Esthetic archwires

Esthetic Archwires
www.indiandentalacademy.com

One promising approach towards achieving an esthetic
arch wire with good overall properties involves the
use of composites which can be a mixture of ceramic
fibers that are embedded in a linear or cross linked
polymeric matrix
Such an archwire could be made with a tooth-coloured
appearance and with stiffness properties similar to
metallic archwires.

studies designed to examine the mechanical
properties, viscoelastic losses, water sorption,
hydrolytic stability, sliding mechanics and post
processing formability of composite wires has shown
strong support for their clinical viability.
There are numerous processes for the fabrication of
continuous fiber-reinforced composite parts. In order
to maintain careful control during fabrication, many
fiber reinforced composite products are produced in
two steps.
The amount, distribution and wetting of the fibers by the
resin are closely controlled in the first step.
In second step, the composite is formed into the desired
final shape.

Of the many fiber reinforced composite technologies,
pultrusion is one, which could tend itself to the
fabrication of archwires. Pultrusions with small
clinically relevant round or rectangular cross sections
potentially could be used for continuous lengths of
wires. .
This continuous molding process produces long,
straight structural members of constant cross-
sectional area

The fiber bundles are pulled through an
extruder simultaneous with the extrusion of a
polymer. The fiber bundle is impregnated by
the polymer, producing a continuous length of
fiber-reinforced composite
With the use of this process of photopultrusion,
arch wire prototypes have been constructed
with stiffness ranging from that of nickel
titanium to that of β-titanium wires.

Bundles of continuous fibers are impregnated with
polymeric Resin.
⇓
Pulled through a Sizing Die that preforms
Composite and establishes resin / fiber ratio
⇓
Passed through Curing Die – imparts precise
shape as it cures the resin.

 . When the fiber and resin contents are equal,
springback is greater than 95%, so that the energy
applied at wire insertion may be retrieved months
later without significant loss. At this same fiber-resin
content the total water sorption is only 1.5% by
weight, so that dimensional stability is good and
stains and odours are minimized

 Reformation of a cross-sectional dimension from
round to rectangular and from straight length to
preformed arches is possible, as well. This
procedure is termed β-staging. The surface chemistry
can be modified to provide enhanced biocompatibility
and low coefficients of sliding friction.
 During pultrusion an intervening process in which partially cured
resin and its bundles of continuous fibers are deformed into
another form (e.g., : Preformed archwire) after which curing is
completed

Properties of Experimental Prototypes
1.    Tooth colored.
2. Vary in stiffness from that of most flaccid multistranded wire to
nearly that of β-Ti archwire. These characteristics can be
varied during manufacture without any change in wire slot
engagement by pultrusion.
3.     Mechanical tests show that
-      Such archwires are elastic until failure occurs.
-       When failure does occur the wire looses its stiffness but
remains intact.
When compared with NiTi, resilience and springback are
comparable.

. 4.Specifics of other characteristics such as formability,
weldability and frictional coefficients are unknown at
this time. Low coefficients of friction and enhanced
biocompatibility should be possible by modifying
surface chemistry of polymer.
5. Like the advanced metal wires, their shape is very
difficult to change once the manufacturing process is
completed which leads to a number of practical
problems for clinical applications.

Goldberg and Burstone fabricated a rectangular fiber
reinforced plastic wire with silane-treated continuous
S-2 glass and 2 kinds of thermoplastic polymers,
polyethylene terephthalate glycol (PETG) and poly
1,4-cyclohexylene dimethylene terephthalate glycol
(PCTG).
Kusy and his colleagues have developed an archwire
containing S2 glass fibers (Owens Corning, Toledo,
OH, USA) embedded in a polymeric matrix formed
from BIS-GMA and TEGDMA; benzoin ethyl ether is
present as a uv (ultraviolet) photo initiator. By
adjusting the ceramic/polymer proportions, these
wires can be manufactured in a wide range of
clinically relevant levels of elastic stiffness, using the
technique of photo-pultrusion with ultraviolet light
illumination to cure the polymer matrix

OPTIFLEX ARCHWIRE
New Orthodontic archwire designed by M.F. Talass in
1992.
Combines unique mechanical properties with a highly
esthetic appearance.
I. Structure of Optiflex Archwire
Made of clear optical fiber comprises of three layers
A – Silicon Dioxide Core
B – Silicon Resin Middle Layer
C – Nylon Outer Layer

Silicon Dioxide Core: Provides the force for moving
teeth.
Silicon Resin Middle Layer:
Protects core from moisture and adds strength.
Nylon Outer Layer :
• Stain resistant.
• Prevents damage to wire and further increased
strength.


Properties:
• Wide range of action.
Ability to apply light continuous forces.
Sharp bends must be avoided since they could
fracture the core otherwise optiflex has
practically no deformation.
Talass reported orthodontic cases that
were treated with his wire.

Application:
- Applications are similar to those of coaxial archwires.
Light continuous force& High elasticity
Effective in alignment of
crowded teeth
AVAILABILITY:
Ormco Corporation:
Optiflex
Sizes – 0.017” and 0.021”

. COATED ARCHWIRES
Coating on archwire material have been introduced to
- Enhance esthetics
- Decrease friction.
These wires are designed to be esthetically more acceptable by the
patient. They are given a plastic tooth colored coating so that it
can blend with the tooth color and also of ceramic brackets.
Normally the coating is 0.002” thick.
The coating frequently used is TEFLON.

Teflon coating is applied in two coats by
- Conventional Airspray OR
- Electrostatic techniques.
Natural tooth shades
Available in
Colors – Blue, Green, Purple.

1. Lee White Wire :
Manufacturers – Lee pharmaceuticals.
Epoxy Coated Archwire, tooth colored.
Superior wear resistance and color stability of 6-8 weeks.
Nickel titanium
Preformed arches
Stainless steel

2. Filaflex
Manufacturer – American Orthodontics
High tensile stainless steel core
Durable tooth colored plastic coating.

3. Orthocosmetic Elastinol
Manufacturer – Masel Orthodontics
   Esthetically coated high performance NiTi superelastic archwire.
   Esthetic coating – Blends exceptionally well with ceramic or plastic brackets.
   Doesn’t stain or discolor and resists cracking or chipping.
4. Nitanium Tooth Toned Archwire:
Manufacturer : Ortho Organizers
Superelastic Ni-Ti wire with special plastic and friction reducing tooth colored
coatings.
Blend with Natural dentition, Ceramic, Plastic and composite brackets.
Maintains its original color.
Delivers gentle constant force.
Round – 0.014”, 0.016”, 0.018”
Sizes
Rectangular – 0.016” x 0.022”
0.018” x 0.025”

DISADVANTAGES OF ESTHETIC ARCH WIRE :
Coated white Colored Wires are routinely succumbed
to
-      Forces of mastication.
-      Enzyme activity of oral cavity.
Uncoated Transparent Wires:
•     Poor mechanical properties that they function merely
as placebo.
•

An investigation of the frictional properties of
composite wires against several orthodontic
brackets showed that reinforcement fibers
were abrasively worn from the wire surfaces
when tests were conducted at normal forces
or angulations This potential release of glass
fibers within the oral cavity was considered
unacceptable, and a polymeric surface
coating was suggested as a potential remedy.

Recently, a research group at the
University of Hokkaido (Japan) has
developed an archwire with a poly
(methylmethacrlate) matrix reinforced
by CaO-P2
O5
-SiO2
-Al2
O3
fibers that are
reported to be biocompatible.

Clinical Selection
Property Stainless Steel Cobalt-
Chromium-Nickel
(Elgiloy Blue)
β-Titanium
(TMA)
Nickel-Titanium
Cost

Force delivery

Elastic range
(springback)

Formability

Ease of joining

Archwire-
bracket friction

Concern about
biocompatibilit
y
Low

High

Low

Excellent

Can be
soldered.
Welded joint m
ust be reinforced
with solder.

Lower

Some

Low

High

Low

Excellent

Can be soldered.
Welded joints
must be
reinforced with
solder.

Lower

Some

High

Intermediate

Intermediate

Excellent

Only wire
alloy that has
true
weldability

Higher

None

High

Light

High

Poor

Cannot be
soldered or
welded

Higher

Some

Esthetic archwires

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