Page 54 - REMOVABLE ORTHODONTIC APPLIANCES

46 Removable Orthodontic Appliances
below) for anchorage reinforcement, it may be 'J' hook safety
sufficient for the patient to wear headgear There have been fewer cases of trauma
only while asleep. Where the risk of anchorage reported with the use of 'J' hooks, but this may
loss is not acceptable, it is wiser to start off be due to the fact that they are not commonly
with wear for 10-12 hours out of each 24 used. They cannot give rise to a catapult injury.
hours. For active retraction of buccal Because of their relative instability and the
segments, wear for 12-14 hours out of each 24
is necessary to ensure a reasonable rate of upward direction of traction, 'J' be hooks, if they
potentially
displaced,
could
become
progress. Headgear is never popular so patient
motivation and monitoring are crucial to its hazardous to the patient's eyes. The closed
successful use. design of the 'O' hook avoids any sharp ends
and the chances of damage must be low.
Safety aspects Patient instruction
Although trauma from 'J' hooks and facebows When an extraoral appliance is fitted and
is very rare, it is potentially very serious. The demonstrated to a patient and parents a warn-
patient is at risk if the facebow or 'J' hook ing of the potential risks should also be given.
becomes dislodged from the appliance. This This should be supported by the use of printed
can happen if the facebow is removed while still instructions, which should include advice to
attached by elastics to the headcap, whether attend a hospital accident and emergency
intentionally by the patient or inadvertently department where ophthalmic advice can be
during play. Other children can also be at risk obtained should an eye injury occur.
from contact with the external parts of head-
gear, facebow or 'J' hooks. A case has been
reported where the facebow became displaced
while the child was asleep and penetrated the Wear instruction and monitoring
eye, with subsequent loss of sight.
It is usually advisable to commence with a train-
ing period and ask the patient to wear the head-
Facebow safety gear appliance in the evenings at home for the
first 2 weeks after it has been fitted. The patient
If a detachable facebow is used then the ends should then return to the surgery for the appli-
that engage the tube on the molar clasp should ance to be checked. Provided it is being managed
be of the recurved design (see Figure 6.8) satisfactorily the patient is instructed to wear it
rather than the unprotected pointed end of the while asleep in addition to indoor daytime wear.
conventional design. Should the bow become The headgear should be checked at every visit
detached there is less chance of facial injury. and the patient asked if the appliance is ever
The extraoral hook should be carefully finished dislodged at night. The cause of this should be
so that it is smooth and not prominent.
investigated and the headgear adjusted. If this
A safety strap should be fitted to prevent fails to remedy the situation then the patient
catapult injuries. This is a relatively rigid length should not wear the headgear while asleep.
of plastic, which stops the elastics being over- A record of the adjustment and checking of
tensioned and helps to prevent the bow from the headgear should be made in the patient's
becoming displaced inadvertently. notes at every visit.
Safety headgear is available and is designed
so that the hook attachment on the headgear
(which engages the external hook of the face-
bow) detaches when a predetermined force Further reading
level is exceeded. This reduces the risk to the
Booth-Mason, D., Birnie, D. (1988) Penetrating eye injury
patient from a catapult injury, if the facebow is from headgear. European Journal of Orthodontics, 10:
pulled out of the mouth while still attached to
111-114
the headcap by elastics. It does not eliminate Quealy, R., Usiskin, L. (1979) High pull headgear with J
the risk of injury if the patient dislodges the hooks to upper removable appliances. British Journal of
facebow while asleep and then rolls onto it. Orthodontics. 6: 41-42