Expansion in orthodontics /certified fixed orthodontic courses by Indian dental academy
INDIAN DENTAL ACADEMY
Leader in continuing dental education
Expansion in arch has been one of the oldest
means of creating space in the dental arches.
It is also one of the conservative method of
It can also be used to correct the intermaxillary
and dental arch relationships primarily in
It enables correction of crossbites early in
• Narrow maxilla was recognized for thousand years
and Hippocrates has also refered to it.
• In 1860 Emerson C.Angell placed a screw between
maxillary premolar of a girl aged 14 yrs and wider
her arch in two weeks.
• In 1877 Walter coffin demonstrated the expansion of
the maxillary arch using spring which caused
separation of the mid palatal suture in children.
• Pfaff, in 1929 described improved nasal function
after maxillary expansion.
• Haas, in 1960 reported increased nasal width,gain in
arch and lowering of mandible with bite opening.
Rapid maxillary appliances
•Marked narrowing of the arches
•Unilateral or bilateral cross bite
•Mandibular prognathism with reduced anterior development
of the maxillary base
•Steep palate with septal deviation and mouth breathing due
to enlarged adenoids
•Cleft lip and palate
•Mild arch length to tooth material deficiency.(1mm of
expansion in post = 0.7 mm increase in arch perimeter)
• No true contraindications
• Anterior open bite cases
• High FMA, convex profile cases
• Skeletal asymmetry of maxilla and mandible with severe
• Older age group due to ossification of sutures
• Patients on dilantin therapy
Tooth utilization maximum
Rapid maxillary expansion appliances
• Banded appliances
- Derischweiler type
- Haas type
- Beiderman type
- Issacson type
- Arnold type
•Tags are soldered to the palatal
aspects of bands to provide
attachments for the acrylic.
•Acrylic also extends to the
palatal of all non banded
teeth except incisors
• A length of the wire is soldered
along the palatal aspects
of the bands.
• Free ends turned back
and embedded in acrylic.
• A screw is incorporated.
• Banding difficult on
• Banding and cementation
difficult on deciduous teeth.
• In late mixed and early
• This design also called
hygienic palatal expander.
• Requires a special screw.
• These have extensions in
heavy gauge wire which are
soldered to the palatal
aspects of bands.
• Acrylic free palate, so no
food entrapment, mucosal
irritation and no ulceration.
Deciduous and early mixed
•This appliance has a special
spring loaded screw
called a minne expander
•It is soldered directly
to the bands
•No acrylic is used
•Easy to fabricate
• Coil spring expander is
attached by means of vertical
half tubes on the molar bands.
• Tubes cosist of coil springs
• It expands the arch by lingual
pressures,using coil springs for
• Raymond Howe in 1982 developed this appliance
• Clears the palate from acrylic
• No banding needed- can be used on malposed teeth where
parallel path of insertion is not possible
• Less error prone as bands don’t have to be placed in
• Easy to make on deciduous teeth.
Full coverage bonded RME appliance
• Developed by John Spolyar in 1984
• Solely for tooth borne anchorage
• Spider type expansion screw is placed as anteriorly as
• Acrylic free palate
• No bands present
• Difficult to remove
Extent of occlusal
Removable RPE appliance
• Developed by Vel Ivanovski in 1985
• Used for correction of crossbite and expansion of both
maxilla and mandible
• No bands, clasps and easy to fabricate
• 2 mm thick acrylic sheet are moulded on the models with
screw stabilized on the models using biostar
• In a single appliance extension are given to the lingual of
mandibular teeth for simultaneous expansion
• Separate upper and lower appliances can also be made
Hilgers palatal expander
•Consist of two molar bands with
soldered horiontal helices and
an acrylic plate
•With embedded jackscrew
•Anterior extension of the wire serve as
the bonded occlusal rest
•Helicles serve to rotate and distalize
the upper molar
•Jack screw produces orthopedic
• Use head gear plier to twist the molar bands distally to
incorporate twice the the amount of rotation needed
• Place the lingual bend in the vertical portion of the wire that
extends out of the acrylic.
• Hold the helical with the head gear plier and bend the
appliance towards palate to place a minor tip back force on
• The appliance is able to make changes in arch width and
• Distal rotation of upper molars
• Creates room for canine eruption
• Anchors the molars during upper retraction
• Regime of screw rotation
Zeibe in 1930 : 180 degree rotations per day
Upto age of 15 years : the turn 180 degree is given as
90 degree in the morning and 90 degree in the
15-20 years : overall rotation of 180 is possible by
splitting the rotation into 4 turns of 45 degree each with
approx equal time lapse between them.
Age over 20 years : 45 degree turn in the morning and
45 in the night initially
Over 25 years: surgical seperation may be required.
Zimring and Isaacson in 1965 :
• Young or growing patients: two turns each day
for the first 4-5 days and one turn each day for
remainder of rme treatment.
• Adult patients: two turns each day for the first
two days and one turn each day for the next 5-7
days and one turn eac other day for the
remainder of the rme treatment.
Effects of RPE
• The separation of midpalatal suture is triangular in all three
• The fulcrum of separation lies at varying distance from MPS
depending on age.
• There is generally downward and forward movement of
maxilla due to zygomatic buttressing.
• The mandible also rotates downward and backward exaggerating
• The alveolar bone bends laterally and the palatine bones inferiorly
increasing nasal cavity.
• Splaying of hamular processes of the sphenoid bone is seen.
• As the maxilla moves forward and downward due to loosening of the
circummaxillary sutures, maxillary protraction may be applied with
face mask or reverse headgear.
• Arch perimeter increase is 0.7 times the intermolar width increase.
• Palatal depth is increased due to overeruption of posterior teeth.
• Mandibular arch length expansion is also seen in RPE: upto 1.1mm
increase in intercanine width and 2.5mm in intermolar width.
Clinical management of RPE patient
• Pain is not usually present in juveniles, adults may complain.
• Pain is usually at the time of activation.
• Midline diastema is most important proof of separation.
• Petechie may be present on the palatal mucosa which
resolves in a week or two.
• Occlusal interference are seen.
• Patient report inability to masticate from back teeth.
• Overexpansion is advised till lingual cusps of upper molars
occlude with lingual inclines of lower buccal cusps.
Both skeletal and dental
changes seen from beginning
Both removable and fixed
appliances can be used
Force levels: 2-4 lbs
Activation: 1mm /week
changes initially (8:2) .later
dental changes take place with
Only fixed appliances can be
Force levels: 10-20 lbs
Activation: .5-1 mm / day
Slow palatal expansion
• W arch
• Quad helix
• Ni-Ti arch wires
• Coffin spring
• Expansion screws
• Functional appliances
•A fixed type modification of coffin spring
•First used by ricketts in cleft palate cases
•Prefered in deciduous and mixed
dentition where mild to moderate
expansion is required
• Can be opened anteriorly at the curve as well as at the posterior apices
•Opened 3-4 mm wider that passive width
•Expansion done at the rate of 2 mm per month
•Unequal arm length can be kept in true unilateral crossbite cases
•Over treatment is done
•Can be kept as a retainerwww.indiandentalacademy.com
for 3-4 months
Introduced by dr. Robert Ricketts in 1975
•All cross bites needing upper arch expansion
•Crowding cases needing mild expansion
•Class II needing molar distal rotation
•Class III with constricted maxillary arch
•Tongue thrusting cases
•Cleft lip and cleft palate cases
• A six week interval is observed before
• 1mm each side in molar region and 1.5mm anteriorly
• Ricketts prescribes 500 gm of force to separate mps
• Triple beak plier is used
• Anterior bridge is bend by keeping single beak
anteriorly for intermolar expansion
• 2nd and 3rd bend on palatal bridges for lateral arms.
Modifications of quad helix
Ricketts 3 in 1
Anterior and posterior
Molar rotation www.indiandentalacademy.com Tongue spurs
Ni Ti palatal expanders
Introduced by wendell arndt in
A fixed – removable appliance
Depends on shape memory
and super elasticity of NiTi
Transition temperature 94°F
Continuous force levels
between 230gms to 300 gms.
Available in 8 intermolar
widths; 26-47 mm
26-32mm width appliances are
of softer wires for younger
Freeze gel packs can be used
to make appliance flexible for
•Constructed from 1.25mm wire
•Two types can be prepared i.e.
• Tags are prepared at the end of the wire
to be embedded in the acrylic.
• It is kept 1 mm away from the palate.
• It is cheaper and less bulky but
unless precise construction and
adjustment these may be rather
• Upper arch expansion where lateral
expansion is indicated.
• It can be used in cases of unilateral as well as
• Antero-posterior expansion required.
Differential expansion in anterior or posterior
region is desired.
• Controlled movement can be obtained.
• When space requirement is less than 3 mm.
• Pits are drilled into the base plates allow the initial width
of the appliance to be checked with calipers .the spring is
expanded anteriorly first, then posteriorly by pulling it
apart, care being taken not to twist the appliance.
• This easier and quicker to adjust than
with pliers as it tends to distort the appliance.
• An expansion of 2-3 mm will generally
•The expansion screw is a very
small metallic appliance which
may be designed to move a
single tooth or a group of teeth
or the skeletal bases as
required. This screw as a
source of force together with the
acrylic segment of the plate
effect the teeth and the alveolar
•Different type of screws may be
used advantageously for certain
procedure during treatment with
removable appliance www.indiandentalacademy.com
• The screw normally transmits its forces by
means of acrylic, which comes in contact
with the teeth.
• The patient usually activates the screw once
or twice a week.
• Fairly high force is generated but it is
intermittent in nature.
• Desirable features in screw are stability and
• Screws can be used for various tooth
movements in antero-posterior and
transverse arch expansion and also in
contracting a wide arch.
According to desired action of screw
•Expansion screw appliance
used for symmetrical expansion
of dental arch.
•Appliance with screw to move
individual teeth or small group of
teeth in a buccal or labial
•Appliance with screw to move
individual teeth or small group of
teeth in a mesial or distal
Guidelines for screw positioning•It is positioned in three dimensions accurately.
•It should be placed in the mid line oriented to median
raphe when bi-lateral expansion is to be planned.Screw
lies on a imaginary line passing between the first and
• In a narrow arch it should be positioned more posteriorly
•The horizontal plane of the screw is placed parallel
to the plane of the occlusal surface.
• In children when expanding 90*turn at each adjustment
is sufficient and adjustment is made twice a week.
• In adults tooth movement has to be carried out more
slowly so a 45* turn or1/4th turn per week is sufficient .
•Controlled movement can be achieved.
•Activation can be done at home.
•Various types of tooth movement possible.
•. It is easily available commercially do not require skill of the
•Can be added to suffix the fuctional appliances
•Reliance on the patient for the activation.
•May cause difficulty in cleaning.
•Does not applies a constant force.
•Requires excellent retention .
•Over- activation may cause problem.
Lower Schwarz Appliance
• This is specific type of active plate used in early stages of the
mixed dentition period, to produce orthodontic tooth
movement in the mandible mainly uprighting the posterior
dentition and increasing anterior arch length anteriorly
•Schwarz appliance may be
useful in patients with mild to
moderate lower incisor crowding
but will not satisfy the arch
length requirements of a patient
with severely crowded
Parts of Schwarz plate
• This is made from wire and acrylic
• Simple ball end clasps are placed in the embrasures
between the lower deciduous molars and lower first molars.
• Adams can be used for additional retention usually not
• Expansion screw is located in the midline and embedded
almost in acrylic.
• Additional acrylic also can be placed on the occlusal surface
of the posterior teeth in case in which a posterior bite block
effect is desired.
• It is easily manageable clinically. Usually delivered without
• Appliance is worn full time for first 3-5 month as an active
plate ( one mm expansion each month can be expected.) and
then as passive appliance for additional period of time for
• Additional arch length of 3-4mm(mcnamara) can be gained
on routine basis .
• Simple and a straight forward technique.
• Not recommended in the treatment of gross tooth size/arch
length discrepancy problem.
Y-plate expansion appliance
• It is an active removable type of appliance which is similar to
that of the bite plate and it is anchored on the maxillary arch
with Adams clasps.
• The labial bow inserts into the acrylic in the lateral incisor –
• The plate has two jack screws that exerts a distalizing force.
•The opening of the jackscrews exerts a distalizing component
on the buccal segment teeth and a reciprocal force is delivered
to the anterior palatal contour and maxillary incisors.
•To reduce the mesial force component, which tend to tip the
incisor labialy and dislodge the appliance, the screws are
activated alternately and unilaterally
• First premolars erupted, giving increased anchorage.
• Upright incisors.
• No extensively bodily movement are required.
• The second premolar have not yet erupted.
This expansion is not produced through the application of
extrinsic bio-mechanical but rather than by intrinsic forces in
the dental arch such as those produced by the tongue.
When the forces of the buccal and labial musculature are
shielded from the occlusion, a widening of the dental arches
Balters in this context states :“ It is unnecessary to
use active forces for arch expansion as interplay of muscle
takes care of dental arch formation, it should be realized that
the orthodontics should lead to jaw orthopaedics i.e..
reforming the jaw and the dental arches on a functional
• Originally developed by
Balters in early 1950 .
• Buccinators loops
eliminates the tension of
the strong buccinator
muscle thus there is
marked arch expansion .
• Coffin spring is not active
but stimulator for the
• Frankel has emphasized on the use of labial
and buccal vestibule.
• Using lip pads and the buccal shield
effectively hold the buccal and labial
musculature away from the teeth and
investing tissue eliminating any restrictive
influence that this functional matrix might
• He has stated that the
vestibular shields should be
extended into the vestibular
reflex so that the tension
produced on the soft tissue
and this pull on the soft
tissue is transferred to the
periosteum and results in
deposition of new bone on
the facial aspect of the
– As for expansion it has tested the
deep waters of time to be
completely trusted and accepted
as a respected treatment
modality in the field of
Leader in continuing dental education