Essential Biomaterials for Orthodontics

INTRODUCTION
Orthodontists need a variety of devices
made from a large array of materials
which is biocompatible.
“All substances are poison; there is none which is not
a poison , the right dose differentiates a poison
from remedy”-PARACELUS.
www.indiandentalacademy.com

GENERAL REQUIREMENT FOR
BIOMATERIALS
1) Non-toxicity.
2) Strength.
3) Hydrolytic stability.
4) High purity.
5) Reproducible quality.
6) Sterilization.

Evolution of orthodontic biomaterials
(1750-1930)
E.H Angle – 19th
century.
Introduction of strips or wires of precious
Metal, wood, rubber, vulcanite, piano wire
& silk thread.
Half century later, it was focus on molar
band versus screw band, German silver arches
versus gold arches and different types of band
materials & ligatures.

Evolution (contd)
(1930-1975)
Major developments in metallurgy and organic
chemistry.
Improvements in metal treatment.
Emergence of new plastics, gave rise to the
mass produced orthodontics devices.

Evolution ( contd )
( 1975- present)
Over past 25 yrs the number of
orthodontic manufactures has grown
both in quality & variety of their
products.To the traditional materials the
manufactures have added ceramic &
composite devices.

TOOTH COLOURED BIOMATERIALS
BRACKETS
Plastic – Reinforced type.
Composite
- ceramic –polymer.
- metal - polymer.
-Ceramic filler, Plastic body, Metal liner.
Ceramics

TOOTH COLOURED BIOMATERIALS
ARCH WIRES
Composite.
Teflon coated.
Plastic coated.
LIGATURE WIRES
Teflon coated.
Composite coated.

PLASTICS- BRACKETS

PLASTICS
Synthetic resins are often called plastic.The
plastics are usually polymers and they
exists as thermoplastics and thermosetting
material.
Ideal requirements for organic polymer:
1) Non-degradable. 2) Stable.
3) Biocompatible with biologic material.
4) Non-mutagenic.

Plastics ( contd )
The first organic polymers used in
orthodontics were rubber & its sulfur
cross-linked derivative,
Vulcanite ( Good year 1840).
Polymethacrylate (O.Rohm 1936)
Polyurethanes (O.Bayer 1937)
Polycarbonates & Polysulfones have made it
possible to the manufacture esthetic
attachments.

STRUCTURE & COMPOSITION OF
PLASTIC
Polymers can be linear & branched .In these
type the carbon chain packed in lamellae
which are folded in different ways without
being interconnected.
Depending on their structure & molecular
weight , their properties can vary significantly.
Elastics –few bonds
Strong elastics-Slightly increases in cross-
linked polymers.
Plastics – highly cross linked polymers.

Contd…….
Plastics brackets---
prepolymer--aromatic di-isocyanate
( filler)---Diol(amphorous matrix).
These bracket were described & tested by
NEWMAN(1969)
They have high strength and show little
elastic deformation under load.
They show low co-efficient of friction against
stainless steel but under excessive rapid
force result in high co-efficient of friction.

CONTD…….
These bracket do not show any
tendency for brittle fracture like ceramic
bracket.
Do not posses any hazard in
debonding(enamel damage).
Re-cycling of the bracket is not
possible.
Bond strength-5.10MPa.

BONDING PLASTICS
ORTHODONTIC ATTACHMENTS
OIS( ORTHODONTIC INTERNATIONAL SERVICS)
ADHESIVE SYSTEM.
Specifically prepared acrylic resin mix which forms a
self-limiting joint for bonding plastics orthodontic
attachments to tooth enamel surfaces.
It is essentially a methyl-methaacrylate, ethyl
methacrylate free radical polymerization system with
filler added to the polymer to reduces shrinkage &
lower the coefficient of thermal expansion.
Surface treating agent: 60%Phosphoric acid, 5% zinc
oxide, 1% sodium fluoride.

Plastics Contd…..
Clinical problems:
Staining and discolouration.
Poor dimensional stability ( water
absorption)
Friction.

Reinforced plastics brackets
Most efforts are directed towards
improving the polymeric brackets by the
plastics matrix apart from strength&
esthetics other benefits are the
roughness brought by the addition of
filler may render conditioning of the
plastics base( reinforced with powder or
fibers).

Reinforced plastics brackets
Polymer fiber reinforcement-Goldberg. AJ.
Glass reinforcement- Adam. RE & at.
Mineral filler reinforcement – Masher. E.
Ceramic liner- Sernate. F.
Metal liner –Wall sherin.M
Metal reinforcement –Andrews. LF

COMPOSITE -BRACKETS

COMPOSITE BRACKETS
Composite is a multiphase material
brought about by combining material
that differ in composition or form in
order to obtain specific characteristics
and properties, the interface between
one another act in concert to achieve
improved synergistic properties not
obtainable by any of the component
acting alone.

Structure & Composition
In orthodontics the 1st
composite resin were
launched in the 1950’s and the first
attachments in the mid-1990’s.
Basis type of composite are dispersion of the
filler (a discontinuous phase made up of
round or irregularly shaped particles,fibers &
whiskers) in a binder as matrix( continuous
phase made of metal,ceramic or resin).
Strength of the composite depends on the
selection of filler (fibers), orientation of the
particles & coupling agent.

Synthesis of composite Brackets
Controlled addition of pretreated solid
filler to liquid / molten matrix of a
synthetic resin.
The manufacturing method by injection
molding technique were molten mass is
forced into a mold and dispersion of
filler in the polymer takes place at
uniform temperature.

Composite brackets
Plastics reinforced with ceramic-Lee fischer( Lee-
pharm).
Plastics reinforced with glass- Image (GAC).
,, ,, ,, ceramic-value line(urec).
,, ,, ,, ,, -Silkon(Am.ortho).
Plastic with metal insert- Spirit(ormco).
,, ,, ,, ,, - Spirit MB (ormco).
,, ,, ,, ,, - New plastic (tomy).
Ceramic with metal insert- Clarity R (unitek).
Plastic reinforced with ceramic & metal insert- New
spirit ( ormco).
Metal with plastic base – Ceramaflex (T.P ortho)
Self ligating(oyster)- Gestenco (GAC)

COMPOSITE SELF LIGATING
BRACKET (oyster)
A unique self ligating aesthetic bracket that
truly marks a new era in orthodontic
appliances
It is composed of strong clear glass fiber
reinforced composite polymer.
Very fast & easy arch wire changing
procedure.
Increased comfort for the patient with
rounded corners.
Heavily reduced friction facilitates rapid tooth
movement in sliding mechanics.

CERAMIC- BRACKET

CERAMIC
A compound of metallic and non-metallic
elements, a compound of metal( such as
aluminum, calcium,lithium, magnesium,
potassium,sodium & zirconium) and
nonmetals( silicon,boron, fluorine& oxygen)
that may be as a single structural component.
Ceramic bracket was first introduced in 1987
and today it has found wide acceptance and
still holds more promise.

Classification
Classified based upon :
• The crystal structure into mono crystalline or
polycrystalline brackets.
• Depending on its retentive mechanism into
mechanical, chemical & combination.
• Material constituents into pure ceramic &
laminated ceramic (or) alumina based &
zirconia based.

Manufacturing process
Monocrystalline brackets:
Aluminium oxide is heated above 2100°C.
The molten mass is cooled & machined.
Polycrystalline brackets:
Blending of aluminum oxide particles with
a binder & the molding of the bracket is
done by machining or by injection mould
technique.The temp used is 1800°C.
Zirconia brackets:
They are tridimensional inorganic macromolecules.At
room temp pure zirconia exists in monoclinic phase
–at 1000°C-tetragonal phase. Crack formation can
inhibited –4-6 wt% of yttria (psz bracket).

Properties of ceramic brackets
Ceramic bracket are 9 times hardness than
the stainless brackets or enamel.
Tensile strength is much stronger in
monocrystalline alumina than in
polycrystalline alumina, that in turn
significantly stronger than stainless steel.
Fracture toughness in ceramics is 20 to 40
times less than in stainless steel
(polycrystalline presents higher fracture
toughness than monocrystalline).

Properties (contd……)
Bond strength:
Mechanical retention-grooves & undercuts-
more bond failure on shear forces.
Chemical bonding-silane coupling agent-over all
distribution of stress-less bond failure-enamel
damage .
Other factors –type of bonding, resin, etching
time, condition, preparation of tooth.

Properties (contd…..)
Frictional resistance:
Stainless steel brackets generates lower
frictional forces than ceramic brackets.
Injection molded ceramic brackets create
les friction than other ceramic bracket.
Arch wire- Beta-titanium & nickel-titanium
wire associated with higher frictional
forces than ss & cobalt-chromium.

Properties (contd……)
Base surface:
Type –I -Mechanical retention.
Type –II – Chemical bonding.
Type –III – Poly carbonate laminate.
Bracket fracture:
Depends upon on shape & bulk of the
material.
The primary causes of fracture-internal defect
& machining interference.
Second order activation-no bracket failure.
Third order activation-frequent bracket failure.

Recycled ceramic bracket
Recycling of ceramic bracket are done by
heating and application of the silane coupling
agents,this method provides clean surface.
Bond strength of recycled brackets appeared
to be clinically adequate,although it was
significantly lower than that of new
brackets(minimizes the unwanted enamel
removed during debonding).

Problems encountered in ceramic
brackets
Enamel fracture & enamel flaking during
debonding.
Increased friction with ceramic bracket.
Pain or discomfort while debonding ceramic
bracket.
Limited rotation of teeth with ceramic bracket.
Difficulty encountered in torqueing & tipping.
Longer treatment time.

Clarity brackets
Clarity bracket system emerged on 2 axioms
1) understanding the needs of the orthodontist.
2) Used advanced technology to address these
needs.
Three key problems are: poor sliding
efficiency, bracket breakage & difficulties in
debonding.

Clarity brackets
Improving sliding efficiency- placing thin
stainless steel linear.
Reducing bracket breakage- reducing
the tensile stress by reinforcing with
metal liner, by building up pressurizing
effect into the bracket.
Ease debonding- collapsible brackets.

New collapsible ceramic brackets
They are design with a metal lined arch wire
slot and a vertical slot designed to create a
consistent bracket failure mode during
debonding.
It has got both esthetic & function advantage.
Debonding:Weingart AEZ plier is used. The
tip of the plier are placed on the mesial &
distal ends of the metal liner then squeed &
little torque is applied.

DEBONDING
TECHNIQUE FOR
CERAMIC BRACKETS

Heat Removal
Heat the tip of the utility plier for about
10 secs with micro torch then with light
rotational force the bracket is removed.

Conventional technique
No-790 tapered finishing bur –adhesive
removed from mesial & distal portion-
Unitek debonding instrument – circular
motion is used.
Disadvantages:
Longer time for debonding.
Aspiration of bracket fragments.
Patient discomfort.

Ultrasonic bracket removal
Decreased chance of enamel damage.
Decreased bracket failure.
Removal of adhesive can be done by same
tip.
Disadvantages:
Increased debonding time.
Excessive wear of expensive tip.
Need to apply moderate force level(sensitive)
Potential for soft tissues injury by a careless
operate.
Need of water spray to reduce the heat
generated.

Electro thermal debonding
Reduces the incidence of bracket failure
Small amount of force required of force to
break the bond.
Minimal potential for enamel damage.
Disadvantages:
Potential for pulpal damage.
Potential for soft tissue injury by careless
operate.
Bulky hand piece design.
Instrument design to fit specific bracket
design.

Laser debonding
It is “cold” universal debracket
instrument.
Significantly reduction in debonding
forces.
Potential to be atrumatic.
Less risk of enamel damage.

Contra indications
of ceramic brackets
Deep bite cases.
Patient with bruxium habit, short clinical
crown or anterior teeth with cracks or
large restoration.
Need of significant incisor torque.
Children (brittleness).

Ceramic brackets
Transcend series 2000 –Unitek.
Star fire bracket- A-Company.
Allure IV – GAC.
Ceramflex – TP.
Intrigue – Lancer orthodontics.
Quasar- Rocky mount.
Lumina –ormco.
Clarity – 3M Unitek.
Crystalline-Tomy.
Fascination-Dentrum.
Dynalock- Unitek.
Contour – Class one orthodontics.

Tooth colored arch wires

Composite arch wire
Composed of S2- glass fibers & acrylic
resin.
Manufacturing process:
Photo pultrusion-mass-uniform fibers-
wetted with monomer- specific
dimension is made via a die – curing
chamber- finical dimension.
-Partial cure arch wire.

Composite - properties
Esthetically pleasing because of their
translucent quality tends to transmit the color
of host teeth.
Prototype have been constructed with
stiffness ranging from that of niti to beta
titanium without change in the cross sectional
dimension.
When the fiber &resin content are equal
,spring back is greater than 95% and the total
water sorption is only 1.5% by wt so that
dimensional stability is good.

Esthetic retainer
Organic polymer retainer wires made up of
poly ethylene terephthalate 1.6 mm diameter.
To contour the material plier is used to bent
and heated for few secs of temp less than
230°C
In prefabricated wire –anterior portion (st) &
posterior portion (wave).
Shrinkage takes place during heating which
compensated by posterior segment.
No significant discoloration & does not absorb
water. www.indiandentalacademy.com

Esthetic retainer- newer version
The anterior plastics part flat organic polymer
wire with 100
labial torque is attachment to .
032’ ss posterior arm each 11cm long.
The plastics comes in 3 inter canine with or
without activating omega loop in posterior
arm.
It requires no special tool or instrument only
on ordinary hair hair dryer.

Fiber- Reinforced composite
FRC materials are superior to polymer
because they offer a structural rigidity &
strength as well as reduction in stress
relaxation.
Modules of elasticity is 70% greater than that
of the highly filled dental composite.
Yield strength is 6 times greater than dental
composite.
24 times resilience than dental composite.
FRC can be bonded to another FRC and
attachment(brackets,hooks) can be added
directly.
They are available in 3-different
configuration-round,strip & woven pattern.www.indiandentalacademy.com

FRC
MAUNFACTURING PROCESS:
The fibers are correctly oriented and excellent
coupling is achieved ,followed by an initial
polymerization makes the matrix flexible and
adaptable, so it can be easily contained to the
teeth. The result is a user friendly polymer
that is as easily manipulated as any plastics,
but as structurally strong as metal.

Clinical application-FRC
Open bite cases.
Space closure.
Up righting molar.
Maxillary anterior intrusion.
Fixed lingual retainer.
Limitation:
They are weakest in shear & torsion.

OPTI-FLEX ARCH WIRE
Designed by Dr.Taloss & manufactured
by Ormco.
It is made up of :1) Silicon-di-oxide.
2) Silicon resin.
3) Nylon.
Available in 10’’ to 6’’ st lengths of 0.17’’
& 0.021’’.

Advantages of opti-flex
Most esthetic arch wire.
Stain resistant.
Light continuous force exerted( showed
low load deflection rates reaching the
proportional limit much earlier when
compared to other wires
More flexible.
It can be used in bracket system.

Disadvantages of opti-flex
Sharp bends are avoided.
Metal ligatures tie are avoided.
Special instruments are used to cut.
Rough diet are restricted.
This arch wire is not recommend for
cuspid retraction.

Teflon coated SS arch wire
Teflon is a commercial synthetic resin
( polytetrafluoroethylene).
ADV:
Used to prevent wetting of the metal surface.
DIS ADV:
Does not discolor.
Grayish hue of these wire makes them
esthetically inferior.
Teflon coating wear off 2-3 weeks exposing
the metal surface.

Marsenol arch wire
Tooth colored niti wire manufactured by
glenroe technologies.
It is a E.T.E coated niti (Elastomeric
poly tetra florethylene emulsion)

Lee white wire
Manufactured by lee pharmaceutical.
To the niti or stainless steel tooth
colored Epoxy coating is bonded.
It is completely opaque and does not
chip, peel, stain or discolor.
Suitable for ceramic & plastics brackets.

Tooth colored – ligature wires

Teflon coated Ligature
No discoloration.
The coating wears off after 2-3 weeks and the
metal is exposed.
Produces less friction when compared with
elastomeric ligatures & stainless steel
ligatures.
It generates lighter forces of engagement of
the arch wire into bracket slot.

Composite ligature
Fabricated from the acrylic monomer n-
butyl methacrylate and drawn poly
ethylene fibers.
Due to stress relaxation properties
within an hour it loss 98% of ligation
forces( not used in sliding mechanism).

CONCLUSION
“Yesterday was a history
Today is present from god
Tomorrow is a mystery”

THANK YOU

Essential Biomaterials for Orthodontics

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Essential Biomaterials for Orthodontics

Similar to Essential Biomaterials for Orthodontics (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Essential Biomaterials for Orthodontics