2017/4/9

Bio Introduction

DDS, MSc, PhD Professor and Chairman Center of Dental Medicine, Union Hospital Tongji Medical College, HUST, China

Vice President of Society of Chinese Dental Research Administration

Vice President of Chinese General Dentistry Society Standing committee member of Chinese Orthodontic Society President of Hubei Stomatological Dr. Lili Chen Doctor Association

AAO 2017 Annual Session Comparison of the Clinical Efficacy of Three Orthodontic Techniques CC: for Skeletal Class III Mandibular Protrusion Concave Profile

Lili Chen Center of Dental Medicine, Union Hospital Huazhong University of Science and Technology WuHan, China

1. Class III malocclusion 2. III°reverse and overjet 3. Lower anterior lingual inclination

1. Orthopedic Treatment? Facial form and 2. Orthognathic Surgery? Teeth form 3. Fixed Orthodontic Treatment? MEAW Tech Contradiction Transmission Straight-Wire Tech Implant Tech

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Anterior & Irregular dentition

Measurements Cephalometric Measurements Mean Measured value value ： analysis SNA (°) 82.8 81.2 Treatment plan SNB (°) 80.1 81.2 1.Non-extraction ANB (°) 2.7 0 2.Hass expansion 1-NA(°) 22.8 25.8 3.MEAW Technique 1-NB(°) 30.3 28.6 N 1-NA(mm) 5.1 5.7 1-NB(mm) 6.7 5.6 Wits (mm) -1.5 -2.0 UL- A SnPg’(mm) 7.2 7.2 LL- SnPg’(mm) 6.3 6.9 B UL-SnPg’-LL- SnPg’(mm) 0.9 0.3 FCA(°) 7.3 5.4

Class III elastics, Correct the crossbite

Asymmetric short class III elastics, Correct mid-line shift

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Comparison of Pre-tx and Post-tx

PP Plane MP Plane SN Plane

CC: Mandibular Protrusion Mandibular Deviation

Asymmetric short class III elastics correct cross bite and Treatment Plan： mandibular deviation 1. Non-extraction treatment 2. MEAW technique Multiloop Torque correct Posterior cross bite

Asymmetric short class III elastics for final occlusion adjustment

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Comparison of Pre-tx and Post-tx

Features of MEAW Technique

Controlling moving 1. The vertical component of loop can move the direction of every tooth teeth independently 2. The horizontal component of loop can control three-dimensional teeth movement exactly Providing sustained 1.The arch wire is three times as long as normal light force wire, with good elasticity and gentle force 2. Load deformation rate of arch wire is only 1/10 of normal wire

Gaining space from 1. Upright and backward movement of posterior uprighting posterior teeth teeth by Tip back bend 2. Provide 1.5-4.5mm space by 5-15°Tip back bend Pre-tx Post-tx 24 hours intermaxillary 1. Take effect for 24 hours elastics 2. Asymmetric elastics can adjust mandibular deviation easily

Focus Key Points of MEAW Technique Mechanism of Class III elastics

Bending and Adjustment of Bending of anterior area The anterior slope of condyle exists tensile stress Multiloop Dealing with compressed gums 1 The posterior slope is compression stress Grasping of tip back bend degree Total displacement is posterosuperior The bigger the tip back bend, the Condylar process rotates anticlockwise Correct using of short and 2 Mand moves backwards long elastics and vertical bigger anterior traction force Long elastics should be used with elastics For low-angle patients with crossbite, long caution in high-angle patients elastics is good for mand backward movement and bite opening 3 Long elastics should be used with caution in Enforceability of 24 hours high-angle Class III patients intermaxillary elastics The key to success Short elastics will be more gentle than long 4 elastics when use same force

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AAO 2017 Annual Session 1. Class III malocclusion 2. III°reverse overbite and overjet CC: 3. Lower anterior lingual inclination Mandibular Protrusion Concave Profile

1. Orthopedic Treatment? 3M Facial form and 2. Orthognathic Surgery? Teeth form 3. Fixed Orthodontic Treatment? MEAW Tech Contradiction Transmission Straight-Wire Tech Implant Tech

9M 12M

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19M NOW

NOW

Fine wire + light force

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Application experience of Class III elastics Features of Transmission Straight-Wire Tech Choose appropriate cases 1. Class III elastics is unsuitable for patients open bite Mystique and magic of 1. Particularity of the position of canine 1 2. Class III elastics is suitable when need to open the bite or transmission effect 2. Teeth tipping and backward movement move the upper dental arch forward one by one only need 50-60g force

Exquisite designed 1. Special design of single bracket： Limit using time of intermaxillary elastics brackets Edge-off structure、step、cross pipe 1. Intermaxillary elastics can not be used for a very long time 2. Particularity of Class III brackets 2 2. During elastics, other treatment should be appropriately limited Solving the overbite and 1. Not bonding brackets in premolar area Employ right methods to avoid side effects overjet at first at first 1. Adding labial crown torque to thick rectangular wire with posterior 2. Using intermaxillary elastics and 3 wire being pre-expanded to aviod the side effect of arch contraction. improving profile from the beginning 2. For the high angle patients with open bite tendency, using TPA to aviod or alleviate side effect. 24 hours thin wire with 1. Take effect for 24 hours light force 2. 50-60g force can modify mild to Use suitable force on appliance moderate skeletal deformity 4 The force of 50-60g on each side is suitable for intermaxillary elastics.

Superiority Combination  Improving the overbite and overjet first Cuspid bracket Improving the overbite Edge-off Structure Fast tipping movement of canine Tip back bend and overjet first Step The oblique ligation is similar to self-ligating bracket  Improving face profile quickly Cross pipe and obviously Horizontal pipe: NiTi wire  Molars reach Class I relationship Vertical pipe: For hooks et al quickly Other brackets Not bonding brackets in premolar area  Incisors can go back to normal No Edge-off Teeth can move accurately position quickly Friction is zero, getting the maximal Step The same as Cuspid bracket transmission effect  The change of the soft and hard Cross pipe The same as Cuspid bracket tissues is obvious Class III elastics 50-60g

Key points of Transmission Straight-Wire Tech CC: Mandibular Protrusion Correct bending of arch wire Concave Profile

The adjustment of the force of Class III elastics

The theory of differential movement

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1. Modify crossbite first 2. No brackets in premolar area 3. Oblique ligation decrease friction Extract 36,47

Extract 36,47

Torquing auxiliary arch

Beginning

3 Months

8 Months Extract 36,47 End

Extract 36,47

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Problems List： Treatment plan： 35 years old 1. Class III malocclusion 1. Extract15、25、34、45 Mandibular Protrusion 2. Anterior crossbite 2. Transmission Straight-Wire Tech Concave profile 3. 45 residual crown, 14 elongation 3. Mini-implant

12M

Not bonding brackets in premolar area first Class III elastics with light force

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Triangle spaces in posterior area The patient asked to do some stripping Adding the difficulties of keeping the inclination of teeth

Pre-treatment Pre-treatment

Post-treatment Post-treatment

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Pre-tx

Post-tx

Problem List： Treatment plan： 1. Skeletal crossbite of anterior teeth, 1. Non-extraction treatment mandibular can't move backwards 2. Transmission Straight-Wire Tech CC: 2. 14、24、32 loss 3. Mini-impant anchorage Mandibular Protrusion 3. Lower anterior bone is thin Skeletal crossbite of anterior teeth 4. Family heredity history Concave profile

14、24、32congenital missing

3 M 8 M

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12 M 17M

12 M

8 M

3 M 17 M Pre-treatment 1.5 year later Begin

CC: Problems List： Mandibular Protrusion 1. Class III malocclusion Open bite and cross bite of anterior teeth 2. Cross bite and open bite of anterior teeth Concave profile

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Treatment plan： 1. Non-extraction treatment 2. Mini-implants in posterior area of Max and Mand Max implants for molars Mand implants for anterior teeth retraction

Features of using mini-implant AAO 2017 Annual Session Extracting the 1. 8 is already erupted normally, or eruption mandibular third molar space is enough 2. 8 is impacted, and the distance from the Comparison of three methods distal crown of 7 to mand ascending ramus is longer than the space we need to distalize MEAW Transmisssion Mini-implant lower dentition Profile change is slight, Profile change is Profile change is Implant position main change is teeth obvious, patient become obvious 1. Distal buccal side of 7 and occlusion plane more confident 2. Between the root of 6 and 7，near to distal Three Adjusting occlusion Light force system, Vertical control can Distalizing the dental 1. Tipping movement of anterior teeth， accurately don’t need special prevent “wedging arch crown:root = 5:1 anchorage devices effect” 2. Whole movement of posterior teeth， Techs crown:root = 5:3 Adjusting midline shift Transmission effect Need to consider the and mandibular shorten course of distal space of the Vertical control the deviation treatment second molar and to height of posterior teeth 1. Preventing posterior extrusion simultaneously extract mand 8 2. Preventing“Wedging effect”

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AAO 2017 Annual Session

Comparison of three methods MEAW Transmission Mini-implant Complexity Complex Simple Medium Need multiloops Minor implant surgery

Comfort Bad Medium Medium L-loop is easy to Need intermaxillary Elastics chain may [email protected] oppress gums elastics oppress gums

Compliance High High Low Need 24 hours Need 24 hours By the doctors elastics elastics

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