leveling and alignment in e.w.a / orthodontic courses by indian dental academy

Bracket Positioning, Sequence of Mechanics

in Edgewise Mechanics

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

www.indiandentalacademy.com

Bracket Positioning, Sequence of Mechanics

in Edgewise Mechanics

Dr. OP Kharbanda, AIIMS, New Delhi


Basics of Edgewise

Dr. O. P. KharbandaAll India Institute of Medical Sciences

[email protected], [email protected] www.indiandentalacademy.com

mailto:[email protected]

Dr. Ashok Jena, Dr. Sandip Kumar,Dr. Priyanka Kapoor, Dr. Hari,Dr. Neeraj Wadhawan, Dr. Vishal Gupta, Dr. Anand Pal Lohia

Contributors


Growth trends

– Type A growth trend– Type B growth trend– Type C growth trend


Type A growth trend• The middle and lower face are growing forward and

downward in unison, with no change in size of the ANB

• Growth is approximately equal in both the vertical and horizontal dimensions

• Approximately 25 % of patients


Type B growth trend• Growth downward and forward with the middle face

growing forward more rapidly than the lower face• Growth of the middle and lower face is predominantly in the

vertical dimension in most instances • ANB reading 60 to 120

• If ANB is less than 40 prognosis is fair• If ANB is 70 to 120 prognosis is poor• Extraction of all four first premolar mandatory for patients

with high ANB angle• Only about 15% patients www.indiandentalacademy.com

Type C growth trend• Lower face is growing downward and forward more rapidly than

the middle face with a decreases in ANB angle• When FMA ranges upward from 200, growth is approximately

equal in the vertical and horizontal dimensions• When FMA 200 or less, growth predominantly horizontal• When growth is virtually confined to the horizontal dimension

with little vertical growth, the growth trend is classified as Type C subdivision.

• 60% patients have Type C growth trend


Anchorage• Tooth anchorage (Anchorage preparation)• Anchorage savers Anchorage preparation• 1st degree• 2nd degree• 3rd degreeAnchorage savers• Headgear or palatal bar• Nance button• Delayed extraction• Lip bumpers• Muscular pattern of low FMA cases


Anchorage saversDr. OP Kharbanda www.indiandentalacademy.com

Bracket placement• Precision bracket placement is essential for good leveling

and alignment.

• Indirect bonding showed better bracket placement. (Koo, Chung, Vanarsdall, 1999)

• Light cure bonding also showed better bracket placement than chemical cure.

• Bonding with orthocad technology shows more accurate bracket positioning.


Bracket placementTweed: Mandibular arch: • Bracket slot should be 3.5mm from incisal edge or cuspal tip • On molars -Between occlusal and middle thirdMaxillary arch:• Bracket slot 3.5mm from incisal edge of cuspal tip except on lateral

incisor (3.0mm)

Dr. OP Kharbanda, AIIMS, New Delhi, Typo Photos Courtesy Dr. Hari PG student www.indiandentalacademy.com

Bracket placementLindquist:

Upper arch Lower arch

Central 4.5mm 4.0mm

Lateral 4.0mm 4.0mm

Canine 5.0mm 4.5mm

Premolar 4.5mm 5.0mm

Molar 3.5mm 4.0mm


Computerized bonding• Generating digital information defining the shape and

location of the malocclused tooth with respect to the patient's jaw

• Generating a mathematical model of the malocclused tooth as positioned in the jaw from the digitized information

• Calculating the finish position in the jaw to which the malocclused tooth is to be moved from the digitized information


Computerized bonding

• Calculating the placement position of an orthodontic bracket on the malocclused tooth required in order to move the malocclused tooth to its finish position by a preselected orthodontic treatment

• A standard bracket is thereafter modified, if desired, individually for the patient, in view of the patient's physical deviations from the statistical averages.

• The shape of a bracket positioning jig is calculated and formed


ALIGNMENT & LEVELING

Goals of first phase

• Bring the teeth in alignment and correct vertical discrepancies by leveling out the arches

• Labiolingual discrepancies (crossbites)

• Axial discrepancies (mesio-distal)

• Correct rotationswww.indiandentalacademy.com

Loop mechanics

• A loop reduces force and increases range by adding wire in inter-bracket span.

• A loop may be open or closed type.• Open loops are most efficiently activated through

compression of the legs.• The force of any loop may be reduced by coiling the wire

at the apex one or more times.• The force developed in loop or arch wire is transmitted to

the tooth through the bracket attachment resulting tooth movement.


Clinical applications of loops

Movements Loop

Labial - Double vertical- open

Lingual - Double vertical- open

Elevation - Double horizontal or Box

Depression - Double horizontal or Box

Rotation - Double vertical- open or box

Root tipping- Box or double horizontal

Canine Retraction – Ricketts Spring

Incisor Retraction T loops /double key hole loops


Clinical applications of loops1. Mesial or distal movement (such as midline correction): double

vertical loop against bracket or fixed to the contained section of the arch, activated by tying back or compression. Combination of open and closed vertical loops.

2. Space closure (contraction of the arch): closed vertical loop, tied back.

3. Space opening (expansion of the arch): open vertical loop, with stops.

4. Bite opening: T-loops mesial to the canine. Note that the arch wire in anterior section between the two loops should have reverse curve to transmit the pressure equally to all 4 incisors.


Principles in the choice of alignment arches

• Initial arch wires for alignment should provide light, continuous forces to produce the most effective tooth movement. Heavy force in contrast should be avoided.

• The arch wire should be able to move freely within the brackets. For mesiodistal sliding along an arch wire, at least 2 mil clearance between the arch wire and bracket is needed, and 4 mil clearances is desirable.


Principles in the choice of alignment arches

• Rectangular wire particularly those with a tight fit within the bracket

slot so that the position of the root apex could be affected, normally

should be avoided. Cupper Ni Ti or BioForce are the exceptions.

• Round wires are preferred for alignment.


Multiple loop arch wire (0.016”)Molar tie back,Vertical loops, L loops

Upper

Lower

Dr. OP Kharbanda, AIIMS, New Delhi, Typo Photos courtesy Dr.Hari PG student www.indiandentalacademy.com

Multiple loop arch wire after ligation

Dr. OP Kharbanda, AIIMS, New Delhi, Typo Photos Courtesy Dr. Hari PG student


Multiple loop arch wire after movement


Leveling with 0.016” Arch wireMolar stops

First order bendsSecond order bends

upper

lower

Dr. OP Kharbanda, AIIMS, New Delhi, Typo Photos Courtesy Dr. Hari PG student


0.016” Arch wire after ligation


0.016” Arch wire after movement


Leveling with 0.018” Arch wireMolar stops, First order bends, Second order bendsCurve of spee- upper, Reverse curve of spee- lower


Typical Upper and lower leveling wire often used in Edgewise appliance just beforeInsertion of the Edgewise wire.

Mild curve of Spee With tip back bends andMolar stops

Mild Reverse curve of Spee With tip back bends and molar stops


Leveling with 0.020” Arch wire

• Molar stops

• First order bends

• Second order bends

• Curve of spee- upper

• Reverse curve of spee- lower


Acknowledgement Sincere thanks to all those staff , PG students, CMET Staff and all

others who have directly or indirectly contributed to this presentation


Thank you

For more details please visit www.indiandentalacademy.com


leveling and alignment in e.w.a / orthodontic courses by indian dental academy

Documents