Class III

Question 1

Functional shift: Class III

Answer 1

A functional shift can be present due to anterior interferences that force the patient to shift the mandible anteriorly to achieve posterior occlusion. Functional shifts need to be identified since the ClinCheck treatment plan will need to eliminate these anterior interferences to allow the mandible to reset to its correct position. The centric occlusion at the beginning of treatment does not take the functional shift into consideration. Typically, this will be done in the ClinCheck treatment plan by programming the tooth movements needed to remove the interferences using the initial centric occlusion bite.

A virtual jump will be programmed showing the expected new centric occlusion once the interferences are removed. This jump visualization can be customized to see it at the beginning of treatment, at the end, along treatment or to be hidden. However, it will take place naturally during treatment. Inter-arch elastics may also be planned as part of the treatment. Functional shifts should be identified in the initial diagnosis.

Question 2

Class III correction simulation versus sequential distalization:

Answer 2

• Class III correction simulation with simultaneous staging of all tooth movements may be more efficient for mild Class III correction under 2 mm where reciprocal movement of both arches is desired.
• The time needed for the Class III correction is independent from the number of aligners needed to align the teeth; time needed for the A-P correction must be considered.
• Sequential distalization of the lower arch can be used when more anchorage management is required to avoid advancing the upper arch but will result in longer treatments.

Wisdom teeth

• Presence of wisdom teeth should be assessed before undertaking a distalization treatment plan.

Question 3

Class III Simple

Answer 3

Classification

A-P Correction < 4 mm

Premolar Extraction: No

Distalization < 2 mm

Mesialization: No

Question 4

Class III Intermediate

Answer 4

Classification

A-P Correction: < 4 mm

Premolar Extraction: No

Distalization: 2-4 mm

Mesialization: < 2 mm

Question 5

Class III Complex

Answer 5

Classification

A-P Correction: > 4 mm

Premolar Extraction: Yes

Distalization: > 4 mm

Mesialization: > 2 mm

Question 6

It is more predictable to treat class III patients with the Invisalign system if:

Answer 6

• The patient is young and is still growing.
• The Class III results from dental issues and not skeletal issues.
• Clinical crowns are not short.
• The molars are in Class I and the canines are in mild Class III.

Question 7

Align Technology has developed three features to help you treat Class III cases:

Answer 7

Passive Aligners

Precision Cuts

Pontics

Question 8

Passive Aligners Class III

Answer 8

• Passive Aligners are placed by default in all Invisalign treatment options.
• They are paired with active aligners on the opposite arch.
• They allow use of Class II/III elastics (Precision Cuts with Full and Teen treatment options) even if the treatment of one arch is finalized.
• They are shown as white rectangles in the Staging bar on the ClinCheck Treatment plan.

Question 9

Precision Cuts for Class III

Answer 9

By default, Precision Cuts will be placed:

Hooks on lower canines.

Button cutouts on upper first molars.

Question 10

Default Hooks placement can be modified on Clinical Preference.

Answer 10

Hooks can be prescribed on the buccal surfaces of canines, premolars and molars.

Button Cutouts can be prescribed on the buccal and palatal/lingual surfaces of canines, premolars, molars.

By default, in case of incompatibility, Optimized Attachments will be prioritized based on your Clinical Preference.

Question 11

Pontics Class III

Answer 11

• Minimize the appearance of a missing tooth during Invisalign treatment.
• Pontics are placed by default in anterior and posterior spaces greater than 4mm.
• If adjacent teeth are being moved (i.e. extraction treatments) pontics adjust their width automatically as the space increases or decreases.
• The default for pontics can be modified on Clinical Preference.

Question 12

For Class III, we’re going to focus on question no. 4 in the Prescription Form. This covers the A-P relationship. What is your goal?

Answer 12

Use the top section of the form to select your treatment goal

Question 13

For Class III, we’re going to focus on question no. 4 in the Prescription Form. This covers the A-P relationship. What is your Strategy to acheive your goal?

Answer 13

Use the lower section to select your treatment strategy

Question 14

If you want, you can also specify extractions for AP correction in

Answer 14

the Spacing and Crowding section:

• Extractions.

Question 15

Posterior IPR Class III

Answer 15

When you select the IPR option, a maximum of 0,5 mm IPR per interproximal space will be planned from lower 3 to lower 6.

Question 16

Class III correction simulation

Answer 16

ClinCheck® bite correction visualization:

Default: AP correction happens throughout ClinCheck treatment plan simulating the A-P bite correction planned with elastics.

Question 17

Distalization.

When you choose the distalization option…

Answer 17

Lower 7: The lower 7s begin distalizing and when they achieve half of their amount of distalization…

Lower 6: …the lower 6s begin distalizing and when they achieve half of their amount of distalization…

Lower 5: …the lower 5s begin distalizing and when they achieve half of their amount of distalization…

Lower 4: …the lower 4s begin distalizing and when they achieve half of their amount of distalization…

Lower 3: …the lower 3s begin distalizing and when they achieve half of their amount of distalization…

Incisors: … the incisors begin retracting.

Question 18

Class III Surgical Simulation

ClinCheck bite correction visualization:

Default: the outcome of the surgery is shown…

Answer 18

in a single-stage shift at the beginning of the ClinCheck Treatment Plan.

Question 19

Treatment Plan

When should I use elastics?

Answer 19

Treatment Goal: Class III correction simulation:

Timing : As soon as possible

Treatment Goal: Distalization

Timing : At the latest when lower 5s begin distalizing

Question 20

Precision Cuts Compatibility with Optimized Attachments

Answer 20

Precision Cuts can coexist with conventional attachments, and with Optimized Attachments for Rotation, Extrusion, Optimized Root Control, Retraction, Anchorage and Deep Bite, provided there is sufficient room.In instances where a Precision Cut and an Optimized Attachment cannot be placed due to insufficient space, this Clinical Preference allows you to resolve the conflict:

Where there is a conflict, the default will be to place Optimized Attachments instead of Precision Cuts.

If there is a conflict, and where possible, default will be to replace a Button Cutout with a Hook in order to keep both Optimized Attachment and Precision Cut.

Question 21

Elastics recommendations*

Answer 21

Typical Application Size Diameter

Class II/III (canine to 1st molar) 3/16 inch, (5 mm) Medium, 4.5 oz, (128g)

Class II/III (canine to 1st molar)1/4 inch, (6 mm) Medium, 4.5 oz, (128g)

Class II/III (canine to 2nd molar) 5/16 inch, (8 mm) Medium, 4.5 oz, (128g)

Question 22

Button recommendations* for Class III (same as class II)

Answer 22

Button, Composite - Ortho Organizers

Bond buttons as gingival as possible after receiving aligners. It is recommended that you insert the aligner when bonding the buttons on teeth to ensure aligner clearance, leaving a 1 mm margin between the button and the aligner for button cutout variability. Please remove buttons before taking a PVS impression or intra-oral scan.

*Other equivalent products can be used where appropriate.