Pacific Coast Society of Orthodontists Bulletin Spring 2021 - 45

Doctors

forward movement, leading to protrusive lower
incisors and an underdeveloped maxilla.

▫▫ Mouth breathing: Skeletal growth in mouth

Influence of Tongue Position on Skeletal Growth
The following are general rules for the influence
of tongue position on skeletal growth and development:

▫▫ Maxillary deficiency or " underbite " : Low
tongue position

▫▫ Mandibular deficiency or " overbite " : Low,
▫▫
▫▫

recessed tongue position
Anterior open bite: Forward tongue position
Maxillary crossbite: Low tongue position; the
maxilla can narrow in the absence of tongue
pressure

Factors that adversely affect tongue position
include, but are not limited to, the following:

▫▫ Tethered oral tissue or " tongue-tie " (ankylo-

▫▫

Spring 2021 PCSO Bulletin

glossia)
** There are two forms of tongue-tie, anterior and posterior. Anterior tongue-tie
is a deficiency in children that restricts
tongue protrusion with tethering of
the tongue tip. Posterior tongue-tie is a
deficiency in children that brings the back
of the tongue up with a lack of range of
motion in the anterior tongue.
** Ankyloglossia is a risk factor for maxillary
hypoplasia and soft palate elongation.
Reduced tongue mobility is associated
with decreased inner canine width and
decreased arch length. Restricted tongue
mobility is an independent predictor for
increased soft palate elongation. Ankyloglossia may be associated with skeletal
and dental Class III malocclusion. When
the lingual frenum is short, the tongue will
not generate enough upward pressure,
resulting in a narrow, underdeveloped palate. Grade 3 and 4 ankyloglossia produce
skeletal discrepancies and airway issues.
Large adenoids and tonsils: Large tonsils lead
to mouth breathing. The way in which we
breathe directly affects skeletal growth.

▫▫

breathers has been found to be in a clockwise pattern. The tongue comes forward,
the lower jaw drops down and backward,
displacement of the condyle is seen. Mouth
breathing continues or becomes more
severe, and posterior supra-eruption of the
maxillary teeth is observed along with an
anterior open bite and long-face appearance.
Nasal blockage: Again, the way in which we
breathe directly affects skeletal growth. A
study that observed blocked nasal passages
in primates from birth to six months found a
narrowing of dental arches, decreased maxillary arch length, anterior crossbite, maxillary
overjet, and increased anterior facial height,
among others.1
Narrow arches: The transverse dimension can
be measured using the mucogingival junction.
In other words, look at the bone instead of the
teeth. The lower arch = X, whereas the upper
arch = X + 5. These equations are based on
approximations of the distance between the
palatal cusp and buccal cusp of the upper first
molar.
Allergies and asthma: Allergies create nasal
blockage through congestion while asthma
creates inflammation that causes swelling
and narrowing of the airway, coupled with
increased mucus production. Both of these
conditions alter breathing, which directly
affects skeletal growth.

Treatment
Treatment options are based on treating the
structure, function, or behavior of the associated
patient. Treatment of the overall structure lies
with the orthodontist. Expansion is indicated in
children with obstructive sleep apnea. Secondary
effects of rapid maxillary expansion include improvement in tongue position and enlargement
of the pharyngeal airway. In children with nasal
obstruction, rapid maxillary expansion reduces
nasal obstruction, raises tongue position, and
enlarges the pharyngeal airway.

Pacific Coast Society of Orthodontists Bulletin Spring 2021

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