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3. 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
4. • First objective in orthodontic treatment
- Correction of discrepancy in
transverse dimension.
• This can be achieved by carrying out
the procedure called “Rapid Maxillary
Expansion”
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5. 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
6. • 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
7. • 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
8. • 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.
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9. • 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
10. • 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.
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11. • 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.
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12. • 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).
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13. 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.
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14. 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
15. • 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.
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16. • 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
18. • 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.
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19. 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.
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21. • 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.
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22. • 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.
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23. • 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
24. 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
25. 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
26. 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.
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28. 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.
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30. 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.
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32. 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.
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34. 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
35. 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.
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37. 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
38. 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.
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39. 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
40. 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.
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41. 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.
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43. • 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
44. 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.
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45. 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
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47. 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.
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48. 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.
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49. 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
50. • 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
51. • 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.
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52. 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.
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53. 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
54. • 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
55. 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
56. 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.
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57. 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.
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58. 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.
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59. 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
60. 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.
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61. 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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