Orthotown November 2023 - 54

CONTINUING EDUCATION
Introduction
Most orthodontists agree that a unilateral
or bilateral posterior crossbite
caused by a narrow maxilla should be
addressed with interceptive treatment
to expand the maxilla during the early
or mid-mixed dentition. The typical
treatment involves rapid
maxillary expansion with
a Hyrax-type appliance
to apply very heavy forces
to the patient's midpalatal
suture. However, it is
important to consider both
whether the application
of this magnitude of force
is necessary to expand
the immature and patent
palatal suture of a younger
child and whether delivering
lighter forces via slow
maxillary expansion is a
superior alternative.
Additionally, it is not
it requires less force to achieve an
orthopedic effect in younger patients
and allows for arch development to
occur before the eruption of a majority
of the succedaneous teeth, including
the permanent canines. Unfortunately,
however, traditional expansion
Storey emphasized the
importance of force control
during expansion and added
that less force is required to
achieve palatal separation before
the fusion of the palatal suture.
[Dr. William R.] Proffit took it a
step further when he stated that
using rapid maxillary expansion in
young children is a 'disadvantage'
and can cause 'facial distortion.'
uncommon for a preadolescent
patient to present
with a transverse deficiency
in the mandibular arch. Yet many
orthodontists do not believe that it's
practical, or even possible, to expand
the mandibular arch, despite decades
of research to substantiate its safety,
efficacy and stability. Consequently,
when the mandibular arch is allowed
to remain narrow, the amount of maxillary
expansion that can be achieved
is significantly limited. This not only
leaves insufficient space for the tongue
and the erupting permanent teeth
but also permits continued aberrant
growth of the craniofacial complex.
The data are clear that the ideal
time to address a transverse deficiency
is when the patient is a preadolescent
in the early mixed dentition, because
appliances are often uncomfortable
for the patient and can be challenging
for the clinician. As such, it is necessary
to explore alternative treatment
modalities that can both deliver light
forces and allow the practitioner to
predictably, effectively, comfortably
and stably expand the arches of
younger patients.
Rapid maxillary expansion
Rapid maxillary expansion (RME)
involves delivering very heavy forces
over a relatively short period of time.
While such heavy forces are often
necessary to achieve orthopedic
expansion in a more skeletally mature
adolescent, they can be damaging to
NOVEMBER 2023 | 54 | ORTHOTOWN.COM
the immature craniofacial complex
of younger children. Isaacson and
Ingram reported that single activations
of a jackscrew-type appliance
produce forces in the 3-to-10-pound
range with accumulated loads of
more than 19 pounds1
-a tremendous
amount of force to deliver to a
young face.
Storey concluded that from a
histological perspective, RME
is a " predominantly destructive
process " whereby the sutural
connective tissue becomes
disrupted and edematous, and
blood vessels hemorrhage into
the extravascular tissue. He
emphasized the importance
of force control during expansion
and added that less force
is required to achieve palatal
separation before the fusion of
the palatal suture.2
Proffit took it a step further
when he stated that using
RME in young children is a
" disadvantage " and can cause
" facial distortion. " He added, " There
is no evidence of any advantage of
rapid movement and high forces in
children and ample evidence that
this can be dangerous. " He concluded
that slow expansion is the preferred
approach to maxillary constriction
in children with primary and early
mixed dentitions.3
Most orthodontists have observed
first-hand the facial distortion
referenced by Proffit. Interestingly,
however, many providers continue
to use RME to address a transverse
maxillary deficiency in preadolescent
patients despite the excessive force
being delivered and the risk of negative
clinical outcomes.
http://www.ORTHOTOWN.COM
Orthotown November 2023

Table of Contents for the Digital Edition of Orthotown November 2023
