Biomechanics of the extrusion arches

Prof. Dr. Maher Abd El Salam
Fouda
Biomechanics of the
extrusion arches
Presented by:

Extrusion of anterior teeth
This approach is indicated in
a number of optimal
conditions: (a) Differential
level of gingival exposure:
more gingiva shows
posteriorly than anteriorly.
(b) Expectation of favorable
smile esthetics (acceptable
level of gingiva showing
during smile) and functional
and stable occlusion.
(A–C) Pretreatment photographs of 22-year-old
patient with apertognathia, who accepted to undergo
orthognathic surgery for the correction of his severe
malocclusion. After alignment of both arches, the
patient expressed his acceptance of a “gummy smile”
if he could avoid surgery.

Extrusion of anterior teeth This
approach is indicated in a
number of optimal conditions:
(c) Moderate level of skeletal
hyperdivergence. (d)
“Predictability” of no or limited
root resorption. Signs of
susceptibility to resorption
include the shape of the root
and the size and position of the
tongue. In these instances,
periodic radiographic
evaluation is recommended
(D–F) Posttreatment facial and occlusal
photographs. Light orthodontic forces were
used throughout treatment with vertical
interarch elastics to further approximate the
incisors when the original treatment plan was
reconsidered.

As its name
implies, the
extrusion arch is
similar to the
intrusion arch, but
with the wire
inverted for incisor
extrusion.
An extrusion
arch is a more
reliable method for
extruding the
incisors in a single
arch.
Extrusion Arch

they can also
cause
undesirable
extrusion of
the opposing
incisors.
Although
anterior
box elastics are
often used for
the correction of
anterior open
bites,

The extrusion
arch is a term
that was
coined to
describe the
reverse action
of the already
existing and
well-
established
intrusion arch.

The term,
extrusion arch,
is probably
somewhat
misleading
because the
action of the
wire is not to
extrude the
tooth from its
attachment
apparatus.

What does happen
when a tooth is moved
vertically within the
alveolar process? when
the open bite closes,
does the tooth move
with respect to the
alveolar process and
leave the alveolar
process behind with a
longer clinical crown
resulting?

All available
evidence shows
that, whether the
tooth is intruded or
extruded, vertical
movement brings
the entire
attachment
apparatus, including
the alveolar process
and the gingival
tissues, with the
tooth.

The principle
of an extrusion
arch has been
applied as a
segmental
wire for some
time,
predominantly
to bring in
impacted
canines.
A)System of forces produced by a cantilever .This
system also reveals a tendency towards
palatalization of #13 with force going in the
vestibular direction of CRes. B) Palatal bar used to
control any undesired effects on the anchorage
unit.

The extrusion
arch is a new
adaptation of the
biomechanical
principle of an off-
center bend, or
asymmetrical V, in
an arch wire to
develop a specific
set of
biomechanical
responses.
Extrusion arch constructed of
0.017“x0.025”TMA wire

The extrusion
arch is a very
efficient and
effective way
to close
anterior open
bites, and
open bites are
the nemesis of
most
mechanics.
Extrusion arch force system. A one-
couple force system with
an anterior extrusive and a posterior
intrusive force. The couple on the
molar produces a tip-forward moment.

The
vertical
elastic has
been the
most
commonly
used tool
in the
past.

The extrusion arch,
however, gives the
orthodontist the
ability to close
anterior open bites
without patient
compliance, and in
addition, to decide
whether the open
bite closure should
come from just the
maxillary teeth
moving down, just
the mandibular teeth
moving up, or both.
Effects of the
anterior force of
the extrusion
arch on the
upper
incisors. The
applied force at
the bracket will
produce in the
center of
resistance
(CRES) of the
incisors a
clockwise
moment plus an
extrusive force of
equal magnitude.

The biomechanics of an
extrusion arch are fairly
straightforward. As with most
clinical problems, the first
question is, Which teeth do I
want to move in what
direction? With an anterior
open bite the answer is clear. I
want the front teeth to move
vertically together. Now,
however, the question is more
sophisticated: Do I want the
upper teeth, the lower teeth, or
both to move vertically?
Vertical elastic added to the upper
buccal segment to negate
the tip-forward tendency produced by
the one-couple force system in the
extrusion arch.

Using a one-
couple force
system in the
form of an
extrusion arch
can overcome
the problems
encountered
with step bends
or anterior
vertical elastics.

Inserting the extrusion
arch into the bracket slots
of the anterior teeth as is
commonly done with
continuous arch
mechanics, creates
statically indeterminate
force systems. A more
viable option is to tie the
extrusion arch over the
anterior segment to create
a single point of force
application.

Once ligated, the
extrusion arch
delivers a single
force at the
anterior segment,
which passes
through the
center of
resistance of the
anterior unit with
no associated
moment.

In accordance with Newton’s
third law, there is also an
equal and opposite force on
the posterior segment,
coupled with an undesirable
moment on the molars or the
buccal segments. This causes
rotation of the posterior
occlusal plane that tends to
open the bite further. This can
be controlled by using seating
elastics from the upper
cuspids to the lower arch.

The preferred
archwire on the
anterior and
posterior
segments is
stainless steel,
.017- x .025-inch
or higher. The
extrusion arch can
be a .017- x .025-
inch or a .016- x
022-inch CNA .

The magnitude of
extrusive force used
is around 40 g for the
four incisors . Placing
a .016- x .022–inch
CNA archwire
directly into the
bracket slots without
any auxiliary
archwires can also
give similar results
for mild to moderate
open bite cases

Note how the
judicious
application of
elastics in
combination with
the extrusion arch
results in the
correction of the
open bite and also
provides the
necessary
overcorrection for
long-term
retention

To prevent any
posterior
extension of the
open bite, the
stainless steel base
archwire is again
segmented. The
overlaid extrusion
arch extends from
the molar and is
tied at a
single point to the
anterior base arch.

The V-bend
is placed adjacent
to the molar
attachment,
producing
a
counterclockwise
moment and
intrusive force
at the molar and
an extrusive force
at the incisor
segment .

Because the extrusive force at
the incisor is anterior to the
CRes of the anterior
segment, a small clockwise
moment can result in
retroclination of the incisors. If
proclination of the
incisors is needed, an anterior
force will be required.
For this purpose, a “stop-
advance” can be
incorporated into the
extrusion arch by placing
crimpable stops distal to the
V-bend or by placing
the V-bend precisely at the
molar tube.

a 14½-year-old male patient
with an anterior open bite
and no evident
parafunctional
habits. Stainless steel base
segments were
placed along with a CNA
extrusion arch. Short
Class II elastics were used
to control the
counterclockwise
moment on the posterior
segment and
thus prevent development
of a lateral open bite.
Two months later, some
bite closure could be seen.
B. Bite closure
noted two
months later.
C. Placement
of continuous
wire after
four months of
extrusion-arch
treatment.
A. Initial placement
of extrusion arch
with intermaxillary
elastics to control
posterior segment in
14½-year-old male
patient.
Case report

The extrusive force of the
elastics is anterior to the Cr
of the upper posterior
segment, creating a moment
that negates the moment
created by the extrusion
arch. The sum of all forces
and moments results in a
pure intrusive force on the
posterior segment and an
opposite and an equal
extrusive force on the
anterior segment.

During extrusive tooth movement,
tension is
induced on the whole of the
periodontal ligament rather than
pressure

A case report
illustrating the
application of
elastics and an
extrusion arch
in the
successful
management
of an open-bite
malocclusion.

Note how the
judicious
application of
elastics in
combination with
the extrusion arch
results in the
correction of the
open bite and also
provides the
necessary
overcorrection for
long-term retention

The extrusion
arch is a very
efficient and
effective way
to close
anterior open
bites, and
open bites are
the nemesis of
most
mechanics.
Extrusion arch force system. A one-
couple force system with
an anterior extrusive and a posterior
intrusive force. The couple on the
molar produces a tip-forward
moment.

The vertical
elastic has
been the most
commonly
used tool in the
past and, too
often, vertical
elastics
became a
contest of wills
between the
orthodontist
and the
patient--a
contest often
Extrusion arch force system. A
one-couple force system with
an anterior extrusive and a
posterior intrusive force. The
couple on the
molar produces a tip-forward
moment.

The extrusion arch, how-
ever, gives the
orthodontist the ability
to close anterior open
bites without patient
compliance, and in
addition, to decide
whether the open bite
closure should come
from just the maxillary
teeth moving down, just
the mandibular teeth
moving up, or both.
Effects of the anterior force of the
extrusion arch on the upper
incisors. The applied force at the bracket
will produce in the center of resistance
(CRES) of the incisors a clockwise
moment plus an extrusive force of
equal magnitude.

The biomechanics of
an extrusion arch are
fairly straightforward.
As with most clinical
problems, the first
question is, Which
teeth do I want to
move in what
direction? With an
anterior open bite the
answer is clear. I want
the front teeth to
move vertically
together.
Vertical elastic added to the upper buccal
segment to negate
the tip-forward tendency produced by the
one-couple force system in the
extrusion arch.

Now, however,
the question is
more
sophisticated:
Do I want the
upper teeth,
the lower
teeth, or both
to move
vertically?
Vertical elastic added to the upper buccal segment
to negate
the tip-forward tendency produced by the one-
couple force system in the
extrusion arch.

Alexander stated that part of
the treatment includes
extrusion of the incisors to
create
more incisor exposure. This
is accomplished by placing a
reverse curve in the 0.016 SS
and 17 × 25 SS maxillary
archwires and later, if
needed, up-and-down
anterior
box elastics
(a and b) Reverse curve of Spee.

Targeted Mechanics for Limited Posterior
Treatment with Mini-Implant Anchorage
ZACHARY T. LIBRIZZI, DMD, MDS
NANDAKUMAR JANAKIRAMAN, BDS, MDS
AFSANEH RANGIANI, DDS, PhD
RAVINDRA NANDA, BDS, MS, PhD
FLAVIO A. URIBE, DDS, MDS
JCO/DECEMBER 2015

A 28-year-old male
reported
with the
chief complaint of an
open bite.
He had received
orthodontic treatment
as an adolescent and
had a
history of a thumb
sucking habit,
which he had
ceased one year
earlier.

Extraoral
examination found
an orthognathic
soft- and hard
tissue
profile, slightly
excessive
lower anterior
facial height, and a
proclined lower lip
in reference to
the E-line .

The patient had
recently
lost a temporary
crown on the
first molar. A dental
anterior open
bite of 7mm was
present as a result
of the digit-sucking
habit, and
the upper incisors
displayed flaring
and intrusion.

A 5mm overjet
was accompanied
by an excellent
Class I buccal
occlusion and a
slightly end-on
canine
relationship;
the maxillary and
mandibular
arches had
different occlusal
planes.

Smile
analysis
revealed a
reverse
smile arc
with 80%
incisal
display on
smiling.

Parallel smile
arc is where
the curvature
of the
maxillary
incisal edges
is parallel to
the border of
the lower lip
in smiling.

The panoramic
radiograph revealed
restorations
on the posterior teeth,
including
full-coverage restorations
with root-canal therapy on
the upper
left second premolar and
first
molar.

The patient was offered two
treatment options. The first
consisted
of placing a tongue crib to
prevent a compensatory
tongue thrust
habit from the open bite,
and, after four to six
months, using
a statically determinate
force
system with an extrusion
arch to
erupt the incisors.

The extrusive
force on the
upper incisors
would
generate an
equal and
opposite
intrusive force
and a tip-forward
moment on the
posterior
anchorage
segment .
Extrusion arch exerts
extrusive force (f) on
anterior segment, along with
intrusive force and
tipforward
moment of couple (Mc) on
posterior anchorage unit.
Beneficial moment of force
(Mf) is generated
on upper incisors because
extrusive force is anterior to
center of resistance. B. Tip-
forward moment can
tip occlusal plane if patient
does not comply with elastic
wear.

Seating
elastics would be
needed to counteract
the tip-forward
moment,
requiring patient
compliance.
Once the anterior and
posterior
occlusal planes were
leveled,
straightwire
mechanics would be
initiated for final
finishing.
Extrusion arch exerts
extrusive force (f) on
anterior segment, along
with intrusive force and
tipforward
moment of couple (Mc)
on posterior anchorage
unit. Beneficial moment
of force (Mf) is
generated
on upper incisors
because extrusive force
is anterior to center of
resistance. B. Tip-
forward moment can
tip occlusal plane if
patient does not comply
with elastic wear.

The second option, which
was recommended and
accepted,
involved targeted
mechanics with
the primary goal of
maintaining
the excellent buccal
occlusion. To
correct the open bite, a
tongue
crib would be delivered in
conjunction
with a one-couple force
system from an extrusion

lower first molars. To
counteract
this side effect, the
molars would
be indirectly
anchored to
miniimplants.
An extrusive force of
40g would
be exerted on the
incisors, generating
an intrusive force
and a tip forward
moment on the upper
and
Statically determinate
one-couple force
system for correction
of anterior open bite
with targeted
mechanics: extrusion
arch inserted in molar
tubes and incisor
brackets, with indirect
anchorage from rigid
.019" × .025" stainless
steel wire segments
between mini-implants
and auxiliary molar
tubes.

one-couple force
with targeted
tubes and incisor
.019" × .025" stainless
steel wire segments
and auxiliary molar
tubes.
With the extrusive
force directed slightly
labial
to the center of
resistance of the
incisors, a favorable
clockwise
moment of force would
be generated
in the upper incisor
segment
and a counterclockwise
moment
of force in the lower
anterior arch.

one-couple force
with targeted
tubes and incisor
.019" × .025" stainless
steel wire segments
and auxiliary molar
tubes.
This
approach
would
require no
premolar
brackets or
patient
compliance
with elastic
wear.

Treatment Progress
After the temporary
crown
on the upper left
first molar was
replaced, a tongue
crib was cemented
to the upper first
molars
and the incisors
were bonded in
both arches.

1.5mm ×
9mm mini-
implants, which
have
slots for full-
dimensional
archwire
engagement,
were placed
interdentally
between the first
molars
and second
premolars.
One-couple force system from extrusion arch
and tongue crib, with indirect anchorage from
stainless
steel wires between mini-implants and upper
first molars.

The
initial setup
was a 2 × 4
appliance
with .017" ×
.025" stainless
steel
wires in the
anterior
segments.
One-couple force system from extrusion
arch and tongue crib, with indirect
anchorage from stainless
steel wires between mini-implants and
upper first molars.

Indirect anchorage was
prepared
with rigid .019" × .025"
stainless
steel wires, passively
adapted
from the auxiliary tubes
of the
upper first molars to the
mini implants
One-couple force system from
extrusion arch and tongue crib, with
indirect anchorage from stainless
steel wires between mini-implants and
upper first molars.
, with the lower
first molars added at a
subsequent
appointment.

One-couple force system from extrusion arch
and tongue crib, with indirect anchorage from
stainless
steel wires between mini-implants and upper
first molars.
A flowable composite
resin was added to stabilize
the
archwire segments over the
screw
heads. An .017" × .025"
nickel
titanium extrusion arch was
then
secured with a single-point
contact
over each lateral-incisor
bracket and inserted in the

Due to the
synergistic
effects
of the tongue
crib and
treatment
mechanics, a
significant
change in
overbite was
observed in
only two
).
.
Patient after two months of treatment

After five
months
of treatment,
a positive
overbite
was achieved,
and the
anterior and
posterior
maxillary
occlusal
planes were
Patient after five months of treatment.

The
mini-implants
were then
removed,
the second
molars were
bonded,
and finishing
was performed
for
two months with
continuous .016"
× .022" beta
titanium

Light seating elastics
and anterior
box elastics were
worn during this
period to maintain the
corrections
achieved with the
segmented
mechanics.
The orthodontic
appliances
were removed after 10
months of treatment.

minor
arch-coordination
discrepancies
in the premolar
region from the
use of indirect
anchorage was
noticed, requiring
orthodontic
attachments to be
bonded to the
posterior teeth
during
the finishing phase.

Fixed 4-4
lingual
retainers
were
bonded in
both
arches,
and
Hawley
retainers
were

Before treatment After treatment

“Convenience” orthodontics: Mechanics
simplified! Geetanjali Gandhi , Atul Sharma,
Prinka Shahi
2016 Journal of Indian Orthodontic Society
A 13-year-old female
patient reported with
an asymmetric anterior
open bite. Since the
cervico-incisal length of
her anterior teeth was
short extrusion was
planned.
Inverted 0.018 NiTi reverse curve of
spee wire placed

Prinka Shahi
An inverted reverse curve of
spee (RCS) 0.018” NiTi wire
was used which was inserted
only in the slot of the second
molar bands keeping in
consideration that the slot of
the buccal tube was incisal to
the slot of buccal tube of the
first molar. Inverted 0.018 NiTi reverse curve of spee wire
placed

Prinka Shahi
Traditionally, it is considered that
involving the second molars in a
patient with open bite will result in
increased open bite due to the tip
forward movement generated in
the anterior segment, but in this
case, placement of the wire above
the bracket slots instead of
engagement in the slots prevented
that. After 1 month

Prinka Shahi
The wire was passed above the first molar
bands and bracket slots of the teeth and
ligated at few points to keep it in its position.
Tying an inverted RCS wire led to more
extrusive force being put on the anteriors
(pertaining to the inversion of anterior curve
of the wire that now exerted an extrusive
force instead of an intrusive force normally
exerted by an RCS wire) compared to the
posteriors as was required in this case.
After 1 month
After 6 months

Prinka Shahi
Extrusion of the posterior
teeth got accomplished
considering the fact that
the bracket slots of all the
teeth were gingival to the
second molar tube . The
complete case was finished
within 10 months .
: After 6 months
Finished case

Open bite is
aggravated probably
due to bracket
design/placement and
wire
manipulation. The
first step is to re-
bracket UL 3 , as
evidenced by bending
(^) of .016 ss wire. No
rebracketing is done
for UR3 .
Xin Wei,
DDS, PhD,
MS 1st
edition
06/16/201
4, last
revision
12/13/201
5
Open Bite Correction

The second
step to fix
open bite is
to make
reverse curve
(as opposed
to Curve of
Spree) on the
upper wire .

When the posterior
segments of the
wire are inserted to
the molar tubes,
the anterior portion
is coronal to the
bracket
slots. When the
anterior portion is
engaged, it tends to
extrude the upper
anterior teeth.

To
emphasize
the 2nd
point, the
upper wire
curvature is
accentuated
before
engagement

Since the
open bite
extends to
the canine-
premolar
region, 1/4
elastics are
used .

Two months later,
the anterior open
bite improves The
lingual tilting of
#19 also improves .
Upper wire 16x16
(reverse
curvature), Lower
16x22. Finally
extraction appears
to be necessary

Non-surgical orthodontic treatment of anterior open
bite in an adult patient.
White life design – Case presentation
Caucasian female, 20 years old
with a chief complaint of
problems in chewing food and
also esthetics, and wanted
orthodontic treatment. She had
no relevant medical history and
no previous history of
orthodontic treatment. She had
a tongue thrust swallowing
pattern and from history taking,
she used the pacifier until the
age of 6.

Extra-oral assessment . She
had symmetrical dolicalfacial
biotype, lips are incompetent
at rest showing 70% of the
upper central incisors. On
smiling she shows 1-2 mm of
gum, upper midline is
deviated 2mm to the right.
She present a convex profile
with an obtuse nasolabial
angle and increased lower
facial height.

Intra-oral assessment : She presents
a good oral hygiene with healthy
periodontal tissues, anterior open
bite from #13-23 of 4-5mm,Class I
molar relationship in the right and
left, class I end-on canine
relationship in the right and class I
in the left. Upper incisors are canted
descending from right to left due to
pen chewing habit. Presents a
negative overbite (-4mm) and 3mm
of overjet

The maxillary arch was
symmetrical ovoid while the
mandibular arch form was
symmetrical and tapered .
Upper crowding of 1 mm and 2
mm of lower crowding. Upper
canine width of 28mm and
molar width of 37mm. Lower
canine width of 22mm and
molar width of 32mm. Upper
and lower curve of spee are
inverted due to intrusion and
proclined incisors

A panoramic radiograph
showed that all teeth are
present, #48 appears to be
impacted against the
crown of # 47. There is no
bone pathology and
mandibular condyles,
nasal floor and maxillary
sinuses appeared normal.
There is a temporary crow
in #21 and both #16 and
#26 have resin fillings.

The patient presents a
Class II skeletal
dolicalfacial biotype
with procline upper
and lower incisors.
Lower facial height
and mandibular plane
angle are increased
due to clockwise
rotation of the
mandible.

Treatment objectives
Eliminate tongue trust
habit .Dental correction of
the open bite problem
Retrocline the upper and
lower incisors Correct
the cant by extruding the
upper incisors Achieve a
proper overbite and
overjet Correct the
midline

Treatment plan: Lingual frenectomy
,tongue crib + tongue exercises
Speech therapist Increase upper
canine width Upper incisors
extrusion + lower incisors extrusion
Ricketts progressive technique in the
upper arch Intermaxillary elastics
Achieve a proper overjet and
overbite .Maintain a class I molar
relationship and achieve a class I
canine

Lower 6-6
bonding
(edgewise
esthetic 0.18
slot brackets) +
0.14 Niti +
deliver of
Hawley with
tongue crib .

Lower 0.16 SS
wire with loops
and step up from
#43 - #33 (
extrusion of
lower anterior
teeth). Continues
use of Hawley
with tongue crib.

Removed lower
wire and engaged
a 0.16 x 22 SS.
Lower spaces are
closed by using a
power chain from
#46 - #36
Open bite is reduced to
1mm in the central incisor
area

Bonding of
superior 6-6
(edgewise
esthetic 0.18
slot brackets) +
engaged a 0.14
NiTi wire.
Finished use of
Hawley.

Reverse
curve of
spee in the
upper wire

Started Ricketts
”utility” therapy
in the upper
arch with a 0.16
x 22 (TMA) from
#16 - #26 tubes
passing over
#15;#14;#24;#25
.

Started use of
intermaxillar
elastics from
#13 to #43 and
#23 to #33 .
(the goal is to
extrude upper
and lower
incisors and
close the bite)

-
Reactivatio
n of Ricketts
+
Intermaxilla
r elastics
from #13 to
#44 - #43
and #23 to
#34 - #33.

Continuous use
of
intermaxillary
elastics.
Engaged 0.16
SS superior
wire and 0.17 x
25 lower TMA.
Progress
treatment
photographs
were taken.
Progress extra-oral photographs
Intra oral upper and lower progress
photographs (left). Good archform
achieved. Intra oral Lateral anterior
progress photograph (up). Notice a
good overjet and overbite almost
achieved.

Intra-oral
frontal and
lateral view
progress
photographs

Debonding of lower
6-3 and 3-6 ,
posterior occlusion
is achieved avoiding
any undesirable
lower posterior
movements. Power
chain lower 3-3 ,
intermaxillary #13-
#12 to #43 and #23
- # 22 to #33
empala elastics.

- Debonding +
lower splint 3-3
and deliver upper
Hawley with
tongue crib. Final
records were
taken (
Photographs;
Casts;
Radiographs).

Pre
treatment
and pos-
treatment
chephalo
metric
measurem
ents :

Nonsurgical approach to Class I open-bite
malocclusion with extrusion mechanics: A 3-year
retention case report
A Hispanic girl, age 12 years 9
months, had a convex
profile, a Class I
malocclusion, an anterior
open bite,
and a tongue-thrust habit. She
was in a good general
health and had no history of
major systemic disease or
accident
or history of a thumb-sucking
habit. Her chief
complaint was an open bite
with crooked mandibular
teeth. The tongue-thrust habit
was observed during
swallowing
and conversation.
American Journal of Orthodontics and Dentofacial Orthopedics
Volume 147, Issue 4, April 2015, Pages 499-508

Pretreatment facial
photographs showed that
the patient had a convex soft
tissue profile with an
obtuse nasolabial angle.
From the frontal view, her
face was slightly
asymmetric, and the chin
was deviated
slightly toward the left. Upon
smiling, she had inadequate
gingival exposure. Intraoral
and dental cast
examinations
demonstrated a Class II
molar
tendency bilaterally.

A 5-mm anterior open bite
was
observed with 2 levels of
occlusal planes, anterior
and
posterior. The only teeth in
contact were the left first
molars and the right second
premolars and first molars.
A significant tongue-thrust
habit was noticed at rest
and
also while swallowing. The
maxillary arch was relatively
narrow compared with the
mandibular arch.

Five millimeters
of anterior crowding in
the maxillary arch and
4 mm of anterior
crowding in the
mandibular arch
were observed. A 3-
mm Bolton
discrepancy with
mandibular anterior
tooth excess was
measured. No
mandibular deviation
or clicking noises
were detected
during opening or
closing of her jaws.

Panoramic and
lateral
cephalometric
radiographs
were taken
before
treatment . The
panoramic
radiograph
showed no
caries, and all
third molars
were
congenitally
missing.

The cephalometric
analysis
demonstrated a Class I
skeletal relationship
(ANB, 2.2; Wits appraisal,
2.2 mm) with a
hyperdivergent growth
pattern tendency (SN-MP,
38.7). The angle between
the maxillary incisors and
the sella-nasion plane
was 107.4, the
mandibular
incisor to mandibular
plane angle was 99, and
the interincisal
angle was 114.8.

Based on the
findings, the
patient was
diagnosed as
skeletal Class I
with a dental
open bite. The
etiology of the
open-bite
malocclusion
appeared to be a
combination of
hereditary and
habitual
factors.

TREATMENT OBJECTIVES
The following treatment
objectives were established:
(1) close the patient's open
bite and create
ideal overject and overbite,
(2) relieve the crowding,
(3) correct the constricted
maxilla, (4) eliminate the
tongue thrust,
(5) correct the midline
deviation, (6)
obtain a stable occlusal
relationship, and (7) ultimately
improve her dental esthetics
by establishing an
esthetic smile.

TREATMENT
ALTERNATIVES
The patient had a
hyperdivergent
growth pattern
tendency, and dental
extrusion mechanics
might create
a more severe open
bite without control
of the vertical
dimension.

TREATMENT
ALTERNATIVES
Orthognathic surgery to
close her open bite
by a segmented 3-piece
LeFort I osteotomy with
a
bone graft, combined
with fixed orthodontic
treatment,
was discussed with the
patient and her parents.

TREATMENT
ALTERNATIVES
Skeletal
discrepancy
correction, facial
and dental
esthetic
change, and
establishment of
an ideal
occlusion would
all be possible
with this surgical
approach.

Fixed orthodontic
treatment alone
could extrude the
anterior teeth and
induce skeletal
alveolar bone
growth
to correct the open-
bite malocclusion
and increase the
anterior gingival
display.

For this patient, both
nonextraction
and extraction were possible:
(1) nonextraction
with maxillary expansion to
correct the posterior
crossbite
and gain space to correct
crowding and also use a
tongue crib or spurs to
modify the tongue-thrust
behavior during the
treatment followed by a set
of retainers
with a tongue reminder

For this patient, both
nonextraction
and extraction were
possible: or (2)
extraction of 4
premolars to gain
space for the
correction of crowding
and in consideration of
the open-bite tendency
for hyperdivergent
growth.

The patient and her parents
declined orthognathic
surgery as well as
orthodontic treatment with
extractions.
Because of this response,
the plan included a
nonextraction approach
with rapid palatal
expansion
and a tongue appliance to
correct the open-bite
malocclusion.

TREATMENT PROGRESS
Before the treatment, the
patient was referred to a
pedodontist to verify that she
had no caries and for a
routine periodontal checkup.
Bands were fitted on the
maxillary first premolars and
first molars, and an
impression was taken
for a Haas rapid
palatal expander.
Medial diastema between the
maxillary incisors after activation of
the Haas rapid palatal
expander.

TREATMENT PROGRESS
The Haas expander with
a 12-mm expansion
screw was
cemented in the
maxillary arch, and the
parents and the
patient were instructed
to turn the screw once
each
day until a buccal
overjet was observed.
Then the
expander was stabilized
for 4 months.
Medial diastema between the
maxillary incisors after activation of
the Haas rapid palatal
expander.

TREATMENT PROGRESS
A 3-mm
diastema
between the
maxillary
central
incisors was
observed at
the end of
expander
activation .
Medial diastema between the maxillary
incisors after activation of the Haas rapid
palatal
expander.

Preadjusted
0.018 x 0.025-in slot
edgewise brackets
were bonded to
each tooth, and a
0.016-in archwire
and a 0.016 x 0.022-
in superelastic
nickel-titanium
archwire
were used for the
initial leveling.

At the same time, a
supplemental 0.016 x
0.022-in stainless steel
archwire
was fabricated as an
extrusion arch using
the Haas expander as
anchorage and ligated
to the
nickel-titanium base
wire at the midline
during the
leveling stage .

0.016 x 0.022-in
stainless steel
archwire
was fabricated
as an extrusion
arch
Ligated to
0.016 x 0.022-
in superelastic
nickel-titanium
archwire

Two 0.030-in
stainless steel
wires
were fabricated as
tongue spurs and
bonded on the
mandibular central
incisors with
composite resin to
modify the patient's
tongue-thrust habit
.

After
removal of the
Haas expander,
a transpalatal
arch was
cemented to
maintain the
transverse
dimension of
her
maxilla .

Class II
triangle
elastics (1/4
in, 4.5 oz)
from the
maxillary
canines to
the
mandibular
canines
and first
molars
Run the elastic from the
upper cuspid to the lower
1st premolar and then to
the lower 1st molar to form
a triangle

and box-vertical
elastics (1/4 in,
4.5
oz) from the
maxillary lateral
incisors to the
mandibular
lateral incisors
were applied
during the entire
orthodontic
treatment.

During the finishing
stage, final detailing
of the occlusion was
accomplished with
0.017 3 0.025-
in titanium-
molybdenum
archwires in
conjunction with
vertical elastics with
Class II vectors
(1/4 in, 6 oz).

While the orthodontic
treatment was in
progress, the patient
learned new tongue
positions at
rest and during
swallowing. Her
compliance was excellent
throughout the treatment.
One and a half millimeters
of interproximal reduction
was performed on the
mandibular anterior teeth
to eliminate the Bolton
discrepancy.

A fixed retainer was attached
to the lingual surface of
the mandibular anterior
teeth. Overlayed Hawley
retainers
were fabricated and
delivered to secure the
stability
of both arches. A tongue crib
was incorporated
in the maxillary Hawley
retainer to prevent relapse of
the tongue-thrust habit. Total
treatment time for this
patient was 24 months.

A 20-year-old
woman presented
with an anterior
open bite and a
unilateral
posterior crossbite .
The open bite was
closed by leveling,
aligning, and
flattening the
maxillary and
mandibular occlusal
planes..
A–D, Facial photographs before treatment.
E–G, Intraoral photographs before
treatment.
H–J, 0.014-inch Sentalloy initial wires.

treatment.
Triangular
vertical
elastics
were used
only on
the buccal
segment at
the
working
and
finishing
stages

An excellent, low-friction, superelastic,
NiTi archwire for straightening and
alignment. Sentalloy wires feature
thermally activated shape memory and
provide nearly constant forces.
Sentalloy wires are designed to deliver a
gentle, light continuous force; moving teeth
without dissipation of force and periodontal
stress. The “secret” to Sentalloy’s superiority
is its use of body temperature to activate the
characteristics inherent in the wire, to give
superelasticity and shape memory qualities
not found in competitors wires. All Sentalloy
wires are individually wrapped to help
prevent cross contamination.

A transpalatal bar
attached to the
maxillary
first molars was
used to help with
arch coordination
and correct the
unilateral
posterior crossbite.
An active self-
ligating straight
wire appliance
was used. Active
treatment was for
15 months.
treatment.

Q–S, 0.021- ×
0.025-inch
stainless steel to
finalize leveling
occlusal plane,
continuing
with triangular
vertical elastics.
K–M, 0.020- × 0.020-
inch Bioforce wires
to
finish stage 1 of
leveling and aligning.
N–P, 0.019- × 0.025-
inch stainless steel
working wire to
flatten the occlusal
plane, coordinate
arches, and
consolidate spaces.
The patient starts using triangular vertical elastics.

BioForce ®Arch Wires
A BioForce wire is a superelastic
shape memory Nickel Titanium
wire that provides gradually
increasing forces from anterior to
posterior segment, all within one
arch wire. Therefore, BioForce
wire can be deflected or activated
in such a way that it will produce
significantly lower forces when
deflecting it in the area that
engages relatively small anterior
teeth, while it will gradually
increase the force moving from
the anterior to the posterior
segment of the wire.

T–V, 0.021- ×
0.025-inch
stainless steel
braided wire,
finishing
archwire. W–Y,
Intraoral
photographs
after treatment.
Z–ZC, Facial
photographs
after treatment.

Anterior open-bite orthodontic treatment in
an adult patient: A clinical case report
International Orthodontics 2016 ; X : 1-13
45-year-old woman consulted
complaining chiefly of her
unpleasant smile esthetics and
masticatory and speech
problems.
Facial analysis showed a round,
asymmetric face, limited
exposure of the upper incisors
during spontaneous smiling.
An occlusal plane cant from the
left side, a convex profile and a
good thickness of perioral soft
tissue were shown .

The intraoral clinical
evaluation, supported by
a panoramic
radiography, showed a
dental anterior open-bite
caused by
inadequate tongue
posture. Angle
Class I on the right side
and a second molar and
canine
Class II on the left,
moderate upper and
lower crowding,

transverse deficiency
of both arches, and a
thin but healthy
periodontal biotype.
Moreover, she
displayed implants at
units
25, 37 and 46, bridge
rehabilitations from 14
to 16 and from 34
to 36, and periapical
lesions at 26 and 36

Cephalometric
analysis showed
a skeletal Class
I, a
Normo divergent
vertical pattern,
a well-positioned
ANS-PNS
plane and
excessive
proclination of
the upper and
lower incisors

All endodontic problems
were resolved before
starting orthodontic
treatment. The bridge
between units 34 and 36
was
removed as we decided in
favor of implant
rehabilitation at 35.
Temporary prostheses
were placed at 34 and 36.
Bonding was done with
the Insignia system using
Damon Q
brackets .

During
orthodontic
treatment, the
following arch
Sequence was
used: .014
CuNiTi, .014X
.025 CuNiTi,
.018 X .025
CuNiTi, .019 X
.025 SS, .019 X
.025 TMA Progress intraoral photographs: lingual spurs

Speech therapy was started
immediately after
initiation of orthodontic
treatment.
Lingual spurs were positioned
at the mandibular incisors to
promote tongue rehabilitation
Vertical elastics were used
from initiation of treatment.
During
alignment and leveling,
triangular elastics were used:
box
elastics were used later.
.

During the working phase,
Temporary Anchorage
Devices wewe placed at
the mandibular anterior
site so as to intrude the
lower left premolars .
When intrusion was
complete, the
screws provided anchorage
to ensure extrusion of the
upper
left premolars and molars
using lateral elastics and to
correct
the occlusal plane cant.
Temporary Anchorage Devices used for intrusion

Extrusion of the incisors
to close an anterior open
bite is inadvisable,
as the condition will
relapse once the
appliances are removed.
Rather,
treatment should aim to
try and intrude the molars,
or at least control
their vertical development

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