the reopened space. The bridge itself often acts as a permanent orthodontic retainer,
and careful thought should be given to this aspect of its design. For example, if an
upper canine has been moved distally, a fixed-fixed design ensures that the canine
cannot relapse mesially. A cantilever design might allow relapse, causing the lateral
incisor pontic to overlap the central incisor.
Where the upper arch is inherently crowded, the lateral incisor space could be closed.
There is some debate as to the merits or otherwise of the resulting aesthetics, but, in
general, it seems unfortunate to extract a sound premolar to open space for a
prosthesis, and in the long term the appearance following space closure is usually
acceptable (968HFig. 14.27 (a) and (b)). The quality of the appearance depends on the
shape of the canine, but pointed canines can be made to look more like lateral incisors
by reducing the cusp tip and adding composite mesio-incisally.
More severe hypodontia with multiple missing teeth
This often needs complex treatment. Preliminary orthodontic treatment can often help
restoration by making the space distribution more favourable, uprighting tilted teeth,
and reducing the overbite. Fixed appliances are usually needed and orthodontic
retention requires careful management (969HFig. 14.28 (a)-(f)).
970H
.
Fig. 14.26 (a) Spaced arch complicated by the absence of 2| and a very diminutive
|2. (b) |2 to be extracted and fixed appliance opening space for replacement 2|2. (c)
Removable retainer⎯note wire spurs to ensure space is maintained. (d) Adhesive
bridges in place, and composite additions to enlarge 1|1. (e) Bridge design