The space starts to close very quickly, within days of losing the tooth, and it should be
maintained by inserting a partial denture immediately (977HFig. 14.30). In a crowded arch
it is often possible to move the lateral incisor into the central space, but the resulting
appearance is usually very poor. Building up or crowning the lateral incisor to mimic
the central tooth is rarely satisfactory as it gives the tooth a very triangular shape, and
it is difficult to maintain periodontal health around the enlarged crown.
Where a premolar is to be extracted for orthodontic reasons it can sometimes be
transplanted into the central incisor site, and then restored to mimic the missing
incisor.
Upper lateral incisor
Lateral incisor spaces can be either maintained or closed, depending on the amount of
crowding in the arch (see 978HSection 14.6.2).
979H
Fig. 14.30 Space loss following avulsion
of 1|1.14.7.2 Orthodontic movement of traumatized teeth
In general, root-filled teeth can be moved orthodontically quite normally, with no
increased risk of external root resorption compared with normal teeth. The risk factors
associated with root resorption during orthodontic treatment are discussed in 980HSection
14.8.3. Traumatized teeth, however, are already at an increased risk of root resorption,
especially those which have been displaced or reimplanted⎯orthodontic treatment
increases the risk further. In these cases the need for orthodontics should be assessed
very carefully, but where it is needed the risk of resorption during tooth movement
should be minimized by: (1) maintaining a calcium hydroxide dressing in the root
canal during orthodontic treatment, and (2) ensuring that orthodontic forces are as
light as possible.
Fixed appliances should be used with great care as they can easily generate high
forces, and treatment with them should be kept to a minimum. Functional appliances
are useful for reducing an overjet as they do not apply high forces to individual teeth.
A tooth that has become ankylosed cannot be moved orthodontically and will
eventually be lost, but in the shorter term it will serve as a space maintainer unless the
ankylosis causes excessive infraocclusion.