During the early teenage years there is a risk of resorption of adjacent incisor roots so
that annual radiographic review is necessary, although the risk of root resorption
reduces with increasing age. The onset of root resorption can be quite rapid, and for
this reason many impacted canines are removed. There may be a case for retaining the
canine in the short term in a younger patient, in case they have a change of heart about
orthodontic treatment to align the tooth.
Key Points
Ectopic canines
- About 2% of children have ectopic upper canines, of which 85% are palatal.
- Always palpate for upper canines from the age of 10 years until eruption.
- Non-palpable upper canines should be located radiographically or referred for
investigation. - Consider extraction of a primary canine if a permanent canine is mildly displaced.
- Untreated, unerupted permanent canines may resorb incisor roots and should be
radiographed annually during the teenage years.
14.5.6 Other anomalies of eruption
In the mixed dentition, three other anomalies of eruption are fairly common:
- Infraoccluded primary teeth (952HChapter 13) usually exfoliate provided that the
permanent successors are present, but they should be kept under review. If they are
not shed and eruption of the permanent tooth is seriously delayed, or if the
infraocclusion becomes very marked, then they should be extracted and a space
maintainer fitted if appropriate. - Impaction of the upper first permanent molar into the distal of the upper second
primary molar causing resorption (953HFig. 14.21). It is possible to disimpact the tooth
with an appliance, but the problem usually resolves spontaneously when the primary
molar is shed. The resorption may cause pain if it involves the pulp, in which case the
primary molar should be removed. This allows the permanent molar to move rapidly
mesially, and a space maintainer or an active appliance to move it distally should be
considered (see 954HSection 14.3.3). - Second premolars in unfavourable positions are sometimes seen as incidental
findings on panoramic radiographs, but fortunately they usually correct spontaneously
and eventually erupt satisfactorily. Very occasionally this does not happen, and a few
cases have been reported of a lower second premolar migrating towards the
mandibular ramus. Upper or lower second premolars that are blocked out of the arch
because of crowding usually erupt, but are displaced lingually.