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CORRECTION OF ADULT SKELETAL CLASS II BIALVEOLAR PROTRUSION
SEO-YE IM
REPUBLIC OF KOREA
ABSTRACT
Tweed-Merrifield force systems provide one of the most
effective ways to correct dentoalveolar protrusions and
Class II malocclusions. Class II correction methodology
must allow the counterclockwise rotation of the mandible
via a force system that maximizes skeletal change during
the adolescent period. Even for an adult patient who has a
severe bialveolar protrusion Class II malocclusion, a greater
than expected esthetic change can be achieved with a proper
directional force system.
canines and the molars have an Angle’s Class I occlusion.
To off-set the protrusion, plastic surgery was performed
on her nose. Even after the plastic surgery, the evidence of
facial imbalance, hyperactivity of mentalis muscle, mouth
breathing, and gummy smile remained. At the time of her
visit, her chief complaint was “I’m still not beautiful.” Due
to such a lack of self-confidence, she was an extremely
motivated and co-operative patient.
DIRECTIONAL FORCE SYSTEM:
This system can be defined as controlled forces that place
the teeth in the most harmonious relationships with their
environment. The resultant vector of all forces should be
counterclockwise so that the opportunity for a favorable
skeletal change is enhanced, particularly for dentoalveolar
protrusion and Class II malocclusion correction. An upward
and forward force system requires the mandibular incisors
be upright over basal bone so that the maxillary incisors
can be moved distally and superiorly. For the upward and
forward force system to be a reality, vertical control is
critical. To control the vertical dimension, the clinician must
control the mandibular plane, the occlusal plane, and the
palatal plane. Source: Seminars in Orthodontics, Vol. 2, No. 4
(December), 1996: pp 237-240, 254-267
CASE REPORT I
CLINICAL FINDINGS AND DIAGNOSIS
The patient is a 45 year, 9 month old female. She presents
with a Class II bialveolar protrusion malocclusion. The
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