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Indian Dental Academy: will be one of the most relevant and exciting training center with best faculty and flexible training programs for dental professionals who wish to advance in their dental practice,Offers certified courses in Dental implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic Dentistry, Periodontics and General Dentistry.
- Current Retainer Designs
- Appliance Delivery
- Telephone Supervision
Active Tooth Movement With Essix Based
- In a Nutshell
- Mechanism of Action
- In Detail
- Retention and Stability
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
However, movements are limited to 2 to 3 mm;
beyond this range, another impression and a new
appliance are needed.www.indiandentalacademy.com
Align Technology, Inc (Santa Clara, Calif),
in-troduced the Invisalign system several
Invisalign takes the principles of Kesling,
Nahoum, others, and Raintree Essix even
further, using computer-aided-design–
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
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
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
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
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
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
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
One must be realistic for the correction to be
The positioner can achieve the perfection
possible in the set up only when that perfection
has been approached in the mouth with
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
At that time the exercise wearing was reduced to
three hours a day.
After four months, the patient just wore thewww.indiandentalacademy.com
The cast is cut using a fretsaw blade to separate
A horizontal cut is made three mm apical to
Vertical cuts are made to separate individual
teeth and the individual teeth are set in desire
position using red wax.
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.
Orthodontists' concept of retention is moving
toward the idea that teeth will move unless
However, permanent retention implies permanent
supervision, and that is where reality clashes with
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.www.indiandentalacademy.com
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.
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-and-money-
saving service to our patients and is sincerely
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
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
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
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.
• 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
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
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
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
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
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".www.indiandentalacademy.com
Store the cast in the patient's model box in case it
is needed for future construction of duplicate
Cut the retainer from the plastic sheet and trim
the edges to the proper form with a curved pair
of 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,
• 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.
• 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
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
In no case, however, should more than two
days elapse between appliance removal and
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
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
The material is so thin that accommodation to
speaking and eating is not a problem.
The retainers should be cleaned with a soapy
cotton-tip swab; brushing with toothpaste dulls
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.
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
Essix retainers have
proven quite versatile.
Their flexibility and
positioner effect make
them an alternative to
spring retainers in
They can be used to
reduce occlusal forces
from the opposing
arch when moving
posterior teeth with
Essix retainer placed on upper arch
to reduce occlusal forces against
lower arch during air-rotor
They can serve as a
temporary bridge for a
missing anterior tooth,
over a pontic placed in
the edentulous space
on the cast.
They can also act as
night guards for
bruxism and as bite
until the bite can be
The use of Essix retainers, in combination
with telephone monitoring, opens the way
to a practical, patient-friendly method of
true permanent retention.
Sheridan has described two methods for
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
Trimmed working cast
for thermoforming Essix
border with scalpel
Cutting window in
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
B. Gingival placement produces more
A. Distal placement of divot produces
B. Mesial placement produces distal
Mesial contact point of lateral
incisor locked within Essix
appliance while divot induces
facial rotation of out-of-line distal
Incisal cap produces pure
A. Incisor alignment
B. After four months
of wearing Essix
A. Incisor alignment
B. After two weeks of
with 1mm divot to
align lower right
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
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
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
Bulk of plastic cut away with acrylic disk
Finished "full Essix" appliance after
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
Palatal acrylic covering
retentive element of
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
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
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
Aligners are made of clear, strong medical
grade plastic that is virtually invisible when
Aligners look similar to clear tooth-whitening
trays, but are custom-made for a better fit to
Some dentists have referred to Invisalign
braces as "contact lenses for teeth."
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
You wear each set of aligners for about 2 weeks,
removing them only to eat, drink, brush, and
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.www.indiandentalacademy.com
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.
- considered the most accurate of impression
- 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
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.
A computer linked
with the scanner
then assembles the
create a 3-
rendering of the
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
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
The VOT can now send the data to the
referring orthodontist so that he or she can
check the proposed treatment (referred to aswww.indiandentalacademy.com
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
These models are then used to fabricate the
aligners on a Biostar pressure molding
machine (Great Lakes Orthodontic Products,
Align Technology engineers have
formulated a proprietary material for use in
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
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
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
1. You can straighten your teeth without anyone
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
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
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.
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
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.
A new system of orthodontic tooth movement
using established methods for minor correction
to achieve greater magnitudes of correction has
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
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