Pedodontic Fifth-year First semester By Lama El Banna Al Azhar University Gaza Palestine

1. ‫الرحيم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬
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2. College of Dentistry
Pedodontic II
Management of Space Maintenance
Problem in Children -1-
Dr. Hazem El Ajrami
Master Degree in Orthodontic & Pedodontic
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3. • Management of space problems associated with
the transitional stages from primary to
permanent dentition is a routine component of
pedodontic practice. The change from primary
dentition to the permanent dentition is a
complex phenomenon, which is composed of a
variety of physiological adaptations of occlusion
during this period.
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4. • Premature loss of primary molars causes,
without doubt, permanent changes concerning
space and sagittal molar relations, in the
permanent dentition. The changes are due to
drifting of teeth and lack of growth, and such
changes should whenever possible, be
prevented.
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5. • Space maintenance:
Whenever primary or permanent teeth are
lost prematurely and arch integrity is lost, loss
of space and arch length, perimeter may result.
Migration of primary and / or permanent teeth
can occur and the available space may be
reduced by an amount sufficient to cause some
degree of crowding in the permanent dentition.
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6. • Determination of arch length adequacy prior
to space maintenance procedure:
The dentist faced with the problem of
maintaining the space after the loss of an
individual primary tooth or the multiple loss of
primary teeth should look beyond the immediate
state of the dentition, think in terms of the
development of the dental arches and the
establishment of a functional occlusion. This is
particularly important during the mixed dentition
period.
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7. • He should determine the size of the permanent
teeth that are yet to erupt, specifically the teeth
in the dental arch anterior to the first
permanent molars. He should also determine
the amount of mesial movement of the first
permanent molars that will occur after the loss
of the primary molars and the eruption of the
second premolar.
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8. • Arch length analysis (ALA) are methods by
which orthodontist can estimate and predict
tooth size / jaw size relationship. Early
determination of future crowding has an
important role in diagnosis and treatment
planning in mixed dentition stage. Mixed
dentition analysis (MDA) is helpful in the
prediction whether there is sufficient space for
the unerupted canines and premolars or not.
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9. • Since mal-aligned and crowded teeth usually
result from lack of space, this analysis is
primarily of space within the arches. 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 properly.
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10. • Classification:
Numerous methods have been proposed for
arch length analysis. These methods could be
classified as follows:
I. Classification according to the method of
tooth size estimation.
II. Classification according to the method of
arch length estimation.
III. Classification according to the
developmental stage of dentition.
IV. Classification according to the method of
estimation and digitizing.10

11. I. Classification according to the method of
tooth size estimation:
1) Methods, which depend on the
measurements from radiographs.
2) Prediction based upon the correlation
between the mesiodistal dimensions of the
erupted and non erupted teeth.
3) Combination of these methods.
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12. II. Classification according to the method of
arch length estimation:
1) Conventional methods: These methods do
not include the use of cephalometric
correction or soft tissue modification.
2) Cephalometric correction methods: The
incisor reduction (IR) measurement is either
added or subtracted from the previous
available space obtained with the brass
wire. This will correct any labial or lingual
deviation of the lower incisors from the true
basal bone. e.g. Tweed's analysis.
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13. 3) Total space analysis: These methods
include the use of cephalometric correction,
soft tissue modification and curve of
occlusion.
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14. III. Classification according to the
developmental stage of dentition:
 Methods used in mixed dentition stage.
 Methods used in permanent dentition
stage.
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15. IV. Classification according to the method of
estimation and digitizing:
A. Computerized arch length analysis:
Arch length analysis methods also
include computerized arch length analysis,
which can be used to determine the
variations from the mean tooth size,
actually set up the teeth, arch form and
treatment plan.
B. Manual measurements and estimation.
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16. Methods in common use:
1. Nance Analysis:
Nance concluded, as a result of
comprehensive studies, that the length of the
dental arch from the mesial surface of one
mandibular first permanent molar to the
mesial surface of the corresponding tooth on
the opposite side is always shortened during
the transition from the mixed to the
permanent dentition.
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17. • Nance further observed that in the average
patient's mandibular arch a leeway of 1.7 mm.
per side exists between the combined
mesiodistal widths of the primary mandibular
canine and first and second primary molars and
the mesiodistal widths of the corresponding
permanent teeth, the primary teeth being larger.
This difference between the total mesiodistal
widths of the corresponding three primary teeth
in the maxillary arch compared with the three
permanent teeth that succeed them is only 0.9
mm. per side.
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18. • For a mixed dentition, arch length analysis
similar to that advocated by Nance, the
following materials are needed: sharp divider,
a set of periapical radiographs, a millimeter
ruler, a piece of 0.026 inch (0.65 mm.) brass
wire and a card for recording measurements. A
set of study models is also necessary.
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19. • The width of the erupted four mandibular
permanent incisors is first measured, from the
stone model. The actual width should be
determined rather than the space the incisors
occupy in the arch. The individual
measurements are recorded. The width of the
unerupted mandibular canines and first and
second premolars on the radiographs should
next be measured.
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20. • The estimated measurements are then
recorded. This will give an indication of the
space needed to accommodate all of the
permanent teeth anterior to the first permanent
molar. The next step is to determine the
amount of space available for the permanent
teeth, and may be accomplished in the
following manner.
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21. • A piece of brass ligature wire, contoured to
arch form, is placed on the lower model
extending from the mesial surface of the first
permanent molar on one side of the arch to the
mesial surface of the first permanent molar on
the opposite side. The wire should pass over
the buccal cusps of the posterior teeth and the
incisal edge of the anterior teeth.
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22. • From this measurement must be subtracted 3.4
mm., which the arch length may be expected to
decrease as a result of the mesial drifting of the
first permanent molars. Thus by comparing the
two measurements, the dentist can predict with
a fair degree of accuracy the adequacy of the
arch circumference.
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23. 23

24. 2. Tanaka and Johnston Analysis:
The Tanaka and Johnston method of arch-
length analysis is a variation of Moyers
analysis except that a prediction table is not
needed. The estimated widths in millimeters
of the unerupted canines and premolars
correspond to the 75% level of probability in
Moyers prediction table. The sum of the
widths of the mandibular permanent incisors
is measured and divided by 2.
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25. • For the lower arch, add 10.5 mm. to the result
and for the upper arch, add 11 mm. to the result
to obtain the total estimated widths of the
canines and premolars. For example, if the width
of the lower incisors was 23 mm., divide by 2
and add 10.5 mm. for the lower arch. The result
is 22 mm. compared with 22.2 mm. obtained
from Moyers table. The corresponding values for
the maxillary arch are 22.5 turn for the Johnston
and Tanaka analysis and 22.6 from Moyers
table.25

26. • It is then possible to take these teeth mass
predictions, compare them with the total
measured arch length, and obtain any
redundancies or inadequacies in the arch
length.
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27. 3. Hixon and Oldfather:
They measured the mesiodistal widths of
unerupted bicuspids on the x-ray film. Then
added to them the size of lower permanent
incisors from the casts. They termed the
resultant "the measured value" which is used
to determine the "estimated value" from their
prediction charts.
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28. 4. Kaplan, Smith and Kenarkf:
They modified Hixon and Oldfather method
by excluding the lower incisors. This method
necessitates only measuring the sum of lower
central incisors and mesiodistal widths of first
and second bicuspids from x-ray film. To
overcome Hixon, oldfather's over-prediction
they have suggested adding 0.3 mm. to value
below 20 mm. and 0.4 mm. to values 20-22
mm. and 0.5 mm. to values 23 mm. and above.
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29. 5. Moyer Mixed-Dentition Analysis:
The analysis advocated by Moyers has
numerous advantages. It can be completed in
the mouth as well as on casts, and it may be
used for both arches. The analysis is based on a
correlation of tooth size; one may measure a
tooth or a group of teeth and predict accurately
the size of the other teeth in the same mouth.
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30. • The mandibular incisors, since they erupt
early in the mixed dentition and may be
measured accurately, have been chosen for
measuring, to predict the size of the upper
canine and premolars from his chart, as well
as the lowers.
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31. Thank You
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