rme for pg students, extempore type

1. 1

2. R.M.E.
IN
ORTHODONTICS
Presented By: Dr. Himali Gupta
P.G. Ist Year Student

3. CONTENTS
• INTRODUCTION
• CLASSIFICATION
• RME
• SURGICAL EXPANSION
• DISADVANTAGES
• CONCLUSION
• REFRENCES

4. INTRODUCTION
• Emerson Collon Angell reported on the procedure in
1860.
• This approach was opposed strongly by McQuillen
(1860) and Coleman (1865).
• Haas reintroduced rapid maxillary expansion.
• Palatal expansion is helpful in other surgical disciplines
as oral ,ENT and plastic surgery

5. • Word “Expansion” refers to lateral enlargement of
dental arches by orthodontic forces :
• (a) Direct forces
• (b) Indirect forces
• First objective is correction of discrepancy in
transverse dimension.
• This can be achieved by “Rapid Maxillary
Expansion”

6. Defintition:
• It is a skeletal type of expansion that
involves the separation of the mid-palatal
suture and movement of the maxillary
shelves away from each other.
• These appliances are the best examples of
true orthopedic expansion.

7. ANATOMY:
• Articulation of maxilla :
• Cranial
• Facial
• Sutures:
In infancy

8. In early adolescence
In Late Adolescence

9. INDICATIONS
Dental indications:
1. Posterior Cross bite (unilateral/bilateral).
2. Tranverse dicrepancies.
3. Activation of the circummaxillary suturs .
4. Cleft palate patients.
5. In patients with tooth size – arch size dicrepancies.

10. Medical Indications (Given by Gray and
Brogan)
1. Poor Nasal airway
2. Septal Deformity
3. Recurrent ear, nasal (or) sinus infections
4. Allergic rhinitis
5. Asthma

11. CONTRA - INDICATIONS:
1. Single tooth cross bites.
2. In patients who are un co-operative.
3. Skeletal asymmetry of maxilla & mandible &
Adult cases with severe antero posterior
skeletal discrepancies.
4. Vertical growers with steep mandibular plane
angle.
5. Anterior open bite.

12. EFFECTS OF RME:
Maxillary skeletal effect:
• On activation compresses the periodontal
ligament and bends the alveolar process buccally.
Amount of expansion achieved:
• An increase in maxillary width upto 10mm can be
achieved by RME.
• The rate of expansion = 0.3 - 0.5 mm per day.

13. • Effect on Alveolar bone: Bends slightly.
• Effect on Maxillary Posterior teeth: Buccal
tipping and extrution.
• Effect on Mandible: Downward & backward
rotation of mandible.
• Effects of RME on nasal cavity: Widening of
conchae.

14. • During RME, maxilla
moves downward and
forward and
simultaneously mandible
moves downward and
backward (Wertz 1977).
• Biedermann (1973)
explained buttressing.

15. R.M.E.

16. CLASSIFICATION
1. Removable Appliance
2. Fixed Appliance
a) Tooth borne
- Derichweiler
- Hass
b) Tooth & tissue borne
- Isaacson
- Hyrax

17. WILL AND MUHL:
I Jackscrew Appliances:
1. Tooth borne, Hyrax appliance
2. Tissue borne, Hass appliance
II Removable Expanders.
Removable jack screw appliances
III Non screw expanders
A) Quad Helix
B) Transpalatal arch
IV Slow expansion:
Minne expander
V Functional appliances

18. Banded Appliances:
•Banding is done
•Wires may be soldered.
•Commonly used appliances are :
1. Derichsweiler
2. Hass
3. Isaacson
4. Biedermann

19. 1) Derichsweiler type :

20. 2). Hass type :

21. 3. Isaacson type :

22. 4.Biedermann type :

23. Bonded appliances :
• Splints can be of two types:
• 1. Cast cap splints 2. Acrylic Splints
• Cap Splints : (Hershey et al 1976)
• These are usually cast in silver / copper alloy.

24. Acrylic splints :
• Made of poly methyl metha-acrylate
•Mondro et al (1977)have described an all acrylic form of cap splints and inter
connection with a screw embedded in the midline.

25. A typical expansion screw :
The pattern of threading on either side is of opposite direction. Thus turning
the screw withdraws it from both sides simultaneously.

26. THE BUTTERFLY EXPANDER FOR USE IN THE
MIXED DENTITION:
• Follows basic design of Hass
• The location high in the palatal
vault.
• The butterfly design thus
minimizes posterior tipping and
extrusion.

27. A FAN-SHAPED MAXILLARY EXPANDER:
• Schellino and Modica have designed a “spider screw” that works
asymmetrically and allows fan opening.

28. Activation Schedule:
1. Schedule by Timms:
Patients </= 15 yrs: 90 degree rotation in morning and evening.
>/= 15 yrs: 45 degree activation 4 times per day.
2. Schedule by Zimring and Isaacson:
Young growing patients: 2 turns per day for 4- 5 days, followed
by 1 turn per day till expansion is achieved.
Non growing adults: 2 turns per day for 2 days, then 1 turn per
day for 5-7 days, followed by 1 turn every alternate day, till expansion
is achieved.
3. Mc Namara and Brudon: Prefer a one per day activation schedule
till expansion is obtained, in order to avoid nasal distortion which has
been associated with 2 expansions per day protocol.

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REQUIREMENTS OF AN RME
APPLIANCE
• Rigidity
• Tooth utilization
• Expansion( dilating unit and action)
• Economy of time and material
• Hygiene

30. RIGIDITY (RESISTANCE TO ROTATION)
• A rigid appliance will exert
parallel opening and
produce expansion at a
greater distance from the
appliance than one which
is flexible and produces
expansion mainly by
lateral inclination.

31. 2). Tooth Utilization: (No. of teeth included in
appliance)
a). Load distribution :
• Best to incorporate as many teeth as possible.
• Bands can be cemented simultaneously only to a few
teeth because of difficulties of multi alignments
whereas splints can be adapted to all teeth.

32. b). Appliance retention:
• Depends on area of adhesion b/w the teeth &
appliance, the precision of fit (or) thickness of the
adhesive agent & shape of clinical crown.
• Bands may be superior to cap splints in view of
their closer adaptation.

33. 3) Expansion : (Dilating unit & action)
The dilating mechanism :
1. spring – decreases rigidity and control
2. Screw – should have adequate length

34. 4) Hygiene :
• Given the lowest priority, as any deleterious effects
are superficial & reversible.eg beiderman type
• Cap splints should be fixation of choice.

35. CLINICAL
MANAGEMENT OF RME
• a).Fitting the appliance :
• Cast cap splints – check cleanliness especially, of
the fitting surface to secure good adhesion.
• Check the direction of the screw for opening.
• Check the seating of appliance.

36. b) Cementation of appliance:
• Only when satisfied then only proceed with cementation.
• Ames black copper cement is used.
• Allow the cement to become hard for
at least 1/2 hr. to assure complete setting,
before strain is imposed by activation

37. C. Instructions : (Initial)
o The appearance of midline diastema .
o Difficulties in speech and mastication must be
mentioned together with points on oral hygiene.
o Patients have been classified into 3 age groups:
1. Upto age of 15 years
2. Age 15 – 20 years
3. Age over 20 years

38. 1. Upto age 15 years : 180o per day 90o morning and
90oevening for 1 week.
2. Age 15 – 20 years : 180o per day 45o four times a day
for 1 week.
3. Age over 20 years: 90o per day 45o morning and 45o
evening for 1 week.
4. For above 25 : Surgical opening of suture followed
by revisit after 3-4 days .

39. • D). Pain during RME:
• Desired expansion in the short time requires strong forces
which often produces painful effects.
• The threshold levels of pain very among individuals.
• Two factors generally are responsible:
1. Rigidity of facial skeleton
2. Mechanical interlocking and synostosis of mid palatal
suture

40. • E). Instructions : (Subsequent)
• First ask the patient & person turning the screw for any
difficulties.
• Then check the central incisors for diastema.
• Then examine the screw to see how much thread is
exposed.
• If all is well, ask the patient to continue

41. • Ask the patients about pain ;it generally disappears if the
suture is open.
• No 45 degree turn of the screw before the pain has
dissipated.
• Patients over 20 years it is difficult to differentiate b/w
the pain from an unopened suture & that from skeletal
rigidity.
• If non opening of suture, surgical freeing should be
considered.

42. • F) How much to expand:
• Study's show that, between 1/3rd & ½ of the expansion was
lost before stability was eventually reached.
• Expansion should stop when the maxillary palatal
cusps are level with the buccal cusps of the
mandibular teeth.

43. Forces of relapse :
• After RME, the teeth effect a partial relapse by
rotating inwards about their bases
• The factors causing relapse are:
1.Genetic – no assistence
2.Environmental - The size & shape of the bones
are determined by function.

44. Expansion generated:
• Most potent factors causing relapse are due to
stretching of soft tissue & the deformation of the
hard tissue under the powerful forces built-up by
RME, but can be controlled by retention.

45. • Forces can be sub-classified into 3 groups
based on nature & time scales:
a) Elastic recoil - shortest active effect
b) Repair & reorientation - A longer process
than elastic recoil
c) Bone remodeling - Time scale is long

46. Retention :
• The objective - to hold the expansion while all
those forces generated by expansion appliance
has decayed.
• A palate covering retainer is satisfactory.
• Heavy labial wire with headgear
maintains lateral expansion.

47. • Long retention period of atleast 2 yrs after removal of
expansion appliance is needed.
• Even with the appliance worn according to instructions
there can be slippage & some relapse creeps in.
• About 9 months after expansion, wear of retention plate can
be reduced from full time to half time (usually evenings &
nights)

48. Integration:
• Malocclusion often has a different appearance & its
easier to treat after RME as result of changed
maxillo-mandibular relationship.
• Extractions should be be done
untill RME

49. STABILIZATION
• The clinician has 2 factors under his control
to achieve a satisfactory result:
1. Over expansion - to allow for the inward
tilt of the teeth.
2. Length of retention - to allow for the
stretching of tissue etc.,

50. • Two environmental forces can be outlined
which largely will determine the final
occlusal relationship.
• 1). Bucco- lingual pressures
• 2). Articulation

51. RAPID MAXILLARY EXPANSION
OF CLEFT LIP & PALATE
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52. RME in cleft palates
RME is carried out only in those cases
where cleft has been closed surgically.

53. ANATOMY :
• Normal lateral relationship of posterior teeth,
with anterior collapse.The maxillary collapse is
stopped by the turbinate bones in contact with the
nasal septum. The nasal airway is reduced.
• By moving the maxilla laterally-nasal airway is
enlarged- reduction in nasal resistance.
• Subtelny (1957), found that, the width
between the pterygoid hammuli were slightly
wider than in non cleft subjects.

54. Appliances :
The basic principles of design apply equally to
clefts.
• The most common problem, is the anterior
collapse, so that parallel (or) near parallel
expansion is undesirable.

55. • Differential expansion puts considerable flexural strain
on the screw in the horizontal plane & may result in
fracture of the screw (or) displacement of the appliance.
•The greater the collapse, the less space available for the
screw, where the longest possible length of thread is
needed.

56. Bone grafting :
• Bone grafting is required if RME is used in
correction of malocclusions associated with cleft.
• RME & consequent bone grafting are not carried
out until early teens.
• Jolleys et al 1972, Robertson et al. 1972 &1978 
reports early grafting suggest inhibition of growth.

57. Treatment summary:
• Normally RME is done before extraction (or) other forms
of appliance therapy.
• RME in CLCP , usually produces less discomfort then in
normal palate subjects of equivalent age. (Jentoff 1965)
•The usual 3 months of fixed retention phase with
expansion appliance left in-situ is advised.

58. • Undesirable situation - the opening of oro-nasal fistula.
• Within the cleft, teeth often are absent (or) unable to take
up satisfactory position in arch because of lack of
supporting bone.
• These teeth are frequently extracted & the resulting
space & fistula are covered by prosthesis

59. SURGICAL ASSISSTED MAXILLARY
EXPANSION
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60. Surgical freeing of the maxilla
1) Age at surgery : Resistance in the maxilla to
separation may be traced to 3 causal factors
1. Mid palatal synostosis
2. Mid palatal inter locking
3. Circummaxillary rigidity

61. • 5% sutural ossification with mechanical interlocking
can be tolerably broken by RME without surgical
assistance, when added to the general bony rigidity of
the maxilla & their surrounding structures.
• All RME patients between 20-25 years must be
treated with utmost respect for early sutural closure.
• At 15-20 years range, surgery can be considered.

62. 2). Surgical techniques:
Dennis Vero, has developed a series of operations in
increasing stages of osteotomies to cope with palatal
synostosis & progressive rigidity of facial skeleton.
The tech has been described in 3 stages:
Stage 1 A and B
Stage 2 A and B
Stage 3 A and B

63. Stage I A: Palatal osteotomy used if patient age is 25yrs & over
(or) younger if RME has been tried with appliances failed.
Advantage :
1. A single flap, which is easier to handle and reposition.
2. Soft and hard tissue wounds are not contagious, healing is
better
Stage IB : Bilateral osteotomies of hard palate there are
bilateral buccal crossbite and in same conditions as 1A.

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STAGE 1

66. • Stage II A: Over the age 30 yrs - lateral
osteotomies in addition to palatal ones.
• Stage II B : In cases of bilateral buccal
crossbite lateral osteotomies extended to
both sides.

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STAGE 2 (OVER THE AGE OF 30)
The soft tissue incision is made in the zygomatic arch forward to
a point over apex of the LI and down to the gingiva of the CI
With this exposure of the lateral wall, the maxillary cut is made
from the piriform aperature , through the anterior and lateral wall
of the antrum and across the buttress at the base of the
zygomatic arch, to stop at the tuberosity.

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STAGE 3 (OVER THE AGE OF 40)
The horizontal incision is made in the alveolar mucosa is made as in
stage 2 but the downward portion is made obliquely across the midline
to give access to the ANS
The bone is cut from the piriform aperture to the midline beneath the
ANS and is continued down between the CI.
Carried along the floor of the nose but it doesn't meet the palatal
incision.

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CONCLUSION
Expansion of the arches has seen its ups and downs in the past.
More and more documentation of the effects and stability of this
procedure has thrown a new light on its clinical application.
Whether it is slow or rapid expansion, proper diagnosis and case
assessment is very essential to ensure consistent results. As more
and more cases are being treated without extractions due to
profile considerations, expansion of the arches forms a valuable
adjunct to treat a wide variety of clinical presentations.

71. REFERENCES
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1. Rapid maxillary expansion- D. J. Timms
2. Contemporary orthodontics- Proffit (3rd ed)
3. Orthodontics and dentofacial orthopedics James A Mc
Namara, Brudon

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