2013-04-10

1

New Options for Aesthetic Appliance

Yeong Sim, DDS, MSD, PhD

Director of Gorman Lingual Orthodontic Seminar

Faculty of Samsung Medical Center & KyungHee Medical School

SIM

Developing lingual orthodontics

Dr Kurz placed clear plastic brackets lingually in 1970

1st generation of ORMCO’s lingual appliance in 1979 by

Dr C Andreiko

ORMCO formed a task force: Drs C Kurz, J Gorman and

JR Smith (first consulting clinicians for a dental company)

3 day lingual courses were taught around world

ORMCO continues to develop the lingual appliances

(Kurz brackets upto 7th G)

SIM

2013-04-10

2

Lingual Orthodontics

Disadvantages

1. Speech

2. Brushing

3. Food impaction

4. Indirect bonding

5. Technique sensitive

SIM

Why lingual approach?

• Patient demand: tendency to choose more

aesthetic orthodontic treatment

• Appliance improvement: smaller, thinner..

• Doctor demand: expand his/her patient pool

• Now: indirect bonding + wire fabrication

• 3D CAD/CAM service to plan treatment sequence

SIM

2013-04-10

3

Market trend

03 05 08

SIM

Recently..

SIM

2013-04-10

4

Satisfying patients

• Lingual technique has a unique value of invisibility.

• There are many patient who would benefit

functionally and aesthetically if they were to have

orthodontic treatment.

• Many of these patients never consider orthodontic

treatment unless implementing this therapy.

-M. Alexander

SIM

Considerations for lingual approach

• Morphological irregularity of

dental arch on lingual side --

Need indirect bonding

• Lingual technique requires

specific laboratory setup to

make a straight wire system

• Need to compensate

mechanics in order to make

proper teeth movements

SIM

2013-04-10

5

Self-ligating lingual bracket

• Because of design complexity, thicker profile has to be

solved

• Durability of clip should be guaranteed during treatment

• Advantage

1) Shorter chair time

2) Better hygiene

3) Low friction

4) Less pain

SIM

Patient comfort

• Bracket profile: reduced dimensions with clip design

SIM

STb: 1.5mm Cliipy-L: 1.8mm

2013-04-10

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Patient’s comfort

0

1

2

3

4

5

6

Kurz 7G Evolution InOvationL 3-3 Retainer

Speech

Eating

Irritation

SIM

N=60

(2010-2012)

WK

Advancement in lingual system

SIM

• Closer to lingual surface:

• Periodontal clearance

• Less bonding failure

• Straight wire system

• Low profile for patient comfort

• 3D CAD/CAM prediction

• No ligation

2013-04-10

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Design with gingival offset

SIM

ORMCO

7G

TOMY

InOvationL DENTAURUM

Time

ORMCO

STb

Periodontal irritation

SIM

Just after debonding lingual brackets

Kurz 7G Br InOvationL Br

2013-04-10

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Reliable wire insertion

SIM

Friction

SIM

Self-ligating bracket has lesser Friction during alignment

2013-04-10

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Mechanical forces acting on tooth

SIM

1. Fld, ligature-derived force;

Fwd, wire-derived shear

force and its counterpart in

the opposite direction.

2. Fld and Fwd together

comprise a resultant

normal force.

Renznikov et al. Measurement of friction forces between stainless steel wires and ‘reduced-

friction’ self-ligating brackets. AJODO 2010.

Components of normal force

SIM

1. The ligature-derived force

depends on the ligation mode

and it is constant.

2. The shear force component

increases linearly with the

wire deflection.

3. The resultant normal force

determines friction resistance

to sliding.

Renznikov et al. Measurement of friction forces between stainless steel wires and ‘reduced-

friction’ self-ligating brackets. AJODO 2010.

2013-04-10

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For sliding mechanics

Clinical studies support the view that resistance to bodily

tooth movement by sliding has little to do with friction

and , instead, is largely a binding-and-release

phenomenon that is about the same with conventional

and self-ligating brackets. The clinical trial data do not

support the contention that treatment time is reduced

with self-ligating brackets.

Burrow SJ Friction and resistance to sliding in orthodontics: A critical review. AJODO 2009.

SIM

Play angle during retraction

SIM

016x022 archwire：7.7°

2013-04-10

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Secure torque during retraction

SIM

Free vs. Active angle

SIM

InOvationL allows X2 more active angle to reduce binding phenomenon

2013-04-10

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Chair Time

20

23 21

17

22

13

Appt No Tx Mo Chair Time

N=100 (50 Conv Br, 50 SL Br) Bimaxillary lingual extraction cases only

Conv Br SL Br

SIM

Final thoughts..

• Actually it does not matter which lingual bracket

system you use. But it does not take a genius to pick

a simpler and reliable system.

• I do not trust wire bending by robotic arms on

animated 3D setup models. I’d rather pick the

manual setup by a trained technician according to

my prescriptions for each different cases.

SIM

2013-04-10

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Conclusion

• Self-ligating lingual bracket system does not shorten

treatment time.

• Advancement in lingual bracket design reduces patient

discomfort and decrease periodontal irritation.

• Self-ligating lingual bracket may reduce patient pain in

initial treatment stage due to lower friction.

• The biggest advantage of using self-ligating lingual

bracket system comes from shortening of chair time!

SIM