known as ELGILOY.
• It is manufactured in four tempers:
SOFT DUCTILE SEMIRESILIENT
RESILIENT

142. • Heat treatment of elgiloy
Softening heat treatment temperature:
1100°C to 1200°C followed by rapid quench
Age hardening temperature range:
260°C to 650°C
According to the manufacturer, alloy for ELGILOY
is held at 482°C for 5 hours

143. • ELGILOY wire is heat treated at 482°C for 7 to
12 minutes - mainly to increase the yield
strength & decrease the ductility.
ELGILOY wires should not be ANNEALED.
• Because the resulting softening effect cannot be
reversed by subsequent heat treatment.
• If only a portion of wire is annealed, severe
embrittlement of adjacent sections may occur

144. The advantages of Co-Cr wires over stainless steel wires
include greater resistance to fatigue and distortion, and
longer function as a resilient spring.
Kapila S, Sachdeva R. Mechanical properties and clinical applications of orthodontic wires. Am J
Orthod Dentofacial Orthop. 1989;96:100–9

145. Recovery heat treatment of ELGILOY
• Stress-relief heat treatment :
ELGILOY wires are heat treated at comparatively low
temperatures (370°C to 480°C) after it has been cold
worked.
Stress-relief treatment:
1)Removes residual stresses during recovery
without pronounced alteration in mechanical
properties.
2)Improves working elastic properties.
3)Reduce failure caused by corrosion.

146. A J WILCOCK WIRES

147. Wilcock archwire have been the main stay of
Begg's tech.
Developed by the late Mr. Arthur J. Wilcock senior of
Whittlesea, Victoria Australia that enabled Dr. Begg to
develop his light wire tech.
They are available in spools and straight lengths
Until recently the grade of wire routinely used was
special plus and for those cases resistant to bite
opening extra special plus was used.
The new grades and sizes of wires are now available.

148. • Properties of AJ Wilcock wires:
TENSILE STRENGTH
STIFFNESS
RESILIENCE
ZERO STRESS RELAXATION
RESISTANT TO DEFORMATION

149. • A J Wilcock wires are graded into:
REGULAR
REGULAR PLUS
SPECIAL
SPECIAL PLUS
PREMIUM
PREMIUM
PLUS
SUPREME

150. Regular grade
LOWEST GRADE
EASY TO BEND
USED FOR
AUXILIARIES
USED WHEN
ARCHFORM
DISTORTION
IS NOT A
PROBLEM OR
BITE
OPENING IS
NOT
REQUIRED
DIAMETER-0.012-0.024

151. Regular plus
Relatively easy to
form.
More resilient
than regular.
Used for making
auxiliaries.
Used for making
an archform when
more pressure and
resistance to
deformation are
desired.
DIAMETER- 0.012-0.020

152. Special grade
HIGHLY
RESILIENT
LESS
BREAKAGE
USED
MOSTLY AS
ARCHWIRES
DIAMETER-0.012-0.020

153. Special plus
HARDNESS AND RESILIENCY IS
EXCELLENT FOR MAINTAINING
ANCHORAGE AND REDUCING
OVERBITE
CHANCES OF FRACTURE MORE
SHOULD BE BENT WITH
CAUTION
DIAMETER-0.012-0.024

154. Premium
High
resilience
• IDEAL FOR OPEN BITE.
DIAMETER-0.012-0.020

155. Premium plus
• In early treatment – alignment and levelling.
• Preferred in high angle and undue molar extrusion.
DIAMETER- 0.011-0.018

156. Supreme
• Unravelling crowded anerior teeth
• Mini uprighting springs.
DIAMETER-0.008-0.011

157. Process of manufacturing
SPINNER STRAIGHTENING
PULSE STRAIGHTENING

158. SPINNER STRAIGHTENING

159. • Deformation
• Decreased yield stress value makes it strain
softened
DISADVANTAGES

160. PULSE STRAIGHTENING
• The wire is pulsed in special machines the
permit high tensile wires to be straightened. •
The advantages
• —It permits highest tensile wire to be
straightened.
• —Tensile yield stress is not altered.
• —Smoother surface of wire hence less
friction.

161. • Greater flexibility of spring fabricated.
• Greater resiliency
• Permits the usage of small diameter wire resulting in
a continuous force with minimal relaxation.

162. • BAUSCHINGER EFFECT
If the wires are straightened by the process of reverse
straining, meaning flexing in a direction opposite to
that of original bend, the yield point of the wire
reduces.

163. Clinical tips and facts
• The higher grade wires especially pulse
straightened are excellent for applying
constant force for a longer time without
undergoing softening.
• For a careless patient and patients with
occlusal interference, chance of wire fracture
is more. So low grade wire is preferred.
• The wire used for making arches is selected
according to the load deflection, we required.

164. Clinical tips and facts
• The higher grade wires especially pulse straightened
are excellent for applying constant force for a longer
time without undergoing softening.
• For a careless patient and patients with occlusal
interference, chance of wire fracture is more. So low
grade wire is preferred.
• The wire used for making arches is selected
according to the load deflection, we required

165. CONCLUSION
• In the last few decades, a variety of new alloys has
been introduced into orthodontics.
• Appropriate use of all the available wire types may
enhance patient comfort and reduce chairside time
and the duration of treatment.
• The restricted use of only stainless steel wires to
treat an entire case from start to finish therefore may
be indicated only in a few patients.
• It may be beneficial instead to exploit the desirable
qualities of a particular wire type that is specifically
selected to satisfy the demands of the presenting
clinical situation.
• This, in turn, would provide the most optimal and
efficient treatment results.

166. REFERENCES
• Phillips' Science of Dental Materials
By Kenneth J. Anusavice
• Krishnan V, Kumar KJ. Mechanical properties and surface
characteristics of three archwire alloys. Angle Orthod.
2004;74:825–31.
• The Use of Gold in Dentistry AN HISTORICAL OVERVIEW. PART
I J. A. Donaldson British Dental Association Museum, London,
U.K
• Gold in Dentistry: Alloys, Uses and Performance
Helmut Knosp, Consultant, Pforzheim, Germany Richard J
Holliday, World Gold Council, London, UK Christopher W. Corti,
World Gold Council, London, UK
• A non-rusting steel". New York Times. 31 January 1915

167. • IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-
ISSN: 2279-0861.Volume 14, Issue 1 Ver. I (Jan. 2015), PP 47-50
• Variations in surface characteristics and corrosion behaviour of metal brackets
and wires in different electrolyte solution.sChia-Tze Kao, Tsui-Hsien
Huang,Europen jounal of orthodontics volume 33 issue 5,page 555-560
By Dr. Claude Matasa
• ORTHODONTIC BIOMATERIALS
Properties, risks and prevention
• Miura F, Mogi M, Ohura Y, Hamanaka H.: The super- property of the Japanese NiTi
alloy wire for use in orthodontics. Am J Orthod Dentofac Orthop 1986; 90: 1-10.
• An Evaluation of Beta Titanium Alloys for Use in Orthodontic Appliances
JON GOLDBERG* and CHARLES J. BURSTONE+
Department of Restorative Dentistry,* Department of Orthodontics+, The University
of Connecticut Health Center, Farmington, Connecticut 06032, and Institute of
Materials Science,*+ Storrs, Connecticut 06268
• Structure, Composition, and Mechanical Properties of Australian Orthodontic Wires
Brian M. Pelsuea; Spiros Zinelisb; T. Gerard Bradleyc; David W. Berzinsd; Theodore Eliadese;
George Eliadesf