Invisalign /certified fixed orthodontic courses by Indian dental academy

INVISALIGN
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Contents
Introduction
Kesling’s Setup
Essix Retainers
- Introduction
- Current Retainer Designs
- Fabrication
- Appliance Delivery
- Telephone Supervision
- Conclusion
Active Tooth Movement With Essix Based
Appliance

Invisalign
- In a Nutshell
- Mechanism of Action
- In Detail
- Retention and Stability
- Advantages
- Disadvantages
- Summary


INTRODUCTION
Movement of teeth without the use of bands,
brackets, or wires was described as early as
1945 by Dr Kesling, who reported on the use
of a flexible tooth positioning appliance.
Later, Nahoum (Vacuum formed dental
contour appliance, 1964) and others (Pontiz,
1971; McNamara, 1985) wrote about various
types of overlay appliances such as invisible
retainers.

Minor tooth movements have also been achieved
with a technique developed by Raintree Essix (New
Orleans, La).
This technique uses clear aligners formed on
plaster models of the teeth.
The aligners are then modified with “divots,” which
create a force to push on the individual teeth, and
“windows,” which create the space for teeth to move
into.
This type of appliance can be effective in correcting
mild discrepancies in the alignment of teeth.
However, movements are limited to 2 to 3 mm;
beyond this range, another impression and a new
appliance are needed.

Align Technology, Inc (Santa Clara, Calif), introduced the Invisalign system several years
ago.
Invisalign takes the principles of Kesling,
Nahoum, others, and Raintree Essix even
further, using computer-aided-design–
computer-aided-manufacture (CAD-CAM)
technology combined with laboratory
techniques to fabricate a series of custom
appliances that are esthetic and removable,
and that can move teeth from beginning to
end.

Keslings setup
The diagnostic setup was first proposed by
Kesling in 1945.
P.R. Begg does not use tooth positioners,
because they are not readily available in
Australia.
However, Kesling uses a tooth positioner as a
finishing appliance on each case.
Not only are the tooth positioners the best
post treatment retention appliance, but they
are the best form of working retainer.

It is possible to obtain more accurate final tooth
positions generally and more accurate final
occlusal relations with tooth positioners than with
any other orthodontic appliance now employed.
At the present time, it is impossible to position
teeth with arch wires and tooth bands with such
final accuracies as can be done with post
treatment use of tooth positioners regardless of the
particular active orthodontic treatment technique
that is used.
The tooth positioners, as being described by
Kesling in 1945, is a one piece, resilient appliance
made from rubber or plastic that fills the free-way
space and covers the clinical crowns of the teeth
plus the portion of the gingival, both buccal and
lingual.

No other appliance has the flexibility to conform to
the discrepancy, and yet has the ability to carry the
teeth to their desired relations- all with no
adjustments required.
The skills required of the orthodontist in positioner
therapy are those of diagnosis and judgment of the
patients willingness or ability to cooperate, not of
manual dexterity.
The positioner is constructed over a per-determined
pattern- the set-up.
Teeth that are to be positioned in the patients
mouth are removed from the patients model and
replaced in the desired positions. The gum area of
the set-up is then contoured to normal form after
changing the teeth.

The positioner is then formed of an elastic material
about the arches in rest position.
This results in the upper and lower teeth slightly
separated, and the lower arch slightly distal to the
upper.
Space closure within reason can be accomplished
with a tooth positioner, especially spaces manifest
during treatment, as in anterior segments.
Within limitations the positioners can be used to
help maintain or change the amount of anterior
overbite.


Labiolingual axial inclination of upper and
lower anteriors can be influenced by a
positioner, however, these teeth should be
uprighted over basal bone as well as possible
with appliances.
One must be realistic for the correction to be
achieved
The positioner can achieve the perfection
possible in the set up only when that
perfection has been approached in the mouth
with conventional treatment.

RESULTS OF WEARING THE TOOTH

POSITIONER AS A FINISHING APPLIANCE
Patients were treated until the correct tooth relations
were achieved.
Tooth positioner has the ability to quickly achieve
the final detailed finishing that is often required.
When the positioner is to be used there is no need
to place finishing arches or to consider a stage 4.
After the teeth have been brought to their
approximate final positions with the proper axial
inclinations, the positioner will close all spaces,
correct slight errors in arch form and develop ideal
occlusion as predetermined by the set up.

The control model made at the time of the appliance
were removed, was duplicated and the teeth were
cut from the model and repositioned in the set up.
In the set up all the spaces have been closed, arch
form has been corrected and the normal amount of
anterior over bite has been created along with text
book normal occlusion in the posterior segment.
Tooth positioner was fabricated over the setup.
The patient then exercised into the positioner four
hours a day and wore it while sleeping.
Results desired by the set up were achieved in two
weeks.
At that time the exercise wearing was reduced to
three hours a day.
After four months, the patient just wore the
positioner at night as a retainer.

PROCEDURE
The cast is cut using a fretsaw blade to
separate individual teeth.
A horizontal cut is made three mm
apical to gingival margin.
Vertical cuts are made to separate
individual teeth and the individual teeth
are set in desire position using red wax.

USES
1. In visualizing and testing the effect of

complex tooth movements and
extractions on the occlusion.
2. The patient can be motivated by
simulating the various corrective
positions on the cast.
3. Tooth size – arch length discrepancies
can be visualized by means of a setup.

Essix Retainers (1993)
INTRODUCTION
Orthodontists' concept of retention is moving
toward the idea that teeth will move unless retained
indefinitely.
However, permanent retention implies permanent
supervision, and that is where reality clashes with
stability.
An orthodontic practice basically consists of
treatment of active cases, which consume the most
time and generate the most income, and
supervision of retention cases, which takes less
time and produces minimal, if any, income. This
balance has been workable because, in due
course, retention patients either are dismissed with
wishes of good luck or simply fade away.

When permanent retention is emphasized,
the equilibrium is upset.
As an example, if 200 patients per year are
given permanent retainers and seen twice a
year, after 10 years this will add up to 4,000
retention appointments per year. At 10
minutes per visit, that would take up about
three months' worth of appointments.
The cornerstone of Essix permanent retention
is the complete delegation of responsibility to
the patient.

Patient before and after placement of
Essix retainers


Essix retainers have nothing to adjust;
the only thing that could be done on a
recall visit would be to check the
patient's compliance and listen to any
comments.
Telephone supervision is a time-andmoney-saving service to our patients
and is sincerely appreciated.

Current Retainer Designs
Fixed retainers must be systematically
monitored, not only for displacement, but for
hygiene problems that can be induced by the
accumulation of plaque and calculus.
Although well-aligned teeth should be easier
to clean, the presence of a bonded retainer
makes cleaning more difficult.
Removable appliances don't interfere with
hygiene, but are at best only adequate
retention mechanisms.

The Hawley-type retainer, which dates from
the 1920s, was originally used to move teeth,
not for retention.
The retaining component for the anterior
teeth— a point contact of wire on the labial
surface and a mass of acrylic approximating
the lingual cervix— is insufficient.
When the appliance becomes loose, the
mechanical constraints are lessened and the
teeth can shift.
In addition, most of the acrylic simply anchors
wire elements that are not critical to the
essence of retention— the stabilization of the
teeth.

Clear, full-arch, vacuum-formed plastic devices
are only marginally esthetic, are removable, and
are difficult to work with.
As in Hawley-type retainers, the bulk of the
appliance is distal to the cuspids, covering and
retaining posterior teeth.
These buccal sections tend to fracture, make the
appliance bulky, and are usually the cause of
complaints of awkwardness of bite.
The limitations of conventional mechanisms, which
may be adequate for limited retention, explain
some of the dismal results that have been
achieved with permanent retention.
These devices are too bulky or unhygienic for the
long term, and sooner or later the patient's
enthusiasm wanes.

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Essix thermoplastic copolyester retainers change the
rules of permanent retention.
They are a thinner, but stronger, cuspid-to-cuspid version
of the full-arch, vacuum-formed devices.
Advantages include:
The ability to supervise without office visits.
Absolute stability of the anterior teeth.
Durability and ease of cleaning.
Low cost and ease of fabrication.
Minimal bulk and thickness (.015").
The brilliant appearance of the teeth caused by light
reflection.
If compliance with permanent retention is to be achieved,
the orthodontist must provide duplicate retainers. Essix
retainers can be produced in the office for only a few
dollars each, and the cost to the patient, with a replacement
retainer included, is about one-third that of a conventional

Fabrication

Since only the anterior teeth are retained, a
universal perforated plastic tray works well for
both arches.
Vinyl polysiloxane is the impression material of
choice. A combination of the light and heavy
(putty) types is preferred.

Heavy and light vinyl
polysiloxane impression
materials in Universal
perforated plastic tray.
Impression has been cut
distal to cuspids with scalpel.

Pour the impression with a high-quality die
stone that has been mixed in a vacuum
spatulator.
If the undercuts gingival to the contact points
are extreme, creating three-cornered spaces,
they must be reduced to a more normal
contour.
It is imperative that adequate undercuts
remain to insure a positive fit of the
appliance.
Apply a coating of a separating medium
before thermoforming.

A pressure-type thermoforming unit such as a
Biostar is superior to a suction device in recording
the critical interproximal undercuts.
Essix 0.75mm (0.030") thermoplastic copolyester
is mandatory for the fabrication of Essix retainers.
Thinner, 0.5mm material is too flimsy, while
thicker, 1 mm material lacks flexibility.
Copolyester, unlike polycarbonates, does not
require heat treatment before thermoforming.
It is much stronger, clearer, and resistant to
abrasion than acrylic sheet, and thus produces
thinner yet sturdier appliances.
During the thermoforming, the thickness of the
plastic is reduced from .030" to .015".

Store the cast in the patient's model box in case it
is needed for future construction of duplicate
retainers.
Cut the retainer from the plastic sheet and trim the
edges to the proper form with a curved pair of
Mayo scissors.
Essix retainer cut away
from plastic sheet and
trimmed with curved
Mayo scissors


Pay particular attention to these details:
• Do not scallop the labial flange of the retainer to
conform to the cervical line. Extend it 2-3mm into the
labial gingiva, and trim it to make a gentle, continuous
curve.

Labial contour of
upper and lower Essix
retainers


• Trim the lower lingual flange similarly. Trim the
upper lingual flange in a straight line across the
palate, from cuspid to cuspid. If chairside
adjustment is necessary, trim with a scissor, ligature
cutter, or scalpel.

Palatal contour of upper
Essix retainer


• Cut a small space at each cuspid between the
gingival margin and the distogingival edge of the
appliance, allowing the patient to remove the
appliance with a fingernail along the long axis of the
incisors.

Space cut at
distogingival margin of
cuspid to allow removal
of retainer with
fingernail


Appliance Delivery
Essix retainers can be placed the same day
fixed appliances are removed.
The vinyl polysiloxane impression is taken
immediately after debonding.
Minor incisor rotations can be corrected by
altering the cast, since the teeth will be
slightly mobile.
In no case, however, should more than two
days elapse between appliance removal and
retainer delivery.


Furthermore, if the patient does not brux,
the retainers should last for years.
With heavy bruxing, retainers need to be
replaced once or twice a year, but that is
still an attractive alternative to irreversible
dental attrition.
A single-arch Essix retainer should be worn
24 hours a day (except for cleaning) for two
weeks, and then at night only.


If both upper and lower retainers are placed, the
patient should wear the lower during the day and the
upper at night for four weeks, then both at night only.
The material is so thin that accommodation to
speaking and eating is not a problem.
The retainers should be cleaned with a soapy cottontip swab; brushing with toothpaste dulls their
brilliance.
If the patient chews gum, a brand that does not stick
to dental appliances should be recommended.
For caries control, we prescribe a fluoride rinse every
night and a fluoride gel once a week.
The retainers make excellent delivery trays.

Attractive, soft retainer cases can be used instead
of the hard, bulky plastic types, since Essix
retainers are nearly impervious to fracture or
distortion. Soft cases do not interfere with the line
of jeans or business clothes, and the clinician's
address and phone number can be printed on the
cases to aid in recovery if they are lost.

A. Soft cloth Essix retainer case usually preferred by adults.
B. More colorful case preferred by adolescents.

Telephone Supervision
Patients are routinely contacted by phone to
confirm appointments; retention monitoring is
merely an extension of this procedure.
The task can be delegated to a staff member
with a personable telephone manner.
Calls should be made when it is most
convenient for the patient— home or work,
daytime or evening.
Calls can be scheduled 30 days after delivery
of retainers, and every four to six months
thereafter.

Conclusion
Essix retainers have
proven quite versatile.
Their flexibility and
positioner effect make
them an alternative to
spring retainers in
correcting minor tooth
movements.
They can be used to
reduce occlusal forces
Essix retainer placed on upper arch
from the opposing arch to reduce occlusal forces against
lower arch during air-rotor
when moving posterior
stripping mechanics.
teeth with air-rotor
stripping mechanics.

They can serve as a
temporary bridge for a
missing anterior tooth,
when thermoformed over
a pontic placed in the
edentulous space on the
cast.
They can also act as
night guards for bruxism
and as bite planes-to
relieve bracket
impingement until the
bite can be opened.

The use of Essix retainers, in
combination with telephone monitoring,
opens the way to a practical, patientfriendly method of true permanent
retention.


ACTIVE TOOTH MOVEMENT WITH
ESSIX BASED APPLIANCE
Sheridan has described two methods
for moving teeth.
One, by the use of windows and divots
whereby minor tooth malalignments,
such as bucco-lingual and mesio-distal
malpositions and rotations. (JCO 1994)
Secondly, with the help of
thermosealing. (JCO 1995)

Trimmed working cast
for thermoforming Essix
retainer.

Cutting window in
thermoformed
appliance with
acrylic bur
Finishing window
border with scalpel


The Divoter:
precision
thermoforming tool

Heating shaft of Divoter

Monitoring inside of
appliance for divot depth

Removing residual plastic
debris from heating shaft
prior to use

A. Incisal placement of divot produces
more tipping.
B. Gingival placement produces more
bodily movement

A. Distal placement of divot produces
mesial rotation.
B. Mesial placement produces distal
rotation.

Mesial contact point of lateral
incisor locked within Essix
appliance while divot induces
facial rotation of out-of-line distal
surface.

Divot-induced moments create torquing
couple

Incisal cap produces pure
root torque

Case 1.
A. Incisor alignment
before treatment.
B. After four months
of wearing Essix
appliance with
successive 1mm
divots.


Case 2.
A. Incisor alignment
after debonding.
B. After two weeks of
Essix appliance
with 1mm divot to
align lower right
lateral incisor.


By thermosealing we can selectively
increase the thickness of the appliance
either anteriorly or posteriorly by
incorporating layer of composite or light
cure acrylic between two sheet of the
Essix plastic.
By thermosealing we can use Essix
appliance as a bite plane, habit
breaking appliance, molar uprighting
appliance or space maintainer.

A. Essix plastic sheets with light-cured
acrylic between them.
B. Plastic sheets thermosealed to
encapsulate acrylic layer

Full-arch working cast made to Essix
standards

Base sheet with center section and
peripheral excess cut away

Prying distal ends of base appliance
with thin-bladed instrument to remove
it from cast

Anterior section of base appliance cut away,
and remainder of appliance replaced on cast

Bead of light-cured acrylic applied to
palatal area of base appliance

Heat Gun used to prepare base appliance
for second thermosealing

Base and second plastic sheets
thermosealed with light-cured acrylic
between them

Bulk of plastic cut away with acrylic disk


Finished "full Essix" appliance after
trimming

Barrier wire tacked to base appliance


Light-cured acrylic placed in palatal
area and covering base of wire barrier

Finished habit appliance after trimming


Active element of uprighting spring
tacked to cast with composite.
Retentive element of spring placed on
base appliance

Palatal acrylic covering
retentive element of
uprighting spring

Finished molar uprighting
appliance after trimming

Thermosealed rigid plastic bar between
two abutment teeth


Finished space maintainer after trimming


Finished bite plane after trimming


Drs. Rinchuse and Rinchuse
successfully used Essix based
appliance to carry out active tooth
movements for correcting single tooth
anterior cross bite and lingually
displaced canine (using finger springs),
and aligning ectopically positioned
canine (using bonded bracket, metal
attachments to the appliance and
various elastics) and for expansion of
maxilla (using a hybrid Essix-nickel
titanium removable palatal expander).

INVISALIGN IN A NUTSHELL
Align Technology, Inc. developed Invisalign
appliance for orthodontic tooth movement in
the USA in 1998.
This appliance was the first orthodontic
treatment method to be based solely on 3-D
digital technology.
Through the use of computer programmes
that can manipulate 3-D images of individual
malocclusions, a series of algorithmic stages
is produced which can move the teeth in a
series of precise movements (0.15 – 0.25
mm), or stages.

Invisalign braces are a new revolutionary
way to straighten teeth without metal.
A series of clear, removable aligners are used
to gradually straighten teeth, without metal or
wires.
Aligners are made of clear, strong medical
grade plastic that is virtually invisible when
worn.
Aligners look similar to clear tooth-whitening
trays, but are custom-made for a better fit to
move teeth.
Some dentists have referred to Invisalign
braces as "contact lenses for teeth."

MECHANISM OF ACTION
Like brackets and archwires, Invisalign
braces move teeth through the appropriate
placement of controlled force on the teeth.
The principal difference is that Invisalign
braces not only control forces, but also
control the timing of the force application.
At each stage, only certain teeth are allowed
to move, and these movements are
determined by the orthodontic treatment plan
for that particular stage.
This results in an efficient force delivery
system.

HOW DOES INVISALIGN WORK?
You wear each set of aligners for about 2 weeks,
removing them only to eat, drink, brush, and floss.
As you replace each aligner with the next in the
series, your teeth will move – little by little, week
by week – until they have straightened to the final
position your dentist has prescribed.
You’ll visit your dentist about once every 6 weeks
to ensure that your treatment is progressing as
planned.
Total treatment time averages 9-15 months and
the average number of aligners worn during
treatment is between 18 and 30, but both will vary
from case to case.

INVISALIGN IN DETAIL
For each patient, the orthodontist
submits a set of polyvinyl siloxane
impressions, a centric occlusion bite
registration, a panoramic radiograph, a
lateral cephalometric radiograph, and
photographs to Align Technology.


Vinyl polysiloxane,
- considered the most accurate of impression
materials,
- has excellent elastic recovery,
- minimal permanent deformation, and
- superior tear strength.
Impressions can be stored for as long as a
week without significant loss of accuracy and
can be disinfected and repoured multiple
times.
The material is available in several viscosities
that bond to one another, allowing flexibility in
impression technique.

The impressions are poured up in
dental plaster and then placed in a tray
and encased with epoxy and urethane.
The tray is placed into a destructive
scanner; the scanner’s rotating blade
makes numerous passes over the
epoxy-encased models, removing a thin
layer with each pass.

DESTRUCTIVE SCANNER


A computer linked
with the scanner
then assembles the
scanned information
to create a 3dimensional
rendering of the
models.


After the bite has been established, the
Invisalign virtual orthodontic technician (VOT)
uses software to “cut” the virtual models and
separate the teeth, allowing them to be
moved individually.
A virtual gingiva is placed along the gingival
line of the clinical crown to serve as the
margin for the manufacturing of the aligners.


Cutters separate teeth

Placement of virtual gingiva


The orthodontist’s prescription is followed in
positioning the teeth and the bite to proper
alignment virtually on the computer with the
company’s Treat software (Align Technology,
Santa Clara, Calif).
Once the final setup has been done, tooth
movements are staged so that there are no
occlusal and interproximal interferences, and
the velocity of the movements is within the
criteria set by the company.
The number of stages necessary depends on
the amount and complexity of the movement.
The VOT can now send the data to the
referring orthodontist so that he or she can
check the proposed treatment (referred to as
ClinCheck) onwww.indiandentalacademy.com
the Invisalign Web site.

When the orthodontist has approved the
treatment plan, the aligners will be
manufactured so that the movements seen
on the computer screen can be transferred
clinically to the patient.
The computer images are converted to
physical models by using a process called
stereolithography.
These models are then used to fabricate the
aligners on a Biostar pressure molding
machine (Great Lakes Orthodontic Products,
Tonawanda, NY).

Stereolithography
machines

Stereolithography
models


Aligners

Align Technology engineers have formulated
a proprietary material for use in the aligners.
The aligners are trimmed and laser-etched
with the patient’s initials, case number,
aligner number, and arch (upper or lower).
They are then disinfected, packaged, and
shipped to the doctor’s office.
The entire process of making the Invisalign
aligners is a marvel of modern technology.
Without the aid of computers and
technologically advanced machinery, it would
be impossible to fabricate aligners in such
large numbers and with such great accuracy.

Fabricating these aligners in an orthodontic
office would be a very time-consuming and
labor-intensive process that probably would
not be practical for everyday treatment.
The Invisalign technique gives patients an
esthetic choice in their orthodontic treatment
that all orthodontists can easily implement in
their offices.


RETENTION & STABILITY
At present, retention protocol with this
appliance is similar to that used with
other types of appliances.
Usually the final appliance or a thicker
version (0.04 inch) of it is worn full time
for six months, followed by night time
wear indefinitely.


ADVANTAGES
1. You can straighten your teeth without

anyone knowing.
2. An Invisalign patient can eat and drink
anything while being treated along with
being able to brush and floss normally to
maintain good oral hygiene. This is not
possible while wearing traditional braces.
3. Another advantage is that the teeth can be
bleached with the appliance at the
beginning of, and during treatment.

4. Invisalign braces are comfortable.
There are no metal brackets or wires
to cause mouth irritation.
5. No metal or wires also means you
spend less time in the doctor's chair
getting adjustments and in some
cases a patient only needs to see the
dentist half as often as with traditional
braces.

DISADVANTAGES
1. Only relatively small magnitudes of change are

possible because of the technical difficulty of evenly
dividing larger overall movements into small precise
stages manually.
2. Most people experience temporary, minor
discomfort for a few days at the beginning of each
new stage of treatment. This is normal and is
typically described as a feeling of pressure. It is a
sign that the Invisalign braces are working sequentially moving your teeth to their final
destination. This discomfort typically goes away a
couple of days after you insert the new Aligner in the
series.

3. Like all orthodontic treatments, Invisalign
braces may temporarily affect the speech of
some people, and you may have a slight lisp
for a day or two. However, as your tongue
gets used to having Aligners in your mouth,
any lisp or minor speech impediment caused
by the Aligners should disappear.
4. Open bite.


SUMMARY
A new system of orthodontic tooth
movement using established methods
for minor correction to achieve greater
magnitudes of correction has been
introduced.
The major advantage of the system is
the esthetic, hygiene, low discomfort
and removable nature of the appliance.

The current limitations are in terms of case
selection, increased cost, experience
required for computer treatment planning,
difficulty obtaining certain tooth
movements, and the lack of potential in
teeth involving mixed dentition or impacted
teeth.
The clinician must have an in-depth
understanding of biomechanics, biology,
periodontal concerns, and optimal
therapeutic occlusion achieved during
orthodontic treatment to successfully plan
and use this appliance.

In future, we may see the replacement of
PVS impressions with emerging intraoral
scanning devices and the recording of
treatment changes or modifications
immediately in a digital format.
Adding the other 3 D compartments
(skeletal, facial, jaw movement and
animation to the surface map of the teeth)
will greatly enhance the diagnostic and
treatment capabilities of this new appliance.

Thank you
For more details please visit


Invisalign /certified fixed orthodontic courses by Indian dental academy

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