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GOOD
MORNING
www.indiandentalacademy.com

RAPID
MAXILLAR
Y
EXPANSION
INDIAN DENTAL ACADEMY
Leader in continuing dental education

INTRODUCTION
• Word “Expansion” refers to lateral
enlargement of dental arches by
orthodontic forces which can be either
direct (or) indirect.
• Direct forces - Exerted against the teeth
to move them in a buccal direction
• Indirect forces - through the pull at the
interseptal fibres.www.indiandentalacademy.com

• First objective in orthodontic treatment
- Correction of discrepancy in
transverse dimension.
• This can be achieved by carrying out
the procedure called “Rapid Maxillary
Expansion”

Historical Background:
• Narrow maxilla - recognized thousand of
yrs ago in Hippocrates.
• No scientific treatment possible as
comparable to present day.
• Before RME, a number of slow expansion
techniques were used by early practitioners.
• Fauchard (1728), Bourdent (1757), Fox
(1830), Delabarre (1819), Lefoulon (1839
Tomes (1848), Allen (1850), White (1859) &
Westcott (1859).www.indiandentalacademy.com

• R.M.E. - Not evolved from above mentioned slow
expansion technique.
• In Sanfrancisco in 1860 Emerson C. Angell
placed screw appliance between max. Premolars
- girl aged 141
/2 yrs - provided with key -
instructed to keep shaft as tight as possible.
• At end of 2 weeks - jaw widened - space between
two front incisors.
• But this bold statement could not be proved with
radiographs as x-rays still to be discovered.www.indiandentalacademy.com

• Angell’s article - stressed importance of per. I.
molars and found alternative in absence of per. I.
molar with double jack screw with opposing
threads.
• Angell work published in Sanfranciso medical
press as “The permanent or adult teeth”.
• In dental cosmos as “Treatment irregularities of
permanent or adult teeth”.www.indiandentalacademy.com

• Angell depressed because one of his diagrams
was published with central incisors together -
instead of showing median diastema.
• This makes Angell’s future silence & RME more
than a generation.

• After 5 yrs a reference was made by A. coleman
1865) this inspired Dr.Coffin to invent a spring
for widening the arch.
• Latter in 1893 professor clarke L. Goddord used
an appliance with bands and a jack screw and
claimed the maxillary separation.
• G.V. Black in 1893 expanded the dental arch by
rapid means using split plates and jack screws.www.indiandentalacademy.com

• Now great debate was started between rapid and
slow techniques.
• E.H.Angle (1910), V.H. Jackson (1904, 1909) &
A.H.Ketcham (1912) stood for slow expansion
while C.H. Hawley (1912), H.A. Pullen (1912) &
M. Dewey (1913, 1914) opted for RME.

• A slow epander’s claimed improved oral hygiene
by using bands with arch wires instead of plates
with screws, which covered the palatal mucosa
and the heavy forces necessary for RME.
• Rapid expanders were not sure of the extent of
the opening of the suture or the general effect.
• Moreover rapid expanders are mostly oral
surgeons not orthodontists.

• M.H. Cryer (1913), an influential anatomist who
considered that the mid palatal suture could not
be opened because of the buttressing and circum
maxillary structures.
• This makes set back for R.M.E. after a
generation gap R.M.E. reawakened by
G.Korkhaus in 1958).

ANATOMY
Bones
• Maxilla - 2nd largest facial bone.
• Unites with its opposite twin forms whole of
upper jaw.
• They form root of mouth, floor and lateral wall
of nasal cavity and floor of orbit.
• Enter into formation of Infratemporal fossae,
inferior orbital and pterygo maxillary fissures.

Various bones articulates with maxillae are
Cranial Facial
1. Frontal 1. Nasal
2. Ethmoidal 2. Lacrimal
3. Inferior nasal concha.
4. Vomer
5. Zygomatic
6. Palatine
7. Opposite maxillaewww.indiandentalacademy.com

• These bone joins maxilla by suture in posterior
and superior aspect. Leaving anterior inferior
aspect free.
• The tenacity of circummaxillary attachments due
to buttressing is strong postero-supero-medially
and postero supero laterally.
• Palatine bones forms an intimate relationship
with maxilla to form complete hard palate (or)
floor of nose and greater part of lateral wall of
nasal cavity.

• It articulates anteriorly with maxilla through
transverse palatal sutures and posteriorly
through pterygoid process of the sphenoid bone.
• The interpalatine suture joins the two palatine
bones at their horizontal plates and continous as
inter maxillary sutures.
• These sutures forms the junction of three
opposing pairs of bones : the premaxillae,
maxilla, and the palatine.
• The entire forms mid-palatal suture.www.indiandentalacademy.com

• The maxillae is in an exposed position, supported
at only part of its circumference and is
vulnerable to lateral displacement especially the
anterior and inferior portions, once the mid-
palatal suture has been ruptured.
• Hence bilateral displacement is relatively easy
when the force is applied on the teeth, which is
deeply rooted in the alveolar process of the
maxillae.

SUTURES
• MPS - Plays a key role in R.M.E. Melsen (1975) -
histological feature.
i. Infancy - Y-shape
ii. Juvenile - T-shape
iii.Adolescence - Jigsaw puzzle
• As sutural patency is vital to R.M.E, it is imp. To
know when does the suture closes by synostosis.

• Persson et al (1973, 1976 & 1977) found the rate
of ossification & Onset. From his study, the
following points are taken.
– Earliest closure in girls aged 15 yrs. Oldest unossified
suture -women 27 yrs.
– Bony spicules appear between age 15 yrs & 19 yrs.
– Greater degree of obliteration occurs posteriorly than
anteriorly.
– On average 5% of suture in closed by age 25 yrs.

• If it is accepted that 5% of sutural closure, can
be broken without surgical assistance then
average age of 25 yrs used only as general guide.
• Ossification comes very late anterior to incisive
foramen - this is imp. When planning surgical
freeing in late instances of RME.

• RME - used from 3-35 yrs of age.
• Younger age - assessing te growth potential &
retention is difficult.
• Older age - Discomfort and pain is experienced.
• Best time - 10 & 15 yrs. But the child may
complain of feeling tension across the floor of
nose which disappears after 2-3 days.www.indiandentalacademy.com

Factors to be considered prior to expansion
• Discrepancy between max of mand 1st molars &
bicuspid width is 4mm or more RME indicated.
• Severity of cross bite
• Initial angulation of molars or premolars
• Assessment of roots of decidious tooth
• Physical availability of space for expansion.www.indiandentalacademy.com

R.M.E. Depends on
• Rate of expansion
– Expansion of dental arch increases as rate of
expansion is increased.
• Form of expansion
– Effect of expansion increases as rigidity is increased
• Age of patient
– Effect of expansion diminishes as age advances.www.indiandentalacademy.com

BANDED R.M.E.
• Derichsweiler type
– I premolars and I molars are banded
– wire tags are soldered onto palatal aspect of bands.
– Wire tags get inserted into split palatal acrylic plate
with screw at its centre.

HAAS TYPE
• I premolar and molar of either side banded.
• 0.045 inch (1.15mm) length SS wire is welded and
soldered in buccal and palatal aspects of bands.
• Lingual wire is kept long and extend anteriorly and
posteriorly.
• Extension - bent palatally and embedded in palatal
acrylic.
• Split palatal acrylic has midline screw. Plate does not
extend over rugae area.

ISAAC SON TYPE
• Tooth borne appliance
• spring loaded screw - MINNE expander (Developed at
university of Minnesota Dental school).
• I premolars and molars banded.
• Metal flanges - soldered to bands - buccal and lingual
sides.
• Coil spring made to extend between the lingual metal
flanges.
• Activated by closing the nut.

HYRAX TYPE
• Use of special type of screw HYRAX (Hygienic
rapid expander)
• Screws have heavy gauge wire extensions
adapted to fallow palatal contour and are
soldered to bands on premolars and molars.

Bonded R.M.E
• Alternative design - splint covering variable
number of teeth on either side to which the jack
screw is attached.
• Splints - 2 types
– Cast cap - silver copper alloy
– Acrylic - polymethyl - metheracrylate.
• Splints are bonded - GIC - after adequate
etching. www.indiandentalacademy.com

Description of a typical expansion screw
• Consists of long body divided into two halves.
• Each half has threaded inner side that receives
one end of a double ended screw.
• Screw has central bossing with four holes.
• Turning of screw -90 degree (ie.) one turn brings
about in linear movement of 0.18 mm.

Cementation of Appliance
• Ames black copper cement is best
• Good adhesive and has germicidal property -
assists oral hygiene
• mixed on glass slab with SS spatula
• generous film is applied to dried internal surface
of cap splints
• max. teeth dried - appliance is pressed firmly
into position
• setting time for cement is 20-30 seconds
• excess cements removed by scalers.www.indiandentalacademy.com

Activation schedule
• Various authors advocated different activation
schedules.
Schedule by Timms:
• Up to 15 yrs - 900
rotation in morning & evening.
• Over 15 yrs - 450
activation 4 times a day.

Schedule by Zimring & Isaacson:
• Young growing patients - 2 turns each day for 4-
5 days & later one turn/day till desired expansion
achieved.
• Non growing adults - 2 turn each day for first 2
days, one turn/day for next 5-7 days and one turn
every alternate day till desired expansion is
achieved. www.indiandentalacademy.com

Schedule by Bishara:
• Young adults - 3 mm first week & 1.75 mm each
week there after.
• Older adolescents - 2.2 mm first week, 1.75 mm
2nd week & 1.0 mm each week there after.

Effect of R.M.E
Maxillary Skeletal Effect
• Opening of mid - palatal suture is fan shaped or
triangular with minimum opening at the incisor
region.
• Similar fan shaped opening is also seen in
superio-inferior direction.
• Max. opening - towards oral cavity .less opening -
towards nasal aspect.

• According to krebs - two halves of maxilla rotate
in sagital & coronal planes.
• In coronal plane - two halves of maxilla rotate
away from each other.
• The point at which rotation takes place is around
fronto max. Suture.
• Sagittal plane - maxilla found to rotate in
downward and forward direction.www.indiandentalacademy.com

AMOUNT OF EXAPNSION ACHIEVED
• An increase in maxillary width of upto 10 mm can be
achieved by R.M.E.
• Rate of expansion is 0.2 to 0.5mm per day.
EFFECT ON ALVEOLAR BONE
• Alveolar bone in area adjacent to anchor teeth bends
slightly. This is due to resilient nature of alveolar bone.

EFFECTS ON MAX ANTERIOR TEETH
• App. Of midline spacing is most reliable clinical
evidence max. separation.
• Incisor sep. is half of distance the screw is opened.
• By 3-5 months midline diastema closes as a result of
trans - septal fibre traction
EFFECTS ON MAX POSTERIORTEETH
• Teeth show buccal tipping and believed to extrude to
limited extent

Effect of Mandible:
• Downward & Backward rotation
• Slight increase in mandibular plane angle.
• Reason for mandibular rotation is extrusion &
buccal tipping of max. Molars.
Effect on adjacent cranial bones & sutures:
• Bones of cranium such as parietal & occipital
were also found to be displaced.

Effect of R.M.E. on nasal cavity:
• Increase in inter nasal space.
• Increase in nasal cavity width is max. in inferior
region and decreases in superior region of nasal
cavity.
• Similar gradient is also found in an anterio-
posterior direction with greatest increase being
in anterior region.

Retention:
• Objective of retention is to hold the expansion,
while all those forces generated by expansion
have decayed away.
• Basis for holding teeth in treated position is to
– Periodontal or gingival reorganisation
– Permit neuro muscular adaptation to corrected tooth
position.
– To maintain unstable tooth positionwww.indiandentalacademy.com

• According to krebs (1964) Timms (1976), 5 yrs of
retention period is required.
• The first removable retention plate consists of
base plate of cold cure acrylic with 4 adams
cribs.
• This allows max. time for recovery and
opportunity for relapse.
• Isaacson recommends the use of RME appliance
for retention. www.indiandentalacademy.com

• The further the teeth moved laterally and more
rapidly, the longer should be period of retention
• if arch widened over short period of time with
more rapid teeth. Chances of relapse is more
and hence over expansion is advised.

COMPARISON OF TREATMENT OUT COMES
WITH BANDED AND BONDED R.P.E. APLIANCES
(AJO-1999)
• Purpose – compare treatment outcomes with
banded versus bonded R.P.E.
• Banded R.P.E – had more vertical change
• Most of these changes less than 10
or 1mm
• This study could not establish superiority of
one type of R.P.E. teeth over another.

SURGICAL ASSISTED R.M.E.: ORTHODONTIC
PREPARATION FOR CLINICAL SUCCESS (AJO –
1999)
• Close root proximity between max central
incisors presents a problem in surgical
management of R.M.E.
• During surgical fracture of Inter dental area –
separation occur between root surface and bone.
• Asymmetric separation places more stress on
mesial gingival attachment.
• Gingival detachment – epithelial downgrowth –
prevents bone apposition in a coronal direction.www.indiandentalacademy.com

• Osseous defect - difficult to treat with osseous
graft procedure.
• Treatment plan - Analysis of a recent periapical
radiograph of incisor roots - to determine the
need for orthodontic root separation before
surgery.
• Post surgical radiograph - taken to determine
where the interdental separation has occurred.
• Expansion schedule should be adjusted depending
on symmetry of separation and health of gingival
attachment. www.indiandentalacademy.com

TREATMENT AND POST TREATMENT CRANIOFACIAL
CHANGES AFTER R.M.E AND FACE MASK THERAPY
(AJO-2000)
• Aim to evaluate treatment and post treatment dento
skeletal changes in early and late mixed dentition
patients.
• The result of this study was
• Increase in sagittal growth of maxilla - enrly mixed
dentition
• Backward positional rotation of mandible with
increase in lower anterior facial height - late mixed
dentition
• Relapse tendency affects
• Sagittal growth of maxilla - early
• Sagittal growth of mandible - late dentition.
• More favourable craniofacial changes - early dentition.www.indiandentalacademy.com

LONG TERM EFFECTS OF R.M.E. (AJO – 2000)
• Aim - investigate long term effects induced by
R.M.E. followed by comprehensive orthodontic
treatment.
• R.M.E - Edgewise appliance therapy - increase
transverse facial dimensions
• Pre treatment deficiencies also corrected.
• Initial deficiency in latero-orbital width also
eliminated.

Comp. Of Dental and D.A. changes between
R.P.E. & Nickel titanium palatal Exp.
Appliance. (AJO – 2001)
• This study show
Both RPE and niti expanders - expands max.
dentition, alveolar process and corrects
posterior cross bites.
MPS separation was less obvious - Niti group.
No correlation between age and D.A. exp in
either group.
More distal molar rotation - Niti group.

A BONDED FUNCTIONAL RAMP TO AID IN
ASYMMETRIC EXPANSION OF UNILATERAL
POSTERIOR CROSS BITES (AJO – 2001)
• Article - describes method for treating unilateral
posterior cross bite and lack of CB correction
after R.P.E.
• Composite ramp is bonded to mesio buccal cusp
of max. I Molar in crossbite
• This adjunctive procedure requires no more than
5 extra minute.

MAX SAGITTAL AND VERTICAL
DISPLACEMENT INDUCED BY SARME (AJO –
2001)
• AIM to investigate sagittal and vertical
effects on maxilla induced by SARME
• SARME - did not significantly affect maxilla
vertically.
• But induce - slight forward movement of
maxilla and slight retroclination of max.
incisors sagitally.www.indiandentalacademy.com

EFFECT OF MODIFIED ACRYLIC BONDED RME
VERTICAL CHIN CAP. (AJO – 2002)
• Aim - sagittal, transverse and vertical effect of
R.M.E. With vertical chin cap
• Nasal width, max. width, man and max inter
molar width, upper molar tipped buccally in both
groups (ie.) RME and RME with chin cap.
• Position of mandible, lower facial height, position
of max. I molar in vertical direction does not
change in RME with chin cap.
• Conclusoin - chin cap prevent vertical effect of
RME.

HISTOLOGIC AND HISTOMORPHOMETRIC
EVALUATION OF PULPAL RECTIONS
FOLLOWING R.M.E (AJO – 2000)
• AIM - investigate effects of pulpal tissue of
anchor premolar teeth.

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