Levelling and alignment - pea

1. LEVELING AND ALIGNMENT IN PEA
Arun Bosco Jerald
2018 Batch
MDS Orthodontics
Seminar on:

2. CONTENTS
• Introduction
• Definition
• Objectives
• Goals
• Alignment
• Principles in the Choice of Alignment
Arches
• Alignment of Asymmetric Crowding
• Arch Expansion for Alignment
• Alignment in premolar extraction cases
• Missing or distorted maxillary lateral
incisors
• Crossbite Correction
• Impacted or Unerupted Teeth
• Diastema Closure
• Deep bite
• Leveling
• Leveling by Extrusion (Relative Intrusion)
• Leveling by Intrusion
• Anchorage control during leveling and
aligning
• Principles of anchorage control
• Mistakes in The Early Years
• Reduction of Anchorage Needs
• Anchorage Support
• Conclusion
• References

3. INTRODUCTION
 All the mechanics to be accomplished in our orthodontic treatments
with the SWA can be divided into three stages:
 The purpose of this initial phase of treatment in the PEA appliance is to
• bring the teeth into alignment and
• correct vertical discrepancies (like deep overbite and open bite)
by leveling out the arches.
Stage 1 Leveling And Alignment
Stage 2 Working Stage
Stage 3 Finishing Stage

4. DEFINITION
The tooth movements needed to achieve
passive engagement of
a steel rectangular wire of 0.019×0.025 dimension
and of suitable arch form,
into a correctly placed preadjusted 0.022 bracket system.
-(Bennet and McLaughlin)

5. OBJECTIVES
 Short term objective :
In the initial months of treatment, to achieve proper aligning and
leveling by passive engagement of a rectangular wire.
 Long term objective :
Towards the end of treatment, to achieve an ideal dentition,
displaying six keys of normal occlusion, and the dentition properly
positioned within the facial profile.

6. GOALS
 Bring the teeth into alignment.
 Control the anteroposterior position of incisors.
 Control width and the form of the dental arches.
 Correct vertical discrepancies by leveling out the arches by:
• Elongation of posterior teeth.
• Intrusion of incisors.
• Combination of the two.
 If the form of the upper arch is not compatible with that of the
lower arch, one or both must be changed if excellent occlusion is
to be obtained

7.  Depending on the individual treatment goals and the treatment
philosophy used, this step may involve leveling and aligning all of
the teeth or may initially exclude some teeth.
 Early alignment of rotated or malposed teeth allows these
corrections to be maintained through the treatment period,
permitting biologic adaptation and enhanced stability during the
retention phase.
 Lining up the brackets is also important in any technique in which
sliding mechanics will be used to close spaces between teeth.

8. ALIGNMENT
 In nearly every patient with malaligned teeth, the root apices are
closer to the normal position than the crowns because
malalignment almost always develops as the eruption paths of
teeth are deflected.
 The major exceptions are the displacement of all tissues in an area,
most often seen as a result of cleft palate surgery, and the severe
tipping from lip pressure that displaces maxillary central incisors in
Class IIdivision 2 malocclusion.
 Bringing teeth into alignment requires a combination of labiolingual
and mesiodistal tipping guided by an archwire, but usually not root
movement.

9. Principles In The Choice Of Alignment Arches
Force:
 Initial archwires for alignment should provide light, continuous force of
approximately 50 gm to produce the most efficient tipping tooth
movement. Heavy force, should be avoided.
Arch form:
 The light resilient archwires used in the first stage of treatment need
not be shaped to the patient’s arch form as carefully as the heavier
archwires used later in treatment, but from the beginning, the
archwires should reflect each individual’s arch form.
 If preformed archwires are used for alignment, the appropriate large,
medium, or small arch form should be selected.

10. PROPERTIES
 The wires for initial alignment require a combination of excellent
strength, excellent springiness, and a long range of action.
 Ideally, there would be an almost flat load–deflection curve, with
the wire delivering about 50 gm at almost any degree of
deflection.
Variables in selecting appropriate archwires for alignment
Archwire material Size Distance between attachments

11. ARCHWIRE MATERIAL
 The flat load–deflection curve of
superelastic NiTi makes it ideal for initial
alignment; can be accomplished simply
by tying 14- or 16-mil A-NiTi
 If a large range is not necessary, a triple-strand 17.5-mil multistrand
steel wire (3 × 8 mil) can be used. If recontoured monthly and retied,
the time to alignment is equivalent to that with A-NiTi.

12.  Other possibilities:
(1)elastic M-NiTi,
( 2 ) a variety multistrand wires (eg: coaxial wires), or
(3)loops in small-diameter steel wires.
 These wires, although they were the standard of treatment for initial
alignment not long ago, have little or no place in current therapy.

13.  The tendency of the wires to “travel” around the arch can be
prevented by:
• crimping a stop onto the archwire b/n any two brackets that are
close together or
• using a wire with a midline dimple

14. S
IZEOF THE ARCHWIRES
 For mesiodistal sliding, at least 2 mil of clearance b/n the archwire
and the bracket is needed, 4 mil desirable, and more than that
provides no advantage.
 The largest initial archwire that should be used with an 18-slot
bracket is 16 mil, and 14 mil would be more satisfactory.
 With 22-slot bracket, a 16 or 18 mil archwire would be satisfactory.
 For the superelastic A-NiTi wires, the manufactures preparation of
the material determines the clinical performance.
 For all other wires, wire size is an important criterion.

15.  Effects of doubling the diameter:
• Strength 𝖺 d3 → Increases by 8 times
• Springiness 𝖺 1/d4 → Decreases by 16 times
• Range 𝖺 1/d → Decreases by ½
 For initial alignment, the smallest diameter wire that has adequate
strength would be preferred.
 When multiple strands of the same diameter wires are used,
strength is added while springiness is relatively unaffected.

16. SHAPE OF THE ARCHWIRE
 A tightly fitting resilient rectangular archwire
is undesirable because:
• Resistance to sliding,
• produces back-and-forth movement of
the root apices as the teeth move,
• making the aligning slower and more
damaging to the roots.
 For that reason, round wires for alignment
are preferred

17. DISTANCE B/N ATTACHMENTS(BRACKETS)
 Effects of doubling the length:
• Strength
• Springiness
• Range
𝖺 1/L
𝖺 L3
𝖺 L2
→ Decreases by ½
→ Increases by 8 times
→ Increases by 4 times.
 The wider the individual brackets the smaller the inter bracket span.
The smaller inter bracket span the lesser is the springiness and range
of action.
 A powerful means of gaining increased springiness and range of
action without sacrificing too much strength is to bend a loop into
archwire b/n two teeth.

18. ALIGNMENT OF ASYMMETRIC CROWDING
 The best way to manage severely asymmetric crowding without
distortion of the arch form is to open space for the displaced tooth
using a coil spring on a 16-mil steel wire, and then add a small-
diameter superelastic wire as an auxiliary spring overlying the stiffer
main wire.
 Advantages:
• the correct light force is provided by
the NiTi wire,
• the reciprocal force is distributed over
all the other teeth by the stiffer main wire
• the arch form is preserved.

19. ARCH EXPANSION FOR ALIGNMENT
 Alignment in non-extraction cases requires increasing the arch length.
 For alignment of crowded incisors to be effective, crimp a stop on a
small round superelastic wire just in front of the molar tube so that the
archwire is “proud” (slightly advanced from the crowded incisors).

20.  Transverse expansion with broad archwires can increase posterior
arch width.
 The limitation in doing this is the risk of fenestration of roots, also it is
difficult to avoid undesirable canine expansion.

21. ALIGNMENT IN PREMOLAR EXTRACTION CASES
 In extremely severe crowding, retract the
canines independently before bracketing
the incisors.
 Here, critical anchorage is an indication for
the retraction loops.
 In less extreme crowding, an A-NiTi archwire
and NiTi coil springs from the first molars or
active tiebacks can be used to tip the
canines distally and simultaneously align the
incisors.

22. MISSING OR DISTORTED MAXILLARY LATERAL INCISORS
 A combination of appropriately stiff archwires and management of
the space is required.
 A bonded denture tooth can be used as a semi-permanent
retainer for the area -slightly oversized pontic to ensure that there
will be adequate space in the long term for the implant.

23. CROSSBITE CORRECTION
 Individual Teeth Displaced into Anterior Crossbite:
• Anterior crossbite of one or two teeth almost always is an
expression of severe crowding.
• Its correction requires first opening enough space, then bringing
the displaced tooth or teeth across the occlusion into proper
position.
• To avoid occlusal interferences, bite blocks may be used
temporarily. (usually on lower 1st molars)
• During rapid growth in early adolescence, opening the bite may
not be required.

24.  Correction of Dental Posterior Crossbites - Three approaches:
1.A heavy labial expansion arch:
• In a patient who is wearing headgear, the inner bow is adjusted
to be slightly wider.
• In others, a heavy labial auxiliary (Jockey arch) can provide the
expansion effect. (36- or 40-mil steel)

25. 2. An expansion lingual arch:
• If anchorage is of no concern, a highly flexible lingual arch such as
the quad-helix design is an excellent choice for adolescents as well
as children.
• When the transpalatal arch is needed for both expansion and
anchorage, the choices are 30-mil steel wire with an adjustment
loop or the newer lingual arch system with
32 × 32 TMA wire, which is flexible enough
to not need a loop

26. 3. Cross-elastics:
• Running from the lingual aspect of the upper molar to the buccal
aspect of the lower molar; used with a stabilizing lingual arch in the
mandible.
 These elastics are effective, but strong extrusive component is
present.
 Adolescent patients usually can tolerate a short period of cross-
elastic wear to correct a simple crossbite because any extrusion is
compensated by vertical growth.

27. IMPACTED OR UNERUPTED TEETH
 Surgical Exposure:
• With a CBCT image, the roots of the adjacent teeth can be
assessed
• Should erupt through the attached gingiva: must be considered
when exposure is planned.
• If the canine is labially positioned and probing shows that the
crown is not covered with attached tissue, the crown can be
exposed with a laser.

28. • If it is more apically positioned in the mandibular arch or on the
labial side of the maxillary alveolar process, a flap should be
reflected and sutured to cover the CEJ & 2-3mm of crown so
that attached gingiva has been transferred to that region
(Vanarsdall and Corn)
• For a very high canine that is positioned labially, a tunnel
method is used.
• If the unerupted tooth is on the palatal side, an open exposure
can be used.

29. • If labially positioned and probing shows
no attached tissue coverage
The crown can be exposed with a
laser
• If it is more apically positioned in the
mandibular arch or on the labial side
of the maxillary alveolar process
A flap should be reflected and
sutured to cover the CEJ & 2-3mm of
crown so that attached gingiva has
been transferred to that region
(Vanarsdall and Corn)
• For a very high canine that is
positioned labially
A tunnel method is used
• If the unerupted tooth is on the palatal
side
An open exposure can be used

30.  Method of Attachment:
• Directly bond an attachment of some type (a button or hook)
• Then, if the flap is replaced, a piece of fine gold chain is tied to
the attachment and positioned so that it extends into the
mouth.

31.  Mechanical Approaches for Aligning:
• Ideally, a fixed appliance should already be in place before
exposing, with a heavy stabilizing archwire in position (at least
18-mil round steel, preferably a rectangular steel), so that the
force can be applied immediately using auxiliary NiTi wire.
• The numerous alternatives include a special alignment spring,
either soldered to a heavy base archwire or bent into a light
archwire, or a cantilever spring from the auxiliary tube.

32. • Ankylosis of an unerupted tooth:
oDisplacement of the anchor teeth will occur.
oOccasionally an unerupted tooth will start to move and then
will become ankylosed
ocan sometimes be freed if the area is anesthetized and the
tooth lightly luxated, breaking the area of ankylosis.
oTo prevent re-ankyloses, apply orthodontic force immediately
after the luxation.

33. UNERUPTED OR IMPACTED LOWER 2ND MOLARS
 When not severely tipped, place a separator b/n the two teeth.
 For more severe problems, an attachment must be bonded to the
second molar. An auxiliary spring can be useful to bring both upper
and lower second molars into alignment.
 The easiest way is to use a segment of 16 × 22 M-NiTi wire from the
auxiliary tube on the 1st molar to the tube on the second molar;
while a heavier and rigid wire remains in place anteriorly.
 Another possibility in adolescents is surgical uprighting of 2nd molar,
when 3rd molar is extracted.

34. DIASTEMA CLOSURE
 It is better to align the teeth before frenectomy.
 If the frenum is removed first, scar tissue forms as healing progresses
and the space closure becomes more difficult.
 If the space is large and the frenal attachment is thick, the space
should be closed at least partially, and immediately after
frenectomy, orthodontic movement should be resumed.

35. DEEP BITE
 In high angle cases,
• the upper incisors can be bracketed and the lower incisors left
unbracketed at the start of treatment.
• After 2-3 months, when the upper incisors are slightly advanced;
the lower incisors can be bracketed.
• This prevents unnecessary extrusion of posteriors.
 In low-angle cases, a bite plate can be placed at the initial
bonding visit, if the occlusion allows it.

36. LEVELING
 There are three possible ways to level a lower arch with an excessive
curve of Spee:
(A)Absolute intrusion
(B)Relative intrusion
achieved by preventing eruption of the incisors while growth
provides vertical space into which the posterior teeth erupt; and
(C) Extrusion of posterior teeth
which causes the mandible to rotate down and back in the
absence of growth.
As a general rule, relative intrusion is quite acceptable for adolescents;
absolute intrusion is used for the most part in patients who are too old for
relative intrusion to succeed.

38. LEVELING BY EXTRUSION (RELATIVE INTRUSION)
 Can be accomplished with continuous archwires by placing an
exaggerated curve of Spee in the upper archwire and a reverse
curve in the lower archwire.
 With both the 18- and 22-slot appliances, when preliminary
alignment is completed, a 16-mil steel, will be sufficient to c omplete
the leveling.

39.  A possible alternative is a 16-mil “potato chip” A-NiTi wire,
preformed by the manufacturer with an extremely exaggerated
curve.
 The extreme curve needed to generate enough force can lead to
problems if patients miss appointments (i.e., the wire does not
failsafe)

40.  In patients those who have little if any growth remaining, an
archwire heavier than 16-mil steel is needed to complete the
leveling.
 With 22-slot appliance, 18-mil a rchwire is used.
 With 18-slot, leave the 16-mil wire in place and add an auxiliary
leveling arch of 17 × 25 mil TMA or steel, tied anteriorly beneath the
base arch.

41. (A) Auxiliary leveling wire before activation
(B)by tying it beneath a continuous mandibular archwire.
The appropriate force in this instance is approximately 150 gm, and the
expected action is leveling by extruding the premolars rather than intruding
the incisors

42.  Although the auxiliary leveling arch looks like an intrusion arch, it
differs in two important ways:
• the presence of a continuous base arch and
• the higher amount of force.
 Leveling will occur almost totally by extrusion as long as a
continuous rather than segmented wire is in the bracket slots, and
segmenting the arch makes intrusion possible.

43.  With either slot size, it is an error to place a rectangular archwire with
an exaggerated curve of Spee in the mandibular arch because the
curve creates torque to move the incisor roots lingually.
 The arch should be level before a rectangular wire is placed, or step
bends rather than a reverse curve of Spee should be placed in the
rectangular wire
 In the maxillary arch, however, a rectangular wire with an
accentuated curve of Spee would be quite acceptable if lingual root
torque of the upper incisors is needed.

44. LEVELING BY INTRUSION
 The key to successful intrusion is ‘light continuous force’ directed
toward the tooth apex.
 Can be accomplished in three ways:
(1)with continuous archwires that bypass the premolar (and
frequently the canine) teeth,
(2)with segmented archwires and an auxiliary depressing arch, and
(3)with aligners that have attachments on the posterior teeth.

45. BYPASSARCHWIRES
 Most useful for patients who are in either the mixed or early
permanent dentition period.
 Three different mechanical arrangements are commonly used,
each based on the same mechanical principle: uprighting and
distal tipping of the molars, pitted against intrusion of the incisors.
 A classic version of this approach to leveling was seen in the first
stage of the Begg technique in which the premolar teeth were
bypassed and only a loose tie was made to the canine.

46.  The same effect can be produced by using the edgewise appliance,
if the premolars and canines are bypassed with a 2 ×4 appliance
(only two molars and four incisors included in the appliance setup) or
if brackets on premolars simply do not have the main archwire tied in.

47.  Ricketts’ utility arch:
formed from rectangular wire; can be placed into the brackets
with slight labial root torque to control the inclination of the
incisors as they move labially while intruding.
 Successful use of any type of bypass arch for leveling requires
keeping the forces light, accomplished by selecting a small-
diameter archwire, and by using a long span ie. b/n the 1st molars
and the incisors.

48.  Wire heavier than 16-mil steel should not be used, and a relatively soft
16 ×16 cobalt–chromium wire is recommended for utility arches to
prevent heavy forces from being developed.
 A more modern recommendation would be 16 ×22 β-Ti wire.
 Whether an 18- or 22-slot appliance is used, the bypass arch should
not be stiffer than 16-mil steel.

49.  Two weaknesses of the bypass arch systems limit the
amount of true intrusion that can be obtained:
• Except for some applications of the utility arch, only
the 1st molar is available as anchorage.
• The intrusive force against the incisors is applied
anterior to the center of resistance, and therefore
the incisors tend to tip forward as they intrude

50. • Tying an intrusion arch distal to the midline (b/n the lateral incisor
and canine) moves the line of force more posteriorly and closer
to the center of resistance eliminates the moment that causes
facial tipping of the teeth as they intrude.

51.  An anchor bend at the molar in a bypass arch creates a space-
closing effect that somewhat restrains forward incisor movement,
but this also tends to bring the molar forward, straining the posterior
anchorage.

52. SEGMENTED ARCHWIRESFOR INTRUSION
 This approach is recommended for maximum control of the
anterior and posterior segments.
 After preliminary alignment, a full-dimension rectangular archwire is
placed in the bracket slots of teeth in the buccal segment
connecting them into a solid unit.
 In addition, a heavy lingual arch (36-mil round or 32 × 32
rectangular steel wire) is used.

53.  For intrusion, an auxiliary rectangular arch is used to apply force
against the anterior segment.
 The auxiliary tube should be 18 × 25.
 In it, 17 × 25 steel wire with a 2½ -turn helix or 17 × 25 TMA wire works
well.
 If the auxiliary tube is 22 ×28, 19 ×25 TMA wire without a helix or a
preformed M-NiTi intrusion arch is acceptable, but the range of light
force is lower.

54.  This auxiliary arch is adjusted so that it lies gingival to the incisor
teeth when passive and applies a light force (~10 gm per tooth,
depending on root size) when it is brought up beneath the
brackets. and tied underneath or in front of them.
 An auxiliary intrusion arch can be placed while a light resilient
anterior segment is being used for alignment, but usually it is better
to wait until a heavier anterior segment wire has been installed.

55.  Full-dimension braided rectangular steel wire or a rectangular TMA
wire is usually the best choice for the anterior segment while active
intrusion with an auxiliary arch is being carried out.
 Two strategies can be used to prevent forward movement of the
incisors as they are intruded:
 Creating a space-closing force by tying the auxiliary arch
back against the posterior segments.
 Tying the depressing arch distal to the midline, b/n the central
and lateral or distal to the laterals

56. (C)Intrusion arch tied in the midline as only the central incisors are intruded, so that
the incisors will tip facially as they intrude.
(D) In the same patient later, an intrusion arch now is tied between the central and
lateral incisors to intrude all four incisors while reducing the amount of facial tipping.

57.  With careful attention to appropriate forces and moments with this
approach, approximately four times as much incisor intrusion as
molar extrusion in nongrowing adults is possible
 To intrude asymmetrically, adjust the teeth that are placed in
stabilizing and intrusion segments and tie the auxiliary intrusion arch
in the area where intrusion is required.
 If intrusion is desired on only one side, either a cantilevered auxiliary
wire extending from one molar or a molar-to-molar auxiliary arch
can be used.

58.  It also is possible to intrude posterior teeth to correct an anterior
open bite.
 Frequently a major component of a skeletal open bite is a tipped
palatal plane, and intrusion of maxillary posterior teeth can provide
an acceptable dental compensation if the problem is not too
severe. This requires skeletal anchorage.

59. ANCHORAGE CONTROL
 Principles of anchorage control: two main aspects
• Reduction of anchorage needs:
the factors which threaten anchorage and which produce
unwanted tooth movements. This reduces the demands on
anchorage.
• Anchorage support:
Where necessary, use anchorage support, such as palatal or
lingual bars to control certain teeth, or groups of teeth

60. MISTAKES IN TOOTH LEVELING AND ALIGNING
IN THE EARLY YEARS
 The tip built into the anterior brackets of the PEA system caused the
crowns of the anterior teeth to incline forward during the initial
phase of leveling and aligning
 To eliminate this anterior and posterior
segments were connected with elastic forces.

61.  If the elastic force were greater than the leveling force of the arch
wire, there was tendency for anterior teeth to tip and rotate distally,
increasing the curve of Spee, and deepening the bite - known as
“'Roller coaster effect”; particularly in 1st premolar extraction cases.
 The 'Roller coaster' effect is seldom seen in
today's cases, owing to
• the reduced tip in the MBT bracket system,
• lighter archwire forces and
• use of lacebacks for canine control
instead of elastic chain.

62. REDUCTION OF ANCHORAGE NEEDS
These measures have been found to reduce demands on anchorage
 Bracket design:
Any reduction in the in-built tip is beneficial. Compared with
original SWA, MBT system has a total of 10˚ less distal root tip in the
upper anterior segment and 12˚ less distal root tip in the lower
anterior segment
 Arch wire forces: The use of very light archwire forces early in
treatment will be more comfortable for the patient, and will put less
demand on anchorage.
 Avoidance of elastic chain

63. ANCHORAGE SUPPORT
ANCHORAGE CONTROL IN A-P PLANE
Lacebacks for A/P canine control
 Lacebacks are .010 or .009 ligature wires which extend from the
most distally banded molar to the canine bracket.
 They restrict canine crowns from tipping forward
during leveling and aligning.
 They are mainly used in premolar extraction cases, but they may
also be required in some non-extraction cases where there is a
local threat to anchorage.

64.  Lacebacks are passive devices and are placed before the archwire.
 At monthly adjustment visits, require 1-2 mm of tightening
 The work of Robinson (1989) in 57 premolar extraction cases confirms
that, lower canine lacebacks have beneficial effect in controlling
proclination of lower incisors

65.  The probable action: initial slight tipping followed by a period of
rebound owing to the leveling effect of archwire, during which the
roots of the canines are allowed to move distally.

66.  Lacebacks are normally continued up to and including the
rectangular HANT stage.
 Thereafter in the rectangular steel wire stage, A/P control is
continued with passive tie backs
 In most treatments, it is preferable not to retract the canine away
from the lateral incisor. However, in cases with small lateral incisors,
midline discrepancies, or a need to maintain a Class Icanine
relationship, it may be appropriate to retract the canine away from
the lateral incisor.

67. Bendbacks for A/P Incisor control
 Bending the arch wire immediately behind the tube on the most
distally banded molar; serves to minimize forward tipping of incisors.
 If opening wire is 0.015 multistrand, it may be turned into a small
circle distal to the molar tubes

68.  The ends of the .016 HANT wires and round steel wires need to be
flamed and quenched in cold water before placement, to allow
accurate bendbacks.
 The rectangular HANT wires may be thinned at their terminal 3 mm
and then flamed and quenched, to avoid de-bonding bonded
molar tubes.
 In cases where it is necessary to increase arch length during
leveling and aligning and where A/P incisor control is not required,
bendbacks should be placed 1 or 2 mm distal to molar tubes.

69. A/P anchorage support and control for upper molars
 The use of headgear
• Posterior anchorage control requirements are normally greater in the
upper arch than in the lower arch owing to five main factors:
1. The upper molars move mesially more easily than the lower molars.
2. The upper anterior segment has larger teeth than the lower anterior
segment.
3. The upper anterior brackets have more tip built into them than the
lower anterior brackets.
4. The upper incisors require more torque control and bodily
movement than the lower incisors, which only require distal tipping
or uprighting.
5. Class IImalocclusions are more than Class III.
 So, extra oral force is the most effective way to provide anchorage
control in the upper arch.

70.  Of the 3 primary types of facebow headgear, MBT favor a
combination of head gear (occipital and cervical pull).
 The force levels used for combination head gears are 150–250gm
for the occipital pull and 100-150gm for the cervical pull.

71.  These force values allow for slightly stronger pull on the occipital
component of the headgear, by keeping forces directed slightly
above the occlusal plane and minimizing the tendency for vertical
extrusion of the upper posteriors while simultaneously allowing
effective distalization.
 The outer bow should extend adjacent to the upper 1st molar to
avoid unwanted molar tipping.

72.  An extended outer bow or an outer bow bent downward provides a
greater tendency for distal tipping of the crown of the 1st molar.
 A shorter outer bow or tipping up of the outer bow, causes a greater
tendency for the roots to be distalized ahead of the crowns.
 In high-angle cases where little distalization is required, an occipital
headgear alone can be used.
 In very low-angle c a ses, a c ervical headgear alone c a n be considered

73.  Nance palatal arch: A/P, transverse and rotation control
 Transpalatal bar:
• Soldered to the molar hook;
• Only for transverse and rotation control
• The palatal bar can be constructed of heavy .045” or .051”
round wire, extending from molar to molar with a loop placed in
the middle of the palate and the wire 2mm away from the
palate

74.  Anchorage Control of Posterior Segments in Lower
Arch
• Lingual arch:
Considered for maximum anchorage premolar
extraction cases throughout the initial stages of
leveling and aligning
•Combination of Class IIIelastics and Headgear:
For maximum anchorage support in the lower
anterior segment.
The class IIIelastics to be delayed until the 0.016
round wire stage to prevent extrusion of the incisors

75. ANCHORAGE CONTROL IN VERTICAL PLANE
Vertical control of the Incisors
 Anterior control is needed to restrict the tendency to temporary
increase in overbite especially in deep-bite cases.
 The effect of bracket tip is more extreme in the upper arch, and
care is needed if the canines are distally tipped in the starting
malocclusion.
 If the wire is fully engaged into the incisors, it will tend to cause
extrusion of these teeth, which is undesirable in most cases.

76.  This effect can be avoided by
• not bracketing the incisors at the start of treatment or
• not tying the archwire into the incisor bracket slots until the
canine roots are uprighted and moved distally under the control
of lacebacks

77. Vertical control of the Canines
 It is important to avoid early arch wire engagement of high labial
canines, so that unwanted vertical movements of lateral incisors
and premolar does not occur

78. Vertical control of Molars - high angle cases
 Upper second molars are generally not initially banded or
bracketed, to minimize extrusion.
 If they require banding, an archwire step can be placed behind
the first molar to avoid extrusion.
 If the upper first molar require expansion, an attempt is made to
achieve bodily movement rather than tipping, to avoid extrusion of
palatal cusps.
 It is accomplished by fixed expander.

79.  If palatal bars are used, they are designed to lie away from the
palate by approximately 2mm. So that the tongue can exert a
vertical intrusive effect.
 In some cases, upper and lower posterior bite plate in the molar
region is helpful to minimize extrusion of molars

80. ANCHORAGE CONTROL IN LATERAL PLANE
 Inter-canine width:
Upper and lower inter-canine width should be kept as close as
possible to starting dimensions for stability and care should be
taken to ensure that crowding is not relieved by uncontrolled
expansion of the upper and lower arches.
 Molar cross bite:
Whenever possible, molar cross bite should be corrected by
bodily movement to avoid extrusion of palatal cusp and
unwanted opening of the mandibular plane angle.

81. CONCLUSION
 Successful tooth alignment depends on recognizing that unwanted
tooth movements can occur early in treatment, mainly owing to
the tip built into the preadjusted brackets.
 These unwanted tooth movements need to be controlled, or the
underlying malocclusion will worsen during tooth alignment which
will increase the time and effort needed to complete the case.

82. REFERENCES
 Contemporary orthodontics- William.R.Proffit, Henry W.Fields, Brent E.Larson,David.M.Sarver,6th edition, 2019
 Systemized orthodontic treatment mechanics. McLaughlin, Bennet, Trevisi. 2001
 Orthodontics current principles and techniques- Lee W. Graber, Robert L. Vanarsdall, Katherine W.L. Vig, Greg J. Huang.
6th edition
 McLaughlin R P, Bennett J C 1989 The transition from standard edgewise to preadjusted appliance systems. Journal of
Clinical Orthodontics 23: 142-153
 Robinson S N 1989 An evaluation of the changes in lower incisor position during the initial stages of clinical treatment
using a preadjusted edgewise appliance. University of London MSc thesis.
 McLaughlin R P, Bennett J C 1999 An analysis of orthodontic tooth movement -the VTO. Revista Espana Ortodontica
29(2):10-29
 Leveling and Aligning: Challenges and Solutions; Bhavna Shroff and Steven J. Lindauer, Semin Orthod 2001;7:16-25
 Comparison of anchorage loss following initial leveling and aligning using ROTH and MBT Prescription - A clinical
prospective study. Rajesh.M etal J Int Oral Health 2014 Apr;6(2):16-21
 A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 1-
duration of treatment. Yassir YA etal Eur J Ortho 2019 Mar 29;41(2):133-142.