Methods of gaining space

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METHODS OF GAINING
SPACE.

Space required to
 Move teeth into ideal locations.
 Correction of crowding,
retraction,intrusion, leveling of curve of
Spee, derotation of anterior teeth,
correction of molar relation.

SPACE CAN BE GAINED
BY
Non extraction method Extraction method.
Expansion
Interproximal
reduction.
Molar
distalization

When to employ the method of Non
extraction for gaining space?
Guide lines:
•8mm/less of crowding-mild to moderate space requirement.
•Severely mesially and lingually tipped posterior teeth-constricted
arches(no skeletal component of malocclusion).
•No need to alter the facial profile.
•Co-operative patient.
•Growing patients-afford more space.

.
A) M-B cusp tips of the upper 1st
molar.
B) Buccal groove at the middle of
the buccal surface of the lower
molar.
Subtract B from A
Mean difference in normal occlusion:
Males: 1.6mm
Females:1.2mm
2. Ashley Howe’s index.
Estimation of need for expansion
Dental constriction with good skeletal transverse dimension.
Based on cephalogram ,model analysis: to quantify
arch length tooth material discrepancy. Up to 5mm

Expansion:
Coffin springs Slow expansion
Screws.
Removable Fixed
RME Quad helix W arch Arch Wire
Skeletal
Dentoalveolar
Jack screws used in removable – slow expansion
In fixed- quad helix, w arch can be used.

Coffin spring
•Walter H. Coffin 1881
•Indications:
Slow dentoalveolar exp
Constricted upper arch
APPLIANCE CONSTRUCTION:
1.25mm hard round S.Steel wire.
U or Omega shaped wire.
Stands 1mm away from palate.
Retention from Adam’s clasps on
U6,U4 or E
Removable appliances:

Appliance activation.
Range of activation 2-4 mm before insertion.
Disadvantage:
Dislodgement of clasps from the teeth.
Heavy intermittent force.
Patient compliance.

Expansion Screws
Baseplate used as working part, divided and driven apart by screws.
•An equal division-create reciprocal anchorage for both parts.
•Unequal:larger-added anchorage for movement of smaller part/s.F/A more.
•90 degrees-plates move apart by 0.2mm.
•PDL-0.1mm on each side.
•Schwartz- first to use this type of plate.
•254types.but basic principles same.
Encased screws
Skeleton screws
• SIZES
Maxillary-broader
Mandibular-narrower

Skeleton type.
Bertoni screw.
Encased screw.

Schematic sagittal section:

Activation of the screws in removable
appliance:
•1mm/complete revolution.
•0.25mm of tooth movement/quarter turn.
•Rate of active movement not exceed
1mm/month
•Only twice a week-1mm bilateral movement.
•Turn screw with appliance in mouth.
•Don’t remove it for several hrs after activation-
better chance of fit.

 All split appliances – only tipping tooth movement(edge
of plate contacts each tooth at only one point) no
couple.
 Activation of screw produces heavy intermittent force.
 Initial high and rapid decay- potential of damaging the
tooth.
 Limited indications .
Disadvantages of removable
appliances.
USAGE WITH FUNCTIONAL APPLIANCES.

Lower Schwartz appliance:
Indications:
Mild to moderate lower ant crowding,
Lingual tipping of post teeth.
Activation:once/week
0.20 to 0.25mm of expn in midline.
3-4months; gain 4-5mm of arch length
anteriorly.
PURPOSE: orthodontic tipping,
uprighting.

Upper Vs Lower expansion stability:
 Upper – more stable.
 Lower – before canine eruption.8- 9yrs.
Force elimination:
Frankel regulator.
Lip bumper.

Rapid Vs Slow Maxillary Expansion.
Expansion across the suture
Rapid
Slow
2 schools of thought - rate of palatal splitting:
1. Rapid expansion: 2-4weeks:min tipping & max skeletal displacement.
0.3-0.5mm/day. Force build up to 10-20pounds.
2. Slow expansion: 1mm/week for 2-6months. 2-4pounds of pressure –
optimum.
The ratio of skeletal to dental exp is 1:1 from the beginning.
More physiological response.

Rapid Maxillary Expansion:
•Skeletal expansion, separation of the mid-palatal suture
• Maxillary shelves away from each other.
HISTORY:
Emerson C. Angell 1860
E.N.T Surgeons.
Korhkaus and Andrew Haas in 1950’s

Indications:
 Unilateral/bilateral discrepancies.
 Skeletal/dental constriction.
 Gain arch length in cases of moderate crowding.
 AP discrepancies-class II div I, class III.
 Inadequate nasal capacity- chronic respiratory
problems.

Contra indications:
 Single tooth cross bite
 Vertical growers-steep mandibular plane angle.
 Pre school children.(fig)
 Non compliant patients.

Fig:

Principle:
Rapid heavy force to teeth- no sufficient time for teeth to
respond.
Transferred to the suture, which opens.
While teeth move minimally relative to their supporting
bone.

Sutural patency.
•Vital to RME.
•when and how quickly synostosis takes place?
•Studies.
•Earliest – 15yr girl. Oldest unossified-27yr woman.
•In general, bony spicules : 15-19yrs.
•Greater obliteration posteriorly.
•On avg, 5% closed by age of 25 yrs.
•Optimal age-before 13-15yrs. Later unpredictable.
•OCCLUSAL RADIOGRAPH.

Effects of RME
On the maxilla.

Krebs (1964) : 2 halves of maxilla rotate in
Sagittal
Coronal
Coronal plane: 2 halves move away from each other.
Fulcrum of rotation around the fronto-maxillary suture.
Sagittal plane: rotate in downward and forward direction.
Final position: unpredictable. Partially/complete relapse.

RME in deciduous and mixed dentition produces, downward and forward
rotation of the palatal plane. Increase in the upper anterior facial height
(N to ANS) Point A is also moved anteriorly.

Triangular split of maxilla.
A. Transverse view B. Frontal view

Coronal Section at the level of 1st
molars
The mid palatal suture opens with an inverted V shape ,the
maxillae separate, the alveolar ridges tip and bend
buccally,the teeth move bodily and also tip within the
alveoli,and the mucoperiosteum of the palate stretches.

The typical triangular opening of the
median palatal suture confirms the
separation of the maxillary process
during the RME.similar opening-in
superio-inferior direction.Max-oral
side,less on nasal side.
The median palatine suture is
repaired totally after 90 days of active
phase of expansion.
Greater opening

Evident splitting of the maxilla
Represents the so called Orthopedic
effect.
Nasal cavity widened. Floor and
lateral walls by maxillary process.

1. Before treatment. 2. During treatment. 3. After treatment
1.
2.
3.

Effects on:
Maxillary anterior teeth: diastema. ½ the distance the screw
has opened.By 3-4months closes.
Maxillary posterior teeth:fig
Mandible: swing downwards and backwards.(disagree)

Changes in angle of tooth
inclination
1st
during active RME
2nd
after RME during controlled relapse.
.’. Need to overcorrect to compensate for the
subsequent up righting of the teeth.

Effects On Nasal Air Flow:
Anatomically:Increase in width of nasal cavity at the
floor,outer walls of the nasal cavity move laterally.
Air flow resistance reduced by 45% thereby improving nasal
breathing.
Total Effect: Increase in the inter nasal capacity.
Wertz(1968): opening the palatal suture for purpose of increasing
the nasal airway, cannot be justified unless the obstruction is in
the lower anterior portion of the cavity accompanied by a
relative maxillary width deficiency.

Types of RME Screws.
Tooth and tissue borne Tooth borne
Derichsweiler Haas Issacson Hyrax
Banded
Bonded

Derichsweiler appliance.
Retentive tags

Haas Appliance
1.2mm S.steel wire

Hyrax type of Screw.

Issacson expansion appliance
Using Minne expander.
A coil spring having a nut
to compress the spring.
ACTIVATION
Expander activated by
closing the nut so that the
spring gets compressed.

Bonded RME
1. Cast Cap Splints.
2. Acrylic cap splints.

Bonded Rapid Palatal Expansion
appliance.

Activation Schedule:
TIMMS:
•Upto 15yrs: 90 degrees rotation in morning and evening.
•Over 15yrs: 45 degrees activation 4 times a day.
•Over 20yrs: initial 90 degrees, 45 degrees morning and
evening.Surgical intervention.
ZIMRING and ISSACSON
Young growing patients: 2 turns/day for 4-5 days.later
1turn/day till desired expansion.
Non growing adult: 2 turns for 1st
two days, 1turn/day for next
5-7 days. And 1 turn every alternate day.

How much to expand?
STABILITY:
1. Growing patients.
2. Before the eruption of canines.
3. Self retention of cross bite correction.

Surgery as an adjunct:
•Unusual resistance to separation-surgical intervention.
•Females over 16yrs, males over 18yrs.
Surgery ( SARPE ) / surgery + RME
(distraction osteogenesis)
Palatal osteotomy.
Lateral maxillary osteotomy.
Anterior maxillary osteotomy.

Clinical Tips:
 4/4 Xn postpone.
 No prior orthodontic
movement.
 Activate, 15-30min after
insertion.
 String/dental floss tied.
 See patient at regular
intervals.
 Monitor with weekly
occlusal radiographs.
 Open within 7-10 days.
 Retention: 3-6months.
 TPA can be placed.
 Symptoms on premature
removal.
 Dizziness,heavy pressure,
face.blanching of soft
tissue. 19hrs.
 Always seated.

Fixed Expansion appliances
Quad Helix
Evolved- original coffin loop.
4 helices - increase range and
springiness of the appliance.
Anterior helices bulk-serve as
reminder.
2 types:
fixed
removable
Indications:
•Bilateral posterior cross bite.
•Finger sucking habit.

38 mil S.Steel wire.
Li wire contact teeth in crossbite.
1-2mm distal.
•Over correction.
•Soft tissue irritation.
•3 months of retention.
Molar rotation
Slow dentoalveolar expansion.
2mm/month.1mm on each side,until
cross bite over corrected.
In primary and early mixed dentition-
skeletal midpalatal splitting.
ACTIVATION

W ARCH
• Originally used by Ricketts.
•36mil S.Steel wire.
•1-1.5mm short of palatal soft tissue.
ACTIVATION:
•2mm/month. Duration 2-3months.
•Remove and then activate.
•3 months retention.

Unequal W arch to correct true
unilateral maxillary constriction.
Side to be expanded- fewer teeth
than the anchorage unit.

Nickel Titanium palatal expander
-Wendell V. Arndt JCO 1993 march
Tandem loop Ni Ti palatal
expander
Light continuous forces.
Simultaneous up righting,
rotating and distalization of the
molar.
Transition temp 94 F
Sizes-8 diff molar widths.
27mm – 47mm.force 180-300g

Degree of compression at 20 degrees below the transition temp. B. effect of
shape memory when the wire is warmed to body temperature.
. Passive appliance. B.initial activation and insertion for
expansion and distal molar rotation. C. After expansion and
rotation correction.

Nitanium Palatal Expander 2
Maurice C. Corbett
JCO April 1997.
Uniform slow continuous forces.
Maintains the tissue integrity.
Regeneration = rate of expansion.
ACTION
Shape memory and transition
temp.

APPLIANCE SELECTION
 Available in 10 sizes, from 26mm to 44mm.
 Determination of the size of expander.
 NPE 2 delivers a force of 350g in 3mm increments.
 If 4mm expansion ,initial force higher, later return to 350g
once 3mm expansion occurs.
 Preprogrammed, .’. Self limiting.
 TETRA FLUOROETHANE refrigerant spray.
 In mouth begins to warm,NiTi stiffen-shape memory.
 Completed in 2-4months. Retention-2-3months.

After 3 months of expansion with NiTi palatal expander 2
After Initial placement.
Ligature should
be tied.

Lip Bumper
Gain arch length in mild to moderate crowding
cases.
Stainless steel 36mil in0.045”tubing or coated
in acrylic and inserted into the molar tubes.
The lateral arms remove the resting pressure of
the buccal musculature .’. Allow the
unopposed action of tongue – increases arch
width
Bodily forward movement of incisor, labial
flaring, distal tipping of molars.
Pressure exerted on the shield-100-300g
LIP BUMPER.

CETLIN’S LIP BUMPER
Reinforce anchorage.
Molar distalization.
Middle of the crown.
Canine 2mm. Premolar 3mm.

DENHOLTZ LIP BUMPER
/muscle anchorage appliance.
Upper lip contraction and
exercises, exert distalizing
force via the coil spring.

T.P.A
Functional appliances:
Functional Regulator.
•0.036” S.Steel wire.
•Fixed or removable.
•Prevents mesial migration
of U 6.
•Molar rotation. Maintain
the inter molar width.

5mm of expansion in the molar
and the canine area.
Arch Expansion in Fixed Appliances:
•In conjunction with TPA /
quad helix
Overlay wires used for arch
expansion.

PROXIMAL STRIPPING.
 Proximal surfaces sliced to reduce the M-D
width of the teeth.
 Conservative method-mild to moderate
crowding.3-5 mm of space requirement.
 Ballard – 1944.
 Routinely carried out in the lower anterior
region.

Indications: Contra Indications:
 3-5mm.
 Bolton’s excess.
 Aid in retention.
 Maintain the profile.
 Maintain Class I canine and
molar relation.
 Carey’s analysis:0-2.5mm
 Young patients- high pulp chamber.
 High caries index.
 Poor oral hygiene.
 Enamel hypoplasia.
Advantages:
•Borderline to non Extraction.
•A favorable overjet and bite can be estbl.(match the U
and L tooth material)
•More stable results –contact area broadened.

Disadvantages:
 Roughened proximal surface- plaque. Ledges, grooves.
 Excess tooth material reduction.
 Increased caries susceptibility
 Sensitivity.
 Alteration of the tooth morphology.
 Loss of contact- food impaction.
Conventional
Air rotor stripping.
Methods

Amount of proximal stripping:
Not more than 50% of enamel thickness
1. Metallic abrasive strips.
2. Safe sided carborundum discs.
3. Long thin tapered fissure bur.

Air rotor Stripping method (ARS)
 John J. Sheridan in 1985.
 Removal in buccal segments (enamel thickest)
 3-8mm of space requirement.
 More space than conventional.
 1mm per contact point.
 No risk of cutting gingival tissue.

Diagrammatic representation of ARS technique

Topical fluoride application
Polishing.
Useful therapeutic tool if done judiciously.
Excessive enamel reduction is irreparable;
Proximal surfaces must be shaped as naturally as
possible.
Polishing.
Done properly- no effects on interproximal tissue and
bone.

Methods of gaining space

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