Slow maxillary expansion/oral surgery courses

SLOW MAXILLARY
EXPANSION
www.indiandentalacademy.com

CONTENTS
• Introduction.
• Rationale of Slow
Maxillary Expansion.
• Indications and
contraindications
• Advantages and
disadvantages of SME.
• Biological response to slow
maxillary expansion
• Influence of Age on
treatment outcome.
• Appliances used for SME:
• Coffin Spring.
• Active Plate.
• Lower Schwartz Appliance
• TPA
• W-Arch.
• Quad Helix.
• Minne Expander
Appliance.
• NiTi Palatal Expander-
NPE 1
• NPE 2
• Spring Jet.
• Spring Loaded Expander.www.indiandentalacademy.com

• Mandibular Influence of SME.
• Retention Period.
• Relapse Tendencies.
• Comparison between RME and SME.
• Conclusion
• References

Introduction
• Transverse problems because of narrow maxilla
are corrected by maxillary expansion.
• SME involves relatively lesser forces (2-4
pounds) over longer periods (2-6 months).

Rationale for slow maxillary
expansion
• Skeletal cross bites resulting from narrow
maxilla are generally treated by heavy forces to
open the mid palatal suture and make the
maxilla wider.
• Dental crossbites are treated by moving the
teeth with lighter forces.
• But in early mixed dentition even modest forces
will cause both skeletal and dental changes.

• Heavy forces in early or mixed dentition –
risk distortion of nose.
• Only 450-900g of force is generated in SME,
which may be insufficient to separate a
progressively maturing suture.

• Storey (1981) recommends slow expansion
at .5-1mm per week.
• “Physiological sutural adjustments”, which
elicit less trauma and a greater repair
response compared to rapid expansion.
• 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
3months.2
•

Indications
• For correction of unilateral or bilateral crossbite(s) in
early or mixed dentition.
• For correction of dental cross-bites in early permanent
dentition.
• In Class II and Class III cases requiring expansion,
SME can be done.
• In Cleft Lip and Palate patients, slow, continuous
forces are required
• For gaining space in case of minimal crowding.

CONTRA-INDICATIONS5
• In adults where growth is completed

Advantages
• It delivers a constant physiologic force until the
required expansion is obtained.
• Maintenance of sutural integrity and the reduced
stress loads within the tissues
• Retention periods of 3 months or less appear
adequate in allowing sutural regeneration and
stabilization of slowly separated maxillary
segments. (Proffit)
• Relapse tendencies are less.

DISADVANTAGE
• Treatment time is long as compared to RME.

BIOLOGICAL RESPONSE TO SLOW
MAXILLARY EXPANSION 4
• Application of transverse biomechanical forces
• 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 continues
• Until the force distribution is reduced below
the tensile strength of the sutural elements
(Storey, 1973; Barber, 1981).14
• Reorganization and remodeling of the sutural
connective and skeletal tissues proceed in the
stabilization of the expanded maxillary arch

Histologic examination
• 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)8
• Less traumatic disruption, a greater
reparatory reaction, and greater sutural
stability than rapid expansion of sutures.

• 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

• In a comparison of slow expansion (with a Quad
Helix) and RPE - Zachrisson (1982)
• Periodontal breakdown on the buccal aspects of
posterior teeth occurred infrequently in both
groups, but that the few patients who exhibited
some attachment loss were mostly in the RPE
group.
• 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)

• The relative amount of skeletal versus dental
changes occurring in maxillary expansion
procedures has been primarily related to:
• Patient’s age and
• Rate of expansion (that is, magnitude of applied
force)

INFLUENCE OF AGE ON
TREATMENT OUTCOME8
• 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.

SME in adults
• 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.
• Aggressive activation causes increased tipping
of the posterior teeth, especially those used for
anchorage.

Skeletal or Dental expansion
• Hicks 1978 using 2-pound forces with
expansion rates of 0.5 to 1.0 mm per week,
achieved maxillary arch width increases of
from 3.8 to 8.7 mm during treatment.
• Hicks estimated that the skeletal changes
represented 24 to 30 percent of the total arch
width increase in 10 to 11-year-old patients
• 16 percent in the 14 to 15-year-olds.

Slow maxillary expansion
(Hicks 1978) 5

• Measure the distance between the tips of the
mesiobuccal cusps of the maxillary 1st molars.
• Subtract the mandibular measureent from the maxillary
measurement
• The average differences in persons with normal
occlusion is around 1.6mm for males and around
1.2mm for females

COFFIN SPRING 12
• Walter Coffin in the year 1881

ACTIVE PLATE 12
• Pierre Robin in 1902 was the first one to
construct a split plate which incorporated a
screw.

Pitch of a screw:
• The number of threads per unit length; or the
distance between threads, also called the thread
pitch.
Types of screws14:
• Nano screws
• Micro screws
• Medium screws
• Special expansion screws

Nano screws
• Nano – expansion screws
• Nano – sector screws
• Nano – traction screws

Micro Screws
• Skeletal micro – expansion screws

Skeletal medium – sector screws

Micro traction screw

Standard screws
• Maxillary expansion screws
• Mandibular expansion screws
• Arched expansion screws

Maxillary expansion screws

Mandibular expansion screws

Arched expansion screws

Stainless Steel micro – expansion
screws

Special screws

Fan-type expansion screw

Mandibular bow screw

• Expansion Screw M for transversal
expansion movements in the upper plates.
Provides 7mm expansion with 0.8mm turn.
Color Code: Blue

• Expansion Screw P: This medium size screw is
for upper and lower plates for 7mm expansion
with 0.8mm turn. Color Code: Pink

• Expansion Screw Y: This large screw is for
upper and lower plates for 9mm expansion
with 0.8 turn. Color code: Green

• Expansion Screw S: For very narrow plates
This tiny screw with trapezoidal design is for
5mm expansion. Color code: Yellow

• Expansion Screw K: Another trapezoidal
design for 7mm expansion with 0.8 turn.
Color code: Orange

• Expansion Screw E: sectional or single
tooth expansion, provides a 6.5mm
expansion with only 0.7 turn. Color code:
Purple

• Expansion Screw B: 9mm expansion with
0.7mm turn. Color code: White

• Expansion Screw T: It is the largest with an
incredible 11mm expansion with 0.8 turn.
Color Code: Beige
•

SCHWARTZ APPLIANCE13
• This appliance was introduced by SCHWARTZ
in 1966

Transpalatal arch13
• It was introduced by Robert Goshgarian in
1972.

Uses
• Expansion or constriction
• Distalisation
• Correction of molar Rotation and production of
buccal root torque
• Intrusion of molars
• Torque
• Anchorage increase
• Transition from mixed dentition to permanent
dentition- to stabilize molar position

Activation (expansion)
• These corrections should be made before rotating
or distalizing the molars.
• Activation should be in the range of 1 to 1.5 mm
of expansion per side and per activation until the
problem has been corrected.
• Lateral movement of the upper molars may be
either coronal tipping or bodily movement. If
bodily movement is required, buccal root torque
is given while expanding.

Buccal root torque

W-Arch 13,5
• The ‘W-arch’ was introduced by Ricketts in
1975.

QUAD-HELIX 13
• Ricketts, in 1978, introduced a Modification of
W-arch known as the ‘Quad-helix expansion
appliance’

INDICATIONS
• For the treatment of all crossbites 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.
• In Class III and Calss II cases, where expansion is
needed.
• In Thumb sucking or Tongue thrusting cases,
Quad helix with ‘spurs’ can be used as a as habit
breaking appliance
• In Unilateral or bilateral Cleft palate conditions,
where light and continuous forces are desired.

• Removable quadhelix constructed of Blue
Elgiloy for increased flexibility adjustability.
(ORTHORAMA® Dentaurum )

3D® (Wilson®) Multiaction
Palatal appliance, RMO

• It inserts into vertical lingual tubes via
vertical extensions on the expander
• The wire tapers from ·0380 to ·0290
anteriorly, thus reducing force in the incisor
region.

MINNE- EXPANDER APPLIANCE 3,5

• Chaconas and Caputo16 (1982)
• The Haas, Hyrax, and stable removable
jackscrew appliances revealed the most
significant amounts of orthopedic force with
each incremental activation of the devices.
• The Minne-expander appliance showed less
force with each activation, but that which was
produced was within the orthopedic range.

• The quad helix appliance produced forces less
than the orthopedic range and was therefore
considered to be an orthodontic appliance
except when used in younger patients in whom
the sutures are patent.
• The quad helix appliance proved to be the least
effective orthopedic device. Although the
effects of palate separation were minimal,
increased activation of the appliance affected
primarily the posterior teeth.

NiTi PALATAL EXPANDER1
(NPE 1)
• It was introduced by Wendell, Arndt 1993.

Action of the appliance
• Nickel titanium's shape memory and transition
temperature effects.
• Nickel titanium can be processed into a set
shape to which it constantly tends to return after
deformation.
• At temperatures below the transition
temperature, the interatomic forces weaken,
making the metal much more flexible.
• Above the transition temperature, the
interatomic forces bind the atoms tighter and the
metal stiffens.

• 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.

ADVANTAGES:
• The nickel titanium palatal expander is self-
activated by body temperature.
• It automatically expands to its predetermined
shape.
• It requires little manipulation by the clinician.
• It produces a light, constant pressure on the
teeth and midpalatal suture.
• It is safe for the patient.

NiTi PALATAL EXPANDER 15
• By- Maurice Corbett, 1997

• Less bulky than the original
• To reduce the risk of fracture of the stainless
steel extension arms.

• 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.

Indications for use of NPE 2:
• For unilateral correction of rotated or displaced
molar.
• For unilateral posterior crossbite correction.
• For bilateral or unilateral contraction of arch
with smaller appliance sizes.
• For Retention of expansion

Other functions of NPE 2
• The appliance initially appears to move
palatally, but as it expands, it will move
occlusally. This produces 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.

Advantages of the Nitanium Palatal
Expander 2 over traditional rapid palatal
expanders
• It has better physiologic response and stability.
• It is preprogrammed to deliver the exact amount of
expansion required and to stop at that point
• It can be used for anchorage.
• It has individually adjustable molar loops.
• It does not require frequent operator or patient
adjustments.
• There is less patient discomfort
• There is less effect on speech and eating.
• It is hygienic www.indiandentalacademy.com

SPRING JET 7
• It was introduced by Aldo Carano in
1999.

• Two coil springs can be used -
• Spring with force application of 240g for
mixed dentition, and 400g – for permanent
dentition

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 move with little change in angulation,
and can be used for anchorage during correction of
the other dental inclinations.www.indiandentalacademy.com

SPRING LOADED EXPANDER
(SLE)10
• The appliance was introduced by Dr.
Claudio lanteri, Dr. Fabrizio Lerda, Cuneo,
the screw was introduced by Leone in
2003.

• 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.

• The device is activated on average, 4-8
activations every 6 weeks.
• SLE may contain either a 500g or a 800g. coil
spring that provides a continuous force which
sufficiently promote a Dental-Alveolar
remodelling
• There is no risk of over-expansion as the
screw, upon reaching the pre-determined
expansion, will become passive

ADVANTAGES
• The appliance is easy to use and less activations are
required.
• Tipping of teeth 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.

MANDIBULAR INFLUENCE OF
SLOW MAXILLARY EXPANSION11
• Haas observed that the mandibular arch tended to
follow the maxillary teeth by tipping laterally
(Haas, 1961).
• 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).

PERIOD OF RETENTION4
• 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)

RELAPSE TENDENCIES (Mew 1983)
• 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).

• 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).3

DIFFERENCES BETWEEN SLOW
AND RAPID MAXILLARY
EXPANSION

CONCLUSION
• Application of light, continuous forces allows
normal arch dimensions to develop at any age
without undue tipping of the abutment teeth.
• Slow Maxillary Expansion (SME) has also been
associated with more physiologic stability and less
potential for relapse than with rapid expansion.
• Hence, various new SME appliances are being
introduced to gain maximum advantage of a
technique which is biocompatible and at the same
time effective to bring about desired treatment
results, with least trauma to the patient at
physiologic and histological levels.www.indiandentalacademy.com

References
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):255-6.www.indiandentalacademy.com

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 (1):3-14.
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. MANUEL O. LAGRAVERE :Skeletal and
dental changes with fixed slow maxillary
expansion treatment, JADA, 2005, 136 (2): 194-
99.
10. Dr. Claudio lanteri, Dr. Fabrizio Lerda, Cuneo,
Italy - Slow Maxillary Expansion using a new
spring – loaded device.

• Roberto, Antonio Carlos: Mandibular
Behavior with Slow and Rapid Maxillary
Expansion in Skeletal Class II Patients, Angl
Orthod, 2007, 77 (4): 625-31.
• Graber and Neumann, The Active Plate;
Removable Orthodontic Appliances, 2nd edn,
Saunders, 1984: 28-34, 67- 74.
• Maurice CorbettSource Slow and
Continuous Maxillary Expansion, Molar
Rotation, and Molar Distalization with a
Nickel Titanium Appliance JCO 1997
Apr(253 – 263)www.indiandentalacademy.com

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