Pacific Coast Society of Orthodontists Bulletin Summer 2021 - 65

Special Section: Class III Correction
Pearls of the Pacific
A Modified Maxillary Hawley
Appliance for Early Class III
Treatment: The " Ibenator "
Dr. Ib Leth Nielsen
San Francisco, CA
PCSO Bulletin Contributor
Class III malocclusion with anterior crossbite or
mandibular overjet is one of the malocclusions
that can benefit from early interceptive treatment.
Frequently, it is difficult in the early mixed
dentition stage to determine if a Class III malocclusion
in combination with mandibular overjet
is skeletal or primarily dentoalveolar in nature. It
often presents as a mild anterior crossbite of several
teeth, as seen in Figure 1, with a mild Class III
molar relationship. Upon further examination, it
becomes evident that some patients also posture
the mandible forward to bite on the posterior
teeth, and this should always be checked before
constructing the appliance.
Young patients with mandibular overjet can often
be treated initially with a removable appliance that
allows proclination of the maxillary incisors while
at the same time preventing mandibular posturing;
an example of such an appliance is seen in Figure 1.
This maxillary Hawley appliance has overlapping
finger springs behind the maxillary incisors that
allow these teeth to be proclined gradually. The
appliance has occlusal coverage over the upper
posterior teeth to provide just enough bite opening
to allow the maxillary incisors to be proclined
and passed over the lower incisors. Furthermore,
there is a Hawley retainer wire that is designed
to lie across the middle of the lower anterior
teeth to help reduce any posturing forward. The
appliance is retained with Adams clasps on the
maxillary first molars. Activation of the springs
should be done very gradually to prevent a
loose-fitting appliance. It is also important not
to create any more bite opening than necessary
for the maxillary incisors to procline and get over
the mandibular incisors. Too much bite opening
can invite a tongue habit and make it harder to
speak with the appliance in one's mouth, so that
is to be avoided. Once the maxillary incisors have
passed over the mandibular incisors, the acrylic
covering the posterior is gradually reduced until
it can be completely removed. Some adjustment
of the labial bow is needed during treatment to
prevent the labial bow from touching the gingiva
in front of the mandibular incisors. At this stage,
the retainer can be used solely at night as an
actual retainer. The continuous movement of the
labial bow can in some cases result in fracture
of the bow, usually at the loop. To minimize this
tendency, we suggest using a round wire made of
blue Elgiloy, because this type of material is less
prone to break.
Figure 1. The Ibenator appliance for treatment of dentoalveolar Class III malocclusion
Summer 2021 PCSO Bulletin
65
Pacific Coast Society of Orthodontists Bulletin Summer 2021

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