considered at this point as part of a programme of serial extractions, but where the
crowding is mild the decision should be delayed until the permanent canines and
premolars are erupting.
The term 'balancing extraction' refers to the contralateral tooth in the same arch, while
a 'compensating extraction' refers to the equivalent tooth in the opposite arch.
14.3.2 Serial extraction
Serial extraction is a form of interceptive orthodontic treatment which aims to relieve
crowding at an early stage so that the permanent teeth can erupt into good alignment,
thus reducing or avoiding the need for later appliance therapy. It consists of a planned
sequence of extractions:
- Primary canines⎯extracted as the permanent lateral incisors erupt to allow them
space to align. - First primary molars⎯about 1 year later, or when the roots of the first primary
molars are half resorbed or more, to encourage eruption of the first premolars. In the
lower arch these often tend to erupt after the canines. - First premolars⎯on eruption to make space for the eruption of the permanent
canines into alignment.
In effect, the extraction of primary canines transfers the crowding from the incisors to
the canine regions where it is more easily treated by extracting the first premolars
(897HFig. 14.2). It is essential to carry out a full orthodontic assessment before embarking
on a course of serial extractions. The indications for serial extraction are:
(1) significant incisor crowding;
(2) patient aged about 9 years;
(3) class I occlusion without a deep overbite;
(4) all permanent teeth present;
(5) first permanent molars in good condition.
The intended advantage of serial extraction is to minimize or eliminate the need for
appliances to align the arches after the permanent teeth have erupted. Sometimes this
is very successful (898HFig. 14.3), but the results can be disappointing. Where crowding is
severe it may be necessary to fit a space maintainer following extraction of the first
premolars, to ensure that mesial drift of posterior teeth does not leave the canines
short of space (see 899HSection 14.4.4).
The great disadvantage of serial extraction is the multiple episodes of extractions,
starting when the child is quite young. These may well be a child's first experience of
dental treatment and might cause subsequent psychological problems with their
attitude to dentistry, especially as the experience is to be repeated as the programme
of extractions proceeds. The likely benefit of the extractions must be considered very
carefully, and in only a small minority of cases would general anaesthesia be justified
for this purpose. In practice, the extraction of the first primary molars is usually
omitted, and the decision thus becomes whether the primary canines should be