Seminar clear aligner 1

Clear aligner Treatment
•By Hardik lalakiya
•3rd year P.G

contents
 Introduction
 Advantages
 Brief history of clear aligner treatment
 Impression techniques and digitization
 what is Clin check software ?
 Smart Force features
and Attachments

 Biomechanics
 Clear Collection instruments for clear aligner treatments
 A Clinical Case Treated with Clear Aligners
 Accelerated Extraction Treatment
with Invisalign
 Periodontal considerations
 Summary

Introduction
• Clear Aligners are an alternative to traditional braces and
are designed to help guide teeth into their proper position.
• Similar to braces, clear aligners use a gradual force to
control tooth movement, but without metal wires or
brackets.
• The aligners are made of a strong plastic material and are
fabricated to fit each person's mouth. If a series of aligners
are made, each aligner moves the teeth a little bit more into
place until the desired movement is completed.

• Aligners are worn for at least 20 hours a day to reach the
desired maximum effectiveness.
• Each aligner is worn for three weeks before changing to
the next one. The length of treatment with aligners
depends upon the severity of each case.
• Typically, aligner treatment can be as short as three
weeks or as long as six months. Still, a much shorter
treatment than traditional braces.

• Each aligner is designed to move the teeth a maximum of
about 0.25 to 0.3 mm over a 2-week period, and is worn
in a specific sequence.
• The Invisalign appliance is currently recommended for
adults and for adolescents with fully erupted permanent
teeth who meet an acceptable standard of compliance.
• Excellent compliance is mandatory since the appliance
has to be worn a minimum of 20 to 22 hours a day and
each aligner should be worn 400 hours to be effective.

• Scheau et al proposed the first thermoforming machine to synthesize
orthodontic appliances in 1966.
• Currently 2 types of thermoforming machines ,The Ministar and Biostar
(scheau Dental)

Advantages
• Clear aligners are removable so it is easier for you to
brush and floss after meals.
• Clear aligners are easier to keep clean.
• Clear aligners are comfortable and less likely to irritate
your gums and cheeks.
• Clear aligners can prevent tooth wear from grinding.

Brief history of clear aligner treatment
• Clear aligner treatment falls into
• ESSIX RETAINER INVISALIGN

• The first category consists of thermoformed appliances
sometimes known as ESSIX RETAINERS.
• This are fabricated by making adjustments to the tooth
positions on plaster or stone models and fabricating one
or more aligners to correct a minor malocclusion.
• The second category is Invisalign is a proprietary
orthodontic technique that uses a series of computer
generated custom plastic aligners to gradually guide the
teeth into proper alignment.
• It is both a brand name and a technique and is used
synonymously.

• Invisalign is the only computer aided design and
manufacturing (CAD – CAM) Precision aligner product
available in united states.
• The company and the technique was the brainchild of
two graduate business student at Stanford university –
1997,Kelsey Wirth and Zia Chishti.

Impression techniques and digitization
• Invisalign impression trays are available in various
sizes to accommodate all patients and can be ordered
online for free from Invisalign.
• Specifically designed for Invisalign treatment planning,
the Invisalign trays fit uniquely in the digital scanners
that “read” the impressions.
• Invisalign scanners read only vinylpoly siloxane (VPS)
material, so it is imperative that other materials (e.g.,
alginate alternatives, polyether materials) not be used.

• Ideal impression material systems (e.g. Flexitime,
Heraeus Kulzer) include putty and light wash materials,
a combination that captures the details necessary for
creating Invisalign aligners.
• Such details include all margins and anatomical
landmarks. Additionally, these materials set easier and
avoid running and slumping.

Scanned impressions of upper and lower arches
and bite index in 3D

Digitization
• The Virtual Setup
• After the impression arrives at Align Technology in
Santa Clara ,California they are scanned using an
industrial CT scan to produce a 3D Virtual model.
• Once the Virtual models are produced they are
segmented using boundary recognition software to
define individual teeth.
• Once the interproximal surfaces of the teeth are
assessed and virtual roots are placed and lastly the
gingival margin also created using morphing type
software.

• The preparation work is finished and than submitted
to TREAT ( Align Technology Inc).
• It is a Proprietary software that align technology
uses to simulate treatment and set the virtual model
to allow the manufacture of the aligners.
• Once the virtual model is completed and approved
by the orthodontist , a series of plastic models is
fabricated using stereolithography on which the
aligners are then made by thermoforming process.

Bite registration converted to 3D models

Clin Check
• The software used by the
orthodontist in the office is called
clin check.
• It allows the orthodontist to view the
treatment in all the aspects as well as
superimpose one stage of treatment
over another to visualize individual
tooth movements so as to gauge the
probability of accomplishing the
desired movement that will be
biologically feasible.

Attachments
• The New Attachment Protocol allows for attachments to be
passive or active. Passive attachments are for aligner retention
and anchorage for intrusion.
• Active attachments are used for rotations of rounded teeth,
extrusion and root correction. Currently Align Technology has
three types of attachments for commercial use: the ellipsoid,
rectangular and the beveled attachment.

• Ellipsoid attachments are often placed horizontally and are the
default for anterior tooth extrusions.
• They are 1mm in thickness and placed between the cervical and
middle third of the tooth.

• Vertical rectangular attachments as seen in are the default for rotations of
canines and premolars.
• In addition, these attachments are used for root control on teeth adjacent to
extraction spaces. For premolar extraction cases, the default is placement of
two rectangular attachments distal to the space and one mesial to the
extraction space.
• Typically these attachments are 1mm thick, 2mm wide and either 3, 4 or 5
mm long.

• The vertical rectangular attachments are very retentive, so take
care when placing multiple attachments in one quadrant. The
aligner can become too retentive for patient convenience. An
interesting option is the beveled attachment for rotations.
• Sometimes the rectangular attachments don’t ﬁ t perfectly and
during rotation can put unintended forces on the tooth, resulting
in side effects. Beveling the attachment can ease the ﬁ t and
make the attachment “active,” causing rotation.

Smart Force features
and Attachments.
Designed to help you treat with confidence.
SmartForce Features are:
Engineered to deliver the force systems necessary to achieve more
predictable tooth movements.
Customised to each tooth using advanced virtual modeling, including such
features as the width, long axis, and contour of the entire tooth.
Positioned more precisely to deliver the necessary forces while eliminating
interferences. automatically placed in accordance to the desired movement.

• IT CAN BE USED FOR
• For diagnosis and treatment planning evaluate the need for
IPR, Expansion, Extraction, Distalization or proclination.
• For verifying that technician has performed modifications.
• As a consultation device to show treatment limits to patient
• For verifying if aligner is tracking.
• Indian journal of Dental Sciences June 2011 Issue 2,Vol 3

Biomechanics
• “ The use of aligners is far more complicated than most people believe
.It takes a knowledgeable clinician with considerable experience to use
the appliance to its maximum. What that maximum is I don’t know”
• In order to determine just what that maximum height be
with invisalign in its current rendition of aligner
materials , we must examine the biomechanics of tooth
movement with invisalign.

• Aligner Bio-Mechanics!
• By: Dr Willy Dayan
• Willy Dayan's Golden Rules of lnvisalign Bio-mechanics
1) Think Like Plastic and Feel Like a Tooth: lnvisalign is a
removable
• appliance and thus cannot glue to teeth in order to "pull" them;
the aligner can only "push" on surfaces of the teeth or surfaces
of attachments. When a force is placed upon at tooth, it will
move according to biomechanical principles that exist, no matter
what the computer screen shows.

2) The Clincheck Video is not Teeth Moving: Stop watching the
• ClinCheck movements as "moving teeth"! Think of the images as
representing the anatomy of the "changing inner aligner
surfaces", and then analyze the resulting forces the aligner will
exert upon the teeth.
www.orthoclined.com
www.orthocoaching.com
drwillydayan@gmail.com

Controlling Torque
• A net force of 40gm (base level force of an aligner after 48hrs)
intended to move the teeth lingually would require the moment
of 320 to 400g-mm (M/F ratio- 8/10) for bodily movement or
greater than 400gmm for lingual root movement.
• Improper attachment design or placement allows the delivery of
only 280g-mm moment in conjuction with 40g force resulting in
controlled lingual crown tipping .
• It must be kept in mind that the aligner provides the same level
of force on both sides of the teeth,even though the forces may be
in opposite direction .

• This means that in the absence of spaces to close, Just as with
fixed appliances, There must be some outside force system such
as interarch elastics to provide a net distalizing force on the
maxillary anterior teeth to produce lingual root movement.
• There is an inherent problem with rectangular attachments,
because it is difficult for the patient to insert and remove the
aligners.
• If the attachment and the aligner are not completely coupled then
the result is an unwanted force system and unpredictable tooth
movement.

• In order to facilitate greater ease of insertion and removal as well
as eliminate the all or none situation the beveled attachment was
developed by rotating a portion of the rectangular attachment
virtually into tooth surface. ( see fig)

• The beveled attachment can be utilized in multiple orientations
simply by having the technician rotate the attachment in a
different manner.
• There are theories that rotating the bevel in a specific directions
will enhance specific movements.
• An alternative to the attachments that help facilitate torque
control is the power ridges. These are engineered corrugations
placed at specific locations to enhance the undercut near the
gingival margin of teeth undergoing torqueing movements.

• The ridge function in two ways . The first is to stiffen the gingival
third of the aligner to make it more resilient .
• The other is to provide additional force as close to the gingival
margin as possible to increase the effective moment arm of the
aligner .
• The obvious advantage to power ridges is that attachment need
not be placed or removed and they are more esthetically
acceptable to the patient.

Root parallelism
• Another aspect of biomechanics especially pertinent to extraction
treatment is to control tipping in order to achieve root parallelism.
• An idea dating back to the late 1800s was to place an attachment
on the gingival aspect of a bracket extending toward the center of
resistance in an attempt to decrease the amount of tipping when
teeth are moved mesiodistally.
• These gingival extensions are often described as power arms, they
are added to the force system with invisalign in an attempt to alter
the force- moment system.

• It accomplishes two things, first it moves the application of force
closer to the center of resistance, second it creates a secondary
moment due to presence against the distal of the aligner.
• Unfortunately, often canines remain upright during retraction into
premolar spaces, while the molars especially maxillary molars
tend to tip mesially.
• This is frequently referred to as dumping. It also occurs when the
molars are simply being used as anchorage for anterior retraction.
This is probably caused by the undesirable crown to root ratio
combined with the large root surface area over which the forces
are distributed.

• Work is currently being done with various attachment designs, to
demonstrate the ability to predictably avoid molar dumping by
placing two 2mm*2mm*2mm attachments on the upper first or
second molar as shown in the fig

Rotations
• Correcting rotations with aligner can be problematic.
• There are primary reasons for this.
• 1) first is that aligners produce tooth movement by the plastic
being slightly distorted and then elastically rebounding back to
the predetermined shape and carrying the tooth with it.
• Even with the properly designed attachment ,another problem
with rotations is that the tooth root is not a cylinder, and because
of dilacerations and root surface variations, there is no way the
computer software can adequately estimate the true rotational
long axis.

• For this reason we need to use auxiliaries either before ,during or
after aligner treatment in order to accomplish the rotational
correction.

Extrusions
• Extrusion can also present problems with the aligners. The
reasons for this is similar to that of rotations.
• One method being used to overcome this problem with some
promising results is to use the gingivally beveled attachment to
provide a longer surface that can be elastically deformed and
provide an extrusive force on the tooth.

• Other auxiliaries can be used to facilitate specific movements.
Class II and class III elastics are frequently needed just as they are
with fixed appliances.
• One can either attach the elastics directly to the aligner or attach
elastics to buttons bonded to the teeth.

• Keep in mind that if the elastics are directly attached to
the aligner, then attachments are generally required to
prevent displacement of the aligner.
• Toe nail clippers can be used to cut slits in the aligners
for elastic placement.
• They have the advantage of producing a slit that is both
contoured to the papillary embrasure form and that has
a blunt apex to the slit does not tend to propagate and
split the aligner.

• Mini screws can also be used effectively with the aligners in the
same manners as they can with fixed appliances, either planned
initially as part of the treatment or to help with movements that
are not progressing as desired.
• H highly placed
• canine

• Another vertical movement that is easily enhanced with mini
screws is the intrusion of molars that have supra erupted into an
edentulous space.

Clear Collection instruments for clear aligner
treatments
• The Tear Drop
• The Tear Drop pliers is an instrument created for the purpose of
adding a notch or hook at the gingival margin of clear aligners.
• A standardized notch is easily cut in a single step, creating a
teardrop-shaped “reservoir” to hold the elastic on the tray ,
thereby making it easier for the patients to seat their aligner and
connect their elastics.

Hu-Friedy’s Clear Collection of instruments
designed to enhance clear aligner treatment
Orthodontic Practice US Volume 6 Numbers 3 & 4

Teardrop-shaped hooks retain elastics when aligners are seated, making the
addition of “rubber bands” easier for patients to manipulate. Notches are
made at an angle to resist forces applied by the elastics

The Hole Punch
• The Hole Punch is used to cut a half-moon shaped hole at the
gingival margin of aligners.
• These half-circle cuts permit the addition of bonded buttons,
bonded orthodontic tubes or brackets with associated hooks, or
are simply used to relieve impingement of plastic on soft tissue.

Class I intramaxillary elastics connected from teardrop hook to a miniscrew (i.e., to support molar
distalization) plus Class II intermaxillary elastics from teardrop notch to bonded button.. Intermaxillary
elastics hookedto bonded buttons to assist with seating of teeth into aligners and improve occlusion

The Hole Punch pliers can be used to
relieve plastic impingement of gingival tissues anywhere
along the aligners (e.g., incisive papilla irritation

Bootstrap mechanics
• If certain teeth are not “tracking” or are lagging behind (i.e., not
fitting into the tray; Aligner Chewies™ are employed (Chewies™
Aligner Tray Seaters, Dentsply Raintree Essix, York, Pennsylvania).
Patients are asked to hold the Chewie between the teeth in
question and squeeze 10-15 seconds, release, and repeat for 5
minutes, 2-3 times per day.

Aligner “lag” or lost tracking is most often characterized as an “air gap”
between the incisal or occlusal of teeth and the plastic, indicating teeth
are not following the prescribed tooth movement

Aligner Chewies are held tightly been specific “lagging” teeth for 10-15
seconds. This process is repeated for 5 minutes, 2-3 times daily, especially
when changing to a new pair of aligner trays

Bootstrap mechanicsto forcibly erupt a “lagging” tooth using
orthodontic elastics . The Hole Punch is employed to clear aligner
plastic to permit the addition of bonded buttons. The Tear Drop is
used to cut notches in mesial and distal embrasures

The Vertical
• The Vertical is used to produce an indentation at the mesial or
distal of a specific tooth in the facial and/or lingual aspects of the
aligner plastic.
• These indentations are made without heating the pliers and at a
very shallow depth so as to not compromise the integrity of the
plastic.

The Vertical pliers are used to accent rotational tooth movement.

The shallow indentations are produced without heating the pliers,
producing “contact points”
to assist with rotational
couples, including situations with composite “attachments”
, enhancing molar distalization , or root paralleling

The Horizontal
• There are instances where we would like to accentuate root
torque for specific teeth during clear aligner treatment.
• In other instances, there is a need to increase the retentiveness
of aligners or clear retainers. The Horizontal is an instrument
designed to accent labial or lingual torque for individual teeth,
and it can also be used to simply increase the retentiveness of
clear aligners or retainers.

In addition, the Horizontal is used to reduce “lag” by
accenting extrusive or intrusive movement by applying
contact points immediately adjacent to composite
attachments

A Clinical Case Treated with Clear Aligners
• Clinical Case
• A 26-year-old female presented with a Class I malocclusion and
an orthognathic profile. She was in the permanent dentition with
retroclined maxillary central incisors, moderate overbite, spacing
distal to the maxillary canines and mild crowding in the
mandibular arch Her primary concern was the alignment of her
maxillary incisors and she refused to have fixed appliances. The
treatment objectives using Invisalign® were to align her front
teeth, close space in the maxillary arch and alleviate crowding in
the mandibular arch
IJO  VOL. 22  NO. 2  SUMMER 2011

• Invisalign® treatment involved 24 upper and 10 lower aligners.
Attachments were placed on several teeth to achieve a more
predictable tooth movement using aligners. The patient wanted
to reduce treatment time as much as possible and was instructed
to change the aligners every 10 days instead of 14 days.
• After 8 months of initial treatment, a Case Refinement with 7
more aligners was needed to finish the maxillary arch. Once
treatment was completed (Figure 7), a bonded lingual fixed
retainer was placed on the maxillary incisors to prevent relapse

• The aligners have demonstrated excellent results in anterior
alignment and good improvement in occlusion, transverse
relationships and overbite correction.
• It is also possible to notice a reasonable improvement in midline
position and overjet.17-18 Invisalign® can be quite effective in
correcting deep bites and mild crossbites by facilitating anterior
intrusion while disocluding the posterior teeth.
• Patients with bruxism are good candidates for this treatment, as the
aligners prevent occlusal wear and reduce pain in facial muscles and
joints. Patients with extensive restorations and/or prostheses can
benefit as well, as bonding orthodontic accessories can be more
difficult

Pre - treatment
Post - treatment

Accelerated Extraction Treatment
with Invisalign
• This 26-year-old female expressed a desire to correct her
maxillary anterior crowding and improve the esthetic appearance
of her smile. The patient’s facial profile was straight, but both lips
were slightly recessive with regard to the E-line.
• Intraoral examination showed a Class II molar relationship with a
3mm overjet, a 1mm overbite, and coincident midlines. The arch
length discrepancy was 13mm in the maxilla and 10mm in the
mandible. We noted infralabioversion of both upper canines

• Aligners are not only esthetically pleasing to adult patients but,
because they are easily removed, extremely safe. In the future,
aligners are likely be used in even more complex cases involving
rotations, deep overbites, open bites, and unusual extractions.
• Further clinical investigations are needed into the effects of
accelerated tooth movement in such cases.

Periodontal considerations
• There is a body of evidence growing that orthodontic treatment
with aligners has less detrimental periodontal impact than that of
fixed appliances.
• Miethke and Vogt and Miethke and Brauner compared the
periodontal health of the patients who underwent the treatment
with aligners to that of patients who underwent treatment with
both labial and lingual fixed appliances
• Boyd found that periodontal health could actually improve during
the course of the treatment.

Summary
• Not all malocclusions are amenable to treatment solely with the
invisalign system.
• Treatment of many malocclusions with proper tip ,torque, arch form
and aesthetic crown inclination is possible to achieve with aligners.

References
• 1) orthodontics current principles and techniques – Graber,
Varnsdall,Vig
• 2) Invisalign – Emperor’s New cloth – Indian journal of dental
sciences june 2011 ;2;3
• 3) INVISALIGN INSTRUCTION MANUAL – McGill University
• 4) Aligner Bio-Mechanics - ORTHODONTIC CLINICAL
• EDUCATION CORP.

• 5) Invisalign ClinCheck 3.0 User Guide
• 6) Invisalign Orthodontic Treatment - Richard Bouchez
• 7) Clear Collection instruments for clear aligner treatments -
• 8) Smart Force features and Attachments – Invisalign.

Seminar clear aligner 1

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