evolution of orthodontic bracket history.pdf
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Sep 05, 2024
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About This Presentation
Orthodontic Brackets
Slide Content
Orthodontic Brackets
Done By:
Ahmad Droubi
Done By:
Ahmad Droubi
History
E-arch (1900):
•Angle’s first appliance.
•Bands were placed on molar teeth, and a heavy labial
archwireextended around the arch.
•The end of the wire was threaded, and a small nut
placed on the threaded portion of the arch allowed the
archwireto be advanced so that the arch perimeter
increased.
•Individual teeth were simply ligated to this expansion
arch.
•Capable only of tipping teeth to a new position.
•It was not able to precisely position any individual
tooth.
E-arch (1900):
•Angle’s first appliance.
•Bands were placed on molar teeth, and a heavy labial
archwireextended around the arch.
•The end of the wire was threaded, and a small nut
placed on the threaded portion of the arch allowed the
archwireto be advanced so that the arch perimeter
increased.
•Individual teeth were simply ligated to this expansion
arch.
•Capable only of tipping teeth to a new position.
•It was not able to precisely position any individual
tooth.
History
Pin and tube (1912):
•It is done by placing bands on all teeth and using a
vertical tube on each tooth into which a soldered pin
from a smaller archwirewas placed.
•With this appliance, tooth movement was
accomplished by repositioning the individual pins at
each appointment.
•An incredible degree of craftsmanship was involved
in constructing and adjusting this pin and tube
appliance, and although it was theoretically capable
of great precision in tooth movement, it proved
impractical in clinical use.
•It is said that only Angle himself and one of his
students ever mastered the appliance.
Pin and tube (1912):
•It is done by placing bands on all teeth and using a
vertical tube on each tooth into which a soldered pin
from a smaller archwirewas placed.
•With this appliance, tooth movement was
accomplished by repositioning the individual pins at
each appointment.
•An incredible degree of craftsmanship was involved
in constructing and adjusting this pin and tube
appliance, and although it was theoretically capable
of great precision in tooth movement, it proved
impractical in clinical use.
•It is said that only Angle himself and one of his
students ever mastered the appliance.
History
Ribbon Arch (1915):
•It modified the tube on each tooth to provide a
vertically positioned rectangular slot behind the
tube.
•The ribbon arch was a success, primarily because the
archwirewas small enough to have good spring
qualities and therefore was quite efficient in aligning
malpositionedteeth.
•The major weakness of the appliance was that it
provided relatively poor control of root position. The
resiliency of the ribbon archwiresimply did not allow
generation of the moments necessary to torque
roots to a new position.
Ribbon Arch (1915):
•It modified the tube on each tooth to provide a
vertically positioned rectangular slot behind the
tube.
•The ribbon arch was a success, primarily because the
archwirewas small enough to have good spring
qualities and therefore was quite efficient in aligning
malpositionedteeth.
•The major weakness of the appliance was that it
provided relatively poor control of root position. The
resiliency of the ribbon archwiresimply did not allow
generation of the moments necessary to torque
roots to a new position.
History
Edgewise (1925):
•Angle reoriented the slot from vertical to horizontal and inserted
a rectangular wire rotated 90 degrees to the orientation it had
with the ribbon arch, thus the name “edgewise”.
•The dimensions of the slot were altered to 22 ×28 mil, and a 22 ×
28 precious metal wire was used. These dimensions did allow
excellent control of crown and root position in all three planes of
space.
Edgewise (1925):
•Angle reoriented the slot from vertical to horizontal and inserted
a rectangular wire rotated 90 degrees to the orientation it had
with the ribbon arch, thus the name “edgewise”.
•The dimensions of the slot were altered to 22 ×28 mil, and a 22 ×
28 precious metal wire was used. These dimensions did allow
excellent control of crown and root position in all three planes of
space.
Other Early Fixed
Appliance Systems
Labiolingual (1926):
•It used bands on first molars and a combination of
heavy lingual and labial archwires to which
fingersprings were soldered to move individual
teeth.
Twin Wire (1932):
•It used bands on incisors as well as molars and
featured twin 10-mil steel archwires for alignment
of the incisor teeth. These delicate wires were
protected by long tubes that extended forward
from the molars to the vicinity of the canines.
Appliance Systems
Labiolingual (1926):
•It used bands on first molars and a combination of
heavy lingual and labial archwires to which
fingersprings were soldered to move individual
teeth.
Twin Wire (1932):
•It used bands on incisors as well as molars and
featured twin 10-mil steel archwires for alignment
of the incisor teeth. These delicate wires were
protected by long tubes that extended forward
from the molars to the vicinity of the canines.
Other Early
Fixed
Appliance
Systems
BeggAppliance (1956):
Begg’sadaptation took three forms:
•He replaced the precious metal ribbon arch with high-strength 16-mil round stainless steel wire
when this became available from an Australian company in the late 1930s.
•He retained the original ribbon arch bracket but turned it upside down so that the bracket slot
pointed gingivally rather than occlusally.
•He added auxiliary springs to the appliance for control of root position.
Binding was minimized because Begg’sstrategy for anchorage control was tipping and uprighting.
Unlike labiolingual, twin-wire, and other partially banded fixed appliances, the Beggappliance was a
complete treatment system in the sense that it allowed good control of crown and root position in all
three planes of space.
Fixed
Appliance
Systems
BeggAppliance (1956):
Begg’sadaptation took three forms:
•He replaced the precious metal ribbon arch with high-strength 16-mil round stainless steel wire
when this became available from an Australian company in the late 1930s.
•He retained the original ribbon arch bracket but turned it upside down so that the bracket slot
pointed gingivally rather than occlusally.
•He added auxiliary springs to the appliance for control of root position.
Binding was minimized because Begg’sstrategy for anchorage control was tipping and uprighting.
Unlike labiolingual, twin-wire, and other partially banded fixed appliances, the Beggappliance was a
complete treatment system in the sense that it allowed good control of crown and root position in all
three planes of space.
Contemporary
Edgewise
Appliances
Evolution of the edgewise appliance included:
Automatic rotational control:
•Now rotation control is achieved without the necessity for an additional ligature, by using
either twin brackets or single brackets with extension wings that contact the underside of the
archwire.
Alteration in bracket slot dimensions:
•There are now two modern edgewise appliances, because the 18-and 22-slot appliances are
used rather differently. The introduction of a 20-slot appliance with greater precision than the
existing ones has been discussed but has not yet occurred.
Straight-wire bracket prescriptions:
•In the 1980s, bonding made it much easier to have different brackets for each tooth, and
Andrews developed bracket modifications for specific teeth to eliminate the many repetitive
bends in archwiresthat were necessary to compensate for differences in tooth anatomy.
•The angulation and torque values which represent the first, second and third order bends are
now built into the bracket are often referred to as the appliance prescription.
Edgewise
Appliances
Evolution of the edgewise appliance included:
Automatic rotational control:
•Now rotation control is achieved without the necessity for an additional ligature, by using
either twin brackets or single brackets with extension wings that contact the underside of the
archwire.
Alteration in bracket slot dimensions:
•There are now two modern edgewise appliances, because the 18-and 22-slot appliances are
used rather differently. The introduction of a 20-slot appliance with greater precision than the
existing ones has been discussed but has not yet occurred.
Straight-wire bracket prescriptions:
•In the 1980s, bonding made it much easier to have different brackets for each tooth, and
Andrews developed bracket modifications for specific teeth to eliminate the many repetitive
bends in archwiresthat were necessary to compensate for differences in tooth anatomy.
•The angulation and torque values which represent the first, second and third order bends are
now built into the bracket are often referred to as the appliance prescription.
Brackets
Prescriptions
Andrews introduced the pre-adjusted edgewise
appliance in the 1970 and revolutionized
orthodontics. This replaced the edgewise appliance
where all brackets were identical and there was great
need for wire bending.
Andrews introduced tip through slot angulation and
torque through slot inclination, along with “in-out”
through bracket base variation.
There have been many modifications in tip and torque
in pre-adjusted edgewise since Andrews. MBT and
Roth are the most used today.
Prescriptions
Andrews introduced the pre-adjusted edgewise
appliance in the 1970 and revolutionized
orthodontics. This replaced the edgewise appliance
where all brackets were identical and there was great
need for wire bending.
Andrews introduced tip through slot angulation and
torque through slot inclination, along with “in-out”
through bracket base variation.
There have been many modifications in tip and torque
in pre-adjusted edgewise since Andrews. MBT and
Roth are the most used today.
Brackets Prescriptions
Andrews (1970):
•The original straight wire appliance used Siamese brackets
placed on facial axis of the clinical crown with heavy forces
to control tooth movement in three dimensions.
•Prescription values took average from 120 models. Andrews
prescription had different sets for various malocclusions,
degree of crowding and extraction/non-extraction cases.
This resulted in many bracket types.
Roth (1975):
•To minimize the number of bracket types, Roth devised one
set of brackets applicable for most cases.
MBT (1990):
•Devised by McLaughlin, Bennett and Trevisiin the 1990s, this
prescription is based around several principles. Bracket
versatility, light continuous forces, anchorage control, group
movement of teeth and a single finishing wire are key
elements of the MBT theory.
Andrews (1970):
•The original straight wire appliance used Siamese brackets
placed on facial axis of the clinical crown with heavy forces
to control tooth movement in three dimensions.
•Prescription values took average from 120 models. Andrews
prescription had different sets for various malocclusions,
degree of crowding and extraction/non-extraction cases.
This resulted in many bracket types.
Roth (1975):
•To minimize the number of bracket types, Roth devised one
set of brackets applicable for most cases.
MBT (1990):
•Devised by McLaughlin, Bennett and Trevisiin the 1990s, this
prescription is based around several principles. Bracket
versatility, light continuous forces, anchorage control, group
movement of teeth and a single finishing wire are key
elements of the MBT theory.
Bracket
Designs
•To overcome the inefficiency of a single bracket to control the
rotation and tipping of a tooth, the Lewis bracket was introduced,
which had mesial and distal extension wings contacting the
underside of the archwire.
•Subsequently, a double-width bracket with two sets of tie-wings,
which allowed better rotational control, as well as better control
of root position in the mesiodistal direction, was introduced by
Swain and called the Siamese bracket (twin bracket).
Designs
•To overcome the inefficiency of a single bracket to control the
rotation and tipping of a tooth, the Lewis bracket was introduced,
which had mesial and distal extension wings contacting the
underside of the archwire.
•Subsequently, a double-width bracket with two sets of tie-wings,
which allowed better rotational control, as well as better control
of root position in the mesiodistal direction, was introduced by
Swain and called the Siamese bracket (twin bracket).
Bracket Designs
•Manufacturers also provided a tri-wing design
which has six tie wings. This design is said to
provide more treatment options than a
conventional twin bracket with added features to
reduce friction and total treatment time (Synergy
FX).
•There are also mini brackets made by several
manufacturers such as 3M UnitekMiniature Twin
Metal Brackets. They are said to provide the same
characteristics of full-size twin brackets in a smaller
size for greater comfort and aesthetics.
•Manufacturers also provided a tri-wing design
which has six tie wings. This design is said to
provide more treatment options than a
conventional twin bracket with added features to
reduce friction and total treatment time (Synergy
FX).
•There are also mini brackets made by several
manufacturers such as 3M UnitekMiniature Twin
Metal Brackets. They are said to provide the same
characteristics of full-size twin brackets in a smaller
size for greater comfort and aesthetics.
Brackets Material
Orthodontic brackets mainly used today are made up of
metal (stainless steel, titanium, cobalt chromium), plastic or
ceramic (monocrystalline, polycrystalline).
The ideal properties that must be present in the material
used in brackets manufacturing are:
•Biocompatible in oral environment
•Low cost
•High modulus of elasticity
•High corrosion resistance
•No magnetic properties
•No friction during bracket wire interaction
•Correct strength and hardness
•Resist staining and discoloration in oral environment
•Resist plaque deposition
•Acceptable esthetics
Orthodontic brackets mainly used today are made up of
metal (stainless steel, titanium, cobalt chromium), plastic or
ceramic (monocrystalline, polycrystalline).
The ideal properties that must be present in the material
used in brackets manufacturing are:
•Biocompatible in oral environment
•Low cost
•High modulus of elasticity
•High corrosion resistance
•No magnetic properties
•No friction during bracket wire interaction
•Correct strength and hardness
•Resist staining and discoloration in oral environment
•Resist plaque deposition
•Acceptable esthetics
Manufacturing
Techniques
Metal brackets can be manufactured in three
different ways:
•Casting
•Milling
•Metal injection molding (MIM)
•3D printing
Techniques
Metal brackets can be manufactured in three
different ways:
•Casting
•Milling
•Metal injection molding (MIM)
•3D printing
Casting
•It is done by melting the ingredients of the alloy and then pouring it into a mold of the desired
shape and left to solidify.
•Casting can be used either to produce a one-piece orthodontic bracket or to produce components
of an orthodontic bracket which are later brazed or welded together.
•Casting is usually used in complex parts like mesh or wings of a bracket.
Casted brackets are softer than milled brackets and stronger than metal injection molded brackets.
Disadvantages of having brazed components bracket:
•Casting is very expensive as a large portion of metal is wasted in sprues and runners.
•Separation of components during orthodontic loading such as torqueing.
•Wings/slot being detached on applying debonding forces making base removal a
cumbersome procedure.
•Releasing cytotoxic agents.
•Areas beneath brazed parts are sites for plaque accumulations.
•Decreased bond strength may be observed due to welding material covering some of the
bracket mesh area.
•It is done by melting the ingredients of the alloy and then pouring it into a mold of the desired
shape and left to solidify.
•Casting can be used either to produce a one-piece orthodontic bracket or to produce components
of an orthodontic bracket which are later brazed or welded together.
•Casting is usually used in complex parts like mesh or wings of a bracket.
Casted brackets are softer than milled brackets and stronger than metal injection molded brackets.
Disadvantages of having brazed components bracket:
•Casting is very expensive as a large portion of metal is wasted in sprues and runners.
•Separation of components during orthodontic loading such as torqueing.
•Wings/slot being detached on applying debonding forces making base removal a
cumbersome procedure.
•Releasing cytotoxic agents.
•Areas beneath brazed parts are sites for plaque accumulations.
•Decreased bond strength may be observed due to welding material covering some of the
bracket mesh area.
Milling
•It is the process of using cutting instruments which are
usually nonabrasive rotatory to give a predetermined
shape.
•Producing a single piece bracket can be done by milling.
Milling is used for economically producing simple parts
such as hooks or slots.
•A new advancement has been made to the milling process
in which the bracket is manufactured by taking a piece of
metal and forming it into the desired shape in a
computerized machine in a process called computer
numerated controlled (CNC) milling.
•It is the process of using cutting instruments which are
usually nonabrasive rotatory to give a predetermined
shape.
•Producing a single piece bracket can be done by milling.
Milling is used for economically producing simple parts
such as hooks or slots.
•A new advancement has been made to the milling process
in which the bracket is manufactured by taking a piece of
metal and forming it into the desired shape in a
computerized machine in a process called computer
numerated controlled (CNC) milling.
Metal injection molding
(MIM)
It is a powder metallurgy process developed in the USA in early 1980s.
Procedure:
•Fine metal powder is mixed with plasticizers, organic binders,
lubricants and dispersants to make a homogeneous mixture
known as feedstock.
•Feedstock is molded by injection molding machine into specific
shapes. The formed product is called the green body which is
fragile and larger than the end product.
•The formed green body is then subjected to a debinding
procedure which is the removal of 90% of the binders (waxes or
thermoplastic resins) from the green body using heat or solvent
or both to form a brown body.
•The brown part then is heated in a high temperature furnace
(1400 °C) under vacuumed environment in a process called
sintering. This process results in the removal of the residual
binders leading to shrinkage which results in the required size.
•Sometimes finishing touches are required which are done by
secondary thermal procedure or surface treatment.
(MIM)
It is a powder metallurgy process developed in the USA in early 1980s.
Procedure:
•Fine metal powder is mixed with plasticizers, organic binders,
lubricants and dispersants to make a homogeneous mixture
known as feedstock.
•Feedstock is molded by injection molding machine into specific
shapes. The formed product is called the green body which is
fragile and larger than the end product.
•The formed green body is then subjected to a debinding
procedure which is the removal of 90% of the binders (waxes or
thermoplastic resins) from the green body using heat or solvent
or both to form a brown body.
•The brown part then is heated in a high temperature furnace
(1400 °C) under vacuumed environment in a process called
sintering. This process results in the removal of the residual
binders leading to shrinkage which results in the required size.
•Sometimes finishing touches are required which are done by
secondary thermal procedure or surface treatment.
Metal
Injection
Molding
(MIM)
Advantages:
•High degree of precision.
•Bracket is made as a single piece thus no wings separation on loading or debonding.
•No welding is done thus no cytotoxicity.
•Free from corrosion risk associated with the galvanic couple of brazing alloys with
stainless steel.
•Decreased frictional resistance due to secondary thermal or surface treatment.
Limitations:
•Surface porosities may be preset due to shrinkage during sintering which decrease
mechanical strength and increase frictional resistance unless surface treatment is done
•Mechanical debonding may be more difficult due to the wings and base being of the
same hardness compared to conventional brackets which are manufactured with soft
steel in the base and hardened steel in the slot.
•Bracket fabricated from MIM has less hardness than conventional brackets thus have
less torque expression than conventional brackets.
Injection
Molding
(MIM)
Advantages:
•High degree of precision.
•Bracket is made as a single piece thus no wings separation on loading or debonding.
•No welding is done thus no cytotoxicity.
•Free from corrosion risk associated with the galvanic couple of brazing alloys with
stainless steel.
•Decreased frictional resistance due to secondary thermal or surface treatment.
Limitations:
•Surface porosities may be preset due to shrinkage during sintering which decrease
mechanical strength and increase frictional resistance unless surface treatment is done
•Mechanical debonding may be more difficult due to the wings and base being of the
same hardness compared to conventional brackets which are manufactured with soft
steel in the base and hardened steel in the slot.
•Bracket fabricated from MIM has less hardness than conventional brackets thus have
less torque expression than conventional brackets.
How to select
brackets
based on
manufacturing
processes?
When sliding mechanics and torque
expression are important, casted brackets are
used as they have the most polished surfaces.
In case brackets are manufactured by milling,
it is preferable to be computer numerated
controlled (CNC) milling as it has less chance
of errors.
In brackets with welded components try to
avoid those brazed with nickel.
brackets
based on
manufacturing
processes?
When sliding mechanics and torque
expression are important, casted brackets are
used as they have the most polished surfaces.
In case brackets are manufactured by milling,
it is preferable to be computer numerated
controlled (CNC) milling as it has less chance
of errors.
In brackets with welded components try to
avoid those brazed with nickel.
Stainless Steel Brackets
Stainless steel remains the standard material for appliance components. They can be produced by
metal-injection molding (MIM), casting, or 3-D printing.
Corrosion resistance:
•Stainless steel corrosion resistance is provided by self-healing passive surface layer of chromium
oxide which works on blocking oxygen diffusion to steel surface.
•Damage to the chromium oxide layer will result in degradation of stainless steel and release of
cytotoxins. This damage may be due to Cl-ions in saliva, food, certain mouthwashes, acidic drinks,
bacteria and their waste products or selective interactions with gases such as oxygen and carbon
dioxide.
Nickel Allergy:
•Nickel sensitivity is more common in females and more common in skin exposures rather than
intraorally. Corrosion resistance properties of stainless-steel brackets are of greater importance
than the amount of nickel because if the corrosion resistance is good no ions will be released from
the bracket.
•Usually higher grades stainless steel has lower nickel contents and better corrosion resistance;
however, it is difficult to machine higher grades stainless steel into brackets.
Stainless steel remains the standard material for appliance components. They can be produced by
metal-injection molding (MIM), casting, or 3-D printing.
Corrosion resistance:
•Stainless steel corrosion resistance is provided by self-healing passive surface layer of chromium
oxide which works on blocking oxygen diffusion to steel surface.
•Damage to the chromium oxide layer will result in degradation of stainless steel and release of
cytotoxins. This damage may be due to Cl-ions in saliva, food, certain mouthwashes, acidic drinks,
bacteria and their waste products or selective interactions with gases such as oxygen and carbon
dioxide.
Nickel Allergy:
•Nickel sensitivity is more common in females and more common in skin exposures rather than
intraorally. Corrosion resistance properties of stainless-steel brackets are of greater importance
than the amount of nickel because if the corrosion resistance is good no ions will be released from
the bracket.
•Usually higher grades stainless steel has lower nickel contents and better corrosion resistance;
however, it is difficult to machine higher grades stainless steel into brackets.
Stainless Steel Brackets
Vickers Hardness:
•It is a test developed by Robert Smith and George Sandland
to measure the hardness of a material. Ideally Vickers
hardness of orthodontic slots should be equal to that of
orthodontic wires to have the prescription in brackets
properly expressed. For easy debonding the Vickers
hardness of base must be lower than that of the slots.
•The more the difference between stainless steel wires and
brackets in terms of Vickers hardness, the more the
ploughing of material and friction in sliding mechanics.
Conventional brackets are more effective in sliding
mechanics and torque expression than MIM brackets.
Vickers Hardness:
•It is a test developed by Robert Smith and George Sandland
to measure the hardness of a material. Ideally Vickers
hardness of orthodontic slots should be equal to that of
orthodontic wires to have the prescription in brackets
properly expressed. For easy debonding the Vickers
hardness of base must be lower than that of the slots.
•The more the difference between stainless steel wires and
brackets in terms of Vickers hardness, the more the
ploughing of material and friction in sliding mechanics.
Conventional brackets are more effective in sliding
mechanics and torque expression than MIM brackets.
Types of stainless steel
Austenitic Stainless Steel:
•It the type mostly used in orthodontic brackets and wires fabrication. It features good corrosion resistance,
excellent formability and low cost compared with other types of stainless steel. 304L and 316L are the mostly
used. 316 is more commonly used in making base components.
Super Austenitic Stainless Steel:
•This type of stainless steel has higher molybdenum and nitrogen content than conventionally used stainless
steel. The advantages of super stainless steel include good frictional properties, higher resistance to chloride
pitting and crevice corrosion.
Precipitation-hardening (PH) martensitic stainless steel:
•This type of stainless steel has equal corrosion resistance with austenitic stainless but has better strength. It is
mainly used for wing components of brackets or in mini brackets manufacturing due to its higher hardness and
strength.
Ferritic Stainless Steel:
•It contains the main alloying elements as chromium, titanium and molybdenum but with smaller amounts of
carbon and no nickel. The lower amount of carbon accounts for its decreased strength. Some manufacturers
use ferritic stainless steel to produce the nickel free brackets.
Duplex Stainless Steel:
•This type is a combination of austenite and delta ferrite stainless steel. Duplex stainless steel is twice stronger
than austenite with improved resistance to localized corrosion particularly pitting, crevice corrosion and stress
corrosion.
Martensitic Stainless Steel:
•This form of stainless steel is very hard but with poor corrosion resistance thus not used in orthodontics.
Austenitic Stainless Steel:
•It the type mostly used in orthodontic brackets and wires fabrication. It features good corrosion resistance,
excellent formability and low cost compared with other types of stainless steel. 304L and 316L are the mostly
used. 316 is more commonly used in making base components.
Super Austenitic Stainless Steel:
•This type of stainless steel has higher molybdenum and nitrogen content than conventionally used stainless
steel. The advantages of super stainless steel include good frictional properties, higher resistance to chloride
pitting and crevice corrosion.
Precipitation-hardening (PH) martensitic stainless steel:
•This type of stainless steel has equal corrosion resistance with austenitic stainless but has better strength. It is
mainly used for wing components of brackets or in mini brackets manufacturing due to its higher hardness and
strength.
Ferritic Stainless Steel:
•It contains the main alloying elements as chromium, titanium and molybdenum but with smaller amounts of
carbon and no nickel. The lower amount of carbon accounts for its decreased strength. Some manufacturers
use ferritic stainless steel to produce the nickel free brackets.
Duplex Stainless Steel:
•This type is a combination of austenite and delta ferrite stainless steel. Duplex stainless steel is twice stronger
than austenite with improved resistance to localized corrosion particularly pitting, crevice corrosion and stress
corrosion.
Martensitic Stainless Steel:
•This form of stainless steel is very hard but with poor corrosion resistance thus not used in orthodontics.
Stainless steel is composed of the following
elements
❑Molybdenum:
Improve resistance of stainless steel to pitting corrosion by chlorides.
❑Titanium:
It is used for carbide stabilization and increasing corrosion resistance.
❑Phosphorus:
Increases strength and corrosion resistance. It also lowers sintering
temperature.
❑Niobium (Columbium) and Tantalum:
Used to stabilize carbon and improve corrosion resistance.
❑Copper:
Produce precipitation hardening properties.
❑Selenium and Sulfur:
It is added to make steel more machinable and workable while decreasing its
hardness and strength.
❑Carbon:
Its function is to provide hardness and strength.
❑Chromium:
It increases steel resistance to oxidation. It forms a thin passive
surface chromium oxide layer which prevents corrosion by
blocking the oxygen diffusion to the steel surface.
❑Nickel:
It is used to stabilize austenitic phases of stainless-steel improving
resistance to oxidation and corrosion.
❑Manganese:
Like nickel and used as its substitute which acts as an austenite
forming element.
❑Nitrogen:
It acts on increasing austenite stability of stainless steel. It is also
an austenite forming element like nickel.
elements
❑Molybdenum:
Improve resistance of stainless steel to pitting corrosion by chlorides.
❑Titanium:
It is used for carbide stabilization and increasing corrosion resistance.
❑Phosphorus:
Increases strength and corrosion resistance. It also lowers sintering
temperature.
❑Niobium (Columbium) and Tantalum:
Used to stabilize carbon and improve corrosion resistance.
❑Copper:
Produce precipitation hardening properties.
❑Selenium and Sulfur:
It is added to make steel more machinable and workable while decreasing its
hardness and strength.
❑Carbon:
Its function is to provide hardness and strength.
❑Chromium:
It increases steel resistance to oxidation. It forms a thin passive
surface chromium oxide layer which prevents corrosion by
blocking the oxygen diffusion to the steel surface.
❑Nickel:
It is used to stabilize austenitic phases of stainless-steel improving
resistance to oxidation and corrosion.
❑Manganese:
Like nickel and used as its substitute which acts as an austenite
forming element.
❑Nitrogen:
It acts on increasing austenite stability of stainless steel. It is also
an austenite forming element like nickel.
Criteria to be
followed in
stainless steel
brackets
Stainless steel
brackets with good
corrosion
resistance.
Good corrosion
resistance is more
important than its
nickel content.
Stainless steel
brackets should
not be used in
nickel sensitive
patients.
Conventional
stainless-steel
brackets with
softer base and
harder slot/wings
component is
preferred.
followed in
stainless steel
brackets
Stainless steel
brackets with good
corrosion
resistance.
Good corrosion
resistance is more
important than its
nickel content.
Stainless steel
brackets should
not be used in
nickel sensitive
patients.
Conventional
stainless-steel
brackets with
softer base and
harder slot/wings
component is
preferred.
Cobalt Chromium
Brackets
These brackets were introduced as low nickel
alternative in mid 1990s that are fabricated
either by casting or by metal injection molding.
Cobalt based alloys can be divided into three
categories:
•Cobalt based wear resistant alloys: which
is used for orthodontic bracket
manufacturing
•Cobalt based high temperature alloys
•Cobalt based corrosion resistant alloys
Brackets
These brackets were introduced as low nickel
alternative in mid 1990s that are fabricated
either by casting or by metal injection molding.
Cobalt based alloys can be divided into three
categories:
•Cobalt based wear resistant alloys: which
is used for orthodontic bracket
manufacturing
•Cobalt based high temperature alloys
•Cobalt based corrosion resistant alloys
Properties of
Cobalt
Chromium
Brackets
Friction Resistance:
•Cobalt chromium brackets show comparable friction
compared with stainless steel brackets when used
with stainless steel wires.
Corrosion Resistance:
•Less chance of corrosion due to increased chromium
contents.
•Even though cobalt chromium brackets have good
corrosion resistance and highly polished surface,
they are rarely selected over titanium or stainless
steel due to less favorable frictional properties with
different types of wires.
Cobalt
Chromium
Brackets
Friction Resistance:
•Cobalt chromium brackets show comparable friction
compared with stainless steel brackets when used
with stainless steel wires.
Corrosion Resistance:
•Less chance of corrosion due to increased chromium
contents.
•Even though cobalt chromium brackets have good
corrosion resistance and highly polished surface,
they are rarely selected over titanium or stainless
steel due to less favorable frictional properties with
different types of wires.
Titanium Brackets
Those brackets were also introduced in mid 1990s to eliminate the
possibility of an allergic response to the 8% nickel content in stainless
steel.
Types of Titanium:
•α Titanium: commercially pure (CP) unalloyed
•β Titanium: alloyed
•α & β Titanium: alloyed
Alloyed titanium has greater strength than unalloyed titanium. If we are
aiming for a higher torque it is preferred to use titanium brackets made of
titanium alloy rather than the commercially pure titanium.
Indications:
•Nickel sensitive patients.
•Patients with deep bites and bruxism due to titanium being of
comparable hardness with the teeth.
Those brackets were also introduced in mid 1990s to eliminate the
possibility of an allergic response to the 8% nickel content in stainless
steel.
Types of Titanium:
•α Titanium: commercially pure (CP) unalloyed
•β Titanium: alloyed
•α & β Titanium: alloyed
Alloyed titanium has greater strength than unalloyed titanium. If we are
aiming for a higher torque it is preferred to use titanium brackets made of
titanium alloy rather than the commercially pure titanium.
Indications:
•Nickel sensitive patients.
•Patients with deep bites and bruxism due to titanium being of
comparable hardness with the teeth.
Titanium
Brackets
Corrosion Resistance:
•Titanium brackets are superior to stainless steel brackets in term of corrosion
resistance due to presence of thin protective layer of titanium dioxide which is more
stable than the layer of chromium oxide on stainless steel.
Frictional properties:
•Titanium has an inherently rougher surface than stainless steel, that means
potentially greater resistance to sliding a tooth along an archwireif the wire or the
bracket is titanium.
•Titanium also has a chemically active surface, and this can contribute to difficulty in
sliding, especially with a TMA wire in a titanium bracket.
Bond Strength:
•Better bond reliability primarily because titanium has the same strength as stainless
steel but is half as stiff. This means that a titanium bracket can absorb 50% more
impact energy than a steel bracket, reducing the load on the bond during function.
Disadvantages of Titanium Brackets:
•May release elements like vanadium which can cause undesirable biological effects.
•Joined components of titanium brackets by laser welding can leave gaps between the
components leading to decreased mechanical strength and making those areas more
plaque retentive increasing the chances of galvanic corrosion.
•Mouthwashes containing fluoride may cause crevices and pitting corrosion to the
titanium brackets.
Brackets
Corrosion Resistance:
•Titanium brackets are superior to stainless steel brackets in term of corrosion
resistance due to presence of thin protective layer of titanium dioxide which is more
stable than the layer of chromium oxide on stainless steel.
Frictional properties:
•Titanium has an inherently rougher surface than stainless steel, that means
potentially greater resistance to sliding a tooth along an archwireif the wire or the
bracket is titanium.
•Titanium also has a chemically active surface, and this can contribute to difficulty in
sliding, especially with a TMA wire in a titanium bracket.
Bond Strength:
•Better bond reliability primarily because titanium has the same strength as stainless
steel but is half as stiff. This means that a titanium bracket can absorb 50% more
impact energy than a steel bracket, reducing the load on the bond during function.
Disadvantages of Titanium Brackets:
•May release elements like vanadium which can cause undesirable biological effects.
•Joined components of titanium brackets by laser welding can leave gaps between the
components leading to decreased mechanical strength and making those areas more
plaque retentive increasing the chances of galvanic corrosion.
•Mouthwashes containing fluoride may cause crevices and pitting corrosion to the
titanium brackets.
Precious Metal
Brackets
•They are usually steel brackets plated with
precious metals like gold, platinum or
palladium. Gold plated (16, 18 and 24 karat)
being the most used especially in lingual
orthodontics. Gold is known for the
property of non-reactivity (biocompatible).
•Gold plated brackets are popular in lingual
orthodontics and can be used in nickel
sensitive patients however it is the more
expensive option compared to titanium
brackets.
Brackets
•They are usually steel brackets plated with
precious metals like gold, platinum or
palladium. Gold plated (16, 18 and 24 karat)
being the most used especially in lingual
orthodontics. Gold is known for the
property of non-reactivity (biocompatible).
•Gold plated brackets are popular in lingual
orthodontics and can be used in nickel
sensitive patients however it is the more
expensive option compared to titanium
brackets.
Bracket Bases
•It is the component of the bracket that is responsible for
the bracket attachment to the tooth.
•An ideal attachment should be strong to transfer
orthodontic forces to the teeth, withstand masticatory
loads and be easily removed at the end of treatment.
•Orthodontic brackets can be attached to teeth, porcelain,
metal, composite and acrylic using different adhesives.
•Manufacturers tend to increase retention of bracket bases
by various chemical, mechanical or combination of both
retention designs.
•It is the component of the bracket that is responsible for
the bracket attachment to the tooth.
•An ideal attachment should be strong to transfer
orthodontic forces to the teeth, withstand masticatory
loads and be easily removed at the end of treatment.
•Orthodontic brackets can be attached to teeth, porcelain,
metal, composite and acrylic using different adhesives.
•Manufacturers tend to increase retention of bracket bases
by various chemical, mechanical or combination of both
retention designs.
Stainless Steel
Brackets
•It mostly uses mechanical retention as stainless
steel doesn’t form any chemical union with
adhesives.
•The base in stainless steel brackets is either
integral part of the bracket or welded to the
main body.
Brackets
•It mostly uses mechanical retention as stainless
steel doesn’t form any chemical union with
adhesives.
•The base in stainless steel brackets is either
integral part of the bracket or welded to the
main body.
Types of bases in stainless steel
brackets
Perforated bases:
•Perforated bases are one of the oldest bracket designs
depending on mechanical retention.
•It is designed with several perforations to allow greater
penetration and free flow of adhesives through bracket
base increasing bond strength.
•This design was later discontinued as it didn’t provide
superior retention and due to excess cement coming from
the holes being plaque retentive and discoloring.
brackets
Perforated bases:
•Perforated bases are one of the oldest bracket designs
depending on mechanical retention.
•It is designed with several perforations to allow greater
penetration and free flow of adhesives through bracket
base increasing bond strength.
•This design was later discontinued as it didn’t provide
superior retention and due to excess cement coming from
the holes being plaque retentive and discoloring.
Types of bases
in stainless steel
brackets
Foil mesh base:
•More esthetic and hygienic than perforated bases due to
their smooth covered surface.
•Superior retention compared to perforated bases.
•It can be simple or microetched, photoetched or plasma
coated by the manufacturer.
•The foil mesh is either brazed or welded to the bracket
base. The spot welding of foil mesh to bracket base
results in decreased base surface area thus decreased
bond strength. This can be overcome by silver-based
laser welding.
in stainless steel
brackets
Foil mesh base:
•More esthetic and hygienic than perforated bases due to
their smooth covered surface.
•Superior retention compared to perforated bases.
•It can be simple or microetched, photoetched or plasma
coated by the manufacturer.
•The foil mesh is either brazed or welded to the bracket
base. The spot welding of foil mesh to bracket base
results in decreased base surface area thus decreased
bond strength. This can be overcome by silver-based
laser welding.
Types of bases in stainless steel brackets
Single mesh base:
•It has a single layer of mesh attached to the bracket base. It
is the most popular design in orthodontic brackets.
Double mesh base:
•It has a double mesh design; the superficial layer is course
mesh (80 gauge) while the deep layer is fine mesh (150
gauge). According to a study by Bishara, comparable bond
strengths were found in single and double mesh brackets.
Super mesh:
•It is like the double mesh base but with the superficial layer
being 100 gauge and the deep layer being 200 gauge.
Single mesh base:
•It has a single layer of mesh attached to the bracket base. It
is the most popular design in orthodontic brackets.
Double mesh base:
•It has a double mesh design; the superficial layer is course
mesh (80 gauge) while the deep layer is fine mesh (150
gauge). According to a study by Bishara, comparable bond
strengths were found in single and double mesh brackets.
Super mesh:
•It is like the double mesh base but with the superficial layer
being 100 gauge and the deep layer being 200 gauge.
Additions To The Mesh
Sandblasted Foil Mesh:
•To increase mechanical retention, the mesh can be chair side sandblasted with 50 μmaluminum oxide particles for 5
seconds. This is usually done on debondedbrackets to recycle them.
Photoetch Bases:
•It is mainly a process in which small indentations are created on the bracket base using chemical reactions. In this process
parts of bracket base that are to be etched are exposed to chemical while the other parts are covered with a photo
etching resistant material. Less bond strength was still reported compared to foil mesh bases.
Microetchedbases:
•This is done by brackets manufacturers using a grit blasting procedure. Microetchingproved to have a more uniform
etching than photoetching.
Metal Sintered Bases:
•A porous structure is created by fusion of metal powder or ceramic particles on the bracket base, this is said to increase
mechanical retention of the base.
Laser Structured Bases:
•Retentive holes are created by laser beam (Nd:YAG) by burning out metal. These bases compared to mesh type have
better bond strength.
Plasma Coated Brackets:
•These brackets are about depositing finely grounded metallic and nonmetallic materials on a molten or semi molten
bracket base to increase roughness and surface area of bracket base.
Chemical Retention of Stainless-Steel Brackets:
Retention of stainless-steel brackets is mainly mechanical; however, silane can be applied to metal brackets to achieve
chemical retention.
Sandblasted Foil Mesh:
•To increase mechanical retention, the mesh can be chair side sandblasted with 50 μmaluminum oxide particles for 5
seconds. This is usually done on debondedbrackets to recycle them.
Photoetch Bases:
•It is mainly a process in which small indentations are created on the bracket base using chemical reactions. In this process
parts of bracket base that are to be etched are exposed to chemical while the other parts are covered with a photo
etching resistant material. Less bond strength was still reported compared to foil mesh bases.
Microetchedbases:
•This is done by brackets manufacturers using a grit blasting procedure. Microetchingproved to have a more uniform
etching than photoetching.
Metal Sintered Bases:
•A porous structure is created by fusion of metal powder or ceramic particles on the bracket base, this is said to increase
mechanical retention of the base.
Laser Structured Bases:
•Retentive holes are created by laser beam (Nd:YAG) by burning out metal. These bases compared to mesh type have
better bond strength.
Plasma Coated Brackets:
•These brackets are about depositing finely grounded metallic and nonmetallic materials on a molten or semi molten
bracket base to increase roughness and surface area of bracket base.
Chemical Retention of Stainless-Steel Brackets:
Retention of stainless-steel brackets is mainly mechanical; however, silane can be applied to metal brackets to achieve
chemical retention.
Mesh designs in other brackets
Titanium Brackets
•Titanium brackets like stainless steel also comes in mesh or laser structured bases
that depend on mechanical retention. However, titanium brackets contain titanium
oxide layer which form chemical bond with the adhesives.
Cobalt Chromium Brackets
•Cobalt chromium brackets come in a mesh type base like stainless steel which
provides mechanical retention. Cobalt chromium bases can be covered with a
chemical layer that adds chemical retention.
Precious Metal Brackets
•Precious metal bracket use mesh type base design for mechanical retention. Precious
metal brackets are mainly stainless-steel brackets coated with precious metals; its
design is the same as stainless steel brackets.
Titanium Brackets
•Titanium brackets like stainless steel also comes in mesh or laser structured bases
that depend on mechanical retention. However, titanium brackets contain titanium
oxide layer which form chemical bond with the adhesives.
Cobalt Chromium Brackets
•Cobalt chromium brackets come in a mesh type base like stainless steel which
provides mechanical retention. Cobalt chromium bases can be covered with a
chemical layer that adds chemical retention.
Precious Metal Brackets
•Precious metal bracket use mesh type base design for mechanical retention. Precious
metal brackets are mainly stainless-steel brackets coated with precious metals; its
design is the same as stainless steel brackets.
Bracket Base
Surface Area
•Surface area plays an important role in bond
strength, the greater the surface area the better
the bond strength. Brackets surface area usually
ranges from 12.5mm to 28.5mm. Increasing or
decreasing surface area proposes practical
limitations.
•Proffit suggested that the width of the bracket
shouldn’t be more than half of the width of the
tooth while MacColl recommended that bracket
base surface area should be around 6.82mm.
Surface Area
•Surface area plays an important role in bond
strength, the greater the surface area the better
the bond strength. Brackets surface area usually
ranges from 12.5mm to 28.5mm. Increasing or
decreasing surface area proposes practical
limitations.
•Proffit suggested that the width of the bracket
shouldn’t be more than half of the width of the
tooth while MacColl recommended that bracket
base surface area should be around 6.82mm.
Bracket Width Significance
The wider the bracket, the easier it will be able to generate the moments needed to bring
roots together at extraction sites or to control mesiodistal position of roots.
The wider bracket reduces both the force needed to generate the moment and the contact
angle and is thus advantageous for space closure by sliding.
Increased bracket base surface area:
Advantages:
•Increased bond strength
•Areas under the wings are covered by the base protecting the tooth from plaque that
accumulates under the wings.
•Better rotational control and better tip expression
Disadvantages:
•Poor esthetics
•Requires more adhesive thus increasing cost
•May interfere with occlusion or gingiva
The wider the bracket, the easier it will be able to generate the moments needed to bring
roots together at extraction sites or to control mesiodistal position of roots.
The wider bracket reduces both the force needed to generate the moment and the contact
angle and is thus advantageous for space closure by sliding.
Increased bracket base surface area:
Advantages:
•Increased bond strength
•Areas under the wings are covered by the base protecting the tooth from plaque that
accumulates under the wings.
•Better rotational control and better tip expression
Disadvantages:
•Poor esthetics
•Requires more adhesive thus increasing cost
•May interfere with occlusion or gingiva
Shapes of Bracket Base
•The shape can vary between
rectangular, round, circular, rhomboid,
oval or triangular.
•The shape of the base is not of great
importance however it should be
compound contoured to match the
shape of the tooth it is made for.
•The shape can vary between
rectangular, round, circular, rhomboid,
oval or triangular.
•The shape of the base is not of great
importance however it should be
compound contoured to match the
shape of the tooth it is made for.
Bracket Identification
Marks
•Some manufacturers put the tooth number
that is designed for on the base for ease of
identification.
Marks
•Some manufacturers put the tooth number
that is designed for on the base for ease of
identification.
Auxiliary features
Power arms:
•Power arms are placed on the gingival side of the bracket to bring it closer to the
center of resistance.
•The power arm must be longer in teeth with long roots.
•Soft tissue present around the teeth limits the height of the power arm as it
impinges the gingiva either making ideal bracket placement difficult or leading to
gingival hyperplasia.
•They are used to control root position during translation of teeth.
Advantages of power arm:
•Facilitates the application of force delivery systems like springs, power chains, and
elastics easily and closer to teeth center of resistance.
•Provides better retention for ligature and settling elastics in the finishing stage. This
makes power arms beneficial even if translation is not needed.
•Useful in orthognathic surgery for tying surgical splints to the main arch wire and
brackets.
•Power arms are available in several shapes like round, mushroom or hook shaped.
Power arms:
•Power arms are placed on the gingival side of the bracket to bring it closer to the
center of resistance.
•The power arm must be longer in teeth with long roots.
•Soft tissue present around the teeth limits the height of the power arm as it
impinges the gingiva either making ideal bracket placement difficult or leading to
gingival hyperplasia.
•They are used to control root position during translation of teeth.
Advantages of power arm:
•Facilitates the application of force delivery systems like springs, power chains, and
elastics easily and closer to teeth center of resistance.
•Provides better retention for ligature and settling elastics in the finishing stage. This
makes power arms beneficial even if translation is not needed.
•Useful in orthognathic surgery for tying surgical splints to the main arch wire and
brackets.
•Power arms are available in several shapes like round, mushroom or hook shaped.
Auxiliary features
Accessory slots
Accessory slots can be present horizontally or vertically.
Horizontal Accessory Slots:
•Used to pass accessory wires.
•Help in intrusion, extrusion and piggyback mechanics.
Vertical Accessory Slots:
•Pass torqueing springs, uprightingsprings, rotation
springs and auxiliary power pins.
•Can be used for indirect anchorage by engaging a
wire from implant to vertical slot of bracket.
Accessory slots
Accessory slots can be present horizontally or vertically.
Horizontal Accessory Slots:
•Used to pass accessory wires.
•Help in intrusion, extrusion and piggyback mechanics.
Vertical Accessory Slots:
•Pass torqueing springs, uprightingsprings, rotation
springs and auxiliary power pins.
•Can be used for indirect anchorage by engaging a
wire from implant to vertical slot of bracket.
Convenience Features
Vertical Mid Scribe Line:
•It is a vertical line that helps in bracket
placement, it follows the long axis of
the tooth.
•The scribe line can be continuous or
interrupted, continuous is preferred.
•Ceramic brackets usually don’t have a
scribe line.
Vertical Mid Scribe Line:
•It is a vertical line that helps in bracket
placement, it follows the long axis of
the tooth.
•The scribe line can be continuous or
interrupted, continuous is preferred.
•Ceramic brackets usually don’t have a
scribe line.
Convenience Features
Tie-wings:
•Extensions of the conventional bracket.
They are used for their undercuts to
secure elastic or stainless-steel
ligatures, which in turn hold the
archwire in place.
Tie-wings:
•Extensions of the conventional bracket.
They are used for their undercuts to
secure elastic or stainless-steel
ligatures, which in turn hold the
archwire in place.
New Advances in Bracket
Designs
Self-Ligating Brackets:
•Placing wire ligatures around tie wings on brackets to hold archwires
in the bracket slot is a time-consuming procedure. At present,
brackets with a built-in ligating mechanism are widely used. They are
called “self-ligating” but most really aren’t, because manually opening
or closing the mechanism still is required.
•Other advantages claimed by bracket manufactures, such as increased
patient comfort, improved oral hygiene, superior patient cooperation
and acceptance, less chair time, shorter treatment time, and
enhanced expansion of arches, have also interested orthodontists.
•The self-ligating brackets perform as well as conventional ones, with
no evidence that their latching mechanism makes any positive or
negative difference in the outcome of treatment.
Designs
Self-Ligating Brackets:
•Placing wire ligatures around tie wings on brackets to hold archwires
in the bracket slot is a time-consuming procedure. At present,
brackets with a built-in ligating mechanism are widely used. They are
called “self-ligating” but most really aren’t, because manually opening
or closing the mechanism still is required.
•Other advantages claimed by bracket manufactures, such as increased
patient comfort, improved oral hygiene, superior patient cooperation
and acceptance, less chair time, shorter treatment time, and
enhanced expansion of arches, have also interested orthodontists.
•The self-ligating brackets perform as well as conventional ones, with
no evidence that their latching mechanism makes any positive or
negative difference in the outcome of treatment.
Self-Ligating Brackets
There are two types of self-ligating brackets the active and
passive:
•Active:has spring clip that encroaches on the slot from
the labial/buccal aspect and presses against the archwire
providing an active seating force on the archwireand
ensuring engagement such as In-Ovation, SPEED, Time
brackets.
•Passive:Clip doesn’t press against the archwire. Instead,
these brackets use a rigid door or latch to entrap the
archwireproviding more room for the archwiresuch as
Damon (Ormco), SmartClip(3M Unitek), and Oyster ESL
(Gestenco).
A study found that passive SLBs exhibit lower friction than
active SLBs, and it was suggested that the wire binding effect
of active SLBs might be higher than passive SLBs.
There are two types of self-ligating brackets the active and
passive:
•Active:has spring clip that encroaches on the slot from
the labial/buccal aspect and presses against the archwire
providing an active seating force on the archwireand
ensuring engagement such as In-Ovation, SPEED, Time
brackets.
•Passive:Clip doesn’t press against the archwire. Instead,
these brackets use a rigid door or latch to entrap the
archwireproviding more room for the archwiresuch as
Damon (Ormco), SmartClip(3M Unitek), and Oyster ESL
(Gestenco).
A study found that passive SLBs exhibit lower friction than
active SLBs, and it was suggested that the wire binding effect
of active SLBs might be higher than passive SLBs.
Tubes in A Bracket
•Tubes usually apply to bands for the molar teeth.
•Sometimes an auxiliary appliance is used in
addition to the base archwire.
•Brackets such as the SPEED self-ligating bracket
have an auxiliary slot incorporated into the bracket
stem and accept an additional wire up to 0.016 x
0.016-inch dimension to assist with tooth
movement where needed.
•Tubes usually apply to bands for the molar teeth.
•Sometimes an auxiliary appliance is used in
addition to the base archwire.
•Brackets such as the SPEED self-ligating bracket
have an auxiliary slot incorporated into the bracket
stem and accept an additional wire up to 0.016 x
0.016-inch dimension to assist with tooth
movement where needed.
Straight Wire Low Friction
(SWLF) System
•The SWLF® System uses the Synergy® bracket, a popular and proven low
friction bracket. Its innovative design allows for individual and selective
control over friction, anchorage and tooth movement, as well as a drastic
reduction in the number of wires used compared to traditional Straight
Wire brackets.
•New super-elastic arch wires have been developed for the SWLF® System.
The superelastic properties of the SWLF® wires make it possible to apply
light, continuous forces over longer periods of time. Extractions are
reduced and tooth movement is improved by stimulating alveolar bone
growth. Heat-activated Thermaloy® NiTi wire can generate light,
continuous forces necessary to effectively manage the beginning stages of
treatment. For finishing and detailing, Bendaloy®, a combination of nickel-
titanium (shape memory) with the benefits of traditional stainless steel
(shape modification). This new molybdenum alloy contains no nickel and
acts as a great finishing wire.
(SWLF) System
•The SWLF® System uses the Synergy® bracket, a popular and proven low
friction bracket. Its innovative design allows for individual and selective
control over friction, anchorage and tooth movement, as well as a drastic
reduction in the number of wires used compared to traditional Straight
Wire brackets.
•New super-elastic arch wires have been developed for the SWLF® System.
The superelastic properties of the SWLF® wires make it possible to apply
light, continuous forces over longer periods of time. Extractions are
reduced and tooth movement is improved by stimulating alveolar bone
growth. Heat-activated Thermaloy® NiTi wire can generate light,
continuous forces necessary to effectively manage the beginning stages of
treatment. For finishing and detailing, Bendaloy®, a combination of nickel-
titanium (shape memory) with the benefits of traditional stainless steel
(shape modification). This new molybdenum alloy contains no nickel and
acts as a great finishing wire.
Individually
Customized Brackets
•The first step in producing the Insignia customized bracket is a 3-D
scan of the dentition to produce an STL file.
•Based on this “anatomically correct” arch form, the software then
aligns the virtual teeth and places them in occlusion, with each
tooth position determined from the best-fit buccal cusp
orientation.
•The doctor can adjust the tooth positions at this point and would
need to be aware of the software assumptions as this is done.
•This digital information then is used to precisely cut each bracket
by using computer-aided design/computer-aided manufacturing
(CAD/CAM) technology, so that the slot for each bracket has the
appropriate thickness, inclination, and torque needed for ideal
positioning of that tooth, and archwireswith an arch form
established for that patient are supplied.
•Attempts are being made now to integrate images of tooth–lip
relationships into the database for Insignia, so that tooth display on
smile is built into where the brackets are placed on the anterior
teeth, and moving the brackets automatically changes the tooth
display.
Customized Brackets
•The first step in producing the Insignia customized bracket is a 3-D
scan of the dentition to produce an STL file.
•Based on this “anatomically correct” arch form, the software then
aligns the virtual teeth and places them in occlusion, with each
tooth position determined from the best-fit buccal cusp
orientation.
•The doctor can adjust the tooth positions at this point and would
need to be aware of the software assumptions as this is done.
•This digital information then is used to precisely cut each bracket
by using computer-aided design/computer-aided manufacturing
(CAD/CAM) technology, so that the slot for each bracket has the
appropriate thickness, inclination, and torque needed for ideal
positioning of that tooth, and archwireswith an arch form
established for that patient are supplied.
•Attempts are being made now to integrate images of tooth–lip
relationships into the database for Insignia, so that tooth display on
smile is built into where the brackets are placed on the anterior
teeth, and moving the brackets automatically changes the tooth
display.
Lingual Appliances
•The introduction of bonding in the 1970s made it possible to place fixed
attachments on the lingual surface of teeth to provide an invisible fixed
appliance, and brackets designed for the lingual surface were first
offered soon after bonding was introduced.
•There were multiple problems in producing a bracket that intruded only
minimally into tongue space and was at least reasonably easy to use.
•One successful German appliance design, Incognito, was purchased by
3M-Unitek in 2012 and widely marketed. It uses a custom precious
metal pad for each tooth that covers a large area on the lingual surface.
Low-profile brackets designed so the archwirecan be inserted from the
top are attached to the pad. Wire bending is eliminated by using wire-
bending robots to form the archwires.
•A German successor to Incognito, which uses a different bracket design,
3-D printing for production of brackets with precise slots (its first
commercial use in orthodontics), and computer-formed archwires, now
is becoming available. It has been shown to significantly decrease
treatment time compared with Incognito.
•The introduction of bonding in the 1970s made it possible to place fixed
attachments on the lingual surface of teeth to provide an invisible fixed
appliance, and brackets designed for the lingual surface were first
offered soon after bonding was introduced.
•There were multiple problems in producing a bracket that intruded only
minimally into tongue space and was at least reasonably easy to use.
•One successful German appliance design, Incognito, was purchased by
3M-Unitek in 2012 and widely marketed. It uses a custom precious
metal pad for each tooth that covers a large area on the lingual surface.
Low-profile brackets designed so the archwirecan be inserted from the
top are attached to the pad. Wire bending is eliminated by using wire-
bending robots to form the archwires.
•A German successor to Incognito, which uses a different bracket design,
3-D printing for production of brackets with precise slots (its first
commercial use in orthodontics), and computer-formed archwires, now
is becoming available. It has been shown to significantly decrease
treatment time compared with Incognito.
References
•Outline the significance of the pre-adjusted
Edgewise appliance system and useful bracket
variations in orthodontics, Dr MJ Rowland-
Warmann BSc BDS (Manc) MSc Aes.Med.
(Lond) MJDF RCS (Eng), December 2017
•SWLF System and Tri-wing Bracket (Synergy FX)
from Rocky Mountains official website.
•Iijima, M., Zinelis, S., Papageorgiou, S. N.,
Brantley, W., & Eliades, T. (2017).Orthodontic
brackets. Orthodontic Applications of
Biomaterials, 75–96.doi:10.1016/b978-0-08-
100383-1.00004-7
•Contemporary Orthodontics 6
th
edition,
William Profitt, 2019
•Orthodontic Brackets: Selection, Placement
and Debonding, Dr. Haris Khan, 2012
•Outline the significance of the pre-adjusted
Edgewise appliance system and useful bracket
variations in orthodontics, Dr MJ Rowland-
Warmann BSc BDS (Manc) MSc Aes.Med.
(Lond) MJDF RCS (Eng), December 2017
•SWLF System and Tri-wing Bracket (Synergy FX)
from Rocky Mountains official website.
•Iijima, M., Zinelis, S., Papageorgiou, S. N.,
Brantley, W., & Eliades, T. (2017).Orthodontic
brackets. Orthodontic Applications of
Biomaterials, 75–96.doi:10.1016/b978-0-08-
100383-1.00004-7
•Contemporary Orthodontics 6
th
edition,
William Profitt, 2019
•Orthodontic Brackets: Selection, Placement
and Debonding, Dr. Haris Khan, 2012
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