Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 54
Doctors
soft tissues will become displaced posteriorly and
inferiorly into the oropharyngeal airway, narrowing
the tube (Figure 5). With this inferior repositioning of
the tongue comes a remodeling of the palate (which
is also the floor of the nasal cavity), and a decrease in
the transverse dimension of the oral and nasal cavity
can occur. This remodeling occurs over time, and the
expressed phenotype is that of narrow dolichofacial
features with a high mandibular angle and steep
mandibular and occlusal planes (Figures 3 and 4). As
the condyles are a primary growth site of the mandible,
a condition that destroys the fibrocartilaginous
cap and reduces condylar volume earlier in life (such
as ICR and JIA) will have a more marked effect on the
formation of the jaws and the nasal cavity than one
that affects an adult, and the severity of the condition
and volume loss also presents as more marked
changes in the facial form.
Another theory for the development of this phenotype
proposes an alternative scenario, one that
identifies the airway obstruction as the culprit and
instigator of the cascade of events that eventually
leads to this phenotype. In this scenario, the
narrowing of the nasal passages either developmentally
or pathologically (due to rhinosinusitis
or a lesion) or the narrowing of the nasopharynx
due to adenoid hypertrophy will precipitate a need
to survive and breathe, which will manifest as a
mouth-breathing habit. With the partial opening
of the mouth comes a partial translation of the TMJ
condyle and disc, and with long-term open mouth
posture, patients develop changes of their facial
skeleton and dentition, which have been coined
" adenoid facies. " With the chronic open mouth
posture, a supereruption of the teeth occurs, with
the last molar teeth being the first to contact,
resulting in an anterior open bite. With the altered
function of the disc and condyle in this new occlusion
comes a biomechanical stress to the disc and
bony articular surfaces, which may result in internal
derangement/disc displacement with possible
subsequent functional remodeling or destruction
of the articular surface (DJD). This can reduce the
volume of the condyles and lead to further occlusal
changes, as noted in the paragraph above. With
inferior repositioning of the mandible in the open
mouth posture comes the inferior position of the
tongue, and the lack of the presence of the tongue
against the palate during growth and development
results in a narrowing of the transverse dimension
of the arches as they succumb unopposed to the
pressure from the buccinator muscles. The narrowing
of the maxillary arch also affects the transverse
dimension of the nasal cavity, further narrowing it
and exacerbating the inability to breathe through
the nose. This scenario is more widely accepted
in dental sleep medicine circles, especially those
working in the pediatric field.
Figure 1. Panoramic reformation of cone-beam computed
tomography data shows the overall condition
of the maxillofacial complex. We note the open bite
as well as the small condyles and steep mandibular
planes.
It is my humble opinion from my own observations
in my oral and maxillofacial radiology practice that
both scenarios are plausible. I have seen cases that
support the first theory and other that support
the second. Regardless of the etiology, it is clear
that these structures are very much related to one
another, and to avoid the risk of relapse, the orthodontist
must develop an understanding of how this
Figure 2. TMJ cross sections of cone-beam computed tomography data show the bilateral reduction of condylar
height with flattening, sclerosism and anterior osteophyte formation, suggestive of end-stage degenerative
joint disease/idiopathic condylar resorption.
54
PCSO Bulletin Spring 2023
Pacific Coast Society of Orthodontists Bulletin Spring 2023
Table of Contents for the Digital Edition of Pacific Coast Society of Orthodontists Bulletin Spring 2023
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 1
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 2
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 3
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 4
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 5
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 6
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 7
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 8
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 9
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 10
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 11
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 12
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 13
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 14
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 15
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 16
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 17
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 18
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 19
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 20
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 21
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 22
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 23
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 24
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 25
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 26
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 27
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 28
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 29
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 30
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 31
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Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 34
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 35
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 36
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 37
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 38
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 39
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 40
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 41
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 42
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Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 45
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Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 47
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 48
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 49
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 50
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 51
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 52
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 53
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 54
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 55
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 56
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 57
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 58
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Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 60
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Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 63
Pacific Coast Society of Orthodontists Bulletin Spring 2023 - 64
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