Arch expansion

Prepared by: Kaushal Goti
Final BDS

• Emerson C AngelEmerson C Angel 1860 was the first person to
introduce the expansion through screws in
Orthodontics.
 Types:Types:
1. Slow expansion
Rapid expansion
2. Dental Expansion
Skeletal Expansion
3. Anterior expansion
Posterior expansion
4.Unilateral expansion
Bilateral expansion
Profit 5th Edition;Elsevier
PublilcationBhalaji 5th Edition;Arya Medi Publication

Slow Expansion
Indications of slow expansion:
• Minimum expansion is required
• Unilateral or bilateral cross bite.
• Asymmetrical or unilateral arch expansion is
required.
Appliances used for:
− Coffin spring
− Quad helix
− Nitanium palatal expansion
− Swartz expansion plate
− Removable appliances incorporating jackscrew

Removable appliances incorporating
jackscrews
• A removable appliance with a midline expansion screw
can be used for achieving maxillary expansion.
• Expansion is produced by tipping molar buccally.
• A very small amount of skeletal expansion by
separation of the midpalatine suture may be expected.
• To produce bilateral symmetrical expansion, the
baseplate of the appliance is sectioned in the middle
so that there is an equal number of anchor molars on
the both sides of the midline.
• If asymmetric expansion is desired it can be produced
by sectioning the baseplate so that more teeth are in
contact with it on the nonexpanding side.

• Retention which is essential for producing efficient expansion,
can be had by placing Adams clasp on the first premolars and
first permanent molars.
Advantages:
• Removed for cleaning.
• To add additional active component like Z spring, finger
springs etc.
Drawback:
• The need for patient cooperation and difficulty to obtain
adequate retention in the mixed dentition.

Coffin Spring
 Walter coffin-1875
 Removable appliance capable of slow dentoalveolar
expansion
 Consists of omega shaped or U shaped wire of 1.25mm
thickness placed in mid palatal region
 Free end of omega wire are embedded in acrylic
covering slopes of palate
 Spring is activated by pulling two asides apart manually.

Quad Helix expander
 It was described by Ricketts.
 The quad helix incorporates four helices
that increase the wire length.
 The flexibility and range of action of this
appliance is constructed using 0.038 inch
wire and is soldered to bands on the first
molars.
 The quad helix may be various
prefabricated sizes.
 A new generation of prefabricated quad
helix constructed from nickel titanium
have been introduced recently.
 The advantages of using nickel titanium
over stainless steel include its more
favorable force delivery characteristics due
to nickel titanium’s superelastic properties.
 This may help to produce more rapid
correction of crossbites.
Profit 5th Editioin;Elsevier
PublilcationbedBhalaji 5th Edition;Arya Medi Publication

 The quad helix consists of a pair of anterior helices and a pair of
posterior helices. The portion of wire between the two anterior
helices is called the anterior bridge.
 The free wire ends adjacent to the posterior helices are called outer
arms. They rest against the lingual surface of the buccal teeth and
soldered on to the lingual aspect of the molar bands.
 The quad helix can be used to expand a narrow arch as well as to
bring about rotation of molars. It can be pre activated by
stretching the two molar bands apart prior to cementation or by
using three prong pliers after cementation.
Indication:Indication:
 All cross bites in which the upper arch needs to be widened.
 Class III malocclusion cases
 Class II malocclusion cases
 Thumb sucking or tongue thrusting cases
 Cleft palate conditions either unilateral or bilateral.

Advantages:
 Patient compliance not required a it is a fixed appliances.
 It is used in conjunction with fixed appliance.
 It has got good retention as it is soldered on to bands that are
cemented on the molars.
 Can produce limited skeletal expansion when it is used on
young individuals.
 They are inexpensive to fabricate.
 It has got a large range of action and differential expansion of
anterior and posterior segments possible.
 Molar rotation and torque is possible.
 Can have limited role as a habit breaker.
Disadvantages:
 Mostly dental expansion. Limited skeletal expansion.
 Molars can tip buccally causing bite to open.

Ni-Ti expanders
 In 1993 Arndt developed a fixed-removable tandem
loop nickel-titanium maxillary expander which is
known by the names Ni-Ti expander or Nitanium
expander.
 This expansion appliance has the capacity to rotate ,
upright, distalize and expand the anterior & posterior
arch with gentle biocompatible force.
 This appliance is capable of a uniform, slow,
continuous force.
 The action of the Ni-Ti expander is made possible
by the properties of shape memory and transition
temperature (84 F).

 At temperatures higher than the transition temperature,
interatomic forces bind the atoms more tightly, producing a
stiffer metal.
 At lower temperatures, the forces weaken, making the metal
more flexible.
 The Ni-Ti expander consists of a dual temperature-sensitive,
0.035-in diameter NiTi transpalatal loops that are connected
to the lingual sheaths of the maxillary molar bands on either
sides.
 Anteriorly, a 0.032-inch diameter stainless steel wire forms a
finger spring designed for lateral expansion in the canine and
premolar region.
 A size that is 3 mm wider than the transverse distance
between the maxillary first molar should be selected.
 The Ni-Ti expanders are inserted into the lingual sheath after
cooling them with freeze-gel packs that allows them to be
easily inserted.

Rapid Maxillary Expansion
History:
Rapid maxillary expansion is also known
as rapid palatal expansion or split palate.
Emerson C Angell is Father of rapid
maxillary expansion.
In 1860 Angell first used a jackscrew type
of device.
Korhkaus and Andrew Hass in 1950’s
reintroduced rapid maxillary expansion in
orthodontic community.

Indications:
 Skeletal posterior cross bite, maxillary transverse
deficiency.
 Cleft lip and cleft palate cases.
 Used along with face mask in class III patients
 To facilitate respiratory function.
poor nasal airway, septal deformities, recurrent ear and
nasal infection, allergic rhinitis.

Contraindications:
 Single tooth crossbites.
 Patients who are uncooperative.
 It is not carried out after ossification of mid
palatine suture unless accompanied by adjunctive
surgical procedures.
 Skeletal asymmetry in case of maxilla and
mandible and adult case with sever antero-
posterior skeletal discrepancies.
 Periodontally weak teeth.
 Vertical growers with steep mandibular plane
angle are usually contraindicated.

Effects of R.M.E
Effect on maxilla :
• Opening of the mid-palatal suture.
• Downwards and forward maxillary movement.
Effect on maxillary teeth :
• Midline spacing between the two maxillary central incisors.
• Maxillary posterior teeth show buccal tipping & extrusion.
Effect on mandible :
• Downward & backward rotation of the mandible.
• Increase in face height.
• Reduction in overbite.
Effects of R.M.E. on nasal cavity :
• Reduced resistance to nasal air flow.
• Increase in intra-nasal space.

Types of Appliances used:
1. Removable Appliance
2. Fixed appliance
a. Tooth borne
b. Tooth and tissue borne

Removable Appliances:
o It consists of a split acrylic plate with a midline
screw.
o It is retained using clasp in posterior teeth.
o The disadvantage is appliance are the need of
patients cooperation and the difficulty in
retaining the plate inside the mouth.

Fixed appliance:
 Fixed onto teeth are more reliable and produce
consistent skeletal effects.
 Two commonly used tooth and tissue borne
appliances are:
1) Derichsweiler type
2) Hass type
 Examples of tooth borne appliances are:
1. Isaacson type
2. Hyrax type

Derichsweiler Type
 First premolar and first molar are banded.
 Wire tags are soldered onto the palatal aspect of
the bands.
 These wire get inserted into the split acrylic plate
incorporating a screw as its centre.

Hass Type
 First premolar and molar are either side banded.
 1.2mm diameter thick stainless steel wire is
soldered on the buccal and lingual aspect of the
premolars and molars.
 Lingual wire is kept longer so as to extend past
the bands both anteriorly and posteriorly.
 The spilt palatal acrylic has a midline screw.
 The plate does not extend over the rugae area.

Isaacson type:
o Tooth borne appliance without acrylic palatal
covering.
o It uses a spring loaded screw known as MINNE
expander.
o First premolars and molars are banded.
o Metal flanges are shouldered onto the bands on
the buccal & lingual sides.
o Expander consist of a coil spring having a nut
that can compress the spring.
o This coil spring is made to extend between the
lingual metal flanges that have been shouldered.

 The expander is activated by closing the nut so that
the spring gets compressed.

Hyrax type:
 Makes use of special type of screw called
HYRAX(Hygenic rapid Expander).
 Screws have heavy gauge wire extensions that are
adapted to follow the palatal contour and are
soldered to bands on premolars and molars.

Banded Hyrax appliance :
 The banded hyrax have bands on the first premolars
and molars & the arms of the expansion screw are
soldered on to these bands.
 The principal advantage of the banded appliance is that
oral hygiene is facilitated because gingival coverage is
limited.
 The main drawback of the banded appliance is the need
for precise wire bending & soldering.
Bonded Hyrax appliance :
 The bonded hyrax comprises of an acrylic cap splint that
covers the posterior teeth on either side.
 The arms of the hyrax appliance are attached to the cap
splint on either side.
 Some of these cap splints have a wire framework to
reinforce the acrylic.

 The occlusal acrylic is one to two mm in thickness and is
kept one mm short of the gingival margin thereby
allowing maintenance of good oral hygiene.
 The acrylic cap seats are cemented over the teeth using
glass ionomer cement.

Activation Schedule
 There are two different schedules :
1) Schedule by Timms
 For patients of up to 15 years of age, 90 degrees
rotation in the morning & evening.
 In patients over 15 years, Timms recommends 45
degrees activation 4 times a day.
2) Schedule by Zimring and Isaacson
 In young growing patients, they recommend two turns
each day 4-5 days and later once turn per day till the
desired expansion is achieved.
 In case of non growing adult patients, they recommend
two turns each day for first two days, one turn per day
for the next 5-7 days & one turn every alternate day till
desired expansion is achieved.

Arch expansion

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