UG Model Analysis Measurement of crowding and spacing

Measurement of Crowding

Crowding of the teeth can be measured in 4 segments for e.g. for the upper arch measurements are taken from distal of 15 to mesial of 13, mesial of 13 to mesial of 11, mesial of 11 to mesial of 23 and mesial of 23 to distal of 25.

FIG 15: Measurement of crowding (Measure along the alveolar ridge from contact point to contact point in segments with a divider)

As can be seen, when we go from one segment to other, a common point is considered between two segments to prevent missing out the crowding present between two segments. In each of these segments the combined mesiodistal measurements of the teeth in the segment are added up and from it, the actual space available is subtracted which will give us the individual crowding present in each segment. The sum of the crowding measured in the 4 segments is taken as the total crowding.

Interdental spacing

Interdental spacing is measured with a transparent scale between all the teeth mesial to 6. (Fig 16)

FIG 16 : Measurement of interdental spacing

A commonly made mistake in cases of palatally or buccally blocked out tooth is calculating the actual space available for the tooth as spacing (Fig 17)

FIG 17