Seminars in Orthodontics Self Ligating Brackets1890

40
Seminars in Seminars in Orthodontics: Orthodontics: Self-Ligating Self-Ligating Brackets Brackets Dr. Adam Cohen Dr. Adam Cohen UMDNJ Orthodontics UMDNJ Orthodontics November 17th, 2008 November 17th, 2008

description

self ligation in orthodontics

Transcript of Seminars in Orthodontics Self Ligating Brackets1890

Page 1: Seminars in Orthodontics Self Ligating Brackets1890

Seminars in Seminars in Orthodontics: Orthodontics: Self-Ligating Self-Ligating

BracketsBracketsDr. Adam CohenDr. Adam Cohen

UMDNJ OrthodonticsUMDNJ Orthodontics

November 17th, 2008November 17th, 2008

Page 2: Seminars in Orthodontics Self Ligating Brackets1890

History of Self-ligating History of Self-ligating bracketsbrackets

Self-ligating brackets do not require an Self-ligating brackets do not require an elastic or wire ligature to secure the elastic or wire ligature to secure the archwirearchwire

Rather they have an internal Rather they have an internal mechanism that allows opening and mechanism that allows opening and closure with either an instrument or closure with either an instrument or fingertipfingertip

In 1935 Stolzenberg introduce the first In 1935 Stolzenberg introduce the first self-ligating bracket - Russell Lock self-ligating bracket - Russell Lock edgewise attachmentedgewise attachment

Since then there have been a variety of Since then there have been a variety of SLB’s available, with a recent surge in SLB’s available, with a recent surge in popularity over the last 8 years or sopopularity over the last 8 years or so

Page 3: Seminars in Orthodontics Self Ligating Brackets1890

Self Ligating Bracket Self Ligating Bracket TypesTypes

Russell Lock - 1935Russell Lock - 1935 Ormco Edgelok - 1972Ormco Edgelok - 1972 Forestadent Mobil-Lock - 1980Forestadent Mobil-Lock - 1980 Forestadent Begg - 1980Forestadent Begg - 1980 Strite Industries SPEED - 1980Strite Industries SPEED - 1980 ““A” Company Activa - 1986A” Company Activa - 1986 Adenta Time - 1996Adenta Time - 1996 ““A” Company Damon SL - 1996A” Company Damon SL - 1996 Ormco TwinLock - 1998Ormco TwinLock - 1998 Ormco/ “A” Co. Damon 2 - 2000Ormco/ “A” Co. Damon 2 - 2000 GAC In-Ovation - 2000GAC In-Ovation - 2000 Gestenco Oyster - 2001Gestenco Oyster - 2001 GAC In-Ovation R - 2002GAC In-Ovation R - 2002 Adenta Evolution LT - 2002Adenta Evolution LT - 2002 Ultradent OPAL - 2004Ultradent OPAL - 2004 Ormco Damon 3 2004Ormco Damon 3 2004 3M Unitek Smart Clip - 20043M Unitek Smart Clip - 2004 Ormco Damon 3 MX - 2005Ormco Damon 3 MX - 2005 Ultradent OPAL metal - 2006Ultradent OPAL metal - 2006 Forestadent Quick - 2004Forestadent Quick - 2004 Lancer Praxis Glide - 2004Lancer Praxis Glide - 2004 Class I/Ortho Organisers Carriere LX - 2004Class I/Ortho Organisers Carriere LX - 2004

Page 4: Seminars in Orthodontics Self Ligating Brackets1890

Properties of an ideal Properties of an ideal ligation systemligation system

Be secure and robustBe secure and robust Ensure full bracket engagementEnsure full bracket engagement Exhibit low friction between bracket and Exhibit low friction between bracket and

archwirearchwire Be quick and easy to useBe quick and easy to use Permit easy attachment of elastic chainsPermit easy attachment of elastic chains Assist good oral hygieneAssist good oral hygiene Be comfortable for the patientBe comfortable for the patient

Page 5: Seminars in Orthodontics Self Ligating Brackets1890

Secure LigationSecure Ligation

Should be no loss of ligation Should be no loss of ligation between appointmentsbetween appointments

Wire ligatures are reliable while Wire ligatures are reliable while elastomeric ligatures are lesselastomeric ligatures are less

Page 6: Seminars in Orthodontics Self Ligating Brackets1890

Full Bracket EngagementFull Bracket Engagement

Want archwire to be fully engaged in Want archwire to be fully engaged in bracketbracket

Wire ligatures allow this and can be Wire ligatures allow this and can be maintained over the lifetime of an maintained over the lifetime of an appointmentappointment

Elastomerics can exert insufficient force Elastomerics can exert insufficient force to fully engage and also degrade as the to fully engage and also degrade as the elastomer stretches over timeelastomer stretches over time

Page 7: Seminars in Orthodontics Self Ligating Brackets1890

Low FrictionLow Friction Frictional forces arising from ligation add Frictional forces arising from ligation add

additional resistance that must be overcome additional resistance that must be overcome by higher forcesby higher forces

This results in a net effective force that is This results in a net effective force that is difficult to assess and a binding force that is difficult to assess and a binding force that is higher between bracket and wirehigher between bracket and wire

Wire ligatures produce lower friction then Wire ligatures produce lower friction then elastomeric ligatureselastomeric ligatures

However, wire ligatures can also result in However, wire ligatures can also result in high and variable levels of friction relative to high and variable levels of friction relative to the force levels optimal for tooth movementthe force levels optimal for tooth movement

Page 8: Seminars in Orthodontics Self Ligating Brackets1890

Static versus Dynamic Static versus Dynamic FrictionFriction

Static friction - the force between two objects Static friction - the force between two objects having no motion; being at resthaving no motion; being at rest

Dynamic (sliding or rolling) friction - to move over Dynamic (sliding or rolling) friction - to move over a surface while maintaining continuous contacta surface while maintaining continuous contact

Friction is affected by bracket material, bracket Friction is affected by bracket material, bracket design, archwire material and shape, ligation design, archwire material and shape, ligation method, bracket-archwire angulation and dynamic method, bracket-archwire angulation and dynamic forcesforces

Although several of these variables are out of our Although several of these variables are out of our control, the use of SLBs can greatly reduce control, the use of SLBs can greatly reduce friction between the archwire and bracket friction between the archwire and bracket

Page 9: Seminars in Orthodontics Self Ligating Brackets1890

Quick and Easy to useQuick and Easy to use

Significant disadvantage of wire Significant disadvantage of wire ligationligation

Page 10: Seminars in Orthodontics Self Ligating Brackets1890

Easy Attachment of Easy Attachment of Elastic ChainElastic Chain

Tie wings on conventional brackets Tie wings on conventional brackets make attachment of elastic chain make attachment of elastic chain very convenientvery convenient

Some SLBs have no tie wingsSome SLBs have no tie wings

Page 11: Seminars in Orthodontics Self Ligating Brackets1890

Maintenance of Optimal Maintenance of Optimal Oral HygieneOral Hygiene

Most people feel that elastomerics result Most people feel that elastomerics result in more plaque accumulation then wire in more plaque accumulation then wire ligaturesligatures

There are some studies that support thisThere are some studies that support this Forsberg et al. Ligature wires and elastomeric rings: two Forsberg et al. Ligature wires and elastomeric rings: two

methods of ligation, and their association with microbial methods of ligation, and their association with microbial colonization of Streptococcus mutans and lactobacilli. 1991. colonization of Streptococcus mutans and lactobacilli. 1991. Eur J Orthod. 13:416-420.Eur J Orthod. 13:416-420.

There are other studies that found no There are other studies that found no differencedifference Sukotapatipark et al. A scanning electron microscopy study. Sukotapatipark et al. A scanning electron microscopy study.

2001. Eur J Orthod. 23:475-484. 2001.2001. Eur J Orthod. 23:475-484. 2001.

Page 12: Seminars in Orthodontics Self Ligating Brackets1890

Patient ComfortPatient Comfort

Elastomerics are easy for the patient Elastomerics are easy for the patient to handleto handle

Wire ligatures require careful Wire ligatures require careful tucking of the ends to avoid tucking of the ends to avoid emergency visitsemergency visits

Page 13: Seminars in Orthodontics Self Ligating Brackets1890

Limitations of Limitations of Conventional LigationConventional Ligation

Inability to provide and maintain full Inability to provide and maintain full archwire engagementarchwire engagement

Increased frictionIncreased friction Elastomeric force decay resulting in Elastomeric force decay resulting in

non-optimal tooth controlnon-optimal tooth control Ligatures can become displacedLigatures can become displaced Wire ligation is time consumingWire ligation is time consuming

Page 14: Seminars in Orthodontics Self Ligating Brackets1890

Core Advantages of SLBsCore Advantages of SLBs

Full archwire engagementFull archwire engagement Low friction between bracket and Low friction between bracket and

archwirearchwire Less chairtime assistance neededLess chairtime assistance needed Faster archwire removal and ligationFaster archwire removal and ligation

Page 15: Seminars in Orthodontics Self Ligating Brackets1890

Low Friction and Secure Low Friction and Secure Full AW Engagement Full AW Engagement

Study by Srinivas (postgraduate thesis in Study by Srinivas (postgraduate thesis in India)India)

Split Mouth study of canine retraction - Split Mouth study of canine retraction - Damon SL on once side and conventional Damon SL on once side and conventional bracket on the other sidebracket on the other side

Damon side resulted inDamon side resulted in More rapid retraction (.24mm per month)More rapid retraction (.24mm per month) Shorter duration for 3mm retraction (12 wks v. Shorter duration for 3mm retraction (12 wks v.

16wks)16wks) Less rotation (8 degrees v. 12 degrees)Less rotation (8 degrees v. 12 degrees) Less anchorage loss (.3mm)Less anchorage loss (.3mm)

Page 16: Seminars in Orthodontics Self Ligating Brackets1890

Alignment of Severely Alignment of Severely mal-aligned teethmal-aligned teeth

Combination of low friction and secure Combination of low friction and secure archwire engagement is useful for archwire engagement is useful for aligning very irregular teethaligning very irregular teeth

With low friction the wire is able to With low friction the wire is able to slide through the brackets of the slide through the brackets of the rotated teeth resulting in rapid rotated teeth resulting in rapid uncrowdinguncrowding

Full engagement results in full control Full engagement results in full control while sliding teeth along the archwirewhile sliding teeth along the archwire

Page 17: Seminars in Orthodontics Self Ligating Brackets1890

Lack of Adoption of SLBsLack of Adoption of SLBs Widespread use of these brackets has been Widespread use of these brackets has been

hindered, until recently, due to several hindered, until recently, due to several problems with bracket design - some problems with bracket design - some examples includeexamples include SPEED: early brackets had clips that were easily SPEED: early brackets had clips that were easily

displaced or brokendisplaced or broken Mobil-Lock: narrowness of the resulting labial Mobil-Lock: narrowness of the resulting labial

face of the slot resulting in poor rotational face of the slot resulting in poor rotational controlcontrol

Activa Brackets: absence of wings, abnormal Activa Brackets: absence of wings, abnormal base shapebase shape

Damon SL: inadvertent opening of the slide, Damon SL: inadvertent opening of the slide, prone to breakageprone to breakage

Page 18: Seminars in Orthodontics Self Ligating Brackets1890

SPEEDSPEED The Speed appliance was developed in the 1970s by Dr. The Speed appliance was developed in the 1970s by Dr.

Herbert Hanson (from Canada)Herbert Hanson (from Canada)

Has been commercially available since 1980.Has been commercially available since 1980. It is a miniaturized self-ligating bracket with an active It is a miniaturized self-ligating bracket with an active

super elastic NiTi spring clip to entrap the archwiresuper elastic NiTi spring clip to entrap the archwire Archwire engagement can result in elastic deflection of the Archwire engagement can result in elastic deflection of the

spring clipspring clip The deflection of the spring clip represents energy stored The deflection of the spring clip represents energy stored

in the spring clip, and as the bracket and its accompanied in the spring clip, and as the bracket and its accompanied tooth are reoriented relative to the archwire, energy is tooth are reoriented relative to the archwire, energy is releasedreleased

Page 19: Seminars in Orthodontics Self Ligating Brackets1890

Advantages of DesignAdvantages of Design

•Highly flexible NiTi clip

•Minimal Friction during sliding mechanics

•Extended range of activation due to energy stored in clip

•Large interbracket span

•Spring clip will not deform or fatigue

•Horizontal auxiliary slot

Page 20: Seminars in Orthodontics Self Ligating Brackets1890

Treatment Philosophy - As outlined by Treatment Philosophy - As outlined by Dr. HansonDr. Hanson

Try to treat without extractions in any case that has the Try to treat without extractions in any case that has the necessary potentialnecessary potential

If extractions necessary, extract 2nd bicuspids to minimize If extractions necessary, extract 2nd bicuspids to minimize any reduction in prominence of dentitionany reduction in prominence of dentition

Preliminary functional appliances as necessary to favorably Preliminary functional appliances as necessary to favorably alter jaw growth if possiblealter jaw growth if possible

Use intraoral distalization instead of headgearUse intraoral distalization instead of headgear Expand arches that have failed to develop to their full Expand arches that have failed to develop to their full

potentialpotential In patients that exhibit lots of gingival tissue, intrude upper In patients that exhibit lots of gingival tissue, intrude upper

anterior teethanterior teeth Correct tooth rotations to ideal alignment without Correct tooth rotations to ideal alignment without

overcorrection - rely on IPR and circumferential supra-crestal overcorrection - rely on IPR and circumferential supra-crestal fiberotomies to enhance retentionfiberotomies to enhance retention

Overcorrect Class II/III where strong tendency for relapse Overcorrect Class II/III where strong tendency for relapse occursoccurs

Page 21: Seminars in Orthodontics Self Ligating Brackets1890

SPEED picturesSPEED pictures

The SPEED finishing archwire has a quarter round shape, which facilitates archwire insertion, spring closure, and is highly effective in torque control.

Supercable consists of seven strands of superelastic nickel titanium wire in a coaxial form. It is impossible to permanently deform Supercable regardless of the malalignment of the dentition. (B) The combined effect of the initial light multistrand Supercable archwire, the wide interbracket span between the narrow SPEED brackets, and the energy storing capability of the spring clip greatly increases the range of appliance activation.

Page 22: Seminars in Orthodontics Self Ligating Brackets1890

DAMONDAMON

Damon Philosophy - use just enough force to initiate tooth Damon Philosophy - use just enough force to initiate tooth movementmovement

Want this force to be low enough to prevent occluding blood Want this force to be low enough to prevent occluding blood vessels in the PDL and allow cells the ability to transport vessels in the PDL and allow cells the ability to transport messengers necessary to produce bone resorption and appositionmessengers necessary to produce bone resorption and apposition

Is a passive-self ligation system - it is suggested that this type of Is a passive-self ligation system - it is suggested that this type of system results in system results in Less anchorage requirementsLess anchorage requirements Less intraoral expansion - because the force of the AW is not Less intraoral expansion - because the force of the AW is not

transformed or absorbed by the ligaturestransformed or absorbed by the ligatures Less need for extractionsLess need for extractions Low levels of static and dynamic frictionLow levels of static and dynamic friction Rigid ligationRigid ligation Control of tooth positionControl of tooth position

The Damon Evolution

-> -> -> ?

Page 23: Seminars in Orthodontics Self Ligating Brackets1890

Effects of Passive Effects of Passive Ligation on FrictionLigation on Friction

Many authors (Thomas et al. 1998 Eur J Orthod, Pizzoni et Many authors (Thomas et al. 1998 Eur J Orthod, Pizzoni et al. 1998 Eur J Orthod, Khambay et al. 2004 Eur J Orthod) al. 1998 Eur J Orthod, Khambay et al. 2004 Eur J Orthod) have found that static friction measured in vitro is much have found that static friction measured in vitro is much less with a passive self ligating appliance that any other less with a passive self ligating appliance that any other type of fixed appliancetype of fixed appliance

When angulation or inclination is applied to the bracket When angulation or inclination is applied to the bracket friction is generated, however it is less for SLB’s than for friction is generated, however it is less for SLB’s than for conventional ligationconventional ligation Figure showing static

friction for passive, active, TipEdge, and conventionally ligated brackets. The value for the passive self-ligating Damon SL bracket was zero except for with the 0.019″ × 0.025″ stainless steel archwire.

The wires were drawn through the brackets and the frictional resistance was measured using an Instron 1193 testing machine.

Page 24: Seminars in Orthodontics Self Ligating Brackets1890

High versus Low Torque High versus Low Torque BracketsBrackets

High Torque Upper High Torque Upper IncisorsIncisors Extraction casesExtraction cases Class II Div I where Class II Div I where

mechanics might mechanics might excessively retrocline excessively retrocline teethteeth

Class II Div IIClass II Div II High Torque Upper High Torque Upper

caninescanines First PM extraction First PM extraction

casescases When crowns of upper When crowns of upper

cuspids are palatally cuspids are palatally tippedtipped

Low Torque Upper incisorsLow Torque Upper incisors Excessively Proclined upper Excessively Proclined upper

incisorsincisors Isolated upper incisors with Isolated upper incisors with

palatally displaced rootspalatally displaced roots Malocclusions where Tx Malocclusions where Tx

mechanics may result in mechanics may result in excessive upper incisor excessive upper incisor proclinationproclination

Moderate and severe upper Moderate and severe upper arch crowdingarch crowding

Anterior open bite casesAnterior open bite cases Low Torque Lower IncisorsLow Torque Lower Incisors

Cases where control is needed Cases where control is needed to avoid proclination of lower to avoid proclination of lower incisors (extreme lower labial incisors (extreme lower labial segment crowding, Class II segment crowding, Class II elastics, fixed class II elastics, fixed class II correctorscorrectors

Page 25: Seminars in Orthodontics Self Ligating Brackets1890

Stages of TreatmentStages of Treatment

Phase 1Phase 1 - Light Round High Technology Wires (.013, .014 or .016 CuNiTi)- Light Round High Technology Wires (.013, .014 or .016 CuNiTi) Level the arches, excluding 2nd molarsLevel the arches, excluding 2nd molars Correct all anterior rotations and partial correction of posterior rotationsCorrect all anterior rotations and partial correction of posterior rotations Initiate arch development with use of light forces to allow soft tissue to influence Initiate arch development with use of light forces to allow soft tissue to influence

arch shapearch shape Phase 2 - Phase 2 - High Technology Rectangular Wires (14x25 CuNiTi --> 18x25 CuNiTi or High Technology Rectangular Wires (14x25 CuNiTi --> 18x25 CuNiTi or

16x25 CuNiti)16x25 CuNiti) Fully correct all rotationsFully correct all rotations Consolidate any anterior space Consolidate any anterior space Initiate torque controlInitiate torque control Initiate bite openingInitiate bite opening Continue arch developmentContinue arch development Use of .025 in first order dimension is critical to obtain tooth alignment by almost Use of .025 in first order dimension is critical to obtain tooth alignment by almost

completely filing the .027 slot depthcompletely filing the .027 slot depth Phase 3 - Phase 3 - Major Mechanics (19x25 pre-posted stainless steel archwires)Major Mechanics (19x25 pre-posted stainless steel archwires)

Maintain archformMaintain archform Finish torque controlFinish torque control Consolidate posterior spaceConsolidate posterior space Completely correct AP, buccolingual and vertical relationshipsCompletely correct AP, buccolingual and vertical relationships

Phase 4 - Phase 4 - Finishing and DetailingFinishing and Detailing Can continue use of SS AW’s or can use 19x25 TMA for individual adjustmentsCan continue use of SS AW’s or can use 19x25 TMA for individual adjustments

Page 26: Seminars in Orthodontics Self Ligating Brackets1890

Damon Case Damon Case PresentationPresentation

14 years old

Page 27: Seminars in Orthodontics Self Ligating Brackets1890

12 Months into Tx

1 yr post-retention (26 month Tx)

Page 28: Seminars in Orthodontics Self Ligating Brackets1890

•Lower Cast Measurements•Intercanine: 19.2 29.4•Inter 1st Premolar 29.6 38.1•Inter 2nd Premolar: 38.2 43.8•Inter 1st Molar: 49.9 50.7

•IMPA – 87.4 97.8•L1-Apo: 0.2 3.4

Page 29: Seminars in Orthodontics Self Ligating Brackets1890

In-OvationIn-Ovation

Page 30: Seminars in Orthodontics Self Ligating Brackets1890

In-OvationIn-Ovation

Innovation RInnovation R – the standard In-ovation – the standard In-ovation bracket we use in clinicbracket we use in clinic

Innovation CInnovation C - esthetic innovation brackets - esthetic innovation brackets Innovation L MTMInnovation L MTM - indirect bonding of - indirect bonding of

anterior teeth (3-3) with these lingual braces, anterior teeth (3-3) with these lingual braces, no wire changesno wire changes

Innovation LInnovation L - lingual innovation braces - lingual innovation braces

Innovation brackets open from the gingival Innovation brackets open from the gingival margin -margin -

Page 31: Seminars in Orthodontics Self Ligating Brackets1890

In-Ovation RIn-Ovation R Bracket design has a closing clip that can apply Bracket design has a closing clip that can apply

pressure or no pressure to the archwire as the pressure or no pressure to the archwire as the situation requires situation requires

This bracket was designed to be a passive or active This bracket was designed to be a passive or active SLBSLB

The clip secures the AW into place but also allows The clip secures the AW into place but also allows the clip to flex buccally if the wire is not fully seatedthe clip to flex buccally if the wire is not fully seated

At max flex the clip can apply 250 g of forceAt max flex the clip can apply 250 g of force

Page 32: Seminars in Orthodontics Self Ligating Brackets1890

In-Ovation RIn-Ovation R Our In-Ovation bracket has an .022 slotOur In-Ovation bracket has an .022 slot

To completely fill the slot without impinging To completely fill the slot without impinging on the clip you would want to place an .022 on the clip you would want to place an .022 x .018 wire x .018 wire

Fully seating this .022 x .018 results in full Fully seating this .022 x .018 results in full in-out, tip and torque control without clip in-out, tip and torque control without clip frictionfriction

Page 33: Seminars in Orthodontics Self Ligating Brackets1890

Smart ClipSmart Clip

NiTi clip mechanism that retains the NiTi clip mechanism that retains the wire by two C-shaped spring slips on wire by two C-shaped spring slips on either side of the bracket sloteither side of the bracket slot

The wire contains no moving door or The wire contains no moving door or latch and thus are the only true self-latch and thus are the only true self-ligating bracketsligating brackets

MBT prescriptionMBT prescription The force required for the removal and The force required for the removal and

insertion of heavy stainless steel wires insertion of heavy stainless steel wires is often uncomfortable for patients is often uncomfortable for patients

Page 34: Seminars in Orthodontics Self Ligating Brackets1890

Active Clip or Passive Active Clip or Passive Slide?Slide?

Active Clips - SPEED, In-Ovation, Quick Brackets, Active Clips - SPEED, In-Ovation, Quick Brackets, Time2 (American ortho)Time2 (American ortho)

Passive - Damon, Smart clip, Praxis Glide, and Passive - Damon, Smart clip, Praxis Glide, and Carriere LXCarriere LX

Intended benefit of storing some force in the clip - “a Intended benefit of storing some force in the clip - “a given wire will have its range of labiolingual action given wire will have its range of labiolingual action extended and produce more alignment than would a extended and produce more alignment than would a passive slide with the same dimension wire”passive slide with the same dimension wire”

However, with increased clearance between a given However, with increased clearance between a given wire and a passive slide, lower forces will be wire and a passive slide, lower forces will be generated along with less binding to possibly allow generated along with less binding to possibly allow teeth to push each other as they slide along the wireteeth to push each other as they slide along the wire

Not many studies have been done to assess the Not many studies have been done to assess the effectiveness of active versus self ligation at this pointeffectiveness of active versus self ligation at this point

Page 35: Seminars in Orthodontics Self Ligating Brackets1890

Current Current Literature…Literature…

Page 36: Seminars in Orthodontics Self Ligating Brackets1890

Evaluation of frictional forces during dental Evaluation of frictional forces during dental alignment: an experimental model with 3 alignment: an experimental model with 3

nonleveled bracketsnonleveled brackets

Aim of study was to evaluate frictional forces generated by Aim of study was to evaluate frictional forces generated by various combinations of brackets and orthodontic wiresvarious combinations of brackets and orthodontic wires

Used passive self-ligating brackets (Damon SL2) and Used passive self-ligating brackets (Damon SL2) and conventional twin SS bracketsconventional twin SS brackets

Tests 3 NiTi wires (.014, .016, .016x.022), 2 SS Tests 3 NiTi wires (.014, .016, .016x.022), 2 SS multistranded wires, and 1 TMAmultistranded wires, and 1 TMA

Used elastic ligatures and SST’s for the twin bracketsUsed elastic ligatures and SST’s for the twin brackets Each 10-bracket AW combo was tested 10 timesEach 10-bracket AW combo was tested 10 times The ability of the wire to slide through the bracket was The ability of the wire to slide through the bracket was

influenced by wire-cross section dimension, wire material, influenced by wire-cross section dimension, wire material, number of wire strands, and type of ligationnumber of wire strands, and type of ligation

Overall conclusions were that frictional forces can be Overall conclusions were that frictional forces can be greatly reduced through the use of SLBs, smaller diameter greatly reduced through the use of SLBs, smaller diameter wires and less stiff wireswires and less stiff wires

Page 37: Seminars in Orthodontics Self Ligating Brackets1890

Torque Expression of Torque Expression of Self Ligating BracketsSelf Ligating Brackets

Purpose of the study was to measure the difference in 3rd Purpose of the study was to measure the difference in 3rd order moments that can be delivered by engaging a 19x25 order moments that can be delivered by engaging a 19x25 SS AW to various bracketsSS AW to various brackets

2 Active SLBs were used - In-Ovation and SPEED2 Active SLBs were used - In-Ovation and SPEED 2 Passive SLBs were used - Damon2 and Smart Clip2 Passive SLBs were used - Damon2 and Smart Clip A bracket/wire assembly torsion device was used - is able to A bracket/wire assembly torsion device was used - is able to

apply torsion to a wire while maintaining perfect vertical apply torsion to a wire while maintaining perfect vertical and horizontal alignment between the wire and the bracketand horizontal alignment between the wire and the bracket

The torque was then measured by a multi-axis force/torque The torque was then measured by a multi-axis force/torque transducertransducer

Results showed that torque started to be expressed at lower Results showed that torque started to be expressed at lower degrees of torsion (7.5) for the active SLBs versus the degrees of torsion (7.5) for the active SLBs versus the passive SLBs (15)passive SLBs (15)

Concluded that active SLBs are more effective in torque Concluded that active SLBs are more effective in torque expressionexpression

Page 38: Seminars in Orthodontics Self Ligating Brackets1890

External apical root resorption in External apical root resorption in patients with conventional and self-patients with conventional and self-

ligating bracketsligating brackets Aim was to investigate the amount of Aim was to investigate the amount of

external apical root resorption between external apical root resorption between conventional and passive SLBs (Damon2)conventional and passive SLBs (Damon2)

96 patients selected96 patients selected Pts received Tx with either SLBs or Pts received Tx with either SLBs or

conventional brackets with .022 slotconventional brackets with .022 slot No difference was found in the amount of No difference was found in the amount of

EARR, but a positive association existed EARR, but a positive association existed between EARR and duration of TXbetween EARR and duration of TX

Page 39: Seminars in Orthodontics Self Ligating Brackets1890

Alignment efficiency of Damon3 self-ligating Alignment efficiency of Damon3 self-ligating and conventional orthodontic bracket system: and conventional orthodontic bracket system:

A randomized clinical trialA randomized clinical trial

Aim of this study was to compare the efficiency of Aim of this study was to compare the efficiency of mandibular tooth alignment and the clinical mandibular tooth alignment and the clinical effectiveness of a self-ligating (Damon 3) and a effectiveness of a self-ligating (Damon 3) and a conventional preadjusted orthodontic bracket (Ormco conventional preadjusted orthodontic bracket (Ormco bracket).bracket).

62 pts from 2 orthodontic clinics (32 male, 30 female) 62 pts from 2 orthodontic clinics (32 male, 30 female) with mandibular incisor irregularities (Little’s with mandibular incisor irregularities (Little’s Irregularity Index) of 5 to 12mm and prescribed Irregularity Index) of 5 to 12mm and prescribed extraction pattern including the mandibular first extraction pattern including the mandibular first premolarspremolars

Wire sequence: .014 NiTi Wire sequence: .014 NiTi 14x25 Niti 14x25 Niti 18x25 NiTi 18x25 NiTi 19x25SS19x25SS

No difference in the initial or the overall rate of No difference in the initial or the overall rate of mandibular incisor alignment between the two bracket mandibular incisor alignment between the two bracket typestypes

Only significant influence of initial rate of alignment was Only significant influence of initial rate of alignment was the amount of initial irregularitythe amount of initial irregularity

Page 40: Seminars in Orthodontics Self Ligating Brackets1890

ReferencesReferences Sadowsky, PL. Self-Ligating Orthodontic Brackets. 2008. Seminars in Sadowsky, PL. Self-Ligating Orthodontic Brackets. 2008. Seminars in

Orthodontics. 14(1).Orthodontics. 14(1). Scott P, DiBiase A, Sherriff M, Cobourne M. Alignment efficiency of Damon3 Scott P, DiBiase A, Sherriff M, Cobourne M. Alignment efficiency of Damon3

self-ligating and conventional orthodontic bracket systems: A randomized self-ligating and conventional orthodontic bracket systems: A randomized clinical trial. 2008. Am J Orthod Dentofacial Orthop. 134:470.e1-470.e8.clinical trial. 2008. Am J Orthod Dentofacial Orthop. 134:470.e1-470.e8.

Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root Pandis N, Nasika M, Polychronopoulou A, Eliades T. External apical root resorption in patients treated with conventional and self-ligating brackets. resorption in patients treated with conventional and self-ligating brackets. 2008. Am J Ortho Dentofacial Orthop. 134:646-51.2008. Am J Ortho Dentofacial Orthop. 134:646-51.

Matarese G, Nucera R, Militi A, Mazza M, Portelli M, Festa F, Cordasco G. Matarese G, Nucera R, Militi A, Mazza M, Portelli M, Festa F, Cordasco G. Evaluation of frictional forces during dental alignment: An experimental Evaluation of frictional forces during dental alignment: An experimental model with 3 nonleveled brackets. 2008. Am J Ortho Dentofacial Orthop. model with 3 nonleveled brackets. 2008. Am J Ortho Dentofacial Orthop. 133:708-15.133:708-15.

Badawi H, Toogood R, Carey J, Heo G, Major P. Torque expression of self-Badawi H, Toogood R, Carey J, Heo G, Major P. Torque expression of self-ligating brackets. 2008. Am J Orthod Dentofacial Orthop. 133-721-8ligating brackets. 2008. Am J Orthod Dentofacial Orthop. 133-721-8

Rinchuse D, Miles P. Self-ligating Brackets: Present and Future. 2007. Am J Rinchuse D, Miles P. Self-ligating Brackets: Present and Future. 2007. Am J Orthod Dentofacial Orthop. 132:216-22Orthod Dentofacial Orthop. 132:216-22

Thomas S, Birnie DJ, Sherriff M. A comparative in vitro study of the fricitonal Thomas S, Birnie DJ, Sherriff M. A comparative in vitro study of the fricitonal characterisitics of two types of self-ligating brackets and two types of characterisitics of two types of self-ligating brackets and two types of preadjusted brackets tied with elastomeric ligatures. 1998. Eur J Orthod preadjusted brackets tied with elastomeric ligatures. 1998. Eur J Orthod 20:589-596.20:589-596.

Srinivas S. Comparison of canine retraction with self-ligated and conventional Srinivas S. Comparison of canine retraction with self-ligated and conventional ligated brackets—a clinical study. 2003. Thesis in fulfillment of postgraduate ligated brackets—a clinical study. 2003. Thesis in fulfillment of postgraduate degree, Tamilnadu Medical University, Chennai, Indiadegree, Tamilnadu Medical University, Chennai, India