aligned and in normal occlusion. An abnormally large upper incisor is associated with
crowding or increased overjet, or both. A grossly oversized tooth may have to be
extracted and replaced with a pontic after completion of any orthodontic treatment. In
milder cases it is possible to narrow the tooth by reducing the enamel interdentally.
Up to 1 mm may be removed after the teeth have been aligned but before appliances
are removed, so that the resulting spaces can be closed.
Key Points
Supernumerary teeth
- Variations from the normal eruption sequence should be investigated.
- Supernumerary teeth that interfere with the eruption of permanent teeth should be
removed. - The space for the permanent tooth should be maintained while it erupts.
- Give the permanent tooth at least 18 months to erupt before considering surgical
exposure. - Spacing due to congenitally absent teeth may be opened or closed depending on the
degree of crowding.
Microdontia
Upper lateral incisors are most commonly affected. Any orthodontic treatment should
precede the restoration of a diminutive tooth, and should leave adequate space for it to
be enlarged (974HFig. 14.29 (a)-(c)). The retainer should carry interdental spurs to prevent
adjacent teeth from drifting into the space, and it should be worn for at least 3 months
before the tooth is built up. Where the upper arch is inherently crowded but the lateral
incisors are diminutive on one side and congenitally absent on the other, it may be
appropriate to extract the diminutive tooth and close the spaces. This relieves the
crowding and gives a symmetrical appearance.