Slow maxillary expansion /certified fixed orthodontic courses by Indian dental academy

SLOWSLOW
MAXILLARYMAXILLARY
EXPANSIONEXPANSION
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTSCONTENTS
• Introduction.
• Slow Maxillary Expansion.
• Classification of Slow Maxillary Appliances.
• Indications and Contra-indications.
• Advantages of SME.
• Expansion Mechanics.
• Appliances used for SME:
Coffin Spring.
Active Plate.
W-Arch.
Quad Helix.
Schwartz Appliance.
Y-plate.
Minne Expander Appliance.
NiTi Palatal Expander- NPE 1
NPE 2
Spring Jet.
Spring Loaded Expander.
www.indiandentalacademy.co
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• Expansion Screw/ Spring.
• Expansion due to Slow Maxillary Appliances.
• Changes in arch width perimeter.
• Retention Period.
• Relapse Tendencies.
• Influence of Age on treatment outcome.
• Skeletal Changes induced at Mid-palatal Expander.
• Mandibular Influence of SME.
• Histological Changes.
• Comparison Between RME and SME.
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INTRODUCTIONINTRODUCTION
Maxillary expansion treatments have been used for
more than a century to correct maxillary transverse
deficiency.
Three expansion treatment modalities include Rapid
Maxillary Expansion (RME), Slow Maxillary Expansion
(SME) and Surgically-assisted Maxillary Expansion.
Since each treatment modality has its advantages
and disadvantages, controversy regarding their use
exists.
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RME has been used extensively. However, clinical
and histological studies have shown that relapse,
micro-trauma of the temporomandibular joint and
the mid-palatal suture, root resorption, tissue
impingement and pain, and external root resorption
are observed in RME procedures (Linder Aronson and
Lindgren,1979; Barber and Sims,1981;
Langford,1982).3,14
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Hence, to eliminate these disadvantages and
obtain increased physiological tissue reaction,
SME has become more popular (Mew, 1983;
Vardimon et al, 1991). 3
So, SME as an effective and biocompatible
treatment of choice for maxillary arch
expansion will be discussed.
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SLOW MAXILLARYSLOW MAXILLARY
EXPANSIONEXPANSION
Slow Maxillary expansion has traditionally been
termed dento-alveolar expansion, which involves
increase of arch width by movement of few teeth (or
many teeth) although some skeletal changes can be
observed.
Slow maxillary expansion with a fixed split acrylic
appliance was evaluated by Hicks (1978) with the use
of frontal and lateral cephalograms. 5
The linear arch width changes are due to bodily
translation of the teeth and the maxillary segments.
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The total expansion is half skeletal and half dental
from the beginning (1:1).
Total treatment time ranges from 2- 6 months.
Large midline diastema never appears .
It employs the use of lingual arch wire appliances
with expansive capability.
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CLASSIFICATIONCLASSIFICATION
REMOVABLE FIXED
• Coffin Spring · Quad Helix.
• Active Plate. · W-arch.
• Schwartz Appliance. · Minne Expander.
• Y-Plate. · NiTi Palatal Expander
(NPE 1, NPE 2)
· Spring Jet
· Spring Loaded Expander.
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INDICATIONSINDICATIONS
• For treatment of mild maxillary deficiency (arch
expansion) in early or mixed dentition.
• For correction of unilateral or bilateral crossbite(s) in
early or mixed dentition.
CONTRA-INDICATIONS
• In adults where growth is completed.
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ADVANTAGESADVANTAGES 88
• It requires minimal adjustment throughout its use, and allows
easy adjustment when necessary.
•It delivers a constant physiologic force until the required
expansion is obtained.
•There is minimum tipping of anterior teeth.
•Least strain is exerted on anchored teeth.
•The appliance is light and comfortable to the patient.
•It can be used for sufficient retention after the expansion .
•Relapse tendencies are less.
•Retention time is less.
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DISADVANTAGESDISADVANTAGES
• Treatment time is long as compared to RME.
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Activation of expansion screw/ spring = One
quarter turn (900
) per week.
The expansion rate is 0.4 - 1.1mm. per week. 5
To produce expansion at this rate, 2 to 4 lbs (10-
20 N) of force is optimal (depending on the age
of patient). (Proffit)5, 16
The expansion of the maxillary dental arch is the
result of dento-alveolar movement as well as
splitting of the midpalatal suture and moving the
maxillae apart.5
EXPANSION MECHANICSEXPANSION MECHANICS
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APPLIANCES USEDAPPLIANCES USED
FORFOR
SLOW MAXILLARY EXPANSIONSLOW MAXILLARY EXPANSION
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1. COFFIN SPRING1. COFFIN SPRING1313
• Walter Coffin – 1875.
• It is a removable appliance
capable of slow dento-alveolar
expansion
• The appliance consists of an
omega shaped wire of 1.25mm
thickness, placed in the mid
palatal region
• The free ends of the omega wire
are embedded in acrylic covering
the slopes of the palate
• The spring is activated by pulling
two sides apart manually.www.indiandentalacademy.co
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2. ACTIVE PLATE2. ACTIVE PLATE 55
• Pierre Robin in 1902
was the first one who
constructed a split plate
which incorporated a
screw.
• Active plate - This
serves as a base in
which screws or springs
are embedded and to
which clasps are
attached.
• Most screws open 1mm
per complete
revolution, so that a
single quarter turn
produces 0.25mm of
tooth movement.
(Proffit)
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3. W- Arch3. W- Arch1313
Ricketts - 1975Ricketts - 1975
• The W – arch is a fixed
appliance constructed of 36
mil Stainless steel wire
soldered to molar bands to
avoid soft tissue irritation
,the lingual arch should be
constructed so that it rests
1-1.5mm off the palatal soft
tissue .
• The w –arch is activated
simply by opening the apices
of w- arch and is easily
adjusted to provide more
anterior than posterior
expansion ,or vice versa if
this is desired .
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• The appliance delivers
proper force levels when
opened 3-4mm wider than
the passive width and
should be adjusted to this
dimension before being
inserted .
• Expansion should continue
at the rate of 2mm per
month until the cross bite is
slightly overcorrected.
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4. QUAD-HELIX4. QUAD-HELIX 1313
(Rickets, 1978)(Rickets, 1978)
• Quad-helix expansion
appliance was popularized
by Ricketts, 1978.
• It is a modification of W-
arch.
• Depending on age of
patient, quad helix can
produce dento-skeletal
(SME) or dental effects.
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INDICATIONSINDICATIONS
• All cross- bites in which the upper arch needs to be
widened.
• Mild expansion in the mixed dentition or permanent
dentition, which frequently exhibits lack of space for the
upper laterals.
• Class III – Expansion needed.
• Class II cases .
• Thumb sucking or Tongue thrusting cases
• Cleft palate conditions either unilateral or bilateral.
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• It is fabricated from .038"
blue Elgiloy wire and is
either soldered to the upper
first molar or bent to fit into a
lingual sheath.
• The lingual arm of the
appliance extends to the
premolar or cuspid.
• The posterior helix is beveled
slightly to lay against the
palatal vault and is as close to
the upper molar as possible to
prevent impingement on the
soft tissue. The anterior helices
are brought as far forward as
possible.
Anterior Bridge
Posterior Bridge
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• The anterior segment of the W expansion should be as
wide as possible so that the appliance is maintained
away from the swallowing position of the tongue.
• All the helices should roll to the top and should be
tightly wound to increase their mechanical efficiency.
• Quad-helix appliance applies approx 5N of force on
the dental structures.16
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The quad-helix appliance demonstrating the ability forThe quad-helix appliance demonstrating the ability for
lateral expansion of the maxillary buccal segments aslateral expansion of the maxillary buccal segments as
well as a rotation of the banded molar.well as a rotation of the banded molar.
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ACTIVATION OF QUAD HELIXACTIVATION OF QUAD HELIX
Quad Helix can be pre-activated by stretching the two molar
bands apart prior to cementation or by using three prong pliers
after cementation.
• Initial activation of quad-helix appliance during
insertion.
In Class II cases, most of the arch form change should occur in
the anterior portion of the buccal segments.
As the upper molars are expanded approximately 1cm per side,
the anterior segments are expanded approximately 3cm overall.
An initial expansion of 8mm will produce approx. 14 ounces of
force.
• Intra-oral activation of quad-helix appliance. When an
intraoral bend is made in the anterior segment to increase the
amount of overall expansion, a reciprocal bend must be made in
the posterior section in order to compensate for the tendency
for mesial rotation of the upper molars.
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EXPANDS MOLARS
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ROTATES MOLARS
&
EXPANDS BUCCAL ARMS
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For rotating
the molars.
For expanding arch.
For breaking a finger
habit, and providing for
headgear attachment.
JCO, 1979, FEB
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5. SCHWARTZ APPLIANCE5. SCHWARTZ APPLIANCE 55
SCHWARTZ 1966SCHWARTZ 1966
• The appliance basically
consists of an acrylic
plate with a midline
split incorporating
one / two expansion
screws, the acrylic does
not cap the occlusal
surface / incisal edges.
• The appliance in
addition has a labial
bow & is retained by
means of Adam's / ball
end clasps.
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6. Y PLATE6. Y PLATE 55
• The acrylic sectioning is
done in a Y shape. The
appliance incorporates
two screws on each side.
• The incisor segment is
expanded anteriorly
whereas the posterior
segment moves laterally.
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7. MINNE- EXPANDER7. MINNE- EXPANDER
APPLIANCEAPPLIANCE 3,53,5
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• Minne Expander is a fixed, Slow maxillary expansion appliance
cemented to the first permanent molars and first premolars.
• It is used to increase maxillary width by activating the palatal
compressed-coil spring.
• The Minne-expander appliance spring applies forces of up to 10
N (2 pounds). (Hicks, 1978)16
• Each incremental activation of the Minne-expander produces
one half the amount of expansion produced by the jackscrew
appliances (0.125 mm. as compared to 0.25 mm.) 16
• It is more physiologic because of the lessened effect to the
maxillary sutures and the consequent healing and repair of the
latter during the expansion procedure.
Disadvantage:
Prevents proper oral hygiene maintenance.
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8. NiTi PALATAL EXPANDER8. NiTi PALATAL EXPANDER77
• It is a tandem-loop,
nickel titanium,
temperature-activated
palatal expander that
produces light,
continuous pressure on
the midpalatal suture
while simultaneously
uprighting, rotating,
and distalizing the
maxillary first molars.
(NPE – 1) By- Wendell, Arndt, 1993
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• It has adjustable
stainless steel
extensions which are
inserted into standard
horizontal lingual
sheaths that are spot-
welded to the molar
bands.
• A locking indent on the
lingual attachment holds
the expander to the
molar band for patient
safety.
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The nickel titanium expander
has a transition temperature of
94°F. When it is chilled before
insertion, it becomes flexible
and can easily be bent to
facilitate placement.
As the mouth begins to warm
the appliance, the metal
stiffens, the shape memory is
restored, and the expander
begins to exert a light,
continuous force on the teeth
and the midpalatal suture.
• Nickel titanium expanders come
in eight different intermolar
widths, ranging from 26mm to
47mm, that generate forces of
180-300g. The 26-32mm sizes
have softer wires that produce
lower force levels for younger
patients
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A. Passive appliance.
B. Initial activation and insertion for expansion and
distal molar rotation.
C. After expansion and rotation correction.
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ADVANTAGES:
• The nickel titanium palatal expander is self-activated
by body temperature.
• It automatically expands to its predetermined shape.
• Requires little manipulation by the clinician.
• Produces a light, constant pressure on the teeth and
midpalatal suture.
• It is safe and permits the patient to mitigate the
pressure response.
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9. NiTi PALATAL EXPANDER9. NiTi PALATAL EXPANDER 88
By-By- ROBERT MARZBAN, NANDA,1999ROBERT MARZBAN, NANDA,1999
• It delivers a uniform, slow, continuous force for maxillary expansion, molar rotation
and distalization, and arch development.
• This appliance expands at a rate that maintains tissue integrity during repositioning
and remodeling of the teeth and bone.
• As the palate expands, regeneration matches the rate of expansion.
(NPE 2)
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• The NPE2 is made up of an innovative lingual attachment
with .036" Ortholoy arms and molar loops for unilateral
and bilateral adjustments.
• A locking indentation in the lingual attachment ties the
appliance securely to the maxillary molar band.
• To prevent removal or accidental dislodging, the
appliance should also be tied in with ligatures.
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DESIGN OF NPE 2DESIGN OF NPE 2
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• The expander is available in sizes from 26mm to
44mm in 2mm increments.
• The appropriate expander is selected as follows-
Measure across the mandibular arch between the
central pits of the first molars , then subtract 4mm to
determine the size of NPE2 to use.
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• The nickel titanium expander has a transition
temperature of 94°F.
• Seating the Appliance: After trial, the band of expander
is coated with triple cure GIC It is sprayed with a
‘tetrafuoroethane refrigerant spray’ before insertion.
As the mouth begins to warm the appliance, the metal
stiffens and begins to exert a light, continuous force on
the teeth and the midpalatal suture .
• The NPE2 delivers a force of 350g in 3mm increments.
If a 4mm expansion appliance is placed, the force will
initially be higher, but will return to 350g once 3mm of
expansion has occurred.
• Because the force application is preprogrammed, it is
self-limiting.
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•Majority of palatal expansion patients need at least
4mm of expansion at the maxillary first molars (2mm
per side). An additional 2-3mm can be gained by
adjusting the palatal Nitanium loop of the NPE2.
•If more than 8mm of expansion is needed, two
separate expanders may need to be used in sequence.
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• Other functions of NPE 2-
• Ortholoy arms of appliance do not contact bicuspids at
initial placement. After molar expansion, distal
rotation, and distalization, Ortholoy arms contact
bicuspids.
The appliance initially appears to move palatally, but
as it expands, it will move occlusally. This will produce
a lower tongue posture that can promote expansion
and transverse growth in the mandibular arch.
• The NPE2 frees the growth restriction of posterior
functional crossbite and provides space for impacted
and causes orthopedic changes in the maxilla and
often mandibular repositioning.
• After expansion, the NPE2 can act as a stabilizing wire
for molar intrusion.
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FUNCTIONS OF NPE 2:
• Unilateral molar correction.
• Unilateral posterior crossbite correction.
• Bilateral or unilateral contraction with smaller appliance
sizes.
• Distal rotation and expansion of both the first molars
and second bicuspids.
• Distal rotation and expansion of the molars and second
bicuspids, followed by initial cuspid retraction.
• Leveling, alignment, and rotation of the incisors while
the buccal segments are expanded—a fixed, three-way
sagittal appliance.
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• Leveling, alignment, and rotation of the buccal
segments while the molars are expanded and the
incisors are retracted.
• Retention of expansion while the incisors are
advanced overexpansion of the palatal Nitanium
loop in cleft palate cases
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Advantages of the Nitanium Palatal Expander2 overAdvantages of the Nitanium Palatal Expander2 over
traditional rapid palatal expanders.traditional rapid palatal expanders.
• Better physiologic response and stability.
• Preprogrammed to deliver the exact amount of expansion
required and to stop at that point.
• No severe suture splitting.
• Less tipping of abutment teeth.
• Can influence the direction of maxillary and mandibular
growth.
• Rotates molars buccally or distally.
• Can be used for anchorage.
• Shorter retention period.www.indiandentalacademy.co
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• Placed at the chair, without laboratory procedures.
• Individually adjustable molar loops.
• Does not require frequent operator or patient
adjustments.
• Built-in safety retention system.
• Less patient discomfort.
• Allows the patient to adjust the wire temperature to
mitigate pressure.
• Less effect on speech and eating.
• Hygienic. www.indiandentalacademy.co
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10. SPRING JET10. SPRING JET 77
Aldo Carano, 1999Aldo Carano, 1999
• The active components of
the spring jet are soldered
or attached to the molar
bands .
• The transpalatal arch
replaced by a telescopic
unit with NiTi coil spring
and a lockscrew
• .
LOCKSCREW
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• The telescopic unit is
placed high 5 mm up
from center of molar
bands so that the line of
force passes close to the
center of resistance of
maxillary teeth . Hence,
tipping is prevented at
molars and pre-molars.
• But it should be 1.5 mm
away from palatal tissue
to avoid irritation to the
tongue.
BALL STOP
LOCKSCREW
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Activation:
•By moving the lock screw horizontally along the
telescopic tube.
• A ball stop on the transpalatal wire allows the spring to
be compressed.
Force Application:
• Two coil springs can be used -
Spring with force application of 240g – for mixed dentition,
and
400g – for permanent dentition.
• Force levels tend to decrease as the springs, hence,
lockscrew is designed to maintain full spring compression
to assure constant force level through out the expansion.
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ADVANTAGES-
•The Spring Jet Appliance allows a constant expansion
force as long as necessary.
•After correction, the appliance can easily be inactivated
and used as a retainer.
•The molars will move with little change in angulation,
and can be used for anchorage during correction of the
other dental inclinations.
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BEFORE
TREATMENT
AFTER
TREATMENT
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11. SPRING LOADED EXPANDER11. SPRING LOADED EXPANDER
(SLE) – By Leone, 2003(SLE) – By Leone, 2003 1010
•The SLE is a new Orthodontic
device designed to provide
expansion of the upper arch by
means of pre – determined,
continuous forces.
•It maintains an accurate control
over the direction and intensity of
the forces applied when Maxillary
Dentoalveolar Expansion (SME) is
carried out in patients whose
growth has almost finished.
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• Nickel-Titanium spring coils were added to the arms of
the expander to absorb the intensity of the force
generated by its screw.
• SLE may contain either a 500g or a 800g. Coil spring
that provides a continuous force, sufficient to promote a
Dental-Alveolar re-modelling that is biologically ideal
and biomechanically controlled.
• The screw has a self-stop mechanism at the end of
expansion to prevent it from disassembling in case of
excessive activation.
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1. SLE is fully compressed 2. Spring coil completely open
at the start of treatment. (passive).
3. SLE has been re-activated 4. 8mm is the maximum expansion
spring coil is compressed again. obtainable with the SLE.
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• The device is activated on average, 4-8 activations (0,
4-0, 8 mm) every 6 weeks.
• A different number of activations will not alter the
intensity of the force delivered to the dental
structures, as this stays constant (500 or 800g.)
• There is no risk of over-expansion as the screw, upon
reaching the pre-determined expansion, will become
passive.
• However, by changing the activation pattern, Rapid
Maxillary Expansion can also be achieved using SLE.
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• Easy, less activations are required.
• Tipping is easy to control through bodily vestibular
movement.
• An accurate monitoring of expansive movement is
possible.
• Occlusal forces cannot influence or alter the activation,
so safety is certain.
• Only continuous, predetermined forces work in
between appointments.
• If patient misses an appointment, there is no harm as
there can be no over-expansion.
ADVANTAGESADVANTAGES
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EXPANSION SCREW/ SPRINGEXPANSION SCREW/ SPRING
Slow Expansion can be accomplished either by activating
a special spring designed to produce desired 2 to 4 lbs of
force, or by turning the typical jackscrew once per week.
(Proffit)
The jackscrew used is similar to the one used for rapid
maxillary expansion but with a comparatively smaller
pitch.
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1. EXPANSION SCREW1. EXPANSION SCREW
• The baseplate in an active plate, when is used as a
working part, is divided and driven apart by screws.
• A typical screw consists of an oblong body divided into
two halves, each half has a threaded inner side to
receive one end of a double ended screw.
• The screw has a central bossing that has four holes.
These holes receive a key to activate the screw. A
single adjustment of the screw brings about 1/4
rotation causing 0.18mm linear movement.www.indiandentalacademy.co
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The screw when turned 900
, will move the parts of plate
apart 0.2mm thereby narrowing the periodontal
membrane 0.1mm on each side without interrupting
any blood supply. Thus, arch expansion is brought
about in a harmless and effective way.
Different Screws for particular action of plate are:
• Encased Expansion Screw.
• Skeleton – Type Expansion Screw.
• Special Screws:
• Encased Pull Screw.
• Encased Screw with Incorporated Spring:
Hausser
• For Expansion in Three Dimensions: Bertoni.
• Eccentric Screwswww.indiandentalacademy.co
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2. EXPANSION SCREW2. EXPANSION SCREW
They are sturdy and resist stress.
They are used in upper expansion plate.
When screw is expanded, the spiral is pulled out of
acrylic.
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3. SKELETON TYPE EXPANSION SCREW3. SKELETON TYPE EXPANSION SCREW
The spiral embedded in acrylic plate does not turn back.
Broader screw is used for maxillary expansion plate and
narrower for mandibular expansion plates.
Smaller size also causes effective distal movement of
teeth.
FOR MAXILLARY EXPANSIONwww.indiandentalacademy.co
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4. SCREW OF HAUSSER: ENCASED SCREW WITH4. SCREW OF HAUSSER: ENCASED SCREW WITH
INCORPORATED SPRINGINCORPORATED SPRING1313
It is the screw that activates limited spring action.
A quarter turn of this screw will expand both the
sides by 0.1mm.
The spring incorporation will limit the pressure on
both sides and further keeps it constant.
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5. SCREW OF BERTONI5. SCREW OF BERTONI
It causes forceful expansion of active plate in all
the three directions.
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6. ECCENTRIC SCREW: FOR FANWISE6. ECCENTRIC SCREW: FOR FANWISE
MAXILLARY EXPANSIONMAXILLARY EXPANSION
The screw is made up of two parts : a hinge, and a
special screw permitting slight rotation inside the
disk.
When opened, the two parts of plate come together
at posterior end while anterior part opening fanwise
about 4mm.
With a special screw, fanwise opening can be
increased to 8mm.
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EXPANSION DUE TOEXPANSION DUE TO
SLOW MAXILLARY APPLIANCESSLOW MAXILLARY APPLIANCES
Upon the application of transverse biomechanical forces,
initial changes involve the lateral tipping of the posterior
maxillary teeth as the periodontal and palatal soft tissues
are compressed and stretched.
If applied transverse forces are of sufficient magnitude to
overcome the bio-elastic strength of sutural elements,
orthopedic separation of the maxillary segments takes
place (Cleafill,1965; Hicks, 1978, Cotton, 1978, Storey,
1973). 4
The separation and repositioning of the palatal segments
continue until the force distribution is reduced below the
tensile strength of the sutural elements (Storey, 1973;
Barber, 1981).14
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Reorganization and remodeling of the sutural connective
and skeletal tissues may then proceed in the
stabilization of the expanded maxillary arch.
Subsequent orthodontic movements occur through
bodily translation as the compressed buccal alveolar
plate resorbs at the root-periodontal interface from
continued force application. (Storey, 1973 ; Barber,
1981).14
No diastema occurs at the end of slow maxillary
expansion.3
Similar to RME, palatal expansion is greater at the
alveolar crest and less at the palatal vault, and maxillary
bones swing laterally with the center of rotation near the
fronto-nasal suture (Storey, 1973).
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CHANGES INCHANGES IN
ARCH WIDTH PERIMETERARCH WIDTH PERIMETER 33
• Mossaz- Joelson and Mossaz (1989)3
reported that
inter-canine width showed a smaller increase than
inter-molar width in the maxillary arch both in bonded
and banded Minne Expander SME devices.
• Arch perimeter gain through treatment 0.60times the
amount of posterior expansion for SME . (Akkaya et
al, 1998)
• SME was found to produce increase in maxillary arch
perimeter at the rate of 0.52 times the change in 1st
pre-molar width at the end of retention period.
(Akkaya et al, 1998)
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• Maxillary arch-width increases ranged from 3.8mm to
8.7mm with slow expansion of as much as 1mm per
week, using 900g of force (Hicks, 1978).
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PERIOD OF RETENTIONPERIOD OF RETENTION44
Retention periods of 3 months or less are reported to
be adequate in allowing sutural regeneration and
stabilization of slowly separated maxillary segments.
(Storey, 1973; Eckstrom,1973; Hicks, 1978; Bell,
1981)
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RELAPSE TENDENCIESRELAPSE TENDENCIES
The slower expansion techniques have been associated with
a more physiological adjustment to maxillary expansion,
producing greater stability and less relapse potential than in
rapid expansion procedures (Krebs, 1959; Krebs, 1964;
Issacson, 1964; Skieller, 1964; Cleall, 1965; Zimring, 1965;
Cotton, 1978; Hicks, 1978; Storey, 1978).
This is due to the lower forces applied on the suture over a
longer period, which permits a continuous adaptation of the
tissues to the skeletal and dental changes.
Hicks,1978 reported that the relapse was 10 to 23 percent
with fixed retention, 22 to 25 percent with removable
retention, and 45 percent with no retention following SME.
Reduced skeletal relapse tendency was also observed in the
slow maxillary expansion cases due to reduced stress within
the involved tissues and in maintenance because of the
sutural integrity (Storey, 1973; Cotton, 1978; Mossaz-
Joelson and Mossaz, 1989).3www.indiandentalacademy.co
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However, overexpansion is necessary to compensate for
the tendency of the posterior teeth to return to their
pretreatment axial inclinations. (Storey, 1973)
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INFLUENCE OF AGE ONINFLUENCE OF AGE ON
TREATMENT OUTCOMETREATMENT OUTCOME
The increase in rigidity of the facial skeleton with
advancing age restricts bony movement remote from
the appliance of expansion.(Chaconas, Caputo, 1982)16
However, expansion can be carried out just before and
during the pubertal growth spurt when response is
increased.
Expansion lingual arches that produce 1-2lbs of force,
open the suture in young children, but in adolescents
these appliances produce more dental than skeletal
expansion. (Proffit) 5
In general, the effect of expansion of the dental arch on
the maxillary bases diminishes as age advances.
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A direct relationship between increased resistance to
skeletal expansion and increasing patient age has been
associated with the formation of mechanical interlockings
at maxillary articulations as early as 12 to 13 years of age
(Isaacson, 1964; Melsen, 1972).16
Also, the enhanced skeletal response in younger age
groups has been associated with a greater cellular activity
in the growing suture (Cleall, 1965; Cotton, 1978; Storey,
1955; Ten Cate, 1977). 3
SME in adults-
During treatment of adults, the intermaxillary and
surrounding sutures are less patent and, in some cases,
fused, which makes orthopedic results difficult to obtain. 16
There is an increase in interdental width along with severe
tipping of the posterior teeth in adults with SME. Increased
activation creates minimal expansion in such cases.
However, aggressive activation causes increased tipping of
the posterior teeth, especially those used for anchorage.
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Bills (1981) stated that, although the literature (Hicks,
1978; Barber and Sims, 1981) has revealed that fixed
appliances may effectively increase maxillary width
during the deciduous and mixed dentitions, older
patients may require the higher force systems of rapid
expansion procedures or surgical intervention (Bell and
Turvey, 1974; Kennedy et al., 1976). 16
m

SKELETAL CHANGES INDUCED ATSKELETAL CHANGES INDUCED AT
MID-PALATAL SUTUREMID-PALATAL SUTURE 44
Skeletal expansion involves separation of the right and
left halves of the maxilla at the midpalatal suture; dental
expansion results from buccal tipping of the maxillary
posterior teeth (Krebs, 1958; Haas, 1961; Wertz, 1970;
Melsen, 1972; Cotton, 1978; Hicks,1978).
Skieller, 1964 demonstrated that 20% of the widening of
the dental arch induced by slow maxillary expansion
devices in younger patients was due to sutural separation.
The slow expansion procedures increase the percentage of
orthodontic movements as the tensile strength of the
suture elements is not overwhelmed. (Moyers, 1974;
Storey, 1973, Hicks, 1978)
m

Sutural separation occurs at a rate allowing the
maintenance of sutural integrity during maxillary
repositioning and remodeling (Storey, 1973; Ekström et
al., 1977; Cotton, 1978), with less traumatic disruption, a
greater reparatory reaction, and greater sutural stability
than rapid expansion of sutures. 8
The rate of midpalatal suture separation by slow expansion
systems apparently allows a more physiologically tolerable
response by the sutural elements than the disruptive
nature of rapidly expanded maxillary segments (Bell,
1982).4
Ekstrom et al (1977) reported that the slowly expanded
suture normally becomes well organized by mineralized
tissue in about 30 days and is established within 3
months.2
m

MANDIBULAR INFLUENCE OF
SLOW MAXILLARY EXPANSION11
It has been observed that the position of the lower
dentition may be influenced more by maxillary skeletal
morphology than by the size and shape of the mandible
itself (McNamara, 1999).
The widening of the lower arch is due primarily to
decompensation, an uprighting movement of the lower
posterior teeth, which often have erupted into occlusion
in a more lingual orientation because of the associated
constricted maxilla.
Haas observed that the mandibular arch tended to follow
the maxillary teeth by tipping laterally (Haas, 1961).
m

The neuromuscular adaption of the mandible to the
maxilla in slow expansion allows a normal vertical
closure.(Bell, Le Compte, 1981)4
Patients whose maxillae had been expanded
orthopedically showed a post-retention increase of 1.1
mm in the mandibular intercanine dimension
(Sandstrom et al., 1988; Adkins et al., 1990).
m

HISTOLOGICAL CHANGESHISTOLOGICAL CHANGES44
Due to slow rate of suture separation, the tearing and
hemorrhaging are minimized.
The increased sutural and skeletal response has been
related to growth periods of high cellular activity with
increased reparability potential and treatment prior to the
formation of bony interlockings at maxillary articulations.
Cleall, 1965; Cotton, 1978; Storey, 1955; Ten Cate, 1977
reported greater cellular activity in the growing suture.4
Brin and co-workers, measured the cyclic nucleotides as
indicators of cellular activity and new bone formation, and
reported that the sutural bone cells of young cats were
more responsive to palatal expansion forces than the
corresponding cells of old animals.2
No midline diastema appears during treatment since the
treatment time for SME is longer that allows trans-septal
fibers to tip the crowns before end of active treatment.www.indiandentalacademy.co
m

SLOW MAXILLARY RAPID MAXILLARYSLOW MAXILLARY RAPID MAXILLARY
EXPANSIONEXPANSION
1.Indicated for correcting
transverse maxillary
deficiencies during early or
mixed dentition.
2.Biomechanical Effect-
Orthodontic (mainly)
3. Light Forces are applied per
activation is- 2-3 lbs (10-
20N).16
4.Screw Activation: Quarter
turn per week.
1.Indicated for correcting
transverse maxillary
deficiencies between 13- 15yrs.
Of age.
2. Orthopedic
3. Heavy Forces are applied per
activation is approx. 10-20lbs
(100N).16
4.Screw Activation:
Up to 15 yrs: 90° rotation
once in the morning & once in
the evening.
15-20 yrs : 45° activation
m

EXPANSIONEXPANSION
5. Rate of expansion- 0.4- 1.1
mm per week.
6. Duration of treatment:
2 - 6 months.
7.No transient diastema appears
during treatment.
8.Low relapse tendencies after
treatment. Hence, shorter
retention periods: 1-3 months.
9.Reduced evidence of tooth
tipping and decreased residual
loads within the expanded
segments reported.
5. Rate of expansion-0.5- 1 mm
per day.
6. Duration of treatment:
1-4 wks.
7. Transient diastema appears
during treatment.
8. Higher relapse tendencies
after treatment. Hence, greater
retention periods: 3-6 months.
9. Mesial tipping of incisors and
lateral tipping of maxillae.
Increased residual loads
reported within expanded
segments.www.indiandentalacademy.co
m

EXPANSIONEXPANSION
10. Rate of midpalatal suture
separation allows a more
physiologically tolerable and
adaptive response by the
sutural elements.
11. Histologically, tear and
haemorrhage of vessels is less.
12. Arch perimeter gain through
treatment is about and 0.60
times the amount of posterior
expansion for SME . (EJO) 3
13.Increase in inter-canine
width – less than that in RME.
14. Increase in maxillary arch
perimeter is at the rate of 0.52
times the change in 1st
pre-
molar width at the end of
3
10. Rate of midpalatal suture
separation of rapidly expanded
maxillary segments is disruptive
in nature .
11.Histologically, tear and
haemorrhage of vessels is more.
12. Arch perimeter gain through
treatment is about 0.65 times
the amount of posterior
expansion. (EJO) 3
????
13.Increase in inter-canine
width – higher than that in SME.
14. Increase in maxillary arch
perimeter is at the rate of 0.54
times the change in 1st
pre-
molar width at the end of
retention period. 3www.indiandentalacademy.co
m

Skeletal and dental
expansion rates in slow
expansion treatment
over a 10-week period.
The amount of skeletal
and dental changes is
consistent through the
total observation period
(Hicks 1978) 5
Skeletal and dental expansion rates in
rapid maxillary expansion treatment
over a 10-week period. The skeletal
reaction is highest at the start of
treatment and decreases constantly
with time. Conversely, the dental
component of the movement is rather
low at the beginning but increases with
treatment time (Hicks, 1978).www.indiandentalacademy.co
m

•Erlangung des and Zahnmedizinischen et al carried out
a retrospective study in 2004 to evaluate the stability of
orthodontically corrected unilateral crossbite by comparing
the patients treated either with rapid maxillary expansion
(RME) or with slow expansion devices in the early (mean age:
7.2 years) or in the late mixed dentition (mean age: 9.9
years).
•Maxillary expansion was performed either with a removable
expansion plate (n= 50), or with a rapid maxillary expansion
technique (RME) using a tissue-borne, fixed, split acrylic
appliance (n= 50).
• The slow expansion appliance (n= 50) was activated by 0.2
mm per week and the result was retained for 3 to 6 months
after expansion had been achieved.
•The RME device (n= 50) was activated twice a day (0.4 mm)
and the treatment result was retained for a minimum of 3www.indiandentalacademy.co
m

The observation periods were approximately 8 years for the
early-treatment groups and 6.5 years for the late-treatment
groups.
The mean change was 1.1 ± 2.8 mm in the maxillary
interpremolar arch width and 2.3 ± 2.1 mm in the intermolar
arch width in the slow expansion groups.
The RME groups showed a mean change of 3.6 ± 2.7 mm in
interpremolar arch width and of 3.8 ± 2.7 mm in intermolar
arch width; this was significantly greater than in the
comparison groups.
•The transverse increase was significantly greater for patients
treated with RME as compared to those treated with SME.
m

BIBLIOGRAPHYBIBLIOGRAPHY
1. Arndt, W.V.- Nickel titanium palatal expander, J. Clin.
Orthod. 1993(27):129-137.
2. Corbett, M.C.-Slow and continuous maxillary expansion,
molar rotation, and molar distalization, J. Clin. Orthod.
1997,31,(3):253- 263,.
3. Akkaya S, Lorenzon S, Ucem TT. Comparison of dental
arch and arch perimeter changes between bonded rapid
and slow maxillary expansion procedures. Eur J Orthod,
1998;20(3):255-61.
4. Bell RA. A review of maxillary expansion in relation to rate
of expansion and patient’s age. Am J Orthod
1982;81(1):32-7.
5. Proffit WR, Fields HW. Contemporary orthodontics. 3rd ed.
St. Louis: Mosby; 2000:508-11.
6. Bishara SE, Staley RN-Maxillary expansion: Clinical
Iimplications. Am J Orthod Dentofacial Orthop, 1987, 91
m

7. Aldo Carano: The Spring Jet for Slow Palatal Expansion,
JCO, 1999, 33 (9): 527- 31
8. Robert Marzban, Ravindra Nanda, Nickel Titanium Palatal
Expander , JCO, 1999,32 (8): 431-441.
9. William L. Wilson Modular 3D Lingual Appliances Part 1
Quad Helix - JCO, 1983 (11): 761-66.
10. Dr. Claudio lanteri, Dr. Fabrizio Lerda, Cuneo, Italy -
Slow Maxillary Expansion using a new spring – loaded
device.
11. Roberto, Antonio Carlos: Mandibular Behavior with Slow
and Rapid Maxillary Expansion in Skeletal Class II Patients,
Angl Orthod, 2007, 77 (4): 625-31.
12. Graber and Neumann, The Active Plate; Removable
Orthodontic Appliances, 2nd
edn, Saunders, 1984: 28-34, 67-
74.
m

13. Roberts M. Rickets, Bio Progressive Therapy, Rocky
Mountain Orthodontics, 2002 , 255- 258.
14. Barber and Sims: Rapid maxillary expansion and
external root resorption in man: A scanning electron
microscope study, AJO-DO: 1981 (6): 630 – 652.
15. Dr. Robert M. Ricketts on Early Treatment: Part 2,
JCO, 1979 (2): 115-127.
16. MANUEL O. LAGRAVERE :Skeletal and dental changes
with fixed slow maxillary expansion treatment, JADA,
2005, 136 (2): 194-99.
17. Robert Marzban, Ravindra Nanda, Nickel Titanium
Palatal Expander , JCO, 1999,32 (8): 431-441.
m

EFFECT ON MANDIBLEEFFECT ON MANDIBLE
m

The intermolar distance, however, was found to be
stable (Gardner and Chaconas,1976; Sondhi et al.,
1980), while Glynn et al. (1987) reported a slight
decrease in molar width.
During the initial expansion, the teeth tilt to some extent
but tend to upright spontaneously during the long period
of retention. A permanent expansion of 3.5 mm was
obtained with little tendency to relapse (Skieller, 1964).
The increase of 1.1 mm in intercanine width found in
that study was clearly the result of treatment and not of
growth, since the presence of the permanent canines in
the initial models was required. It has been shown that
no further increase in intercanine width is to be expected
after the eruption of the permanent canines, but a
decrease, ranging from 0.5 to 1.5 mm is 16 Literature
review possible (Brown and Jensen, 1951; Barrow and
White, 1952; Moorrees and Chadha, 1965;
Knott, 1972).
m

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