This document provides an overview of clear aligners. It discusses the advantages of aligners over traditional braces, the history and fabrication process. It describes ClinCheck software for treatment planning and attachments that can be used. Biomechanics of tooth movement with aligners is covered, along with some clinical cases. Instruments for adding elastics or relieving pressure from aligners are presented. In summary, the document is a comprehensive guide to clear aligner therapy.

1. Aligners
Presented By:
Dr. Anil Kumar Godara
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2. Contents
 Introduction
 Advantages
 History of clear aligner treatment
 Fabrication of clear aligner
 what is Clin check software ?
 Smart Force features and Attachments
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3.  Biomechanics
 Clear Collection instruments for clear aligner treatments
 A Clinical Case Treated with Clear Aligners
 Accelerated Extraction Treatment with Invisalign
 Periodontal considerations
 Conclusion
 References
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4. Introduction
• Aligners are an alternative to traditional braces and are designed to help guide
teeth into their proper position.
• Similar to braces, 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.
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5. • Each aligner is worn for two to 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.
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6. • 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)
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7. Advantages
• Aligners are removable so it is easier to brush and floss after meals.
• Aligners are easier to keep clean.
• Aligners are comfortable and less likely to irritate gums and cheeks.
• Aligners can prevent tooth wear from grinding.
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8. History of clear aligner treatment
• Clear aligner treatment falls into
• ESSIX RETAINER INVISALIGN
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9. • 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 computer aided design and manufacturing (CAD – CAM) Precision
aligner product.
• The company and the technique was the brainchild of two graduate business
student at Stanford university – 1997,Kelsey Wirth and Zia Chishti.
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10. Fabrication of clear Aligners
Clear aligners are virtually invisible, made from thermoplastic material
developed in such a fashion to achieve desired results. They are custom-
made trays, worn in a sequential manner to successfully achieve treatment
outcome.
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There are a few steps to fabricate
•Clinical steps
1.Impressions
2.Images
3.X- rays.
•Laboratory steps
1.Scans
2.3D models
3.Aligners
4.Quality check

11. • PVS impressions (Polyvinyl siloxane) with a light body for
the margin as aligners are custom -made – as aligner
snuggly fits the tooth surface to apply active forces for
tooth movement. Other substitutes for impressions are
intraoral scans.
• Dental impressions are scanned in order to create a
digital 3D representation of the teeth
• Technicians move the teeth to the desired location with
the program Treat, which creates the stages between
the current and desired teeth positions.
• Anywhere from six to forty-eight aligners may be
needed. Each aligner moves teeth .25 to .33 millimeters.
IMPRESSIONS 11

12. IMAGES
• It is very important to help to plan and
understand the treatment plan. It is
important to record both extra-oral
and intraoral images of the patient.
• The orthodontic treatment is a
comprehensive treatment plan not
only skeletal and dental but also, soft
tissue.
• Your lips, nose, chin and other facial
structures contribute while planning
treatment.
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13. X -RAYS
An important tool to help determine the number of teeth,
there roots positioning and more.
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14. CLEAR ALIGNERS LABORATORY PROCEDURE
• It is simple yet very precise and planned step.
• The impressions/ scans are prepared to achieve a replica of your teeth.
Once the scans are ready.
• The three – dimensional models are prepared.
• Virtual set up is prepared to show the planned treatment result in the end.
• This gives an edge to clear aligner therapy compared to traditional
orthodontic treatment.
• The models are checked, and your trays are prepared.
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15. • A computer graphic representation of the projected teeth movements, created
in the software program ClinCheck, is provided to the doctor for approval or
modification before aligners are manufactured.
• The aligners are modeled using CAD-CAM (computer-aided-design and
computer-aided-manufacturing) software and manufactured using a rapid
prototyping technique called stereolithography.
• The molds for the aligners are built in layers using a photo-sensitive liquid resin
that cures into a hard plastic when exposed to a laser.
• The aligners are made from an elastic thermoplastic material that applies
pressure to the teeth to move into the aligner's position.
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16. 3-D MODELS
• 3D models are prepared using 3d printing which is built in layers using a light-
sensitive liquified resin which solidifies when exposed to the laser. The
models are prepared then the thermoplastic trays are compressed to achieve
the desired shape, snuggly fitting the model. These trays are called aligners
which move teeth to the desired position.
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17. GingivalContouring 17

18. ClinCheck
• 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.
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19. 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.
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20. • 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.
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21. • 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.
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22. • The vertical rectangular attachments are very retentive, so care should be taken
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 fit perfectly and during rotation can put
unintended forces on the tooth, resulting in side effects. Beveling the attachment can
ease the fit and make the attachment “active,” causing rotation.
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23. 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 and automatically placed in
accordance to the desired movement.
Smart Force features and Attachments. 23

24. 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.
• 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.
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25. • Aligner Bio-Mechanics!
• By: Dr. Willy Dayan
• Willy Dayan’s Golden Rules of Invisalign Bio-Mechanics
1) Think Like Plastic and Feel Like a Tooth:
• Invisalign is a removable appliances 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.
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26. ControllingTorque
• A net force of 40 gm (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 400g-mm for lingual root movement.
• Improper attachment design or placement allows the delivery of only 280g-mm
moment in conjuction with 40g force resulting in uncontrolled 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 .
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27. • 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.
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29. • 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.
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30. • 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.
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31. • 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.
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32. Rootparallelism
• 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.
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33. • 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.
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34. • Work is currently being done with various attachment designs, to
demonstrate the ability to predictably avoid molar dumping by placing
attachments on the upper first or second molar as shown in the fig
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35. Rotations
• Correcting rotations with aligner can be problematic.
• There are primary reasons for this.
• 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.
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36. • For this reason we need to use auxiliaries either before ,during or after
aligner treatment in order to accomplish the rotational correction. 36

37. 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.
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39. • 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.
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40. • 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.
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41. • 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.
highlyplaced
canine
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42. • Another vertical movement that is easily enhanced with mini screws is the
intrusion of molars that have supra erupted into an edentulous space. 42

43. Clear Collection instruments for clear
aligner treatments
• 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.
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44. Hu-Friedy’s Clear Collection of instruments
designed to enhance clear aligner treatment
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45. Teardrop-shaped hooks retain elastics when aligners are seated, makingthe
addition of “rubber bands” easier for patients to manipulate. Notches are
made at an angle to resist forces applied by theelastics
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46. TheHolePunch
• 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.
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48. The Hole Punch pliers can be used to relieve plastic impingement of gingival tissues anywhere along the aligners (e.g.,
incisive papilla irritation
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49. Bootstrap mechanics
• If certain teeth are not “tracking” or are
lagging behind (i.e., not fitting into the
tray; Aligner Chewie 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
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50. 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
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51. • Bootstrap mechanics to 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
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52. The Vertical pliers are used to accent rotational tooth movement.
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53. `
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 and applying to the contact points immediately
adjacent to composite attachments that increase sharps
of the contact between plastic and composite attachment
to avoid lose of tracking.
.
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54. In addition, the Horizontal is used to reduce “lag” by
accenting extrusive or intrusive movement by applying
contact points immediately adjacent to composite.
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55. 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
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57. • 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, a bonded
lingual fixed retainer was placed on the maxillary incisors to prevent relapse
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59. • 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. 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.
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60. Pre- treatment
Post- treatment
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61. 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. They noted infra labioversion of both upper
canines.
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71. • 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.
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72. 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
• They found that periodontal health could actually improve during the course of the
treatment in cases treated with aligners.
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73. Conclusion
• 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.
• Treatment using clear aligners is becoming increasingly common in orthodontics. A
better understanding of how tooth movement is achieved may lead to treatments
that are more efficient.
• All in all Invisalign is a great alternative to braces ,owing to its comfort level and
ease of use. Though its not very cost effective, we hope in the future newer
technology and materials will make it more affordable.
• More research in the field of complex tooth movement is still needed, but apart
from that, Invisalign has the potential to replace conventional orthodontic
appliances.
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74. 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
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75. • 6) Invisalign Orthodontic Treatment - Richard Bouchez
• 7) Clear Collection instruments for clear aligner treatments - Orthodontic Practice
US Volume 6 Numbers 3 & 4
• 8) Smart Force features and Attachments – Invisalign.
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76. Thank you
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