root movement in orthodontics / orthodontic courses by indian dental academy

ROOT MOVEMENT ROOT MOVEMENT IN ORTHODONTICS IN ORTHODONTICS

……INDIAN DENTAL ACADEMY

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CONTENTS• Introduction• Need for axial corrections• Torque • Diagnosis & Evaluation for root correction• Biomechanical considerations• Root movement in Removable Appliances• Root movement in Beggs• Root movement in PEARoot movement in PEA• Root movement in segmental arch technique


• Root movement in Segmental SurgeryRoot movement in Segmental Surgery• Cortical AnchorageCortical Anchorage• ComplicationsComplications• ConclusionConclusion• BibliographyBibliography


INTRODUCTIONINTRODUCTION


Control of the Control of the axial inclinationsaxial inclinations of teeth during of teeth during orthodontic therapy is critical for achieving orthodontic therapy is critical for achieving excellent results and ensuring excellent results and ensuring long term long term stabilitystability after completion of treatment. after completion of treatment.

The careful evaluation of individual tooth axial The careful evaluation of individual tooth axial inclinations is often carried out as a inclinations is often carried out as a second second stage of space closurestage of space closure in extraction therapy or in extraction therapy or before completion of treatment in non-extraction before completion of treatment in non-extraction therapy.therapy.


Need For Axial Need For Axial CorrectionsCorrections


Good axial inclinations and Good axial inclinations and adequate adequate root parallelismroot parallelism with regular bone with regular bone distribution between teeth distribution between teeth helps to obtain and helps to obtain and maintain a maintain a stablestable treatment result.treatment result.


Raleigh William Raleigh William The lower incisor roots, rather than The lower incisor roots, rather than

their crowns, should betheir crowns, should be divergent divergent. If . If the roots are left the roots are left convergentconvergent, the , the crowns tend to bunch together and crowns tend to bunch together and cause cause relapse. relapse.


STABLE

UNSTABLE


The evaluation of The evaluation of root axial root axial inclinationsinclinations is also critical in patients is also critical in patients with with congenitally missing teethcongenitally missing teeth when the goal is to replace these when the goal is to replace these teeth with either teeth with either implantsimplants or or bridges. bridges.


CREATING SPACE FOR IMPLANTS CREATING SPACE FOR IMPLANTS


Parallelism of the Parallelism of the abutments rootsabutments roots as wells as as wells as adequate bone distribution are important factors in adequate bone distribution are important factors in the prognosis and successful outcome of treatment. the prognosis and successful outcome of treatment.

Root correction, which may involve individual teeth Root correction, which may involve individual teeth or groups of teeth is also instrumental in or groups of teeth is also instrumental in positioning positioning teeth over basal bone to achieve an ideal occlusal teeth over basal bone to achieve an ideal occlusal relationshiprelationship in the anterior and posterior portions of in the anterior and posterior portions of the dental arches. the dental arches.


Providing good Periodontal Providing good Periodontal EnvironmentEnvironment

Gingiva folded and Gingiva folded and bunched upbunched up

Plaque harboring pseudo Plaque harboring pseudo pocketpocket


TORQUETORQUE


In terms of In terms of Engineering principlesEngineering principles, it is defined as , it is defined as a a force causing twistforce causing twist in a structure, the resulting in a structure, the resulting twist of the mechanical part is called twist of the mechanical part is called TorsionTorsion. .

In terms of In terms of orthodonticsorthodontics it is defined as the it is defined as the buccolingualbuccolingual or or labiolinguallabiolingual root tipping in which root tipping in which the movement of the crown is minimized and the movement of the crown is minimized and movement of the root apex is maximized. movement of the root apex is maximized.


Torque can be effectively employed in Torque can be effectively employed in removable appliance and in fixed appliances. removable appliance and in fixed appliances.

Torquing mechanics are more effective and Torquing mechanics are more effective and widely used in widely used in fixed mechanotherapyfixed mechanotherapy than in than in removable appliances. In removable removable appliances. In removable appliances springs are used for torquing the appliances springs are used for torquing the tooth.tooth.


Torque in the fixed appliance can Torque in the fixed appliance can be employed in different ways.be employed in different ways.

• By giving a By giving a twisttwist in the arch wire in the arch wire commonly used in Edgewise technique.commonly used in Edgewise technique.• Torque exerted by the Torque exerted by the bracketbracket itself e.g., itself e.g., PEAPEA• By the use of By the use of Torquing auxiliariesTorquing auxiliaries widely widely used in Begg technique and Edgewise used in Begg technique and Edgewise technique.technique.


Diagnosis & Diagnosis & Evaluation for Root Evaluation for Root

CorrectionCorrection


Root correction may be considered the Root correction may be considered the second phase second phase of space closureof space closure and most often completion of space and most often completion of space closure is recommended before evaluating for the closure is recommended before evaluating for the potential need to correct potential need to correct root axial inclinationsroot axial inclinations. .

Clinical assessment of root positionsClinical assessment of root positions during space during space closure is often very useful and may be done by closure is often very useful and may be done by monitoring the inclinations of the canine and anterior monitoring the inclinations of the canine and anterior brackets. brackets.


Lateral cephalometricLateral cephalometric head films, head films, IOPAIOPA taken at taken at 454500 and and Panoramic Panoramic radiographs are commonly radiographs are commonly used to assess the need for not correction.used to assess the need for not correction.

Lateral head films primarily assist in evaluating Lateral head films primarily assist in evaluating the the axial inclinations of the anterioraxial inclinations of the anterior teethteeth by by comparing a film taken before initiation of comparing a film taken before initiation of treatment and one taken after completion of treatment and one taken after completion of space closure. space closure.


Checking Lateral Ceph for Torque Requirement

Finish with upper incisors parallel to the facial Axiswww.indiandentalacademy.co

m

Radiographs taken at 45Radiographs taken at 4500 indicate the indicate the axial inclinations of canines, premolars, axial inclinations of canines, premolars, and molars and are helpful for and molars and are helpful for assessing assessing proper root parallelism, adequate bone proper root parallelism, adequate bone distribution and bone levels. distribution and bone levels.


Despite the amount of Despite the amount of deformationdeformation inherent inherent in in panoramic radiographspanoramic radiographs routinely used to routinely used to assess the axial inclinations of the posterior assess the axial inclinations of the posterior teeth. teeth.

This is primarily because panoramic This is primarily because panoramic radiographs are easily available and radiographs are easily available and comparison with a pretreatment panoramic comparison with a pretreatment panoramic radiograph is usually possible.radiograph is usually possible.


PRE RX

POST RX


BIOMECHANICAL CONSIDERATIONS


Moment-to-Force ratioMoment-to-Force ratioThe ratio of The ratio of counter-balancing counter-balancing moment moment produced to produced to net forcenet force that is applied to that is applied to

a tooth.a tooth.


Uncontrolled Uncontrolled Tipping Tipping

MOMENT : FORCE


Controlled Tipping

MOMENT : FORCE


TRANSLATIONTRANSLATION

MOMENT : FORCE


ROOT MOVEMENTROOT MOVEMENT

MOMENT : FORCE


PEA & Begg

Moment arm of couple

Moment arm of couple


ROOT MOVEMENT IN ROOT MOVEMENT IN REMOVABLE APPLIANCESREMOVABLE APPLIANCES


Apron springApron spring derive their main flexibility derive their main flexibility from the twisting of the section and the from the twisting of the section and the length of the torque bars.length of the torque bars.

These torque springs are These torque springs are flexibleflexible,, easy toeasy to construct, easilyconstruct, easily positioned and positioned and adjusted.adjusted.


Apron springApron spring


• VERTICAL PLANEVERTICAL PLANE• SAGITAL PLANESAGITAL PLANE• TRANSEVERSE PLANETRANSEVERSE PLANE

ROOT MOVEMENT IN BEGGSROOT MOVEMENT IN BEGGS


VERTICAL PLANEVERTICAL PLANE


SAGITAL PLANESAGITAL PLANE• LABIO-LINGUAL ROOT MOVEMENTLABIO-LINGUAL ROOT MOVEMENT• TORQUINGTORQUING• UPRIGHTINGUPRIGHTING


TORQUINGTORQUING AUXILLARIESAUXILLARIES• Two spur & Four spur


Pre Wound Torquing AuxiliaryPre Wound Torquing Auxiliary Base arch wire .020” Special Plus Auxiliary .012”, 014”


KITCHTON AUXILIARYKITCHTON AUXILIARY

.014” Special Plus Can be used with Beggs

& edgewise


Auxiliary modified to apply labial Auxiliary modified to apply labial root torque to root torque to max lateralsmax laterals only. only.


Reciprocal lateral Torquing Reciprocal lateral Torquing AuxiliaryAuxiliary

Situation where Central Situation where Central incisors require palatal incisors require palatal root torque & Laterals root torque & Laterals require labial root require labial root torque.torque.


Lower Reverse Torquing AuxiliaryLower Reverse Torquing Auxiliary


MAA AuxiliaryMAA Auxiliary


Uprighting springsUprighting springs Mini – 0.5 mm diameterMini – 0.5 mm diameter Midi – 0.9 mm diameterMidi – 0.9 mm diameter Maxi – 1.5 mm diameterMaxi – 1.5 mm diameter


UprightingUprighting


Reciprocal uprightingReciprocal uprighting


Transverse planeTransverse plane• Buccal root torque to molarsBuccal root torque to molars


Root Movement In PEARoot Movement In PEALawrence AndrewLawrence Andrew developed the developed the

straight wire appliance which straight wire appliance which became widely available in the mid became widely available in the mid 1970s. 1970s.

Six keys to normal occlusion.Six keys to normal occlusion.


• Crown inclination:Crown inclination: Is defined as an angle between a line Is defined as an angle between a line

perpendicular to the perpendicular to the occlusal planeocclusal plane and a line and a line that is parallel and tangent to the that is parallel and tangent to the FACCFACC at its at its mid point (FApoint) crown inclination is mid point (FApoint) crown inclination is determined from the mesial and distal determined from the mesial and distal perspectives.perspectives.


In In PEAPEA, torque or inclination of the tooth is , torque or inclination of the tooth is expressed by the bracket itself this because expressed by the bracket itself this because of the bracket slot is cut at an angle.of the bracket slot is cut at an angle.

The third key in the optimal occlusion is The third key in the optimal occlusion is crown inclinationcrown inclination, most maxillary incisors , most maxillary incisors have positive inclination where as mandibular have positive inclination where as mandibular incisors have a slightly negative inclination.incisors have a slightly negative inclination.


The maxillary central incisors have a more The maxillary central incisors have a more positive inclinationpositive inclination than laterals where as than laterals where as canines and premolars have a canines and premolars have a negative negative inclinationinclination. Maxillary first and second . Maxillary first and second molars also have negative inclination.molars also have negative inclination.

InclinationInclination of the mandibular teeth are of the mandibular teeth are progressively more negative from the progressively more negative from the incisors to the molar.incisors to the molar.


Normally in Normally in PEAPEA if we engage a full sized if we engage a full sized arch wire into the slot it will automatically arch wire into the slot it will automatically express the torque which is incorporated express the torque which is incorporated in the bracket. in the bracket.

But in some situations it we need torque But in some situations it we need torque in the individual or more number of teeth in the individual or more number of teeth we have to we have to twist the arch wiretwist the arch wire to express to express the desired torque (third order bend).the desired torque (third order bend).


Torque in Face V/s Torque in Base

Torque in FaceTorque in Face Torque in BaseTorque in Base


First Generation Of PEAAndrews appliance

5/7 9/3 11/-7 2/-7 2/-7 5/-9 5/-9

2/-1 2/-1 5/-11 2/-17 2/-22 2/-26 2/-35

UPPER

LOWER

Tip/torque in degreeswww.indiandentalacademy.co

m

Second Generation Of PEARoth appliance

5/12 9/8 13/-2 0/-7 0/-7 0/-14 0/-14

2/-1 2/-1 -1/-11

-1/-17 -1/-22 -1/-30 -1/-30

UPPER

LOWER


m

Third Generation Of PEAMBT appliance

4/17 8/10 8/0 0/-7 0/-7 0/-14 0/-14

0/-6 0/-6 3/-6 2/-12 2/-17 0/-20 0/-10

UPPER

LOWER


m

EFFECT OF BUILT IN TIPEFFECT OF BUILT IN TIP


BUCCAL ROOT TORQUEBUCCAL ROOT TORQUE


TORQUE +10 TORQUE -10

Blocked in Lateral incisor


Root movement in Root movement in Segmental Arch Segmental Arch

TechniqueTechnique


Root movement is generally divided Root movement is generally divided into two categories;into two categories;

• En masse root movement & En masse root movement & • Individual root movement (as separate Individual root movement (as separate

canine root movement or separate canine root movement or separate incisor root movement).incisor root movement).


En masse root movementEn masse root movement is required when is required when the entire anterior segment must be moved the entire anterior segment must be moved as a unit, commonly after en masse space as a unit, commonly after en masse space retraction.retraction.

If the anterior segment has been retracted If the anterior segment has been retracted through controlled tipping, through controlled tipping, all the roots are all the roots are retracted as a unit.retracted as a unit.


Separate canine root movementSeparate canine root movement may be may be necessary following separate canine retraction.necessary following separate canine retraction.

When an anterior segment with flared incisors When an anterior segment with flared incisors is retracted by controlled tipping, the incisors is retracted by controlled tipping, the incisors may assume normal axial inclinations while the may assume normal axial inclinations while the canine develops a canine develops a distal axial inclinationdistal axial inclination, hence , hence only the canines need separate root correction.only the canines need separate root correction.


En masse En masse root movement, or root retractionroot movement, or root retraction (rotation around a point on the crown of the (rotation around a point on the crown of the tooth), forms a second phase of space closure tooth), forms a second phase of space closure after tipping movement. after tipping movement.

It is accomplished by using a mechanism that It is accomplished by using a mechanism that places moments on the teeth with centers of places moments on the teeth with centers of rotation located at the level of the brackets. rotation located at the level of the brackets. The mechanism which delivers these moments The mechanism which delivers these moments is known as a root spring.is known as a root spring.


HORIZONTAL PLANEHORIZONTAL PLANE

ANTERIOR ROOT SPRING ANTERIOR ROOT SPRING


HELICAL SPRING FOR HELICAL SPRING FOR ENMASSE ROOT MOVEMENTENMASSE ROOT MOVEMENT


Cantilever for En Masse Root Cantilever for En Masse Root CorrectionCorrection


CANINE ROOT CANINE ROOT UPRIGHTINGUPRIGHTING


T-Looped spring in 17x25 SS to upright T-Looped spring in 17x25 SS to upright molarmolar


VERTICAL PLANE

INTRUSION UTILITY INTRUSION UTILITY ARCHESARCHES

INTRUSION & PROTRACTION INTRUSION & PROTRACTION UTILITY ARCHESUTILITY ARCHES


BURSTONE INTRUSION BURSTONE INTRUSION ARCHARCH

3 PIECE INTRUSION 3 PIECE INTRUSION ARCHARCH


ROOT MOVEMENT IN SEGMENTAL ROOT MOVEMENT IN SEGMENTAL SURGERYSURGERY


CORTICAL CORTICAL ANCHORAGEANCHORAGE


The The cortical bonecortical bone is characterized by being more is characterized by being more dense and laminated, with a very limited blood dense and laminated, with a very limited blood supply.supply.

The The blood supply in the boneblood supply in the bone is the key factor in is the key factor in tooth movement, since it carries the cellular tooth movement, since it carries the cellular elements that resorb away bone and also the elements that resorb away bone and also the cellular elements that build up new bone. cellular elements that build up new bone.

In cortical bone, where the In cortical bone, where the blood supply is limitedblood supply is limited, , the physiological process is delayed and tooth the physiological process is delayed and tooth movement is slower, movement is slower,


Tooth movement can be Tooth movement can be further delayedfurther delayed where excess force against the cortical where excess force against the cortical bone can press out the blood supply and bone can press out the blood supply and limit the physiology and the tooth limit the physiology and the tooth movement.movement.

Bio-progressive TherapyBio-progressive Therapy applies this applies this principle of cortical bone anchorage in principle of cortical bone anchorage in stabilizing the teeth in those areas where stabilizing the teeth in those areas where it desires to limit their movement.it desires to limit their movement.


Lower molar anchorageLower molar anchorage is enhanced by is enhanced by expanding the molar roots into the dense expanding the molar roots into the dense cortical bone on their buccal surface.cortical bone on their buccal surface.

Excessive Excessive buccal root torquebuccal root torque and and expansionexpansion is placed in the archwires to is placed in the archwires to locate the roots into the cortical bone. locate the roots into the cortical bone.


COMPLICATIONSCOMPLICATIONS•ANCHOR LOSSANCHOR LOSS

•ROOT RESORPTIONROOT RESORPTION


ANCHOR LOSS


ROOT RESORPTIONROOT RESORPTION• Fixed versus Removable:Fixed versus Removable: only one study only one study

compared root resorption resulting from fixed and compared root resorption resulting from fixed and removable appliances, concluding that the use of removable appliances, concluding that the use of fixed appliances is more detrimental to the roots. fixed appliances is more detrimental to the roots.

• KetchamKetcham claimed that normal function is claimed that normal function is disturbed by the splingting effect of orthodontic disturbed by the splingting effect of orthodontic fixed appliances over a long period that can fixed appliances over a long period that can cause root resorption. cause root resorption.


• Stuteville on the other hand, suggested that the juggling forces caused by removable appliances are more harmful to the roots.


It is often stated that the light wire Begg technique causes less root resorption than Edgewise, although maxillary incisor root resorption during the Begg third stage has been documented.

Begg versus Edgewise


Intermaxillary elastics:Intermaxillary elastics:• Lee & LangeLee & Lange found significantly more found significantly more

root resorption on the side where root resorption on the side where elastics were used and suggested elastics were used and suggested that jiggling forces due to elastics are that jiggling forces due to elastics are responsible for root resorption.responsible for root resorption.


Orthodontic Movement TypeOrthodontic Movement Type It seems that there is It seems that there is no safeno safe tooth tooth

movement.movement. IntrusionIntrusion is probably the most is probably the most

detrimental to the roots involved, but detrimental to the roots involved, but tipping, torque, bodily movement, tipping, torque, bodily movement, and palatal expansion can also be and palatal expansion can also be implicated. implicated.


Orthodontic ForceOrthodontic ForceThey concluded that higher stress They concluded that higher stress

causes more root resorptioncauses more root resorption.. According toAccording to SchwartzSchwartz Applied Applied

force exceeding the optimal level of force exceeding the optimal level of 20 to 25 gm/Sq.cm causes 20 to 25 gm/Sq.cm causes periodontal ischemia, which can periodontal ischemia, which can lead to root resorption. lead to root resorption.


Continuous versus Intermittent Continuous versus Intermittent Forces:Forces: The pause in treatment with intermittent The pause in treatment with intermittent

forces allows the resorbed cementum to forces allows the resorbed cementum to heal and prevents further resorptionheal and prevents further resorption..

Treatment Duration.Treatment Duration. Most studies report that the severity of Most studies report that the severity of

root resorption is directly related to root resorption is directly related to treatment duration. treatment duration.


ConclusiConclusion…on…


Root correction is a Root correction is a critical stepcritical step of of orthodontic treatment before orthodontic treatment before finishing. finishing.

Proper root alignment and axial Proper root alignment and axial inclinations are key factors for the inclinations are key factors for the attainment of a attainment of a functional, stable functional, stable and esthetically pleasing and esthetically pleasing occlusion.occlusion.


• Adequate Adequate root parallelismroot parallelism and bone and bone distribution will also be beneficial to distribution will also be beneficial to long term periodontal health and are long term periodontal health and are therefore important to ensure a therefore important to ensure a good good prognosisprognosis for treatment. for treatment.


BIBLIOGRAPHYBIBLIOGRAPHY• The design construction and use of Removable orthodontic The design construction and use of Removable orthodontic

Appliances By: Philip AdamsAppliances By: Philip Adams• Robert J. Nikolai Bio Engineering Analysis of orthodontic Robert J. Nikolai Bio Engineering Analysis of orthodontic

MechanicsMechanics• Orthodontic management of the Dentition with the pre Orthodontic management of the Dentition with the pre

adjustedadjusted• Bennett & Richard P. Mclaughlin 2nd Bennett & Richard P. Mclaughlin 2nd Edition Edition • Edgewise Orthodontics By: Raymon C. ThurowEdgewise Orthodontics By: Raymon C. Thurow• Contemporary Orthodontics By: William R. ProfitContemporary Orthodontics By: William R. Profit• Roth RH Treatment mechanics for the straight wire Roth RH Treatment mechanics for the straight wire

Appliance ;Graber T.M & Vanarsadall R.RAppliance ;Graber T.M & Vanarsadall R.R


• The straight wire Appliance 17 years later J.C.O Vol The straight wire Appliance 17 years later J.C.O Vol 21; 1987; 632-64221; 1987; 632-642

• Andrews six keys to normal occlusal Am J Orhod Andrews six keys to normal occlusal Am J Orhod 1972; vol 62: 296 – 3091972; vol 62: 296 – 309

• Begg Orthodontic Theory & Technique By: P.R. Begg Begg Orthodontic Theory & Technique By: P.R. Begg & Kesling& Kesling

• The Begg Appliance & Technique By: G.G.T. FletcherThe Begg Appliance & Technique By: G.G.T. Fletcher• Barry Mollen hauer Aust Orthodontic J 11 Oct 1990Barry Mollen hauer Aust Orthodontic J 11 Oct 1990• T.P Orthodontics catalougeT.P Orthodontics catalouge



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