Management of space in orthodntics

Management of
Space in
Permanent
Dentitionwww.indiandentalacademy.com

CONTENTS
• Introduction
• Space Analysis
• Space Planning
• Considerations of Space Deficienct
– Non Extraction Line of Treatment
– Extractions in Orthodontics
• Considerations of Space excess
• Conclusion
www.indiandentalacademy.com

Over the years the quality of orthodontic
treatment has improved with the increasing
sophistication of materials and appliance systems. As
ideal occlusion has become a realistic goal for the
treatment of many types of malocclusion, the need for a
thorough understanding of how space is used within the
dental arches increases.
This presentation aims at an overview of the
diagnosis and management of space problems in the
dental arches encompassing both its deficiency and
excess and the possible treatment modalities that
provide solutions to these problems.

Space
Analysis

Space analysis quantifies the amount of crowding within the
arches estimating the severity of space discrepancy. Space
analysis requires a comparison between the amount of space
available for the alignment of the teeth and the amount of
space required to align them adequately.
Space Available Space Required
Compare
Excess OK Deficiency

The space analysis can be divided broadly into the
following categories
1. Permanent Dentition Analysis
1. Analysis of Arch Form
2. Analysis of Arch length
3. Analysis of Tooth size discrepancy

PERMANENT
DENTITION ANALYSIS
Analysis of Arch Form

MAXILLARY EXPANSION INDICES
•Numerous indices have been proposed to help the clinician
decide how much maxillary expansion will be required to
alleviate crowding.
•If the indices and guides to be considered useful, the
amount of crowing in any given untreated case should
correlate with the discrepancy between observed arch width
and predicted or recommended arch width.
•Research support the contention that intermolar arch width
is associated with amount of crowding in males and inter-
premolar width in males and females

PONTS INDEX
•Pont in 1909 devised a method of pre-determining an ideal
arch width based on mesiodistal widths of the crowns of
maxillary incisors.
•Pont suggested that the ratio of combined incisor to
transverse arch width, as measured form center of occlusal
surfaces of the teeth was ideally 0.8 mm the first bicuspid
area and 0.64 in the first molar area in an ideal uncrowded
dentititon.

• Mesiodistal widths of four maxillary incisors are measured and
added. This forms sum of incisors (SI).
• Width of the arch in the premolar region from the deepest point in
the transverse fissure of first premolar to its counterpart on the
other side is measure.
• Width of the arch in the molar region from the point of intersection
of tranverse fissure with buccal fissure of first permanent molar to
its counterpart on the other side is measured.


• If the upper central or, lateral incisors are missing as
hypoplastic determinations may be made based on
sum of lower incisors width using ‘Tonn’ formula of all
four upper incisors which calculates appropriate width.
Tonn Formula: SIu = SI (lower) x 4/3 + 0.5
• Expected arch width in the premolar region is
SI/80x100. Expected arch width in the molar region is
SI/64x100.
If measured value is less than the calculated value it
indicates the need for expansion. Pont suggested that
maxillary arch be expanded 1-2 mm more than required
to account for relapse.

Disadvantages.
•At best , Ponts index is only a crude guide even though it is widely used.
Researched at the University of Washington found very poor correlations
between combined maxillary incisors width and the ultimate arch width in
the bicuspid and molar areas.
•Its was found in subsequent studies that points index over estimate
interpremolar and intermolar width by 2.5 mm- 4.7. mm.
•Ponts index does not take into account the alignment of teeth or
malformations (peg laterls).
•Anatomic variations are seen with more frequency among upper incisors
than lower incisors.
•This study was conducted on French population . it may not apply to
other ethnic groups

LINDERHARTH INDEX
•Linderharth modified ponts original formula for anterior
and posterior arch width.
Ideal anterior arch width= SI/85x100

Ideal posterior arch width = SI/65x100
•Schmuth, Ritter, Werse and Benthake have suggested
different anterior and posterior ideal arch widths for a given
sum of upper incisors.

SCHWARZ ANALYSIS
•Schwarz presented an analysis for ideal inter-premolar and
intermolar widths that were correlated for particular facial
type.
•Facial types were classified as narrow, normal or broad by
him.
•The intermolar measured width of Schwarz differs from
Pont’s. it is the distance between central pits of occlusal
fissures of first molars
•Schwarz analysis is calculated with appropriate formula.

•In narrow faces, the first premolar width is SI+ 6mm while
intermolar width is SI+12mm
•In an average face intermolar width is SI+7mm and
intermolar width SI=14mm.
• Inter-premolar widths SI+8mm and intermolar widths of
SI+16mm are seen in broad faces.
•But’ further research has conclusively proved that Schwarz
analysis over estimated interpremolar widths of male and
females by 2.5mm. –4.3mm.

Analysis of Arch Length

KORKHAUS ANALYSIS
•According to Korkhaus (1938). There is a specific value of
distance from labial surface of central incisors to
interpremolar line for a particular added width of incisors.
•This value called as anterior arch length is defined as the
perpendicular from most anterior labial surface of incisors to
connecting line of reference points of anterior arch width.
•This measurement reveals the anterior-posterior
malpositioning of incisors, the formula for anterior arch
length by Korkhaus is as follows

The formula for calculating the standard
value of the upper arch length given by
Korkhaus in 1938 is as follows
Lu = SIu x 100/160

ASHLEY HOWE’S ANALYSIS
• Howes devised a formula for determining whether apical
bases could accommodate patients teeth.
• He considered tooth crowdind to be due to deficiency in
arch width rather than arch length.
• He proposed a relationship between the tooth width of
12 teeth anterior to second permanent molars and width
of arch in the first premolar region.
• This analysis is applicable to both arches.

Method:
• Add the widths of all the teeth from first permanent
molars forward on both sides to get tooth material (T.M)
• Determine premolars diameter (P.M.D)) by measuring
the arch width between buccal cusp tips of first
premolars on either side.
• Premolar basal arch width (P.M.B.A.W)is the diameter
of apical base. The measurement of the distance from
canine fossa on one side of the arch to the other side
gives PMBAW (If the canine fossa is not clearly
distinguishable take the point 8mm below interdental
papilla distal to canine.

• Basal arch length is measured at the midline from the
estimated anterior limits of apical base to a
perpendicular that is tangent to distal surfaces of first
molars. The ratio of basal arch length to tooth material
BAL/TM is obtained by dividing arch lengths by sum of
widths of 12 teeth.
• If the PMBAW is greater than PMD, the it is an
indication that arch expansion is possible.
• According to Howe, to achieve normal occlusion with full
complement of teeth the basal arch width at the
premolar region should be44% of the sum of
mesiodistal width of all the teeth mesial to second
molar.

• This condition can be treated without extraction.
• If it goes below 37% that indication need for extraction
of premolars. 37-44% is treated as border line case.
• Since this method was introduced rapid palatal
expansion has come into more common use, Now the
clinicians can alter the apical base itself by rapid palatal
expansion.

TOOTH SIZE DISCREPANCIES
•Tooth size discrepancies are thought to exist frequently in
the human dentition.
•If a patient has significant tooth size discrepancy,
orthodontic alignment of the teeth into ideal occlusion may
not be possible.
•Prior to discovery of different mathematical formulation,
diagnosis plaster set-ups were the only diagnostic tool
available.
•But, now due to its’s convenience and relative usefulness,
Bolton analysis is most widely used.
•However, when a large anterior tooth-size problem is
suspected a set up is likely indicated.

BOLTON ANALYSIS
•The Bolton analysis based on ratio’s between the mesio-
distal tooth diameter sums of mandibular and maxillary
dentitions, remains the most recognized and widely used
method for detecting inter-arch tooth size discrepancies.
•Study of the ratio proposed by him help in estimating the
overjet and overbite relationships that will likely obtain after
the treatment is finished, the effect of contemplated
extraction on posterior occlusion and incisor relationship and
identification of occlusal misfit produced tooth size
incompatibilities.

• The equations to quantity the tooth material excess are as
follows
Maxillary tooth material excess
= Sum of max 12- sum of mand 12x100
91.3
Mandibular tooth material excess
= Sum of mand 12-sum of max 12x91.3
100
Maxillary anterior excess
= Sum of max 6- Sum of mand 6x 100
77.2

Mandibular anterior excess
= Sum of mand 6- Sum of max 6x77.2
100

Disadvantage
• Accuracy and dependability of bolton’s have been
challenged. Good occlusal relationships have been
demonstrated in cases with significant Bolton
discrepancies.
• Bolton analysis predictions do not take into account the
sexual dimorphism in maxillary canine widths.
• population and gender composition of Bolton sample
are not specified. This implies potential selection bias.
• Bolton estimates of variation were underestimated
because his sample was derived from prefect class I
occlusions.

• Blacks have larger maxillary canines premolars and first
molars than whites and Asians. So blacks differ
markedly in posterior arch relationship.
• Lavella (1972) studied the tooth sizes in different
populations and concluded that blacks have larger
overall and anterior ratios than whites and Asians.
• Whites had the least. He also showed that overall and
anterior ratios are consistently larger in males than
females, regardless of race.

• In the University of Michigan growth study separate
anterior and overall ratios were established for males
and females.
Male Female
Anterior ratio 73.5 73.4
Overall ratio 91 90.6

EXTRACTION DECISION MAKING
WIGGLEGRAM
The decision to extract teeth is one of the
critical decision in orthodontic treatment.
The main reasons for extraction are well
documented: crowding, dentoalveolar
protrusion, the need for facial profile
alteration, and mild anterioposterior maxillary
discrepancies
In borderline cases there can be considerable
disagreement.
Wellington and Alfonso JCO 2002

According to Buchin, a case is borderline when
extraction of permanent teeth is required to reach a
stable and functional occlusion, but when the patient
has good facial esthetics that could be disturbed by
extraction.
Wigglegram:
18 factors have been selected from dental,
cephalometric, facial and growth variables

Dental Variables:5 variables
•Dental discrepancy: 4-8 mm, 8mm> extraction
•Curve of Spee: 3-6 mm
•Bolton discrepancy: proximal stripping with discrepancy of 4 mm
•Peck and Peck Index: normal 88-95, above 95%-proximal
stripping, less than 88% - extraction
•Irregularity Index: normal-0, mild irregularity-3.5-6.5, greater
than 6.5 indicates extraction

Cephalometric variables:7 variables:
4 – vertical facial proportional;
Relationship of the horizontal planes: according to Sassouni,
the horizontal relationship of the supra-orbital, PP, occlusal,
and mandibular planes reflects the vertical proportionality of
the craniofacial skeleton. Highly divergent planes indicates a
skeletal open bite – extraction,
parallel planes indicates – skeletal deep bite – nonextraction.
FMA: normal values - 20°-30°,
SN-mandibular plane angle: normal- 30°-34°
Jarabak ratio: proposed by Jarabak and Fizzel normal- 61%-
69%, less than 61% - skeletal open bite and more than 69% is
skeletal deep bite.

3 – lower incisor position
IMPA: Margolis, 85°-95° is normal greater than 96° indicates
for extraction.
FMIA: 60°-70° is normal, less than 60°indiacates proclination,
and more than 70° indicates retroclined incisors.
Lower incisor to A-Pog line distance: -2 and 3mm indicates
good sagittal position of the lower incisors

Facial Variables: 5 variables
•Lower lip to E line: normal -5 to 1 mm
•Distance between B line and lower lip: 2.5 ± 1.5 mm anterior to
B line
•Nasiolabial angle: normal - 85° - 105°. According to Drobocky
and Smith, the nasiolabial angle increases by an average of 5.2°
with four bicuspid extraction;
•Upper lip morphology: Holdaway’s soft tissue analysis for upper
lip morphology and lip strain.
•Dental midline Deviations: severe dental midline deviation
supports extraction

Growth status: extraction must be cautiously
considered in patients with considerable
remaining growth potential because growth
of the soft and hard tissues has significant
influence on the facial results of the
orthodontic treatment.

SPACE PLANNING AND
THE ACHIEVEMENT OF
TREATMENT OBJECTIVES

AJODO 2000; 118:448-455
SPACE PLANNING
STAGE I :- Assessment of space requirement
STAGE II :- Assessment of any additional space to be
created of used during treatment including a prediction of
anteroposterior molar movements required for occlusal
correction and an estimation of future growth.

AJODO 2000; 118:448-455
Stage I – Assessment of Space requirement
Six specific aspects of the occlusion are considered for which
any change has an effect on the space required.
1.Crowding and Spacing
2.Level the Occlusal Curve
3.Arch Width Change
4.Incisor A/P Change
5.Angulation Change
6.Inclination Change

AJODO 2000; 118:448-455
1. Crowding and Spacing
Should be quantified in relation to the arch
form that reflects the majority of teeth, not
necessarily the imaginary arch that passes
through the incisal edge of the most
prominent central incisor in each arch.
The incisor chosen for the assessment of
crowding should also be used for ceph
analyses and overjet estimation.
A clear plastic ruler is used to measure the
mesiodistal width of misaligned teeth.
Crowding and spacing are assessed mesial
to the first molar.

AJODO 2000; 118:448-455
2. Leveling Occlusal Curves
An increased occlusal curve is due to a series of slipped contact points in
the vertical dimension; it is the restoration of these contacts that requires
the increased space within the dental arches. This also explains the non
linear relationship reported between depth of curve and the amount of
space required.
Braun et al (1996) and Woods et al (1986) showed that the 1mm of
allowance of space for every millimeter of depth of curve was an
overestimate.

AJODO 2000; 118:448-455
The space implication for the flattening of the curve of Spee
should be assessed only if the premolars have not been
assessed as crowded as it would be double counting for
premolars.
Secondly clinical judgment is necessary as leveling of the
curve of Spee may not be required in all cases.
The depth of the curve is assessed from the cusps of the
premolars to a flat plane extending from the distal cusps of the
first molars to the incisors.
Allow 1mm space for 3 mm depth of curve, 1.5 mm for 4 mm
depth of curve and 2 mm for 5 mm depth of curve.

AJODO 2000; 118:448-455
3. Arch Expansion and Contraction
For the purpose of space planning each millimeter expansion
of the intermolar width will create approx 0.5 mm space within
the arch.
The buccal and lingual movement of an individual tooth does
not constitute a change in arch width as this would be assessed
in the analysis of crowding.

AJODO 2000; 118:448-455
4. Incisor A/P Change
Changes in the anteroposterior position of
the labial segments have a profound effect
on the arch perimeter length.
The loss of 7.2 mm from each side of the
arch led to the incisor retraction of 7.7 to
8 mm depending on the intermolar width.
The additional amount of incisor
retraction is due to a minor amount of
increase in the intercanine width and
decrease in the intermolar width as both
these segments are drawn towards each
other after premolar extraction.
For the purpose of space planning each
millimeter of incisor advancement or
retraction will create or consume 2 mm of
space within the dental arch

AJODO 2000; 118:448-455
If upper incisors are too vertical, they
take up lessspace in the arch than if
correctly angulated.
However, incorrect angulation does
not necessarily signify that a space
requirement exists; for example, a
tooth angulated 5° distally may take
up no more space than one angulated
5° mesially.
Very occasionally, teeth are over
angulated,and space is gained by
correction to normal angulation.
5. Angulation (Mesiodistal
Tip)

AJODO 2000; 118:448-455
6. Inclination
Andrews pointed out the
importance of the inclination
of upper incisors if they are to
occupy the correct amount of
space, and that failure in this
respect would lead either to
incorrect buccal occlusion or
to spacing. Correct inclination
is also important to ensure
optimum esthetics.

AJODO 2000; 118:448-455
Space implication varied according to incisor size and
morphology. The palatal root torquing of large or parallel-
sided teeth required the greatest amount of space within the
arch, whereas small or triangular teeth with contact points
close to the incisal edges needed the least space. Barrel-
shaped teeth needed an intermediate amount of space

AJODO 2000; 118:448-455
STAGE II :- Assessment of any additional space to be
created of used during treatment
1. Tooth reduction and Enlargement
2. Extraction
3. Absent Teeth
4. Distal and Mesial Molar movement

AJODO 2000; 118:448-455
5. Differential Maxillary and Mandibular growth
Estimate the A/P growth differences between the maxilla and
mandible during treatment (not necessary for most patients). A
positive upper space assessment applies to forward growing
Class II cases, but a negative lower assessment applies for the
creation of additional space in Class III cases where a
deterioration in arch relationship is anticipated during and after
treatment.

AJODO 2000; 118:448-455
The first stage quantifies the space required in each
dental arch to attain the treatment objectives. The
second stage combines this information with the
space implications of planned treatment procedures.
The outcome is an ability to identify whether the
treatment objectives are attainable and whether the
planned treatment mechanics are appropriate.

The mode of gaining space in the permanent dentition can
be broadly classified into
1. Non extraction methods of gaining space
a. Proximal Stripping
b. Expansion
c. Distalisation
d. Molar Uprighting
e. Derotation of Posterior Teeth
f. Proclination of anterior teeth
2. Extraction

NON EXTRACTION
PROCEDURES

PROXIMAL
STRIPPING

Interproximal enamel reduction (IER) is understood to be the
clinical act of removing part of the dental enamel from the
interproximal contact area.
The aim of this reduction is to create space for orthodontic
treatment and to give teeth a suitable shape whenever
problems of shape or size require attention.
In the literature, this clinical act is normally referred to as
“stripping,” although other names can be found, such as
“slendering,” “slicing,” “Hollywood trim,” “selective
grinding,” “mesiodistal reduction,” “reapproximation,”
“interproximal wear,” and “coronoplastia.”
World J Orthod 2002;3:223–232.

INDICATIONS
1.Tooth size discrepancy. In 1944, Ballard recommended careful stripping of
the proximal surfaces of the anterior teeth when there was imbalance.
2. Crowding of mandibular incisors. Stripping was first used to obtain space
for the correction and prevention of crowding.
3. Tooth shape and dental esthetics. Stripping can and should be used for the
reshaping of enamel on some teeth, thus contributing to an improved finishing
of orthodontic treatment and dental esthetics.
4. Normalization of gingival contour and eliminationof triangular spaces above
the papilla, thus greatly improving esthetics and smile.
5. Moderate dentomaxillary disharmony. This is a primary area of application
for interproximal enamel reduction in the technique developed by Sheridan
in 1985 and 1987, which allowed space to be obtained for the correction of
moderate dental crowding; up to 8 mm per arch could be achieved without the
need for extraction or excessive expansion.
6. Correction of the curve of Spee. For the correction of an exaggerated curve
of Spee, it is necessary to create a few millimeters of space in the arch. This
can be achieved through moderate stripping.

CONTRAINDICATIONS
1. Severe crowding (more than 8 mm per arch). With application of IER, it
would be hazardous to carry out orthodontic correction. There would be
risk of excessive loss of enamel and all of the ensuing consequences.
2. Poor oral hygiene and/or poor periodontal environment.
3. Small teeth and hypersensitivity to cold. Stripping should not be used in
these situations, as the risk of the appearance of or an increase in dental
sensitivity is great.
4. Susceptibility to decay or multiple restorations. There is a risk of causing
imbalance in unstable oral situations, although the stripping of
restorations,instead of enamel surfaces, is an option to consider.
5. Shape of teeth. Stripping should not be carried out on “square” teeth—
teeth with straight proximal surfaces and wide bases—as these shapes
produce broad contact surfaces, and could potentially cause food
impaction and reduced interseptal bone.

METHODS
1. Manual Method
• Metallic strips, impregnated with abrasive
metal oxides, and numerous holding
devices .
• This method was first described in the
literature by Hudson.
• The technique is seldom used for three
reasons:
(1) it is time consuming;
(2) there is technicaldifficulty in working
on posterior teeth; and
(3) It causes much deeper grooves on the
abraded enamel than those caused by
mechanical instrumentation.

MECHANICAL METHOD
This technique greatly reduces working
time. The tools for its use mainly consist
of disks for handpieces or contra- angles,
high-speed handpieces, and mechanical
files for contra-angle heads with shuttle
movement.
A new generation of perforated disks
was recently tested by Zhong and
colleagues. In Zurich, van Waes and
Matter have developed an “orthostrips
system” (Intensiv; GAC International,
York, PA, USA) of flexible strips for
contra-angle shuttle heads composed of
four small metallic strips of decreasing
grain size

AIR ROTOR SLENDERIZATION (ARS)- Sheridian
(1987,1985)
JCO 1985; 19(1): 43-59
JCO 1987; 21(11): 781-788

TREATMENT SEQUENCE
The following treatment steps are to be carried out
1. Complete treatment planning, with accurate measurement of
study casts.
2. Ensure that no contraindications to IER exist.
3. Place orthodontic appliances and correct rotation.
4. Place elastic or spring separators.
5. Carefully do the IER (carried out sequentially).
6. Shape and polish the stripped surface.
7. Measure and control the obtained space.
8. Check posterior anchorage.
9. Reduce friction and perform the progressive distalization.
10. Apply fluoride.
11. Align anterior teeth.
12. Retain properly to maintain optimal results.

Advantages of IER
• The space obtained can be continuously monitored to adjust it to the
space needed to achieve the treatment goals.
•Overexpansion of the dental arch is avoided.
•Extraction of teeth is greatly reduced.
•The need for excessive tooth movement, as well as the possible loss of
bone and of root cementum, is reduced due to the fact that the
iatrogenic potential is considered less than with extraction.
•Treatment time is reduced.
•The quality of treatment is significantly improved in patients with
crowding and contraindications for extraction, as in the case of
closed bites.
•Esthetics are improved, as is the final health of the gingival papilla,
which adapts better to a reduction of interdental space than to the
space left by extraction.
•Treatment of adults with slight or moderate crowding is possible,
without the need for extraction.
•Greater post treatment stability is possible.www.indiandentalacademy.com

Disadvantages of IER
It is a technique sensitive procedure
Possibility of caries incidence and periodontal breakdown
Increased sensitivity
Unaesthetic change in shape of the tooth

KEY POINTS
•Carry out stripping sequentially.
•Limit stripping to 0.5 mm per contact surface or, in other words,
1 mm per mesial contact area of second molars to the distal
of the canines.
•Measure space accurately.
•Parallel stripped contact areas.
•Shape dental surfaces to their original configuration, without
abraded grooves.
•Carefully polish the stripped surface.
•Topically apply fluoride after stripping.
•Reduce, as much as possible, inadvertent loss of space obtained,
by using anchorage on posterior teeth and reducing friction
through the use of round arch and metallic ligatures.

EXPANSION

CLASSIFICATION OF EXPANSION APPLIANCES
According to the rate
a) rapid
b) slow
According to type of expansion
a) orthodontic
b) orthopedic
c) passive e.g Vestibular shield, FR2, Lip bumper
According to type of appliance
a) removable
b) fixed -- banded or bonded
1. Tooth borne e.g. HYRAX , Issacson
2. Tooth and tissue borne e.g Hasswww.indiandentalacademy.com

CROSS BITE
PALATAL HEIGHT INDEX
Palatal height Index
=
Palatal height x 100
Posterior arch width
The average index
value is 42%
-By Korkhaus

ASHLEY’S HOWE ANALYSIS
P.M.B.A.W% = P.M.B.A.W x 100
T.T.M
If P.M.B.A.W is more than P.M.D then it is an indication
that arch expansion is possible. If on the other hand
the P.M.D is less than P.M.B.A.W, then arch
expansion is not possible and might require
extraction.

Frontal Cephalometrics:
Practical Applications

DIFFERENCE BETWEEN ORTHOPEDIC
AND ORTHODONTIC EXPANSION
ORTHODONTIC
FORCE
By use of this force
the teeth alone are
supposed to move .
Adaptive changes in
specific alveolar
bone adjacent to
moving teeth.
ORTHOPEDIC
FORCE
Result in major
change occurring in
basal structures of
mandible & maxillae.
Involves interaction
between basal bone
& alveolar bone.

RAPID EXPANSION
• Results in major change occuring
in basal structures of mandible and
maxilla
• More than 5 ounces
• Rate of separation varies from
0.2 to 0.5 mm / day
• Intermolar width – 10mm
• Requires 1- 4 weeks
• Skeletal changes – 50%
SLOW EXPANSION
• By use of this force the teeth
alone are supposed to move
• Slow expanders like Quad Helix &
W-Spring can transmit forces
ranging from several ounces to 2
pounds.
• They can separate maxillae,
particularly in the deciduous &
mixed dentitions.
• Rate of separation varies from
0.4 to 1.1 mm / week
• Intermolar width – 8mm
• Requires 2 – 6 mons
• Skeletal changes –
16 – 30% of total change and vary
with age

Contra - Indications:
Absolute:
1. Single tooth cross bites.
2. In patients who are unco-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.
Relative:
1. Normal buccal occlusion.

Dental arch and arch perimeter changes
RME - HYRAX
Results:
1. Increase in upper intercanine width greater in RME group than in SME.
2. Regression analysis indicated maxillary arch perimeter gain :- arch perimeter
gain = 0.65 times of posterior expansion in RME & 0.60 times in SME
group.
3. Evaluation of the prediction equation shows maxillary arch perimeter gain :-
0.54 times at premolar width in RME & 0.52 times in SME group.
SME – Minne Expander
By Lorenzon & Ucem

DISTALIZATION

• Current orthodontic philosophies have
been oriented toward conservative
treatment modalities to avoid extractions
and, at the same time, to try to eliminate
the need for patient cooperation;
consequently, there are many devices for
gaining space, particularly for the
distalization of the maxillary molars.

• The appliances used for molar distalization
can be divided into
• Removable appliances and
• Fixed appliances.
Removable appliances are:
• Extra oral traction
• Removable appliances with finger springs
• Sliding jigs with intermaxillary elastics.

The fixed appliances are
A. Intramaxillary appliance
1. Wislons 3D appliance
2. Repelling Magnets
3.The pendulum appliance
4. Niti based appliances : archwires – single loop,
double loop; Compressed coil springs
5. Jones jig
6. Distal Jet
7. Fixed piston appliances
8. IBMD 9. K-loop 10. Distalix
11.Franzulum appliance 12. Lokar appliance
13. First class appliance 14. Carriere’s Distalizerwww.indiandentalacademy.com

B. Intermaxillary appliance:
1. Herbst appliance
2. Jasper Jumper
3. Eureka Spring
4. Klapper superspring
C. SAS supported distalization:

DISTALIZATION DIAGNOSIS
• The first step is to confirm the diagnosis of
a forward maxillary molar position.
• 1. Check the centric relation position (and
vertical status). Before considering the
molar relationship in terms of dental or
skeletal malocclusion, it is desirable to
check the TMJ status. All records must be
correlated, ie, cephalometrics, functional
axiographics, and radiologic exams (MRI,
CT scan).

• Korn has cautioned against using
extraoral force in patients with
undiagnosed meniscus disorders
who are borderline clickers with
an "end-on click.
• a. Korn has shown that the
distalization may push back the
maxillary molar ----
• b. causing more posterior tooth
contacts and then moving the
condyle backward into a more
posterior position, now with a
"true click”.
• c. The mandible then assumes
its normal position, but the
meniscus is now too far forward.

• 2. Check the sagittal relationship.
(1) The pterygoid vertical plane (PTV)/maxillary molar
relationship and
(2) the convexity prognosis.
• According to Ricketts, the normal maxillary molar (M1)
position is given by the distal face of the molar to the
PTV. The clinical norm is age + 3 mm, and clinical
deviation is 3 mm.
• In good skeletal and dental Class I relationships, the
facial axis normally crosses the mesial cusp of M1.
• However, the maxillary molar analysis must not be
static only, but also dynamic. If the distance M1/PTV is
shorter than the normal measurement, the possibility for
distalization is low and possible extractions will depend
on growth potential and the presence of 3rd
molar.
• Therefore, posterior dental arch analysis must include
mesiodistal measurement of all molars to determine the
posterior space available at maturitywww.indiandentalacademy.com

• To determine a positive convexity, differentiation must
be made between a forward maxilla and a backward
mandible.
• Patient age must be considered, to determine what the
positive convexity will be with time and growth.
1.Brachyfacial
2.Mesofacial
3.Dolichofacial

INDICATIONS & CONTRAINDICATIONS
THE INDICATIONS FOR MOLAR
DISTALIZATION
• 1. In non-extraction treatment of Class II malocclusion
cases.
• 2. In low & average mandibular plane angle cases.
• 3. In class I skeletal pattern cases.
• 4. In patients with mild arch length discrepancy.
• 5. In cases where the upper permanent molars have
moved mesially due to early loss of deciduous molars.
• 6. In patients where the second molars extractions are
planned or where it has not yet erupted.
• 7. In second molar extraction cases where the third
molars are well formed and erupting properly.

CONTRAINDICATIONS FOR MOLAR
DISTALIZATION
• In high mandibular plane angle cases.
• Skeletal and Dental open bite
• Class II & III skeletal pattern
• Severe arch length discrepancy patients.

INFLUENCE OF 2ND
MOLAR ON DISTALIZATION OF 1ST
MOLAR
• A controversy exists concerning the influence of second
molars on the distal movement of the first molars.
• Graber noted that extraoral traction on the first molars,
when the second molars have not totally erupted, led to
distal tipping only and not to bodily distal movement.
Bondemark et al (AO 94 Magnets vs NiTi coils) stated
that the presence of second molars did influence tipping
and distal movement of the first molars.
• Gianelly (AJO 91 NiTi coils) also found that treatment
time was increased with the presence of second molars.
• Muse et al (AJO 93 Wilsons BDA) found that the
presence of maxillary second molars did not correlate
with the rate of maxillary first molar movement or with
the amount of tipping that occurred.www.indiandentalacademy.com

MOLAR
DEROTATION

The simplest method of derotating the molar is by
using a Transpalatal arch
The palatal bar was introduced by Goshgarian as an
anchorage appliance and modified by Cetlin and Ten
Hoeve as a removable tooth moving appliance. It is
made of .036-inch S.S. wire double backed at the
ends so that it can be inserted into a 0.036 x 0.072
inch horizontal lingual sheath.
The palatal U shaped coffin loop can be made distally
if an intrusive force is desired posterior to the Cres of
the molar to tip the molar crowns distally. This effect
can be achieved if the palatal bar is placed low in the
oral cavity.
Cetlin & Ten Hoeve, JCO 1983

TPA can be used for the following purposes
1. Distalization
2. Rotation
3. Expansion
4. Vertical control
5. Torque
6. Anchorage control
Rotation:
To derotate the molars the TPA when inserted into
the lingual sheath on one side the other side should
be so adjusted that the terminal on that side should
lie distal and lateral to its sheath,
To check the same configuration on the other side
the method is repeated by first inserting the terminal
in that lingual sheath.

EXTRACTIONS

“To extract or not to extract” was one of the early debates that
clouded orthodontic world ever since its beginning.
2 main reasons for extraction:
• Provide space to align remaining teeth – crowding.
• Allow teeth to move – skeletal Class II / skeletal Class III
camouflaged.

From 1930’s – 1970’s
Charles Tweed re-treated with extraction; the relapse cases
previously treated with non-extraction methodology, &
found occlusion to be much more stable.
Angle’s dogma:
Every patient could be treatment with expansion of dental arches
and rubber bands.
Extraction not necessary for stability or esthetics.
Calvin Case argued that although the arches could always be
expanded so that the teeth could be placed in alignment,
neither esthetics nor stability would be satisfactory in the
long term for many patients.

Between 1970-1990’s:
Saw the revival of non-extraction philosophy.
Reasons?
Premolar extraction does not guarantee stability of tooth alignment.
Little, Wallen and Riedel – 1981 AJO.
MC Reynolds and Little – 1991 Angle Orthod.
Argument 
“If result not stable either way, why sacrifice teeth at all”.
v/s.
“If extraction cases are unstable, non-extraction would be worse”.
1. Changing views of esthetics – fuller and more prominent lips,than the
orthodontic standards of 1950s & 1960s.
2. Change from banding to bonding and introduction of functional
appliances eliminated the need for band space,made it easier to
expand arches – border line case generally treated better without
extraction.
3. The ill-famous litigation – Witzig and Spahl (1980)
4.Premolar extraction causes distalization of mandible posteriorly, displacement
of condyle resulted in perforation of articular disc  TMD.
5. Both Tweed’s and Begg’s rational for extraction, lost some of their

Majority of patients can be treated without extraction, but by no
means all.
Extraction can be undertaken to compensate for:
Crowding.
Incisor protrusion.
Camouflage skeletal discrepancies.&
For surgery.

Treatment modalities converting borderline cases
into non –extraction cases:
Early intervention:
•Use of ‘E’ space.
•Proximal stripping of primary teeth.
•Space regainers with space maintainers.
•Arch expansion.
•Use of functional appliances.
•Molar distalization.
•Bonded attachments rather than banded ones.
Adult:
•Molar distalization.
•Inter-proximal reduction.
•Arch expansion.
•Surgery for skeletal discrepancies.

Recommendations for expansion V/S extraction:
1) Esthetic considerations:
Expansion makes teeth more prominent
Extraction makes teeth less prominent
Facial esthetics – unacceptable on either too-protrusive or too-
retrusive.
Acceptable range of protrusion and biologic limitations –
expand.
Control space closure by combination of retraction (anteriors)
and protraction (posteriors) – extract.

Soft tissue is the major factor:
• Lip separation – increases with tooth prominence.
• Thick, full lips – can afford prominent incisors.
• Cephalometric readings can serve as guidelines.
• Size of nose and chin.
• Lip strain i.e. lack of well defined labiomental sulcus.
Profile:
• Concave profile with thin lips – little vermillion border 
unaesthetic appearance.
• Lower lip as prominent as chin.
• Upper lip slightly forward from soft tissue point A.

2) Stability considerations:
Expansion:
Lower.
Upper
Skeletal – opening mid-palatal suture.
Dental - Tipping
- Bodily
Limiting forces - Cheeks
- Buccal cortical bone – fenestration (> 3mm

For Class I crowding / protrusion:
(1) < 4mm of arch length discrepancy with no vertical
discrepancy: non-extraction.
(2) Arch length discrepancy – 5-9mm
Non-extraction – transverse expansion of premolar
segment.
Extraction – any pattern depending on hard and soft tissues.
(3)> 10mm : EXTRACT

• I] Indications for extraction of 1st
premolars (Tweed and Begg):
• Maximum anterior retraction and camouflage of
Class II div I.
• Less taxing of anchorage – maximum
anchorage.
• Eruptive sequence – space for canines.
• Space discrepancy > 10mm for Class I M.O. –
crowding.
• Class I with bimaxillary protrusion.
• Convex profile with severe crowding.

• II] Indications for 2nd premolar
extraction: Nance, Carey, Dewey and
Thompson (Begg)
• Good profile and mild crowding.
• Straight profile and moderate crowding.
• Class II div. 1 dental on class I skeletal with mild
mandibular crowding.
• Mild Class III and mild maxillary crowding in
Class III - 5 5 extraction Niwa et al.
• Case of maxillary set back surgery.
• Crowded and out of arch.
• Correction of molar relation.
• Grossly destructed/heavy restoration.

• III] Indications for incisor extraction:
• Severely crowded mandibular arch – Reidel – increased
stability – 1940 Jacobson – extracted mandibular incisors.
• Severe protrusion.
• Periodontal breakdown.
• Severely fractured.
• Bolton discrepancy.
• Reidel  extraction of mandibular incisors
decreases treatment time – 2 laterals instead
of 4 4
• Kokich and Shapiro (Ang Orthod 1984) – 4
successfully treated cases with single
mandibular incisor extraction.
Am J Orthod 1977;72:560-567.www.indiandentalacademy.com

• Maxillary central incisors: Rarely indicated
• Caries.
• Fracture.
• Dilacerated.
• Badly impacted.
• .
• Maxillary lateral incisor:
• a. Crowding in incisor region with mesial displacement of root
apices of 3 3 - Gardiner.
• Mandibular incisors- therapeutic value
• 1st sign of incipient malocclusion
• Difficult to treat as they relapse easily.
• Extreme crowding / protrusion.
• Gingival recession & loss of overlying bone on labial surface.
• Lateral incisors severely # in young children.
• Rarely-discrepancy in sizes of U & L incisors themselves, 1
incisor can be removed.
• minimum facial change.

• Advantages:
• Maintains/ reduces intercanine width
• General arch form is maintained – greater stability
• Retention period- less
• Anterior segments can be retracted readily if need
be.
• Immediate solid tooth support of entire buccal
segments.
• Easy reduction of overbite- intrusion, reshaping
• Mechanotherapy is simplified. Space closure quick.

• Disadvantages:-
• Reopening of space . Central Incisor.
• Danger of creating a tooth size
discrepancy.
• Reidel- 2 mandi incisors Xed to
maintain intercanine width.
• 1 incisor Xn- deepbite- if normal tooth
size relationship is present before Xn.
• Color difference of canine

Indications for 1st molar extractions
(Wilkinson):
• Carious / endo treated/ multifilled.
• Esthetic considerations with properly
developed 2nd and 3rd molars – large
nose and chin – 4 4 dished face.
• Open bite cases ???
• Supraerupted teeth.
• Crowding in premolar region and
incisors in good relation.
Am J Orthod 1973;64:115-136.

Wilkinson’s Extraction: 1942
• 8 ½ to 9 ½ yrs. Extraction of all Ist molars.
• Basis:
• Additional space for eruption of 8s.
• Crowding of lower arch minimized
• Problems with Xn of 4s:
• Tipping, opening of space (5 small to fill the space)
• Mesial tipping of 6, hanging palatal cusp
• Avoided with 6 Xn.
• Good molar relation.
• U 4 occlude with L4
• 8s erupt normally.
• Min patient cooperation
• Stable results.
• Tuberosity not crowded.
• Results similar to nonext.
• Rx duration is reduced.
• Profile maintained

• POTENTIAL PROBLEMS
– Large amount of space to close
– Root Paralleling
– Increased tendency of rolling in with Class
II elastics
– Long Span Archwires
AJO DO 2000; 117: 418-34

• Indications for canine extractions:
(Creekmore):
• In case of 1st premolar in good contact
with 2 2 and palatal cusp not visible.
• Periodontally involved.
• Horizontally impacted – tooth movement
is questionable
• Distally tipped/ severely rotated / grossly
displaced buccally/palatally
AmJ Orthod 1983;84:125-132.

VI] Indications for 2nd molar
extraction: (Chipman)
• Mild –moderate arch length discrepancy
with good esthetics.
• Distalization of first molar.
• Relieve lower incisor crowding.
• Relieve impaction of 2nd premolar.
• Severely carious / ectopically erupted /
rotated.
• Passed average physiologic age of
eruption and 5 5 are normal – size,
shape and root area.
Am J Orthod 1977;72:599-616.

• David W.Liddle- AJO 1977
• Malocclusion: potential force by developing 7,8.
• Xn of 7s to intercept this forward force.
• 4 Xn: treating the effect and not the cause.
– 10-12mm of space :satisfies arch length
problem, not apparent when patient smiles.
– 91% 7 Xn.
• 6 move distally in response to pressure.
• Over compressed CT fibers- move 3 &4
to a more normal occlusion.

Advantages and indications of second molar extraction
According to Wilson and Graber - the following reasons were
proposed as the major advantages and favorable results of second
molar extraction.
- Facilitation of treatment using removable appliance.
- Reduction in the amount and duration of appliance therapy.
- Disimpaction of third molars.
- Faster eruption of third molars.
- Prevention of dished - in appearance of the face at the end
of facial growth.

- Prevention of late incisor imbrication.
- Facilitation of first molar distal movement.
- Distal movement of the dentition only as needed to correct
the overjet.
- Fewer residual spaces at the end of the orthodontic
treatment.
- Less likelihood of relapse.
- Good functional occlusion.
- Good mandibular arch form.
- Reduction in incisal overjet.

Disadvantages:
• Too much tooth substance removed in Cl I mal
occlusion with mild crowding.
• Location far from area of concern.
• No help in correction of A-P discrepancy
without patient cooperation .
• Possible impaction of 3rd molars even with
2nd molar Xn
• Unacceptable positions of erupted 3rd molars
–second, late stage of fixed therapy.
• 9-20% missing 3rd molars.
Am J Orthod 1961;47:498-520.

• Indications:
• Chipman:
• Xn 7 - caries, ectopic, rotated.
• Mild – moderate discrepancy with good profile.
• Crowding in tuberosity area ,with a need for
distal movement of 1st molar.
• Lehman - preconditions
• 8 in favorable angulation 15-30*angle to the
long axis of the 1st molar.
• Normal in size/shape & root area is sufficient
w.r.t 2nd molar.
• No congenitally missing teeth.

Timing for mandibular second molar extraction.
Kokich in his summary of presentation given by Scholz Stressed
three criteria is to be met when making the decision on timing of
the dentition.
The third molar crowns should be completely formed but
extraction should be performed before the root begins to develop.
The axial inclination of the third molar buds should not be greater
than 30° relative to the occlusal plane.
Mandibular third molar should be in close proximity to the second
molar roots to ensure adequate mesial drift of the third molar as it
erupts.

Halderson, Higgins, Lehman and Smith agree that the optimal
timing of the extraction of the second molar is when the crowns of
the third molar are fully formed but before any radiographic
evidence of root formation.
Cryer and Fanning believe that the optimum age for this treatment
is between 12 to 14 year and both stresses the importance of the
position of the third molars.
According to Wilson second molars should be extracted as soon as
they erupt particularly in patients with severely tipped third molars.
The third molars should be observed for 6 to 12 months for possible
spontaneous correction.
Rix suggested that the optimal time for extraction is as soon as the
second molars erupt provided the mesial angulation of the 3rd molar
is not greater than 45°.

Liddle on the other hand advocates early diagnosis and possible
enucleation of the second molar (8-12 year). He notes that third
molar would erupt by 13 years of age and are in occlusion by 14
years.
Breakspear recommends not extracting second molar if the roots of
the 3rd molars are half formed even if the latter have a favorable
angulation.
In summary, the consensus of opinion in both anecdotal and
quantitative reports is that the optimal time of the second molar
extraction, is as soon as it erupts if the third molar crown is
complete, but before radiographic evidence of root formation, the
angulation of the third molar bud plays a crucial role in the
extraction decision.

• Single arch extraction: (Raleigh
Williams) ( 6 - 6 extraction)
– Class II div 1 –
• Perfect lower arch alignment, but growth
expected inadequate for non-extraction.
• With mild anterior open bite.
• Minimal patient cooperation.
• Vertical growth pattern – no molar distalization.
• Minimal growth expectation.

Asymmetric extractions
Asymmetric extractions in Class II subdivision with acceptable
midlines can result predominantly in Class I space closure
Semin Orthod 1998; 4:180-188

Class II subdivision malocclusions treated with 4 premolar
extraction can require significant unilateral Class II elastic
wear. Complete one sided space closure is often required in
full step Class II buccal segments.
Semin Orthod 1998; 4:180-188

SPACING

Spacing may occur because the teeth are small in relation to
the size of the arch or because teeth are missing. Sometimes
this is acceptable to the patient but where this is not the case it
is important to discuss fully the implications of treatment.
Complete closure of appreciable spacing may not be possible
and it is often best to concentrate it at appropriate sites and to
fit bridges or prostheses as necessary. In these circumstances,
patients are usually keen to avoid a denture but the cost of
maintaining expensive bridge work for life should not be
under estimated and technical considerations may make
bridge work undesirable.
Where lateral incisors are missing it will usually be best to
collect available space at this site and use adhesive bridges
where the occlusion permits this. For most other cases it will
often be best to collect space in the premolar region.

Etiology
- Arch length – tooth materIal discrepancy
- Microdontia
- Missing tooth
- Abnormal tooth form
- Large tongue
- Pathology
- Cystic lesion between teeth
- Unerupted supernumerary teeth

Treatment
1. Removal of etiology
Abnormal habits / bony or cystic pathologies should be eliminated, large
tongue
2. Space closure
If maxillary anterior teeth are spaced, the incisors are protruded, the teeth may
require tipping / bodily movement during retraction.
Large spaces, rotations, bodily displacement – indication for fixed appliance.
Arch form alteration / post space closure can only be accomplished with fixed
appliance.
3 methods to eliminate space (MBT)
Contraction of dental arches
Replacement of missing teeth with bridges, transplants or implants after
redistribution or recreation of space
Building up of individual teeth with composite / crown

Missing Teeth
• If there is congenitally missing tooth in one area, but crowding in
another – auto transplantation is a possible solution
• If teeth are congenitally missing – best to retain primary tooth as long
as possible / close allow adjacent teeth to migrate partially into the
place of missing tooth so that alveolar bone development occurs
• Space can be consolidated together and space left can be replaced with
prosthesis
• Space can be closed by mesialising all the posterior teeth and
recontouring the crown of the meniatured teeth
• Microdontia – crowns / composite build ups
• Peg laterals – crowns / composite build ups

CONCLUSION
At one stage or another, orthodontics is usually a space
management procedure, particularly during the correction of
a Class I or Class II malocclusion. Orthodontists use space
that is available or create space to correct malocclusions.
There are anterior, posterior, lateral, and vertical dimensions
of the dentition and its supporting structures. If the muscular
balance is normal, the clinician should try to respect these
dimensions. The orthodontic clinician should not be an
extractionist or a nonextractionist. Rather, the clinician
should use differential diagnostic skills and artistic ability to
arrive at the most appropriate treatment outcome for each
patient.

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Management of space in orthodntics

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