THIS PPT INCLUDES THE PROPRTIES OF STAINLESS STEEL,AJ WILCOKS WIRES ETC.

1. STAINLESS STEEL
Presented by
Dr.AMAL GOPU
PGT-1st Year

2. CONTENTS
• HISTORY
• ORTHODONTIC WIRES
• INTRODUCTION
• COMPOSTION
• TYPES
• PHYSICAL PROPERTIES
• CLINICAL APPLICATIONS
• DISADVANTAGES AND ADVANTAGES
• AUSTRALIAN STAINLESS STEEL & ITS CLINICAL USES
• BENDING OF WIRES
• CONCLUSION

3. HISTORY
• In mid 21st century ,stainless steel was applied to dentistry and
orthodontics
• The honors of developing the stainless steel alloy is shared by
Harry Brearley,F.M.Becket,Benno Strauss and Edward Maurer.
• Stainless steel entered dentistry in 1919
• Stainless steel in orthodontics started in mid
1920’s .

5. COMPOSTION
= IRON +CARBON
= STEEL +CHROMIUM

6. CHROMIUM
• Passivating film effect
• Minimum 12-13%
12

7. CARBON
• In pure form iron is soft and not useful for mechanical purposes
• The principal method of strengthening and converting it into steel
is by small amount of carbon
• Carbon forms :
a) solid solution (austenite)
b)Carbide (ferrite)
Cemntite(Fe3C)

8. NICKEL
formability Weldability
Ductility
Increase
corrosion
resistance

9. SENSITIZATION
• Heating of Stainless steel in 400-900° C
• Cr and C reacts and forms CrC at the grain boundaries,which cause
in reduction of Cr content from the matrix of stainless steel .

10. STABILIZATION
• To manage sensitization by addition of some other element like
titanium or niobium which in turn eliminate chromium carbide
precipitation.
• Titanium is added 6 times to the carbon content
• Carbon has more affinity towards Ti than Cr to form the carbide.

11. TYPES
TYPES CHROMIUM NICKEL CARBON
FERRITIC (BCC) 12-27% <2% 0.12%
AUSTENTIC(FCC) 17-20% 8-12% 0.02-0.05%
MARTENSITIC (BCT) 12-18% >0.75% 0.15-1%

13. MARTENSITIC STAINLESS STEEL
• BCT
• High strength and hardness ,so can be used for the surgical and
cutting intstruments
• But it is having very less corrosion resistance,so in vivo placement
of martensitic form interferes in the biocompactibility

14. FERRITIC & MARTENSITIC ALLOYS
Both ferrite
& martensitic
grades belong
to 400 series
Have
strength but
with minimal
corrosion
resistance
MARENSITIC FERRITIC
• Martensitic alloys are hardenable
by heat treatment
• Ferritic alloys are not

15. DUPLEX
• Duplex = (50% ferrite+50% Austenite)
• Modern duplex alloys contains nitrogen which add strength and
corrosion resistance ,but also improves weldability
• Higher alloyed duplex materials are known as the ‘superduplex
alloys’
• Lowered alloyed duplex is called ‘lean duplex’ ,offers higher
strength with corrosion resisitance similar to standard austenitic
grades

16. AUSTENITIC STAINLESS STEEL
• Have highest corrosion resistance
• Widely used In dentistry
TYPES (AISI) (provides corrosion resistance to a wide variety of waters)
1.200 series
2.300 series
a)302-A1 18/8 -0.15% C
b)304-A2 18/8 –most common-0.08% C
c)316- 0.03% carbon

17. • L-grade 300 series grades such as 304L have
guaranted low carbon contents ,which is
important for welding
• L-grade have lower minimum yield and tensile strength.
• 304/304L has both the guaranteed low carbon & guaranteed
minimum strength of non L-grade

18. Important terms :
• Cold working :The process plastically deforming metals at room
temperature.
• Annealing: Heating a deformed metal to restore properties to values prior
to deformation.
• Proportional limit: Is the elastic stress above which the linear relationship
between stress and strain no longer exists on the stress –strain plot
• Yield strength: the amount of stress needed to cause 0.2%plastic
deformation of material ,which is why it is called 0.2% offset yield strength.
• Spring back: Capacity or tendency of a bent or shaped elastic material to
revert to its original form.

19.  Range: The distance the wire will bend elastically before
permanent deformation
 Stiffness: Proportional to the slope of the elastic portion of
the force deflection curve .
 Springiness=1/Stifness
 Formability : Refers to the ability of metal alloy to be formed into
a desirable shape without necking or cracking .
 Hardness: Is a measure of resistance of surface to indentations

21. STRAIN HARDENING/COLD WORKING
YIELD STRENGTH
σy deformed >σy
undeformed
A B

22. HEAT TREATMENT
• Forms :
FERRITE: Less Carbon more ductile
CEMENTITE: Hard and brittle
AUSTENITE : forms at upper critical temperatue
PEARLITE: Ferrite(87-88%) + Cementite (12-13%)

23. Temperature Vs Time

24. Temperature Vs Carbon

25. CLINICAL APPLICATIONS
• SS wires of medium hardness may be bend is incorrectly placed
,straightened out ,but it may not be bend again at the same point.
• If not at the time of making ,then before long period of time the
wire breaks in the mouth.
• So while making bends accuracy in placing them without
overworking is essential.

26. Properties of Ideal Wire Material
High strength Low stiffness High range Large spring back
High formability Biocompactibility Resilence
Low surface
friction
Weldable and
solderable
Corrosion
resistance
Ecnomical

27. AUSTRALIAN STAINLESS
STEEL

28. • Mr.Arthur Wilcock of Whittlesea, Victoria ,Australia Originally
developed this special Orthodontic wire at the request of of
Dr.P.R.Begg
• Available in a variety of diameter sizes ,grades of resilency
• Each grades is easily identified by a colored label
INTRODUCTION OF WILCOCK WIRES

29. COLOUR CODING
WIRE GRADE COLOR LABEL
REGULAR WHITE
REGULAR PLUS GREEN
SPECIAL BLACK
SPECIAL PLUS ORANGE
PREMIUM PURPLE
PREMIUM PLUS ORANGE
SUPREME YELLOW
SUPREME PLUS CREAM

30. PROPERTIES
• Heat treated stainless steel wires
• More resilient
• Ultra high tensile austenitic steel arch wires.
• Zero stress relaxation ( allows the wire to maintain its force over
a longer period of time,yet resists permanent deformation from
elastic load
• Used in Begg light wire technique.
• Avialable in size ranging from 0.012” to 0.024”

31. • REGULAR
• REGULAR PLUS
• SPECIAL
• SPECIAL PLUS
• PREMIUM
• PREMIUM PLUS
• SUPREME
RESILENCY INCREASES

32. AUSTRALIAN WIRES
• Regular & Regular plus:Easily formed and are excellent
wires for general use and utility wires
•
• Special ,Special Plus & Premium: Ideal for bite
opening and arch shape maintance and also where high resilence
is required
• Premium plus & supreme: Ideal for auxillaries like
torquing springs ,mini springs.
• Combination wire : the wire is a combination of two
diameters ,rectangular in the anteriors to maintain torque while
the round posteriors allow sliding mechanics
• Respond wires: Is a spiral wrap with a central core wire
(coaxial) ,It can deliver light ,intial forces while filling the
archwires slot for greater control.

33. GRADES
Regular/Regular plus/Special/Special
Plus/Premium
0.016” 0.018” 0.020” 0.022”
Premium Plus 0.010” 0.012” 0.014” 0.016”
Supreme 0.008” 0.009” 0.010” 0.011” 0.012”
DIMENSIONS OF AUSTRALIAN WIRES

34. PROCESS OF MANUFACTURING
1. SPINNER STRAIGHTENING
2. PULSE STRAIGHTENING

35. SPINNER STRAIGHTENING
• Mechanical process of straightening resistant materials in cold
drown condition.
• Decrease the yield strength ,makes it strain softened.

36. PULSE STRAIGHTENING
• The wire is pulse in special machines they permit high tensile wires to be straightened.
• ADVANTAGES:
• Tensile strength
• Yield strength
• Load deflection rate
• Cost
• Friction resistance
• Percentage elongation

37. ADVANTAGES Vs DISADVANTAGES
ADVANTAGES DISADVANTAGES
1. Excellent resilency ,allows more
flexibility of wires
1. Excessive pororsity
2.Higher yield strength allows the
wires to with stand more force
without plastic deformation
2.Irregular surfaces
3.Have square accurately made
edges for precise torque control.
3.More brittle in nature
4.Arches have midline markings to
identify upper and lower arches
4.Increase in roughness also effects
the orthodontic sliding mechanism

38. GRADES UTS YIELD STRENGTH HARDNESS SURFACE
ROUGHNESS
REGULAR LOW LOW HIGHEST
REGULAR PLUS
SPECIAL
SPECIAL PLUS Less than Regular
&Regular +
PREMIUM
PREMIUM PLUS HIGH
SUPREME HIGH HIGH LOW LOW

39. Australian Vs regular Stainless steel wires
Yield strength increase by
bcold working
Working range = yield strength
MOE

40. CLINICAL APPLICATIONS OF STAINLESS STEEL
0.7mm soft wire Intermaxillary traction hooks
0.9,0.8 & 0.7mm Bows and arches
0.6mm & 0.7mm clasps and self supporting springs
0.5,0.4,0.35,0.3mm Finger springs
0.25mm,0.2mm,0.15mm coil spring on heavier arch or support of some kind.
• High forces-dissipate of very short amount of deactivation(high load deflection rate)
• Ideal choice of wire during space closure with sliding mechanism

41. BENDING OF WIRE
• Heavy stainless steel wire is hard to bend
DIFFICULTIES:
1. The making of sharp bends in heavy wires
2. The accurate placing of such bends
3. The construction of complicated shapes for bows,arches,and
clasps

43. PRINCIPLES and METHODS of wire Bending
• Length of wire should be adequate
• The wire should be bent with the thumb;the fingers cant apply such a strong
and controlled pressure.
• Sharp bends are made by bending the wire over the corner of the plier blade
,not around the end of the blade
• If the wire has been sharply bent at a slightly incorrect position,a correction
may be made by gripping the incorrect portion in the tips of plier beaks and
squeezing.

44. CONCLUSION
• Though a number of materials with different grades are available
,it is mandatory for every orthodontist to know the fundamental
principals and properties of orthodontic arch wires.
• Its in the hands of clinician to thoroughly analyze the clinical
picture and select the appropriate material of choice.
• The right selection of these materials is essential for proper
clinical practice.

45. Refernces:
• Brantley WA. Orthodontic wires. In: Brantley WA, Eliades T,eds.
Orthodontic Materials: Scientific and Clinical Aspects.Stuttgart,
Germany: Thieme; 2001:78–103.
• The Design ,construction and use of Removable Orthodontic
Appliances(5th edition)-C.Philips Adams
• Reviews in Orthodontics-Ashok kumar Jena
• Orthodontics prep manual –Sridhar Premkumar 3rd edition
• Gowri sankar, Singaraju & V, Surendra & Karanth, Divakar. (2011). A
Comparative Study of Physical and Mechanical Properties of the Different
Grades of Australian Stainless Steel Wires. Trends in Biomaterials and
Artificial Organs. 25. 67-74.

46. • Structure, composition, and mechanical properties of Australian orthodontic
wiresPelsue B.M., Zinelis S., Bradley T.G., Berzins D.W., Eliades T., Eliades G.
(2009) Angle Orthodontist, 79 (1) , pp. 97-101.
• Asgharnia MK, Brantley WA. Comparison of bending
and tension tests for orthodontic wires. Am J Orthod.
1986;89:228–236
• World Famous A.J. Wilcock Australian Wire, G&H Wire
Company. Available at: http://www.ghwire.com/orstore/sa1.aspx. Accessed January 2, 2008