attacchi Damon

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11/26/200

6 Keys to Derotational Success

Six Keys to RotationalControl (in MX)

• Bracket Placement

• Variable Torques

• Archwire Bends

• TMA

•• Closing Chain



11/26/200

Finishing Cases with a

Low-Friction Appliance• Finishing begins with good bracketp acemen

• This is a precision appliance – Errors show up early due to the rapidity in

leveling to rectangular wires

– Reposition as needed

– Slot size is .028, not .027

– Because there is more play in the system,doctors may have to compensate for it

Most Common Issueswith Bracket Placement• Brackets not placed more ginigivally

•

• Upper and lower cuspid brackets not placed on theheight of contour

• Upper and lower lateral brackets not placed moremesial to the height of contour

• Not viewing O-G reference points from theincisal/occlusal aspect using a mirror

– Position of the height of contour will look different!

• Maxillary bicuspids placed too mesially



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Damon ConventionalKEY OFF THE MAXILLARY CANINES!MD: A l ign bracket scr ibe l i ne o f upper anter io r b racketsw i th the c row n l ong ax i s a t the he igh t o f con tou r

Maxillary Bracket Positioning

w i th the c row n l ong ax i s a t the he igh t o f con tou r

The OG positioning of the upper canine is slightly gingival to themesial-distal contact line with the lateral and central incisorsequentially more gingival to the canine.

Central: Slot is approx. .5 mm gingivally to slot of canine bracket.Lateral: Slot is approx. .25 mm incisally to slot of central bracket.

Denotes recontouring

Bracket Slot

Bracket Base

M-Dcontactline isslightlycanted

ConventionalDamon

MD: Al ignscr ibe l i new i t h c r o w n

Mandibular Bracket Positioning

Cuspids

w i t h c r o w nlong ax is a tthe he i gh t o fcon tou r

VIEW FROMINCISALSURFACE!

IF VIEWEDFACIALLY,

OG: Posi t ion inc isa l edge o f w i n gs sl i h t l

PLACEMENTWILLAPPEARMESIAL TOCROWNLONG AXIS!

gingival ly to mes ia l - d i s ta l con tac t l ine.



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Variable Bracket Torques

• Get anterior torque control early intreatment by selecting properbracket torques and using high-tech archwires pre-torqued in theanterior

Main reasons to use variable


torque options:1. Since the system is designed to

incorporate play between thebracket and the slot throughout alltreatment hases variable tor ueoptions help to maintain idealanterior tooth position.



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7°-11° of play


and .019 x .025RectangularWire(factoring in both

bracket and wiretolerances)

7°

Main reasons to use torque options:


2. With so little friction and bindingin the system, elastics and ClassII correctors move teeth muchmore quickly. Torque selections

are es gne o ma n a n an er orposition and avoid roundtripping.



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Archwire Bends

• .016 x .025 Damon stainless steel, typically used onthe lower arch during major mechanics and finishing,s pa en -spec c, mean ng a s orme o epatient’s archform prior to transitioning from .018 x.025 Damon Copper Ni-Ti.

• It is not uncommon however for Damon clinicians toremove play from the system by making appropriatetorque bends to the archwire. Effectively, this

introducing a minor degree of friction, which precludesundesired tooth movement near the end of treatment.At this stage of treatment, a certain amount of frictioncan be advantageous as long as the system remainspassive.

TMA• Many clinicians favor .017 x .025 Damon TMA over

steel in terms of making necessary bends because ofits flexibility.

• Another important benefit is derived from its cross-section. Because the width of the wire is greater (.017versus .016), the diagonal is also greater than .016 x.025 steel. This archwire occupies more space in thebracket lumen. This yields not only more effectivetorque, but more rotation control as well.

• Furthermore, this wire is manufactured at the higherend of the tolerance spectrum, which also aids inrotation control.



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Tiebacks

• Tieback modules are intended to hold space, not toclose it.

• When too much force is applied, it is not uncommonfor lower cuspids to roll distal lingual, breaking contactwith the lower laterals, and thus affecting loweranterior contacts. Lower laterals may then rotatemesial lingual.

• The aforementioned is a function of both heavy

tieback forces and play in the bracket slot, which isinherent in passive self-ligating appliances.

Closing Chain

• Chain is used on the lower anteriors 3-3 to close minors acin . Once s ace is closed it is im erative to remove it and hold space by either lacing L3-3 orcrimping archwire stops distal to both lower cuspids.

• Chain that is not removed may continue to deliver anunwanted force, leading to rotations near the end of

.

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