Pacific Coast Society of Orthodontists Bulletin Spring 2021 - 46

Doctors

Why Upper and Lower Expansion?
Skeletal sutures have been found to change as
we age. Skeletal expansion can be accomplished
through a variety of orthopedic appliances. That
being said, expanding only the maxilla can place
the patient in crossbite. To compensate for this, the
orthodontist can upright the lower posterior dentition, distalize the mandibular molars with a lip
bumper, or achieve dentoalveolar expansion using
various appliances, among other techniques. The
one thing to keep in mind is that true expansion
cannot be achieved because there is no mandibular
suture. In terms of bimaxillary expansion, narrow
arch forms and collapsed tooth positions are adaptive responses to an altered breathing state and
changes in tonicity of orofacial musculature. As the
dentition tips inward toward the tongue, it creates
a narrow intraoral space. Rapid maxillary expansion
increases the nasal cavity width, and bimaxillary
expansion increases the intraoral volume, dental
arch circumference, and dental arch width.
Contributing Factors
Contributing factors to breathing problems and
skeletal growth are tonsils and adenoids. The
removal of tonsils and adenoids does not necessarily resolve breathing issues and neither does
orthopedic intervention. Removal of adenoids
and tonsils alone showed a 60% improvement in
airway, palatal expansion alone showed a 60%
improvement in airway, but a combination of
the two showed complete correction of airway.
This needs to be taken into consideration when
deciding whether to refer to an ear, nose, throat
specialist (ENT) for adenoid or tonsil removal or
to use orthopedic expansion first. The main takeaway is that combining the removal of tonsils and
adenoids with rapid maxillary expansion resolves
obstructive sleep apnea.
What's Next?
Modern progressive approaches include adult
expansion using temporary anchorage devices
(TADs) or miniscrews, such as acrylic TAD expanders, which can significantly improve nasal airway

breathing as compared with normal tooth-borne
expanders. A decision to consider in the design of
these expanders is the positioning of the TADs.
If the TADs are parallel to the midpalatal suture,
then we get a better result at the midsagittal
level.
When Do We Treat in a Child?
Early intervention is needed in children when they
are vertical growers or have an anterior open bite.
This intervention could consist of a referral to an
ENT, identification of allergies, or orthodontic
intervention, among others. One exception is that
you do not necessarily want to perform expansion on a child younger than three years. After
expansion, an acrylic plate retainer is needed
while the adult dentition erupts. On the opposite
end of this spectrum, 12 years old is too late for
expansion because growth has already occurred.
At this point, you are looking at doing the best
you can do as an orthodontist which includes performing orthodontic camouflage or even surgical
intervention.
Take-Home Messages

▫▫ Ask new questions.
▫▫ We can make our patients healthier.
▫▫ The tongue plays a key role in skeletal growth
and development.

▫▫ The maxilla is the diagnostic arch in terms of
airway health for both children and adults.

▫▫ Common skeletal patterns result from airway
issues.

▫▫ Solving airway issues and soft-tissue function▫▫
▫▫

ality early can alter the trajectory of skeletal
growth.
If airway issues are treated too late, the ideal
treatment plan is often a surgical correction.
An early correct diagnosis and an interdisciplinary approach to treatment are key to a
successful outcome.

References
1. Harvold EP, Timer BS, Vargervik K, Chierici G. Primate experiments on oral respiration. Am J Orthod
1981;79:359-372.

PCSO Bulletin Spring 2021

Pacific Coast Society of Orthodontists Bulletin Spring 2021

Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Spring 2021