2. THE BEGINNINGS
Teeth were regarded by
the ANCIENTS as:
(Very Precious) to the
extent that:
‘‘. . . special Penalties
[were exacted] for
knocking out the teeth of
an individual, either
freeman or slave.’’
القدماء
العقوبات
3. Greece were:
burying their dead with appliances that were used to
maintain space and prevent collapse of the dentition
during life
As early as 400 BC, Hippocrates :
referenced in his writings
the correction of tooth irregularities
دفنموتاهم
4. In a Roman tomb in Egypt, finds:
a number of teeth bound with a gold wire
at the time of Christ,
Aurelius Cornelius Celsus first records:
the treatment of teeth by finger pressure
فيرومانية مقبرة
5. - inherent malocclusions and the
use of corrective forces are
recognized,
- the first orthodontic material is documented—a gold ligature wire
- the virtue of maintaining space
is appreciated, and
Thus,
7. In 1887, Edward Angle used:
- Nickelsilver alloys in his
orthodontic accessories.
- Subsequently he replaced them
with copper, nickel and silver-
free zinc alloys.
- Eventually, gold alloys became
his favorite choice
8. CLASSIFICATION OF ORTHODONTIC MATERIALS
I Classification according to the structure of orthodontic materials
II Classification according to usage
9. I Classification according to the STRUCTURE of orthodontic materials
Wire alloys
Orthodontic band
Orthodontic brackets
Ceramic brackets
Filler particles in cements
Polycarbonates for brackets
Adhesive resins for bonding
Polyurethane elastomers for tooth
movement
Ceramic materials Polymeric materialsMetallic materials
10. II Classification according to usage_1
- Gold alloys
- Stainless steel
- Co-Cr-Ni (elgiloy)
- B-titanium
- Nickel –titanium
- Stainless steel
- Titanium
- Plastics
- Polycarbonates
and ceramics
Wire Brackets
Conventional ligatures fluoride
releasing elastomerics
Elastomeric ligature and chains
Ii- Non-metallic with Optiflex
i- Metallic wires
12. OPTIFLEX ARCHWIRE
Optiflex is a non metallic
orthodontic arch wire
It was designed by DR. TALASS
In the year 1992
and manufactured by Ormco.
Ii- Non-metallic with Optiflex
It has got unique mechanical
properties with a highly aesthetic
appearance
Made of clear optical fiber
13. OPTIFLEX ARCHWIRE
It comprises of 3 layers.
A) A silicon dioxide core that provides
the FORCE for moving tooth.
B) A silicon resin middle layer that
PROTECTS the core form moisture and
adds strength.
C) A strain resistant nylon outer layer
that PREVENTS damage to the wire
and further increases strength
14. OPTIFLEX ARCHWIRE
1) It the most aesthetic orthodontic
archwire
2) It is completely stain resistant,
and will not stain or loose its
clear look even after several
weeks in mouth
3) Its effective in moving teeth
using light continuous force
15. OPTIFLEX ARCHWIRE
4) it is Very flexible ,
5) has an extremely wide range of
actions,
6) when indicated it can be tied with
electrometric ligatures to severely
malaligned teeth without fear of
fracturing the arch wire.
7) Due to superior properties
optiflex can be used with any
bracket system
17. Ideal requirements of these cements are
• Adequate working and setting time
• High strength
• Resistance to dissolution
• Clinically acceptable bond strength
• Anti carcinogenic property
Zinc phosphate cement
Zinc polycarboxylate cement
Glass ionomer
The cements that are widely used for cementation orthodontics bands are:
Cements used in Orthodontics
Orthodontic application of cements are limited to luting of bands and appliances
18. - Alginate is the most extensively used impression material today
- Irreversible hydrocolloids: used for recording minimum detail; e.g. study models
ALGINATE
19. 1. Easy to manipulate
2. Relatively inexpensive
3. Comfortable for the patient
4. They are hydrophilic
5. Have pleasant taste
6. Long shelf-life
1. tear easily
2. Models should be poured
immediately
3. They have limited detail
reproduction
4. Can retard gypsum setting
DISADVANTAGESADVANTAGES
ALGINATE
28. Ceramic brackets
Brackets
– Bulkier than metal bracket
– Fractures of brackets
– Friction is bigger than that in metal bracket
– Wear on teeth contacting a bracket
– Enamel damage on debonding
Disadvantages over metal brackets
31. The negative space between the buccal surface of the maxillary first premolar
and the inner point at which the lips join when the patient smiles.
Buccal Corridor Width عرضالشدقى الممر
34. Step 1:
Visit your
orthodontist
or dentist
Step 2:
Invisalign®
makes your
aligners
Step 3:
You receive
your aligners
in a few
weeks.
Step 4:
You wear
your aligners.
Step 5:
You've
finished
treatment!
Invisalign
38. •Dental expansion for blocked-out teeth
•Extrusion of incisors*
•High canines
•Severe rotations (particularly of round teeth)
•Leveling by relative intrusion
•Molar uprighting (any teeth with large
undercuts)
•Translation of molars*
•Closure of premolar extraction spaces*
CAT does not perform well:
Clear aligner therapy (CAT) applicability
39. • patients treated with Invisalign RELAPSED more than
those treated with conventional fixed appliances.
Invisalign vs. braces
42. Properties of arch wires
– related to force levels,
rigidity, formability, etc.
43. • Maintains force over a range of tooth movement
General Characteristics of Orthodontic Forces
• Optimal: light, continuous
– Ideal Material
• Maintains elasticity
44. 1.Cantilever Beam:-
is one whose:
- one end is fixed and the
- other end carries a point or
concentrated load.
2. Simply Supported Beam:-
is one which:
- carries two reaction forces at
its two ends &
- a point load at its mid-point.
Types of Beams
47. – Defined by stress-strain response to external load
Materials & Production of Orthodontic Force
• Strain= internal distortion produced
by the load
- deflection/unit length
• Stress= internal distribution of the load
- force/unit area
• Elastic behavior
49. • Measure deflection = strain
- examples:
• Bending
• Twisting
• Change in length
Orthodontic Model: Beam Metal Spanning
• Force applied to a beam = stress
50. – Stiffness
– Range, springback
– Strength
- Resilience, formability
Beam Properties in Orthodontics
• Defined in force deflection or stress-strain diagrams
• Useful properties:
51. 3. Ultimate tensile (yield) strength
1. Proportional limit
2. Yield strength
• Maximum load wire can sustain
Bending Properties of an Orthodontic Wire
• Point at which
permanent
deformation is
first observed
• Similar to
“elastic limit”
• Point at which 0.1%
deformation occurs
Defined by 3 points
Stress Strain
Proportional limit
Yield strength
Ultimate tensile strength
0.1%
52. – Young’s modulus
Stiffness of an Orthodontic Wire
Modulus of elasticity (E)
– Slope of load deflection curve
– Stiffness α E
– Springiness α 1/E
Resistance of a body to elastic
deformation caused by an
applied force
- Describes the stiffness or springiness of a wire
المرونة معامل
الجسم مقاومةالناجم للتشوهالمستخدمة القوة عن
53. Low stiffness leads to:
- an ability to apply lower forces
- a more constant force to be delivered
over time and
- greater ease and accuracy in applying
a given force.
STIFFNESS or LOAD DEFLECTION RATE
more Horizontal, and vice versa
As the springiness (elasticity) of a wire increases,
The slope of the stress -strain curve becomes
54. Spring back is also referred to as maximum elastic deflection or working range
Decreasing the number of arch wire changes
Higher springback values provide:
The ability to apply large activations
with a resultant increase in working time of
the appliance
SPRINGBACK
thus
55. • Related to elastic
portion of force deflection
curve (slope)
Stiffness versus Springiness
Springiness= 1/stiffness• Reciprocal relationship
– More horizontal= greater springiness
– More vertical= stiffer
56. • Range
Distance wire will bend elastically
before permanent deformation
Range versus Springback
• Springback
– Found after wire deflected beyond its
yield point
– Clinically useful
• Wires often deflected past yield point
النطاق
المسافةشكله فيها الى ويعود السلك ثني يتم التي
قبل السابقدائم تشوه حدوث
57. • Strength = stiffness x range
Relationship of Strength, Stiffness & Range
58. • Resilience
– Area under stress-strain curve to proportional limit
– Represents Energy Storage Capacity
Resilience, Formability
High formability provides:
the ability to bend a wire into desired configurations
such as loops, coils .etc. without fracturing the wire
• Formability
– The amount of permanent
deformation a wire can
withstand before breaking
59. • Deflection properties:
– High strength
– Low stiffness (usually)
– High range
– High formability
Ideal Orthodontic Wire Material
• Strength = stiffness x range
• Other properties:
– Weldable, solderable
– Reasonable cost
• No one wire meets all criteria!
64. • In the past:
• the arch wire & springs were
constructed from GOLD or
platinized gold,
• But because these materials are
very expensive; therefore the
stainless steel alloy is used as an
alternative alloy in orthodontic
appliance.
• Alloys: are mixtures of two or more metallic elements.
65. First and foremost alloys used in orthodontics in forms of wires, bands and brackets
History – The advent of stainless steel
- Stainless steel was introduced into
orthodontic practice in 1929,
when Renfert, a North American
company, began selling wires made
from these alloys, which were
produced by a German company
named Krupp
Stainless Steel Alloys
66.
67. Properties of Stainless Steel
Passivation
Sensitization
Stabilization
• Composition: Stainless steel alloy
Fe 71%
Ni 8%
Cr 18%
C <0.2%
Resist Tarnish and corrosion
The loss of chromium from the alloy that occurs with heat
Stabilized against the formation of chromium carbide
Stainless Steel Wires
Rectangular
Round
gauges from 0.15mm – 1 mm
68. Properties of Stainless Steel
Passivation
known as a passavating film
They Resist Tarnish and corrosion because of:
- The presence of chromium:
If the oxide layer is disturbed by
mechanical or chemical actions
the wire can corrode
Chromium + Oxygen = chromic oxide
forms on the surface of the wire
and prevents corrosion
A thin, transparent layer
69. (-) The nicks and rough places left
on a wire after it is bent with
pliers may produce localized
electric couples that allow
corrosion
- Acetic and lactic acids do not attack the passavating
film
- can be used in the cleaning of Hawley retainers
containing stainless steel wires
(-) If bits of carbon steel are
incorporated into the surface of a
stainless steel wire that comes
into contact with carbon steel
pliers, cutters, or burs, starts the
process of corrosion
(-) Chlorine cleansers attack 18 - 8
steels and cause corrosion
70. The loss of chromium from the alloy that
occurs with heat is known as sensitization
Sensitization
Cr + C Chromium carbide
400 - 900 ° C
Reduction in corrosion resistance
Chromium carbide most rapidly
forms at 650 ° C and begins to
decompose above that temperature
Loss of passivating effect
Weakening of the metal
71. Stabilization
Stainless steel can be
stabilized against the
formation of chromium
carbide by adding an element
such as titanium that
precipitates as carbide in
preference to chromium.
Very few of the stainless steel
wires used by orthodontists
are stabilized.
72. 40% Co
20% Cr
15% Ni
15.8% Fe
7% Mo
2% Mn
0.15% C
0.04% Be
Composition
COBALT – CHROMIUM – NICKLE (or) ELGILOY
Cobalt – chromium – nickel orthodontic wire (elgiloy) was developed
during 1950’s by elgiloy corporation
73. - Elgiloy is available in four
different temper (levels of
resistance) & color coded :
- Blue (soft)
- Yellow (ductible)
- Green (semi-resilient)
- Red (resilient)
Properties
- Elgiloy has excellent Resistance to Tarnish and corrosion
similar to stainless steel because of passivating effect
- It can be subjected to soldering and
welding procedure
74. However, because of their
- high values of modulus of elasticity,
wires manufactured from these alloys have
- the highest force delivery, along with lower elastic ranges and springback.
The stainless and Elgiloy blue wires are:
- the least expensive, and have excellent formability and good
joining characteristics
75. • Introduced 1980’s
– Demonstrate superelasticity
• Large reversible strains
– Over wide range of deflection,
force nearly constant
– Very desirable characteristic
Austenitic NiTi (A-NiTi)
76. • Good choice:
– Initial stages of Tx
– Leveling and aligning (good stiffness, range)
• Poor choice:
– Finishing (poor formability)
Uses of Ni-Ti Arch wires
79. • Wire properties
– Significantly affected by wire
(beam) cross section and length
Elastic Properties:
Effects of Size and Shape
• Magnitude of change varies
with wire material
80. • Strength
– Changes to third power
• Ratio between larger to
smaller beam
• E.g., double diameter:
deliver 8x strength
• Springiness
– Changes to fourth
power
• Ratio between smaller
to larger beam
• E.g., double diameter:
wire 1/16 as springy
Effects of Diameter: Cantilever
Strength d 2d = 8 (2d/d)³
Springiness d 2d = 1/16 (d/2d)⁴
Rang d 2d 1/2 (d/2d)
81. • Strength = stiffness x range
• Strength = 1/(1/16)x 0.5
Springiness= 1/stiffness
1/16= 1/stiffness
Stiffness = 1/(1/16)
• Strength = 16 x 0.5 = 8
Distance wire will bend elastically before
permanent deformation
Effects of Diameter: Cantilever
82. • Range
– E.g., double diameter:
half the range
Effects of Diameter: Cantilever
83. • Strength
– Decreases
proportionately
– E.g., double length: half
the strength
• Springiness
– Increase by cube of
ratio
– E.g., double length: 8x
the springiness
Effects of Length: Cantilever
Strength 1/2 1/4 1 2
Springiness 1 8 1 1/4
Rang 1 4 1 1/2
• Range
– Increases by square of ratio
– E.g., double length: 4x the range
84. – Light wire:
• Low strength, low force, high range
• Example: removable appliance
– Finger spring
– High strength needed to avoid deformation
– Force can be reduced by increasing wire length
• Add helix
Spring Design
• Requires appropriate balance:
– Heavy wire:
• High strength, high force, low range
85. The most important allergies in relation to orthodontics
treatment are those associated with exposure to:
- Latex
- Nickel containing alloys
- Acrylic
- Impression materials
Hypersensitivity reaction: either
- Type I (immediate)- present as localized urticaria
or anaphylaxis
- Type IV (delayed) – results in localized allergic
contact dermatitis (those related to nickle)
Allergy to Orthodontic Materials
86. - Staff should be aware of emergency protocol
for dealing with anaphylactic reaction
Management of latex allergy
- The use of elastomeric ties could be avoided
with the use of self-ligating brackets
- The use of latex products
should be avoided
87. Management of latex allergy
- Inter-maxillary elastics replaced with
latex-free elastics
- Space closure should be undertaken with nickel-titanium coils
88. Nickel Allergy
- Typically, Type IV hypersensitivity
reactions present on the skin as contact
dermatitis;
- however, intra-oral manifestation are
less common
- there appears to be a higher threshold
nickel concentration intra-orally to
induce a reaction
- Nickel-titanium archwires, stainless steel products
- (archwires, brackets, headgears) – all containing
nickel
- Affecting over 10% of females
89. Management of Nickel Allergy
- Brackets- Ceramic, gold,
titanium or polycarbonate
- Use of fiber-reinforced
composite wires
- Use of clear plastic aligners
Use of nickel free products:
![THE BEGINNINGS
Teeth were regarded by
the ANCIENTS as:
(Very Precious) to the
extent that:
‘‘. . . special Penalties
[were exacted] for
knocking out the teeth of
an individual, either
freeman or slave.’’
القدماء
العقوبات](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)