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A combination of mini-implant and MEAW to correct a skeletal

Class II open bite

Tae-Woo Kim DDS MSD PhD Professor, Department of Orthodontics

School of Dentistry Seoul National University

Seoul, Korea

Before treatment After treatment

CASE 1

Before treatment After treatment

CASE 2 Before treatment After treatment

CASE 3

MEAW

Intrusion methods of posterior teeth

Extrusion or Intrusion Mechanics

Combination of two mechanics

Extraction options

Contents

There are two mechanics, extrusive and intrusive. Next, I would like to suggest guidelines, cases and indications for each of them.

Etiology of Open bite

In my clinic, I have many open bite cases with TMD, because they are referred from local clinics and other dentists. Seoul National University Dental Hospital is the final destination of problem cases.

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Open

bite

Mouth

breathing

Tongue

thrusting

TMD

Macro-

glossia

Thumb

sucking

Ankylosed

incisors

Open-bite cases look very similar. All of open bites have different causes.

Open

bite

Mouth

breathing

Tongue

thrusting

TMD

Macro-

glossia

Thumb

sucking

Ankylosed

incisors

Italia

Brazil Difficult to finish

Sometime it goes back!

Open bite cases have causes, some of which are not uncontrollable or even unknown. This makes it very difficult to treat them and/or retain their fine results.

Methods to intrude the posterior teeth

Methods were summarized into 6 categories.

Method 1 Method 2 Method 3 Method 4 Method 5 Method 6

Supplied by RMO

1. Place a mid-palatal mini-implant(1.6 mm x 6 mm) , as far distally as possible. 2. Use a TPA with hooks. 3. Insert an 019x025” ss archwire. 4. Apply a power chain tightly.

Method 5 : Use a mid-palatal mini-implant

System of Method 5 is as follows;

Structure

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Method 1 Method 2

Method 3 Method 4

Method 5

Four methods use buccal mini-implants between 6 and 7. But Method 5 doesn’t use buccal mini-implants.

In open-bite cases, the buccal screws between the first molar and the second molar fail very

frequently.

Disdvantages of Buccal Mini-implants in Open bites

1) The inter-radicular space between the first molar and the second molar is very small.

2) In open bite cases, as the posterior teeth being intruded, the screw becomes closer to the alveolar crest and the periodontal membrane.

Disdvantages of Buccal Mini-implants in Open bites

• The stability is compromised when the implants are placed near the alveolar crest and/or into the periodontal membrane.

Shingo Kuroda, Kazuyo Yamada, Toru Deguchi, Takashi Hashimoto, Hee-Moon Kyung, Teruko

Takano Yamamoto, Root proximity is a major factor for screw failure in orthodontic anchorage, Volume

AJODO 2007:131(4) :S68-S73

Disdvantages of Buccal Mini-implants in Open bites

In most of cases, the inter-radicular space between 6 and 7 is narrow. 1) Then, it is inevitable to place a mini-implant between 5 and 6. The mechanical efficiency to intrude the posterior teeth will be decreased. 2) Possibility of Root trauma is high.

Disdvantages of Buccal Mini-implants in Open bites

Advantages of Method 5

1. A mid-palatal mini-implant is more stable than a buccal mini-implant between 6 and 7.

2. A mid-palatal mini-implant can be placed more distally than a buccal mini-implants between 5 & 6. The mid-palatal one is better in biomechanical aspects (longer lever arm) to intrude the posterior teeth.

3. Only one mini-implant is required.

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Orthognathic

Surgery

Orthodontic

treatment

vs

Intrusion of

Posterior Teeth

Mini-implant

Extrusion of

Anterior Teeth

MEAW

Extrusion or Intrusion mechanics to treat the open bite

1. Incisal display 2. Lip incompetency 3. Skeletal pattern

Open bite always means the intrusion of upper posterior teeth? No. I would like to emphasize three factors in differential diagnosis to select the adequate mechanics.

MEAW

Orthognathic

Surgery

Orthodontic

treatment

vs

Intrusion of

Posterior Teeth

Mini-implant

Extrusion of

Anterior Teeth

MEAW

Extrusion or Intrusion mechanics to treat the open bite

1. Incisal display 2. Lip incompetency 3. Skeletal pattern

Some cases were treated by combining the MEAW technique and the mini-implant intrusion.

Non-ext

77 77

77 88

77 88

Non-ext

Extraction options in Class II open-bite cases

77 77

77 88

44 or 55 55

88 88

88 88

Extraction

1. Extraction of third molars brought spaces for second molars to be intruded and tipped back.

88 88

Extraction

By extracting third molars, bite closing is facilitated.

77 77

Extraction

1. Center of rotation moves forward. Lever arm becomes longer than third molar extraction.

Effects of seond molar extraction are as follows,

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77 77

Extraction

2. Wedge (second molars) is removed. 3. Number of teeth to be intruded are reduced. 4. RAP can be utilized.

55 55

Extraction

1. Number of teeth to be intruded are reduced.

44 55

(or )

Extraction of bicuspids also helps bite closing, because

55 55

Extraction

2. Wedging molars are moved forward.

55 55

Extraction

2. Wedging molars are moved forward.

55 55

Extraction

2. Wedging molars are moved forward.

55 55

Extraction

2. Wedging molars are moved forward.

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55 55

Extraction

2. Mesial movement of wedging molars are good to resolve the open bite.

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

1. Third molars are good in shape. 2. The angle between 7 & 8 is between 20~30

degrees. 3. Third molars have erupting potential. Adolescent

patients are good.

Indications

00 08

88 88

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

Clinical notes

Third molars erupt faster than usual. But the secondary minor orthodontic treatment may be required to align the third molars especially, for lower ones.

00 08

88 88

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

1. Upper third molars are good in shape. But lower ones are abnormal in shape or impacted.

2. The angle between upper 7 & 8 is between 20~30 degrees. Lower ones are impacted.

3. Upper third molars have erupting potential. Adolescent patients are good.

Indications

00 08

88 88

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

00 08

88 88

1. In adolescent or adult patients, third molars are not good in shape or impacted.

Indications

Clinical notes 1. Bite closing is slower than in 7-extraction cases.

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

00 08

88 88

Clinical notes

1. Bite closing is much slower than in 7-extraction cases.

2. This option is not recommended. Please, extract third molars before closing the bite.

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Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

00 08

88 88

1. Class II canine and molar relationship 2. Severe upper anterior protrusion and labial

inclination, 3. Or upper anterior crowding.

Indications

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

00 08

88 88

1. Class II canine and molar relationship 2. Mild to moderate upper anterior protrusion with

normal labial inclination, 3. Or slight upper anterior crowding.

Indications

Extraction options in Class II open-bite cases

77 77

77 88

Non-ext (presence of 8)

44 55

55 55

00 08

88 88

Clinical notes 1. Bite closing is facilitated by extraction of 5s.

Clinical Tips for Method 5 (Mid-palatal mini-implant & TPA for intrusion of upper posterior

teeth)

Tae-Woo Kim DDS MSD PhD Professor, Department of Orthodontics

School of Dentistry Seoul National University

Seoul, Korea

Copyright belongs to Dr. Tae-Woo Kim. Please, don’t copy and distribute without permission.

• There should be some space between the TPA and palatal tissue, which prevents the palatal bar to impinge the palatal tissue as the molars are being intruded.

Clinical Tip I for a mid-palatal mini-implant

Clinical Tip II for a mid-palatal mini-implant: How to ligate the power chain

Hole Big screw head

Method 1 using an undercut Method 2 using a hole

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Insert the ligature wire into the holes of the power chain as the figure shows.

Put the center ring around the screw neck. Pull the ligature wire with a hemostat.

Hook the ligature wire around the neck of screw. Twist the ligature.

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Cut the ligature and bend the remaining portion around the neck. Stretch the power chain tight and hang it up to the hook of TPA.

Use a long shank wrench. Please, give a 6 mm space between the bottom of the handpiece and the incisial edge. If the bottom of the angle touches the incisal edge, it will be impossible to remove or insert the screw anymore.

Clinical Tip III for a mid-palatal mini-implant

Long shank

(113-MD-204)

2010.7.16

In every patients, please measure a mid-palatal bone thickness. A mid-palatal mini-implant, 1.6x6mm, is used.

X≥6

6>X≥5

5>X≥4

4>X≥3

3>X

2mm

3mm

Male Female

•2-way ANOVA •Post-hoc test

Kang, SM, Kim, TW, AJODO:2007:131(4)-Supplement 1:74-81

Award of the best poster at KAO 2004

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Clinical Tip IV for a mid-palatal mini-implant

582424 이민아 566513 박명인

Place the mini-implant more distally + Extend the arch anteriorly! (O) (X)

Place the mini-implant more distally + Extend the arch anteriorly!

Then, upper poster teeth will be intruded more efficiently.

Clinical Tip V for a mid-palatal mini-implant

582424 이민아 566513 박명인

Attach the hooks distally and gingivally.

(O) (X)

2010.9.10

566513 박명인

Extract the upper third molars or second molars to remove the wedging effect and to provide the space for intrusion.

Clinical Tip VI for a mid-palatal mini-implant

Clinical Tip VII for a mid-palatal mini-implant

• If the insertion torque is higher than 30Ncm, use predrilling.

• Orthonia® (RMO)

- Wireless rechargeable handpiece

- Stops automatically when torque increases over 30 Ncm.

Jeilmedical Co. Seoul, Korea

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Problems experienced in mid-palatal mini-implants I experienced mini-implant fracture in two cases. In these cases I felt that their bones were much harder than usual. My fault was that excessive torque was applied more than 50Ncm. (In most of cases, less than 30Ncm is enough to place mid-palatal mini-implants without drilling.) Orthonia is good because it stops automatically at 30Ncm. If it stops, remove and drill. Then we can avoid fracture of a screw.

Trephine (=2 mm) adequate to the size of fractured tip was selected.

Implant Trephine kit

How to remove the fractured tip

1) Expose the fractured tip after retracting a flap.

2) Reposition the flap and suture.

29759(536480)이민형

Method 5

A TPA with crown buccal torque and a midpalatal mini-implant was used to intrude the molars. The main arch wire is 019x025 ss with a slight crown buccal torque. This arch is expanded a little.

1.6x6mm

Clinical Tip VIII for a mid-palatal mini-implant

Clinical Tip IX for a mid-palatal mini-implant

:How to control 2nd molars

Sometimes, upper 1st molars are intruded but 2nd molars don’t follow.

1) Solder hooks to intrude 2nd molars palatally

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2) Add a L loop with an intrusion step between 6 and 7

to intrude 2nd molars buccally

Clinical Tip X for a mid-palatal mini-implant

1) Monitor the extrusion of lower molars

1.6x6mm

Clinical Tip X for a mid-palatal mini-implant

2) If lower molars extrude, then apply the mechanics of lower molar intrusion.

This is the method using a Burstone lingual arch with lingual crown torque and a buccal mini-implants to intrude the lower molars. Crown lingual torque is applied slightly to counteract the buccal tipping by the intruding force from the power chains.

Burstone

lingual arch

Clinical Tip XI for a mid-palatal mini-implant

Intruding force should be strong.

(O) (X)

Clinical Tip XII for a mid-palatal mini-implant

; Retain the TPA and mid-palatal mini-implant during the finishing stage.

2011.5.4 After intrusion

2012.2.29 Debonding

Initial counterclockwise rotation of mandible relapsed during the detailing stage. Extrusion of upper molars was a cause of the changes. It is recommended to retain them as long as possible during the finishing stage.

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Clinical Tip XIII for a mid-palatal mini-implant ;

Fixed retainer + Labial buttons + U/D elastics

How will you solve the relapse after debonding? 1. Exercise not to thrust tongue during

swallowing. 2. Check TMJ pains. 3. Chew thirty times for one bite. 4. Fixed retainers + labial buttons (22/33) +

u/d elastics 3/16” 3½ oz

How to make labial button?

Etching Drying

How to make labial button?

Adhesive application Curing

How to make labial button?

Separator Ring

Placement

Flowable Resin Application

How to make labial button?

Curing Separator Removal

How to make labial button?

Labial Button

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Multiloop Edgewise Arch Wire (MEAW)

– 018x022 stainless steel

MEAWs are made of 018x022 ss wire.

Upper Lower

.022 X .028

He invented MEAW technique

Nov. 25, 2002, After lecture at Department of Orthodontics, SNU

•Class II correction

U: MEAW

L: Ideal arch wire

•Class III correction

U:Ideal arch wire

L: MEAW

Closing anterior open bite

U: MEAW

L: MEAW

MEAWs can be used to correct Class II relation, Class III

relation and open bite. To close the anterior open bite, MEAWs

are used both in upper and lower arches.

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•Class II correction

U: MEAW, L: Ideal arch wire

5/16” Class II elastics

To correct Class II relationship, MEAW is applied in the

maxillary arch and Ideal arch(019x025ss) is used in the

mandibular arch. Class II 5/16” 6oz elastics are applied.

•Class III correction

U: Ideal arch wire, L: MEAW

5/16” Class III elastics

To correct Class III relationship, MEAW is applied in the

mandibular arch and ideal arch(019x025ss) is used in the

maxillary arch. Class III 5/16” 6oz elastics are applied.

•Openbite correction

U: MEAW, L: MEAW

3/16” up/down elastics

To close the anterior open bite, MEAWs are used both in maillary

and mandibular arches. 3/16” 6oz elastics are applied from the first

upper loop to the first lower loop.

•018x022 stainless steel

To make MEAWs, 4 to 5 L-shaped loops are made between teeth.

An 043-CK plier is used to make a MEAW. First, anterior curvature is bent with a turret.

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Between #2 and #3, the first L loop is made.

1 3

6mm

2.5mm

4.5mm 2

Between #2 and #3, the first L loop is being bent.

7 1 3 4 5 6 7mm

8mm 6mm 7mm 6mm

2.5mm

4.5mm 2

7mm

Sequentially, upper L loops are being made.

The final upper and lower MEAWs were made.

7 1 3 4 5 6 7mm

8mm 6mm 7mm 6mm

2.5mm

4.5mm

7mm

8mm 6mm 6mm 7mm 6mm

2.5mm 4.5mm

2

7mm

7 1 3 4 5 6 2

Size of L loops

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Upper and lower MEAWs showed a good coordination.

20~25°

5~10°

To avoid gingival impingement or cheek mucosa irritation, L

loops have a buccal tipping. The angle increases progressively

distally.

Upper

But the upper and lower MEAWs don’t have torques.

Lower

The arch is made flat.

Tip back bends

Provides reverse curve of Spee

Tip back bends are applied to each loops, 3° to 5°. Finally, the upper arch has a compensating curve and the

lower arch has a reverse curve of Spee.

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1. Extrusion of anterior teeth is the main effect.

2. Very slight intrusion of posterior teeth is also secondary effect,

“Rocking chair effect”.

“Rocking Chair”

v

Up & Down

elastics

1. Extrusion of anterior teeth is the main effect.

1. Extrusion of anterior teeth is the main effect.

2. Very slight intrusion of posterior teeth is also secondary effect,

“Rocking chair effect”.

“Rocking Chair” “Handle of a car”

1. Extrusion of anterior teeth is the main effect.

2. Very slight intrusion of posterior teeth is also secondary effect,

“Rocking chair effect”.

3. Distal tipping contributes to the correction of molar relationship.

“Handle of a car”

1. Extrusion of anterior teeth is the main effect.

2. Very slight intrusion of posterior teeth is also secondary effect,

“Rocking chair effect”.

3. Distal tipping contributes to the correction of molar relationship.

This effect is increased by Class II elastics (In Class III, by

Class III elastics).

4. .

“Molar movement in open-bite”

Very slight intrusion + Distal tipping

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Reasons why I use MEAWs instead of curved TMA or NiTi wires?

“Handle of a car”

Distal tipping or intrusion of a molar can be controlled very

accurately and effectively with a stiff stainless wire. And also the

load-deflection rate is decreased well with the L loops.

“Handle of a car”

1. If the handle is made of a flexible material, it would not be easy

to control well (tip-back and intrusion) and

2. it would be hard to adjust the wires (vertical or in-&-out steps)

for compensating the minute errors of bracket positioning.

Summary

• Some of skeletal open-bite cases can be treated orthodontically,

– by extrusive mechanics (MEAW) or

– by intrusive mechanics (Mini-implant).

• Three factors- incisal display, Lip

incompetency, and skeletal pattern - were suggested to select the mechanics differentially.

Summary

• Combination of a MEAW with a mid-palatal mini-implant

– produces intrusion of upper posterior teeth and extrusion of anterior teeth at the same time. And this may close open bite very rapidly just after extraction of 2nd molars.