extracted. Extraction of these teeth might be indicated where it is clear that
orthodontic appliances should be minimized or avoided for some reason, or where the
crowding is obviously severe and is causing gross incisor displacement or cross-bite.
It is also sometimes indicated to encourage the eruption of an ectopic permanent tooth
(see 900HSection 14.5.4). However, it must always be borne in mind that the extractions
will allow some mesial migration of the buccal segments, so increasing the crowding.
The extractions should always be balanced by removing the contralateral canine to
prevent a centreline shift, but it is not necessary to compensate by extracting the
canines in the opposite arch.
901H
Fig. 14.2 Serial extractions. (a) Class I occlusion with incisor crowding in the mixed
dentition. (b) Improved incisor alignment following extraction of primary canines.
The primary first molars are extracted to encourage eruption of the first premolars.
(c) First premolars are extracted on eruption to relieve crowding of the permanent
canines. (d) The result following eruption of the canines.