How SPEED Appliance is Effective in Torque Control, Space Closure and Sliding Mechanics

How SPEED Appliance is Effective in Torque Control

Effective Torque Torquing momentSliding mechanics

Enmasse retraction

[email protected]

©Dr Sylvain Chamberland

Effective Torque .022 slot• Torque play

! .017 x .022 = 22,3°

! .019 x .025 = 10,5°

! .021 x .021 = 5°

! .021 x .025 = 3,9°

! .020 x .025 SW ! 4°

• Effective torque

! 0°

! 5°

! 6°

! 7,1°

! ! 7°.020 x .025


Effective Torque .018 slot

• Torque play

! .017 x .022 = 5,4°

! .017 x .025 = 4,5°

! .018 x .025 = 2°

• Effective torque

! 5,6°

! 6,5°

! 9°


• A rectangular arch wire fitting into a rectangular slot can generate the moment of a couple necessary to control root position. !The wire is twisted (placed into torsion) as it is put into the bracket slot. !The two points of contact are at the edge of the wire, where it contacts

the bracket.

• The moment arm therefore is quite small, and forces must be large to generate the necessary MC.

• Using the same tooth, a 50 gm net lingual force would generate a 750 gm-mm moment. To balance it by creating an opposite 750 gm-mm moment within a 0.5 mm bracket, a torsional force of 1500 gm is required.

Downloaded from: Proffit: Contemporary Orthodontics, 4th edition (on 5 April 2009 03:18 PM) © 2007 Elsevier

Mc / Mf > 1


• Moment of force, MF1, = F1 X D1

• Moment of couple Mc = F2 X D2

• D1 > D2

• Therefore, to produce moments of equal magnitude, the forces F2 creating the couple must be of greater magnitude than F1


• Moment required to torque maxillary incisal segment

! = 3000 -3500 g-mm (Nikolai 1985)

! 1000 g-mm for 2 incisors, 2500 g-mm for 4 incisors (Burstone)

! 2000g-mm ! 20 Nmm

• To not overcome the torquing moment of 20 Nmm, the retraction force should be of low magnitude


• At 12° & 24°: A-SLB > P-SLB

• At 36° of torsion

• No difference in the torquing moment between P-SLB and A-SLB

Torque expression of self-ligating brackets compared with conventional metallic, ceramic, and plastic brackets Morina et al EJO 2008 (30) 233-238

Badawi, et. al. AJODO 2008; 133:721-8 • At 20° of torsion; .019 x .025 w; .022 slot

• SPEED = 8 Nmm, torque loss 11°

• This is consistant with Badawi study: 24°! 11,8 Nmm

• One would assume that with a .020 x .25 SW or .021 x .021 x .020 torque would be first expressed at a smaller angle

• Higher torquing moment would be generated at smaller angle of twist

Nmm


Comparison of torque expression between SS, TMA and CuNiti in metallic SLB AO 2010 #80; 884-889

Damon 3MX

In-Ovation-R

SPEED

• Speed and In-Ovation-R: Ealier engagement of torque at 5°•Damon 3Mx: Engagement at 10-12°

•At 36°: Mean torque difference within 5% between all brackets when SS was compare with either NiTi or TMA

•At 24° • SS ! 1.5 to 1.8 times the torque of TMA • SS ! 2.5 times the torque of Niti


Damon Q

In-Ovation-R

SPEED NTP

•At 25° of twist: Mc ! 35Nmm•No statistic " between the 3 Bk

•At 20° of twist: Mc ! 21 Nmm• More than Morina et al because it is measured at the bk

and not at 10 mm away

• SPEED brackets that clip did not opened have similar torque curve as Damon and In-Ovation R

TwinDashed line = expressed torque

• Conclusion"Bracket

deformation occurs above 30° of twist

"Likely a significant factor in loss of torque expression for both SLB and conventional Bk

Journal of Dental Biomechanics Vol 2010 (2010), Article ID 397037, 7 pages

Mechanical effects of 3rd movement in SLB by the measurement of torque expression AJODO 2011;139:e31-e44


Weakness & Bias of this Study

Mechanical effects of 3rd movement in SLB by the measurement of torque expression AJODO 2011;139:e31-e44

• Data of SPEED bracket that clips opened are pooled with bracket that did not opened, even if a statistical differences between the 2 sub-group was established

! "SPEED NTP have similar torque curves as Damon and In-Ovation R"

• Plastic deformation of wire or the brackets alone are unknown

• Torquing moment behond plastic deformation of the wire is unknown

• Torquing moment at yield point of the brackets is unknown

SPEED-NTP N = 14


• H1: A 45° or so angle of twist in a .019 X .025 SS wire do not create plastic deformation

Home Made Fancy Study

• H1: REJECTED


• H2: A 45° or so angle of twist do not debond a bracket


• H2: REJECTED



• H3: A 45° or so angle of twist create plastic deformation of the bracket

• Since bond failure occurred, a fancy lab study is required

• To know at which angle and torquing moment bracket deformation occurs, a non deformable material should be used instead of a SS wire

Torque play of various SLB


What are the limits of 1/-SN

1/-SN = 126°1/-SN = 72° 1/-SN = 103°- 31° + 23°


• A single force applied at the crown create uncontrolled tipping which improve incisor torque

! The crown move in the opposite direction of the root

16SC for 6 weeks !16x22 neost for 6 weeks !20x25 nitisw for 6 weeks !21x21 Dwire

GR 21-06-1020x25 nitisw

GR 20-09-1021x21DW

GR 01-11-1016x22 neost


• 16SC (6 w) !16x22 neost (6 w) !20x25 nitisw (6 w) !21x21 Dwire (6 w) !Stop ABP, bond 6's/ & 7's/, 16x16sent (6 w) ! 20x20neost (6 w) !20x25 niti (6 w) !20x25 SS (6 w) ! 20x25 SS + ART (6 w)

• Significant torque increased was obtained in 65 weeks through a progression of at least 5 wires

• 28° is below the angle at which bracket deformation could occur

1/-SN = 72° 1/-SN = 100°+28°


Wire progression = torque correction

+14°

•.016SC (6w)!.018SC (6w) !.020x.020NiTi (12w) !!.020x.025 Niti (12w)!.020x.025 SW (16w)!!.021x.025SS

1/-SN = 96°

Em.Ja. 0910

1/-SN = 82°

Em.Ja. 0909

•Torque has improved with engagement of full size archwire


MxMd advancement for OSA

Em.Ja. 0909 Em.Ja. 0611


Maintain torque while retracting

Se.Ma. 0308

1/-SN = 112°

Se.Ma. 0810

1/-SN = 96°-16°•.016SC (6w)!.016x.022Niti (8w) !!.020x.020NiTi (14w) !.019x.025 TMA (10w)!!.021x.021x.020 retmasse SW (12m)!!.021x.021Dwire SS

• Maintain low force module while retracting to not overcome Mc generated at the bracket interface• Increased wire cross section to increase stiffness

in torsion and reduce torque play • Mx & Md advancement is planned



Ja.Le. 0808 Ja.Le. 0510

Maintain initial torque

• .016SC (12w)!.018SC (16w) !.016x.022NiTi (6w) !!.020x.025 Niti (6w)!.019x.025 TMA (12w) !!.020x.025 Niti (6w) ! .020x.025 SW (8w)

• 1/1 improved because /1-MP improved• Early engagement of full dimensional archwire

helped to maintain adequate torque

103° to 104° = maintain


Ectopic lateral incisor

• Early engagement of rectangular wire and 0° torque Bk on lateral incisor was efficient and effective to obtain alignement in the 3rd order plane of space• .020 x.020 Niti!.020x.025Niti!

!.020x.025SW• Finishing: .021x.025SS (8 m)

Lateral incisors Bk prescription: 0°


• Aim: to assess the slot dimensions in the 0.022-inch bracket of an upper left central incisor, in six different commercially available self-ligating bracket systems, using electron microscopy, in order to determine the accuracy of manufacturers published dimensions

• SmartClip, Clarity SL, SPEED, Damon MX, In-Ovation R, In-Ovation C

Assessment of Slot Sizes in Self-ligating Brackets using Electron Microscopy

N.B. BHALLA, S.A. GOOD, F. MCDONALD, M. SHERRIFF, A.C.CASH


• Results! All of the brackets systems measured had slot sizes that

were significantly greater than their stated 0.022-inch dimension

! Speed brackets (Strite Industries) were 5.1% larger, and found to be the closest dimensions to those published.

! The largest bracket was the Smartclip bracket (3M) measured to be 14.8% bigger than 0.022 inches

Assessment of Slot Sizes in Self-ligating Brackets using Electron Microscopy

N.B. BHALLA, S.A.GOOD, F.MCDONALD, M.SHERRIFF, A.C.CASH Aust Orthod J 2010, may 26


• Clinical implication

! Increased slot dimensions reduces the expression of bracket prescription in all three dimensions.

! Dimensional inaccuracies lead to teeth moving by tipping, rather than bodily movement.


Orthodontic Bracket Manufacturing Tolerances and Dimensional Differences between SLB

Major T et al, J Dental Biomechanics, v 2010

• SPEED: Smaller than nominal height, larger at bottom than the top

• In-Ovation: Taper!Smaller at the bottom, larger at the top

• Damon: Larger than nominal height

Nominal height=0,559 mm


Orthodontic Bracket Manufacturing Tolerances and Dimensional Differences between SLB

Major T et al, J Dental Biomechanics, v 2010

• Tolerance of slot height of SPEED = 15#m smaller than nominal

• Tolerance of slot height of In-Ovation = 15#m smaller at bottom & bigger at the top

• Tolerance of slot height of Damon Q = 43#m bigger (oversized)

• An oversize/undersize of 15#m means ±2,3° of torque play

• An oversize/undersize of 43#m means ±4,7° of torque play and a reduced torque expression (Mc) of 5-10 Nmm

• Difference between SPEED and Damon = 15 + 43#m or 7° of torque play


• If an .022" slot bracket is actually .0235" (~ 7%)

! An .019 X .025 or an .0215 X .028 archwire will have 5° of wire bracket play beyond that usually anticipated for an .022" slot.

• When protracting posterior teeth,

! If the mechanics depend upon moments generated at the incisor brackets with rectangular archwires, the above slot-size errors can induce lingual tipping of the incisors

! Such results are undesirable, to say the least. If the archwires are smaller than their stated sizes, the impact is even worse

SIATKOWSKI, JCO 1999, p 509

TABLE 1TIPPING DUE TO LOSSOF TORQUE CONTROL*

Torque Loss5° 8° 10°

Maxillary 1.3mm 2.1mm 2.7mmMandibular 1.2mm 1.9mm 2.3mm

*Lingual change in incisal edge position (incisors of average dimensions).

Tooth translationEnmasse retraction

Phases of treatment


Some thoughts about friction

• Most study are bench study

! Test .019 x .025 SS wire or similar

• Bracket held steady (no angulation) & wire is pulled at a rate of 10 mm/ minute (Stefanos S., Secchi A. et al, AJODO 2010)

• Bracket sliding on a steady wire at a rate of 1 mm/minute (Budd S., Dask J. Tompson B. EJO 2008; Oliver C. Dask J. Tompson B. AO 2011)

SUCH CONDITIONS NEVER OCCUR CLINICALLY


Change over time in canine retraction: an implant study

Parsekian, R, Bushang, P.H., Gandini L.G., Rossouw P.E., Am J Orthod Dentofacial Orthop 2009;136:87-93


Rate of tooth movement

• 10 mm / minute ! 432 000 mm per month

• 1 mm / minute ! 43 200 mm per month

• Average of 1,42 mm / month ! 0,00003287 mm per minute


Some other thoughts about friction

• Findings:

! Passive SLB produce less frictional resistance than Active SLB

! However, this decreased friction may result in decreased control compared with actively ligated systems

• All wire tested were rectangular ! activate the clip (active zone)


• If bracket held steady (no angulation)

! RS is lower for all SLB than for conventional bracket tied with wire or an elastomeric ligature and lower with passive clip than active

• This condition never occurs clinically!


• As soon as the corners of the bracket contact the wire (2nd order), binding occurs, and this contribute most of the resistance to sliding

• Binding do not appear to be affected by the method of ligation

• Same binding and notching could be expected in the 1st order

# Heavy forces = more rotation and anchorage lossYee et al, AJODO 2006; 136:150.e1-150.e9


• Clinical studies support the view that resistance to 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 limited clinical trial data now available do not support the contention that treatment time is reduced (presumably because of lower friction) with self-ligating brackets

Friction Conclusion

Friction and resistance to sliding in orthodontics: a critical review. AJODO 2009; 135:442-7


Ligature derived force

• Depends on ligation mode

! Can be smaller in SLB or greater in conventional systems

"Shear force increase linearly with wire deflection relative to the bracket slot

"Friction resistance is proportional to the grade of the wire securing elements rigidity and to the extent of wire deflection

• Correlation between passive clip design and wire surface scratching

Reznikov, N et al, Measurement of friction forces between stainless steel wires and reduced-friction self-ligating brackets, AJODO 2010; 138:330-8


• Some clip flexibility might provide a considerable benefit during the working stage of the orthodontic treatment, when residual malalignment of the teeth still persists.

• Either an active clip or an elastomeric module can absorb minor, clinically undiscernible tooth irregularities and does not hinder sliding mechanics.

• In contrast, a passive clip demands ideal alignment of the teeth subjected to a retraction force.

Reznikov, N et al, Measurement of friction forces between stainless steel wires and reduced-friction self-ligating brackets, AJODO 2010; 138:330-8


Therefore

• Swinging the teeth on a very small wire

• Few if any friction is involved:

! Passive zone

! No binding

! No notching

Wi.Be.290609 Wi.Be.250909Wi.Be.120809

Wi.Be.131109 Wi.Be.100510


• The width of the bracket on a tooth determines the length of the moment arm (half the width of the bracket) for control of mesiodistal root position. • Bracket width also influences the contact angle at which the corner of

the bracket meets the arch wire. The wider the bracket, the smaller the contact angle.• In the 1st order, the clip prevent rotation and help reduce the moment

arm in that plane

Downloaded from: Proffit: Contemporary Orthodontics, 4th edition (on 5 April 2009 03:23 PM)© 2007 Elsevier


Do We Need a Fancy Study to...

• Know that .019x.025 TMA (or SS) will generate more Friction (FR) than a smaller wire ?

• Know that increased retraction force will cause more tipping of the tooth to retract and therefore Binding (BI) and Notching (NO) is more likely to occur?

An.No 310308

Resistance to slide


Do We Need Fancy Study to...

• Know that .020 SS wire has less friction than .019x.025?

An.No 250608

Resistance to slide



• Know that pulling on 1 side and pushing from the other side make it easier to translate teeth over a rounded corner of an anterior arch form?

Resistance to slideAn.No 110309

An.No 081209



• Know that T loop retraction springs are...frictionless?


Sliding a single tooth

• .021 x .021 x .020 HDG

• Elastomeric chain 7-6-5-o-3

! Round wire to reduce Friction

! Lower force to reduce Binding & Notching

Re.Ba. 0906

Re.Ba. 0107

Re.Ba. 1007

Re.Ba. 0907


Sliding a single tooth

• .021 x .021 x .020 HDG

• Compressed coil 22-24

! Round wire reduced Friction

! Low force reduced Binding & Notching

• Auxilliary wire .016

• .016 x .022 HA niti

Re.Ba. 0906

Re.Ba. 0107

Re.Ba. 0907

Re.Ba. 1007

• Mx: 021x021x020: #13 is retracted individually

Es.Gr1210

• Md: 021x021x020: #46 is protracted + upright spring to increase anchorage

• Mx: $ E link: space is opening mesially

• Md: New 021x021x020 X 58 mm ! To include 1st premolar! Increase wire stiffness

• Mx: $ 020 SS wire. ! Class I canine achieved ! Elastomeric chain activated ~ 2 mm

for the lateral

• Md: $ E link

Es.Gr0111

Es.Gr0311


Rate of tooth movement under heavy and light continuous orthodontic forces

Yee J.A., Elekdag-Türk T., Cheng LL, Darendeliler MA, AJODO 2009; 136:150e1-150e9

• Initial tooth mvt benefits from light forces

• Heavy forces increased rate of tooth mvt and amount of canine retraction BUT increased anchorage loss and loss of canine rotation control

• Maximum anchorage cases benefits from light forces


Tipping and translating

• Distal tipping + rotation

• T-loop for root uprighting

Am.Bu. 0800

Am.Bu. 0101 Am.Bu. 1000

Am.Bu. 0500


Hills DUAL-GEOMETRY Wire™

• Made of an ultra-high tensile strength stainless steel for optimum stiffness.

• Full sized square anterior section fills the slot of optimal torque control

! Torque play = 5°; Effective torque ! 6°

• Rounded posterior section is polished to minimize friction

! Estimated torquing moment: ~ 15 Nmm

.021 X .021 X .020


Hills DUAL-GEOMETRY Wire™

Anterior section - square

Posterior section- round

•Mx:!38 mm: to include 4 incisors!55 mm: to include canine to canine

•Md:!45 mm: to include canine to canine!58 mm: 1st premolar to 1st premolar


En masse retraction

Downloaded from: Proffit: Contemporary Orthodontics, 4th edition (on 3 May 2007 06:18 PM)© 2007 Elsevier

• .021 X .021 X .020 Hills Dual geometry

• Cl I module: E-Link E-5

! Force 100 to 125 g

• Reverse curve of Spee

! Moment to counteract tipping

! Posterior toe in or constriction


• Translation: ~ 100 g

! To maintain torque control when closing space

! Use low force module

Force system

Downloaded from: Proffit: Contemporary Orthodontics, 4th edition (on 3 May 2005

(M/F =10:1)


01-03

11-03

05-03

• Enmasse space closure

! 021 X 025 SS + oxydoreduction of the posterior section distal to 1st premolar

• Molar protraction

! Note that flat curve of Spee is maintained


08-04

09-04

11-04

Enmasse retraction: Anchorage A

• .021 x .025 SS DG

! Upright spring on /3's

! E5, 75g/side

! Protraction of lower 5's

• .021 x .021 x .020 HDG

! OJ and Cl I molar relationship is improving

$ E-links 5

$ E-links 5


12-04

01-05

03-05

• Use cl II to improve molar relationship

• Upright spring to PM2

• E6 47-P; E5 P-36


Molar protraction

01-05 03-05

09-04 11-04 12-04

04-05

• Time: 8 months

• Note space opening between the premolar and the molar


.021 x .025 SS + oxydoreduction

Space close in 5 months

Flat curve of Spee is maintained

Pa.Ge.0803

Pa.Ge.1003

Pa.Ge.0104


• Adult, cl II div 1, missing #36

• Tx plan:_________

Ka.Sw.200504

Ka.Sw.050804


• Note space opening distal to 46 & 37

• Once 46 is contacting 44, start protraction of 47

Ka.Sw.300505 at 1 year into tx

Ka.Sw.210905


• TPA removal, reassessment of Bk position, cl II elastic

Ka.Sw.191005


• Duration: 108 weeks

Ka.Sw.160106

Ka.Sw.260606

Ka Sw


Moment / Force

• Problem

! Loss of incisor torque

! Mx: reverse curve of spee

! Md: increased curve of spee

•Solution: Mc > MF

–Increase moment at the wire/bk interface!! wire stiffness!RC in Md!AC in Mx

–Reduced force level

Mc / Mf > 1


Molar protraction

• Enmasse .021 x .021 x .020

• E-links : 7's - hook

Fo.Mi 1208

Fo.Mi 0206

Fo.Mi 0407


Mi.Fo. 0206

Mi.Fo. 1208


Molar protraction

• Enmasse .021 x .021 x .020

• E-links : 6's - hook

• Uprighting spring 17-15

! to overcome tipping in the 2nd orderDa.Ga.210209 Da.Ga.300910


Molar protraction

• Such large protraction of the 2nd molar resulted in mesial rotation in the 1st order

• Class I force module from the lingual helped to correct rotation in the 1st order while the uprighting spring corrected the tipping in the 2nd order

Da.Ga. 0109 Da.Ga. 0410 Da.Ga. 0910


2nd Molar Protraction

Na.Ru.140907

Tx initiated: Dec 07

Na.Ru.261009

Na.Ru.030809 At 19 m

At 23 m

Na.Ru.121010

Na.Ru.121010 At 34 m


Enmasse incisor retraction

• .017 x .025 ß-Ti mushroom wire

• Preactivation bend

! Accentuated curve of Spee

! Anterior step up

! Posterior toe in

• Activation

! Pull & cinch


Bé.-De. Sa 120802

• .017 x .025 TMA mushroom loop

Frictionless anterior retraction

Bé.-De. Sa 220902

Phases of treatmentFinishing


SPEED Wire™

•Active • Passively seated• Actively maintained

• Spring-Clip activated by "cam" action of SPEED archwire

• Archwire and archwire slot in perfect alignment

• Torque play on top• Wire is seated at the

bottom of the slot

Seating the spring clip 0.01 mm created an arc of 5,4 mm at the apex

• Torque play! .020 x .025 ! 4°

• Effective torque! .020 x .025 ! 7°


Other finishing wireD-Wire

D-Wire• Torque play

! .021 x .021 = 5°

• Effective torque! .021 x .021 = 6°

.019 x .025 SS or %-Ti

• Torque play! .019 x .025 = 10.5°

• Effective torque! .019 x .025 = ±9°

(for the lower anteriors)! .019 x .025 = 5°

(for upper anteriors)

.020 x .020 SS• Torque play

! .020 x .020 ! 6°to 7°

• Effective torque! .020 x .020 ! 4° to 5°


Finishing

• Prior to surgery .020 x .025 SW + finishing bend

• Root torque achieved

Ca.Gr.0309Ca.Gr.0907

Ca.Gr.0907 Ca.Gr.1208 Ca.Gr.0309

Ca.Gr.1208


3rd order problem

• Most of my problems encountered in the 3rd order plane of space where caused because I used (from 1998 to 2005) an undersized .019 x .025 archwire (SS or %-Ti)during finishing stage

• Since I reintroduced .020 X .025 or .021 X .025 archwire, I significantly reduced the needs of torquing spring in finishing except for a few particular situations

Ev. Ca.0507 Ev. Ca.0309

Ev. Ca.0909

Lingual root torqueLabial root torque


Torque issue in finishing stage

Da.Pa 0908.

Da.Pa 0706

Da.Pa 280109

• Engaging a continuous archwire will cause 3rd order discepancy that will need to be address in the finishing stage

• .020 x .025SS was engaged in June. Torquing spring were added in september• Adequate alignement of incisors's talon was achieved in January


• Tx time = 130 weeks

• Got it straight + a new born baby

An.No 05-7, tx initiated 0607

An.No 12-09



• Tx time: 92 weeks

• Slight residual midline deviation

Ja.Le. 07-8, tx initiated 0808

Ja.Le. 05-10

Md deviation

©Dr Sylvain Chamberland$ issues explain /8's


• Tx time: 92.7 weeks

Ta.Po. 09-08, tx initiated 011008

Ta.Po. 12-07-10

11 y. 4 m.


1/ :Torque improved


Class IIISevere ALD

Vi.Lé.02-10-07

• Hopeless #16 (UR 1st molar)

• Mx midline deviated to the right


• Dentoalveolar Protrusion

• Lower lip procumbency


Tx planning

• Tx goals

! Reduce lip procumbency

! Obtain coincident midline

! Achieve cl I canine

! Achieve cl I molar on the left

! Achieve cl III molar on the right

• Extraction: ?


• Mx:.020 x .020 neost + .016 SC

• Md: .021 x .021 x .020 enmasse retract.

Vi.Lé.03-07-08


• At 50 weeks

• Mx: .016 X .022 neost; #13 engaged

Vi.Lé. 01-10-08


• Reassessment of bracket position

! 14, 13, 12, 11, 22, 23, 24, 33


• At 67 weeks

• Mx & Md: .019 x.025 Resol, finishing bend

Vi.Lé. 28-01-09


• At 75 weeks

• Mx: .019 x .025 resol., finishing bend 21, 12

• Md: .020 x .025 SW, finishing bend 43, 45

Vi.Lé. 23-03-2009


• At 87 weeks or 20 months

Vi.Le. 15-06-09


Vi.Le. 0609

Health & Medicine

How SPEED Appliance is Effective in Torque Control, Space Closure and Sliding Mechanics