Page 112 - REMOVABLE ORTHODONTIC APPLIANCES

104 Removable Orthodontic Appliances
- Figure 11.3 A Begg retainer with
a continuous labial bow and 'U'
loops (0.8 nnm).

from canine to canine might permit sponta- tooth show signs of mobility or relapse. There is
neous improvements in the buccal segments but evidence that these retainers, like bonded
would also carry a possible risk of inhalation. bridges, are much less likely to suffer bond fail-
ure when only two teeth are bonded.

Bonded retainers
Periodontal retainers
Direct acid-etched bonding technique allows
groups of teeth to be bonded together on the Non-metallic fibre strips are commercially
lingual or palatal side. Commercial retainers available for splinting. They are intended to
are available and are particularly suited to stabilize teeth that have become mobile
holding two upper central incisors together or because of advanced periodontal disease. Such
maintaining lower anterior tooth position when material can be used for orthodontic retention.
bonded to the lower canines. These devices are It is inclined to spread vertically and encroach
less satisfactory in controlling multiple rota- on the gingival margins in young patients,
tions and they can, on occasion, result in decal- particularly in lower incisors. For this reason
cification or even caries if one side becomes multistrand wires are to be preferred.
unbonded while the other remains firmly
attached.
It is probably better to use custom-made Retention regime
bonded retainers with a multi-flex wire adapted
to the palatal surfaces of those teeth to be Retention can be divided in to short-term reten-
retained. A flexible plastic template can be made tion, standard retention and long-term retention.
on a vacuum-forming machine as an aid in
correct location of the wire in an indirect bond-
ing technique. Such bonding should be done Short-term retention
under rubber dam to ensure a dry field (much
more difficult to achieve on the lingual than the Following removable appliance treatment to
labial surface) and to guard against accidental correct a reverse overjet, the existing appliance
inhalation. Chemical or light cured agents can be can be used to act as a retainer, any springs or
used to bond these retainers. Once this has been screws being made passive. The appliance can
achieved an impression should be taken for a be worn on nights-only basis for 3-6 months.
removable retainer either of the 'U' loop or
vacuum-formed type, as appropriate, as an addi-
tional safeguard. Bonded retainers can be left in
situ for many years but the patient should be seen Standard retention
from time to time and is given careful instruction Standard retention would involve the fitting of
to return should any part become unbonded or a a custom-built retainer which would be worn