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leveling and aligning in orthodontics
LEVELING AND ALIGNINGLEVELING AND ALIGNING
DR JASMINE ARNEJA PRECEPTOR
DR SHALAJ BHATNAGAR
GOALS OF THE FIRST STAGE
CHOICE OF ARCHES
ALIGNMENT IN SYMMETRIC CROWDING
ALIGNMENT IN ASYMMETRIC ARCHES
LEVELING BY EXTRUSION
LEVELING BY INTRUSION
According to Raymond Begg, the major
stages of comprehensive orthodontic
treatment are ;
alignment and leveling,
correction of molar relationship and space closure,
Tooth leveling and aligning is normally the
first orthodontic objective during the initial
stage of treatment.
GOALS OF THE FIRST STAGE OFGOALS OF THE FIRST STAGE OF
In almost all patients with malocclusion, at least
some teeth are initially malaligned.
The great majority also have either excessive
overbite, resulting from some combination of an
excessive curve of Spee in the lower arch and an
absent or reverse curve of Spee in the upper arch,
or (less frequently) anterior open bite with excessive
curve of Spee in the upper arch and little or none in
the lower arch.
The goals of the first phase of treatment are to
bring the teeth into alignment and correct vertical
discrepancies by leveling out the arches.
For proper alignment, it is necessary not only to
bring malposed teeth into the arch, but also to
specify and control the anteroposterior position of
incisors, the width of the arches posteriorly, and
the form of the dental arches.
Similarly, in leveling, it is important to determine
and control whether leveling occurs by elongation
of posteriors, intrusion of anteriors or a
combination of these two
Current Trend :Current Trend :
In the past the usual method of regulating the
magnitude of force from an orthodontic appliance
was primarily variation in the cross sectional
dimensions of the wires used. Although
configurations such as loops have been used to
lower forces, small wires were used for light
forces and large wires for heavier ones. Hence
traditional orthodontics may be described as
"variable cross section orthodontics".
Further development of materials in orthodontics
was influenced by the orthodontist's demands to
have appliance systems that were relatively resistant
to permanent deformation, thus providing a large
range of activation. This blend of characteristics
required the use of materials that had high yield
strength to elastic modulus ratio, as demonstrated
by NiTi and TMA. With the introduction of these
materials to orthodontics, a new clinical strategy
evolved, namely the "variable modulus
The generation of superelastic and
thermodynamic nickel-titanium wires like neo-
sentalloy, Cu-NiTi, etc, represents another major
advance from the previous concepts.
By taking advantage of the body temperature, and
by setting the alloy's transformation temperature
for the martensitic transformation, precise control
of the memory phenomenon can be effected.
This is called "variable transformation
WIRE SEQUENCEWIRE SEQUENCE
ACCORDING TO DIFFERENTACCORDING TO DIFFERENT
ORTHODONTIC CONCEPTS :ORTHODONTIC CONCEPTS :
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
To bring teeth into alignment, a combination of
labiolingual and mesiodistal tipping guided by an
arch wire is needed, but root movement usually is
Several important consequences for
orthodontic mechanotherapy follow from
Initial arch wires for alignment should provide light,
continuous force of approximately 50 grams, to produce
the most efficient tipping tooth movement. Heavy
force, in contrast, is to be avoided.
The arch wires should be able to move freely
within the brackets. For mesiodistal sliding
along the archwire, atleast 2 mil clearance is
needed, 4 mil is desirable and beyond that
provides no advantage.
This means that the largest initial arch wire that
should be used with an 18-slot edgewise bracket
is 16 mil, whereas 14 mil would be more
satisfactory. With the 22 slot bracket, an 18 mil
arch wire would be close to ideal from a bracket
clearance point view.
Rectangular arch wires, particularly those with a
tight fit within the bracket slot so that the
position of the root apex could be affected,
normally should be avoided.
A, Diagrammatic representation of the alignment of a malposed lateral
incisor with a round wire and clearance in the bracket slot. With minimal
moments created within the bracket slot, there is little displacement of the
root apex. B, With a rectangular archwire that has enough torsional
stiffness to create root movement, back-and-forth movement of the apex
occurs before the tooth ends up in essentially the same place as with a
round wire. This has two disadvantages: it increases the possibility of root
resorption, and it slows the alignment process.
The springier the alignment arch wire, the more important
it is that the crowding be at least reasonably symmetric. If
only one tooth is crowded out of line a rigid wire is needed
that maintains arch form except where springiness is
required, and an auxiliary wire should be used to reach the
PROPERTIES OF ALIGNMENTPROPERTIES OF ALIGNMENT
The flat load deflection curve of superelastic NiTi makes
ideal for initial alignment. Under most circumstances initial
alignment can be accomplished simply by tying 14 or 16
mil A-NiTi that delivers about 50 gm into the brackets of
all the teeth.
NITI has the property of delivering light forces over a
Other options are
◦ multistranded niti---lower force values with and
higher fracture resistance
◦ Copper niti- 15, 27, 35, 40
◦ Bioforce- graded thermodynamic niti
Alignment in Premolar ExtractionAlignment in Premolar Extraction
In patients with severe crowding of anterior teeth,
it is necessary to retract the canines into premolar
extraction sites to gain enough space to align the
incisors. In extremely severe crowding, it is better
to retract the canines independently before
placing attachments on the incisors. Sliding the
canines produces more stress on the posterior
anchorage, so critical anchorage is an indication
for the retraction loops.
In more typical and less extreme crowding, it is
possible to simultaneously tip the canines distally
and align the incisors. The same independent
distal movement of the canines now can be
obtained with an A-NiTi arch wire, and A-NiTi
coil springs from the first molars or active
tiebacks to tip the canines distally. When this is
done, the spring should be chosen to deliver
only 50 gm, and an arch wire preformed by the
manufacturer to have an exaggerated reverse
curve of spee should be chosen, to limit
forward tipping of the molars.
Alignment in Non-extraction SituationsAlignment in Non-extraction Situations ::
Alignment in non extraction cases
requires increasing arch length,
moving the incisors further from
the molars. In this circumstance,
just tying a superelastic wire into
the bracket slots is ineffective.
Crimp a stop ahead of the molars
Don’t cinch back
Alignment of Asymmetric CrowdingAlignment of Asymmetric Crowding
If a niti archwire is tied into an asymmetrically
maligned arch, teeth distant to the site of
malalignment will be moved
Tie superelastic wire as an auxilliary to a heavier
ANCHORAGE CONTROLANCHORAGE CONTROL
DURING LEVELING ANDDURING LEVELING AND
LACEBACKS FOR A/P CANINELACEBACKS FOR A/P CANINE
Lace backs are 0.010 or 0.009 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.
The initial purpose of lace backs was to prevent canines
from tipping forward, but it was observed that, where
necessary, these ligature wires were an effective method of
distalizing the canines without causing unwanted tipping
Lace backs are normally continued throughout the leveling
and aligning arch wires sequence. .
BENDBACKS FOR A/P INCISORBENDBACKS FOR A/P INCISOR
CONTROL :CONTROL :
If the arch wire is bent back immediately behind the
tube on the most distally banded molar, this serves to
minimize forward tipping of incisors.
In cases where it is necessary to increase arch length
during leveling and aligning and where A/P incisor
control is not required, bend backs should be placed 1
or 2 mm distal to molar tubes.
A/P ANCHORAGE SUPPORT ANDA/P ANCHORAGE SUPPORT AND
CONTROL FOR MOLARSCONTROL FOR MOLARS
TPA- only for transverse and rotation
Nance palatal arch
Vertical Control of the IncisorsVertical Control of the Incisors
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
In such cases, as the arch wire passes through the canine bracket
slot it will lay incisally to the incisor bracket slots. If the wire is
fully engaged into the incisors, it will tend to cause extrusion of
these teeth, which is undesirable in most cases.
This effect can be avoided either by not bracketing the incisors
at the start of treatment, or by not tying the arch wire into the
incisor bracket slots, but allowing it to lay incisally to the
brackets until the canine roots have been uprighted and moved
distally, under the control of the lace backs. The incisors can
then be engaged without causing unwanted extrusion.
SPECIAL PROBLEMS INSPECIAL PROBLEMS IN
Individual Teeth Displaced into AnteriorIndividual Teeth Displaced into Anterior
Correction of the crossbite requires first opening
enough space for the displaced teeth, then
bringing them into proper position in the arch
It may be necessary to use a bite plate temporarily
to separate the posterior teeth and create the
vertical space needed to allow the teeth to move.
Correction of Dental Posterior Crossbite :Correction of Dental Posterior Crossbite :
Three approaches to correction of less severe dental
crossbite are feasible :
a heavy labial expansion arch,
an expansion lingual arch, or
Removable appliances, although theoretically possible,
are not compatible with comprehensive treatment and
should be reserved for the mixed dentition or adjunctive
Minimal molar crossbite can usually be corrected in the final
stage of leveling and aligning using rectangular wires which
are slightly expanded from the normal form.
The inner bow (36 or 40 mil) is simply adjusted at
each appointment to be sure that it is slightly
wider than the headgear tubes and must be
compressed by the patient when inserting the
facebow. The effect of the round wire in the
headgear tubes, however is to tip the crowns
outward, and so this method should be reserved
for patients whose molars are tipped lingually.
If anchorage is of no concern, a highly flexible
lingual arch, like the quad helix design, is an
excellent choice for correction of a dental
crossbite. When the lingual arch is needed for
both expansion and anchorage, however, the
choices are 36 mil steel wire with an adjustment
The third possibility for dental expansion is the
use of cross-elastics, typically running from the
lingual of the upper molar to the buccal of the
lower molar. These elastics are effective, but their
strong extrusive component must be kept in
Care is needed to avoid arbitrary correction of
molar crossbite by tipping movements. This
allows extrusion of palatal cusps and unwanted
opening of the mandibular plane angle in
treatment of high angle, and even routine, Class
II/I problems. Whenever possible, molar
crossbite should be corrected by bodily
Cases with Unerupted Teeth, or TeethCases with Unerupted Teeth, or Teeth
Significantly Out of the Arch FormSignificantly Out of the Arch Form
Such teeth can be left unbracketed until adequate
space is provided for their movement and
positioning. Once space is created, these teeth can
be bracketed and lightly tied with elastic thread to
the main arch wire. The creation of adequate space
allows bodily movement of these teeth into the arch
form and more correct root positioning, reducing
the treatment needs in the finishing phase.
Surgical Exposure ofSurgical Exposure of
unerupted/impacted teeth:unerupted/impacted teeth:
It is important for a tooth to erupt through the
attached gingiva, not through alveolar mucosa, and this
must be considered when flaps to expose an unerupted
tooth are planned.
Surgical Procedures: 2 basic types
1. Closed eruption – full thickness muco-periosteal flap is
raised and crown exposed, attachment is fixed & flap
sutured back over crown leaving only a twisted wire
passing through the mucosa to apply orthodontic traction
2. Open eruption:
a) Punch incision is made on crown to make window &
cemented pack is placed on it
According to Johnston, Gaulis & Joho:
For Palatally impacted tooth: Closed eruption indicated
For Labially impacted tooth : Open eruption is indicated
with repositioned mucoperiosteal flap to avoid any future
mucogingival problem (Vanarsdall &Corn)
Vanarsdall and Corn suggested that flap containing the keratinized
tissue be placed to cover the CEJ & 2-3mm of crown
METHODS OF ATTACHMENT:
1. Lasso technique
2. Threaded posts
3. Bonded brackets/ button
Mode of Traction:
1. Ligature wire
2. Elastomeric chain
3. Coil springs
4. K9 spring
5. Elastic thread
6. Killroy spring
7. Cantilever spring
8. Niti arch wire
Occasionally, an unerupted tooth will start to move and
then will become ankylosed, apparently held by only a
small area of fusion. It can sometimes be freed to
continue movement by anesthetizing the area and
lightly luxating the tooth, breaking the area of ankylosis.
If this procedure is done, it is critically important to
apply orthodontic force immediately after the luxation,
since it is only a matter of time until the tooth re-
The correction of deep overbite involves :
Eruption / extrusion of posterior teeth.
Distal tipping of posterior teeth
Proclination of incisors
Intrusion of incisors
A combination of two or more of the above tooth
INTRUSION OF ANTERIORS
defined intrusion as, “Apical movement of the
geometric center of root (centroid) in respect to the
occlusal plane or a plane based on long axis of the tooth.”
Intrusion of incisors is commonly indicated in pseudo
deep bite cases or the cases with increased anterior face
It is also indicated in cases where there is an excessive
gingival display during speaking or smiling.
2. EXTRUSION OF POSTERIOR TEETH20
Extrusion of posterior teeth is commonly indicated in
patients with decreased lower anterior face height.
It is also indicated in true deep bite cases.
If the incisal edges of the maxillary anterior teeth are
positioned above the inferior margin of upper lip, in these
cases extrusion of posterior teeth is indicated.
Extrusion of molars of an average of 1mm results in 2 to
2.5 mm of bite opening.
PROCLINATION OF INCISORS
Numerous deep bite cases present with
Proclination of incisors is indicated when there is
an increased nasolabial angle and retruded lip.
So soft tissue should be evaluated before
proclinating the incisors.
NON-EXTRACTION TREATMENT :NON-EXTRACTION TREATMENT :
Non-extraction treatment generally favors bite opening.
This is because distal tipping of posterior teeth and
proclination of incisors normally occurs in these cases.
There are a number of mechanical factors that lead to
arch leveling and control of the deep overbite.
Initial Arch wire PlacementInitial Arch wire Placement
When flat arch wires are placed into dental arches with
curves of Spee, the arch wires attempt to return to their
original shape and this starts the bite-opening process.
Also, expression of the tip in the brackets begins the
bite opening process.
The Bite Plate Effect :The Bite Plate Effect :
Introducing the bite plate effect in deep
bite cases is helpful in the bite opening
process in three ways :
It allows for early placement of brackets on lower
incisors, which begins their movement.
Anterior bite plates can produce an intrusive force
on lower incisors which limits any future
extrusion of these teeth.
Anterior bite plates allow for the eruption,
extrusion, and/or uprighting of posterior teeth.
Anterior bite plane
material on upper
Bite-Opening Curves :Bite-Opening Curves :
In the great majority of cases after rectangular stainless
steel wires have been in place for 6 weeks, the arches
are normally level and adequate bite opening has been
achieved. If this is not so, then bite opening curves can
be placed into the rectangular steel wires.
Burstone in 1977, suggested 50 gram of intrusive force
for upper central incisors, 100 gram force for centrals and
laterals and 200 gram for six upper anteriors. He
advocated use of 40 gram for four lower incisors and 60
gram for all six lower anterior intrusion.
Ricketts in 1980 advocated the use of 125 gram to 160
gram of force for upper incisor intrusion and 60 to 75
gram for lower incisors.
Karanth and Shetty in 2001 advocated 60 gram of force
for four upper incisors and 100 gram of force for six
anteriors; where as 40 gram of force for lower four
incisors and 80 gram for six lower incisors.
Thus the force ranges on an average from 15 - 20 gm
for each upper incisor and 10 - 15 gm for each lower
Bypass ArchesBypass Arches ::
This approach to intrusion is most useful in
patients who will have some growth (i.e. who are
in either the mixed or early permanent dentitions).
This is based on the same mechanical principle :
uprighting and distal tipping of the molars, pitted
against intrusion of the incisors.
Antero-Posterior Issues and Elastics :Antero-Posterior Issues and Elastics :
Inter-maxillary elastics can contribute to the bite-
opening effect by assisting in the extrusion of molars as
the A/P problem is corrected. They are beneficial in
the treatment of most growing patients. If possible
they should be avoided in most non-growing and adult
high angle cases.
SKELETAL ANCHORAGESKELETAL ANCHORAGE
Incisors to be tied back to prevent tipping
Quick facts:Quick facts:
Photobiomodulation (The surface of the
cheek irradiated with near-infrared light
with a continuous 850-nm wavelength and
a power density of 60 mW/cm2
for 20 or 30
min/day or 60 min/week) has shown to
hasten leveling and alignment
(Kau et al. Progress in Orthodontics 2013, 14:30 )
Quick facts:Quick facts:
Nagar et al proposed a modification in the
K9 spring to prevent lingual tipping of
molars (Contemporary Clinical Dentistry, Vol. 5, No.
2, April-June, 2014, pp. 272-274)
No stastical difference was seen in the
leveling and aligning phase with self ligating
and conventional brackets. (Comparison of self-
and conventional-ligating brackets in the alignment stage.
Wahab, EJO, 2011)
Pain exprienced in the first phase was rather more
during archwire removal and insertion in the SLB
group than in the CB group. (Pain Experience during
Initial Alignment with a Self-Ligating and a Conventional
Fixed Orthodontic Appliance SystemA Randomized
Controlled Clinical Trial. P. S. Fleminga.
Orthodontist: January 2009, Vol. 79, No. 1, pp. 46-50.)