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Quantification of space problems Space analysis : Quantification of space problems

Because reducing protrusion reduces the amount of available space. The space analysis results must be considered in the context of the profile, Because reducing protrusion reduces the amount of available space.

It is important to quantify the amount of crowding within the arches because treatment varies, depending on the severity of the crowding.

Space analysis, using the dental casts.

Space available Space required compare Space deficiency Space excess OK

Space available: Measuring arch perimeter: from the mesial of one first molar to the other

Over the contact of posterior teeth and incisal edge of anteriors: 1- dividing the dental arch into segments

2- contouring a piece of wire

Space required: Mesiodistal width of each erupted teeth, Summing the widths of the teeth

For a child in the mixed dentition estimating the size of unerupted permanent teeth

Important assumptions: 1- the anteroposterior position of the incisors is correct

2- the space available will not change (growth, compensatory tipping)

3- all the teeth are present

Estimating the size of unerupted permanent teeth

1- measurement of the teeth on radiographs

2- estimation from proportionality tables Moyers Table:

معیارهای پیش بینی مایرز (سطح 75%) 23.0 22.5 22.0 21.5 21.0 20.5 20.0 19.5 Total mandibular- incisors width 22.6 22.3 21.8 21.3 21.2 20.9 20.6 Maxilla Predicted width of canine and premolars 22.2 21.9 21.6 20.7 20.4 20.1 mandible

29 28.5 28 27.5 27 26.5 26.0 25.5 25.0 24.5 24.0 23.5 25.9 25.6 25.3 24.8 24.2 23.7 23.4 23.1 22.9 25.7 25.4 25.1 24.6 24.3 22.8 22.5

Hixon and Oldfather prediction graph (Staley and Kerber revision)

Tanaka and Johnston + 10.5 mm = estimated width of the mandibular canine and premolars in one quadrant + 11.0 mm = estimated width of the maxillary One half of the mesiodistal width of the 4 lower incisors

Tooth size analysis (Bolton analysis)

Any questions??