may also be seen in cases of severe congenital neutropaenia, cyclical neutropaenia,
Chediak-Higashi syndrome (where it is associated with gross periodontal destruction)
and in the Langerhans cell histiocytoses
13.9.2 Delayed exfoliation
Infraocclusion
The terms infraocclusion, submerged teeth and ankylosed teeth are often used to
describe teeth which have failed to come into normal occlusion or, more typically,
have remained in their relative position in the arch while other teeth have continued to
erupt. This is most commonly seen when one or more premolars fails to develop,
hence the primary molars have no stimulus to become resorbed. As the adjacent
permanent teeth erupt alveolar growth occurs, but in some cases the primary molars
become ankylosed within the bone and fail to alter their position (883HFig. 13.45 (a)). As a
result, there is an open bite in the affected area with the occlusal plane of the primary
molars being lower than that of the adjacent permanent teeth. It should be recognized
that the process of physiological resorption of primary teeth is not unremitting and
there are phases of resorption and repair. If there is an imbalance between the two,
with the latter predominating (particularly in the absence of normal physiological
stimulus for resorption), then the net result is ankylosis. Genetic factors may be
important but the aetiology has not yet been resolved.
Treatment
A substantial study has shown that removal of infraoccluded primary molars will lead
to progressive space loss at that site with a potential either to give rise to or to focus
crowding at that site; that all of the infraoccluded teeth in the study were shed within
the expected time limits and that a more conservative approach to the management of
these teeth may be indicated.
Where there is no permanent successor, the infraoccluded primary teeth may be
retained and the crowns built up with acid-etch composite restorations or other
restorative material. Onlays, either in metal or laboratory cured composite, may be
considered. (884HFig. 13.45 (b)) If extraction is contemplated, then consideration needs to
be given to orthodontic alignment, a denture, bridge, or implant.
Other causes of delayed exfoliation
Delayed exfoliation of primary teeth may be seen in association with a number of
local causes, including fused/geminated primary teeth, ectopically developing
permanent teeth and subsequent to trauma or severe infection of primary teeth.
Key Points
- There is a time range in which teeth erupt⎯but this range will affect the dentition as
a whole. - Dentitions falling substantially outside this range, or individually affected teeth
delayed by 6 months, should be investigated. - Premature exfoliation always demands investigation.
- There is a place for a conservative approach to the management of infraoccluded