Introduction Anatomy Naso – respiratory function and craniofacial growth Methods of analysis Clinical examination Otorhinolaryngology tests for upper airway Supplementary examinations LC CBCT Airway and skeletal patterns Obstructive Sleep Apnoea Mouth breathing Effect of orthodontics on airway Extraction cases Expansion Mandibular advancement Orthognathic surgery Adenoidectomy or tonsillectomy Role of orthodontist Conclusion

1. - Dr. Miliya Parveen
AIRWAY ANALYSIS AND ITS
RELEVANCE IN ORTHODONTICS

2. CONTENTS
• Introduction
• Anatomy
• Naso – respiratory function and craniofacial
growth
• Methods of analysis
- Clinical examination
- Otorhinolaryngology tests for upper airway
- Supplementary examinations
• LC
• CBCT
• Airway and skeletal patterns
• Obstructive Sleep Apnoea
• Mouth breathing
• Effect of orthodontics on airway
• Extraction cases
• Expansion
• Mandibular advancement
• Orthognathic surgery
• Adenoidectomy or tonsillectomy
• Role of orthodontist
• Conclusion

3. INTRODUCTION
• Upper and lower airway has always been an area of interest because
the oropharyngeal and nasopharyngeal structures play important roles
in the growth and development of the craniofacial complex.
• In particular, upper airway assessment and its interactions with
craniofacial growth and development are studied by ENT specialists,
laryngologists, speech therapists, pediatricians and dentists.
• The airway, mode of breathing, and craniofacial formation are inter-
related during growth and development that form can follow function
and function can follow form .
• So, it is imperative to normalize form and function as early as
possible, so that function is optimized for life.

4. • Airway obstruction impairs respiration which leads to craniofacial
malformation, malocclusion and jaw deformation.
• Research also shows that abnormal craniofacial formation can lead to
airway obstruction, impaired respiration, impaired nasal breathing,
chronic mouth breathing, sleep apnea, sleep disorders and lifelong ill-
health.

5. ANATOMY
• The essential organs of the respiratory
system are the lungs, located on either
side of the thorax, on each side of the
heart, and the great vessels.
• To reach the lungs, atmospheric air
follows the airway, which comprises of
the nasal cavity, the mouth, the pharynx,
larynx, trachea, and bronchi. The upper
airway is formed by the nasal cavity and
the pharynx.

6. A. Nasal cavity
• The normal airway starts, from the functional perspective, in the
nostrils. The nasal cavity includes the nose, the nasal cavities, and
extend to the back with the nasopharynx.
• A deviated septum, a narrow nasal cavity, and turbinate hypertrophy are
some of the signs that cause mouth breathing and OSAS.
• In allergic rhinitis, which is also related to upper airway obstruction, the
nasal mucous membrane swell with dust particles, pollen or even cold,
also affecting the eyes and nose and causing a decrease in air flow

7. B. Oral cavity
• It is an essential organ for mastication, phonation, taste, deglutition and
breathing, formed by the maxillary, palatal and mandible bones, the
tongue, lips and cheeks, and the oropharynx at the back.
• The tongue plays many important function but as its muscle tone
decreases during sleep, the tongue can block the upper airway.
• Jointly with the loss of muscle tone of the pharyngeal walls and the soft
palate, it contributes to the collapse of the airway, one of the main causes
of obstructive sleep apnea syndrome.

8. C. Pharynx
• The pharynx is a tube-like structure formed by muscles and
membranes. It measures approximately 12-14 cm and is divided into
three parts: nasopharynx, oropharynx and laringopharynx.
• The nasopharynx is the upper part of the respiratory system - located
behind the nasal cavity and on the soft palate.
• In the roof sub-mucosa, there is a collection of lymphoid tissue called
pharyngeal tonsil (adenoids) - when large in size, is the main
obstruction to the passage of air through the nasopharynx.

9. • The oropharynx extends from the 2nd to 4th
vertebra and opens into the oral cavity
through an isthmus. The upper end - soft
palate & lower end - lingual side of the
epiglottis.
• The tongue is the main blocking element
in the oropharynx- contraction of the
genioglossus muscle moves the tongue
forward during inspiration, and thereby
acts as a pharyngeal dilator.
• The laringopharynx joins the oropharynx
at the pharyngoepiglottic fold and hyoid
bone, and continues up to the sixth
vertebra. It is behind the opening in the
larynx.

10. NASO – REPIRATORY FUNCTION AND
CRANIOFACIAL GROWTH
• Dentofacial morphology can be altered by naso-respiratory obstruction
depending on the magnitude, duration & time of occurrence.
• Quinn in 1978 reiterated that mouth breathing is one of the early
symptoms of unnatural acts of breathing and that dramatic deformities
of the face, jaws and dentition can be caused by inability to breathe
through the nose properly.

11. • Ricketts in 1979 stated that when there is a lack of function in the
nose, there can be a growth inhibition. Under normal function in
breathing, a pressure develops. In the abnormal, this pressure is
changed to vacuum and the maxillary complex is sucked inward,
restricting the basal cone.

12. • In 1918, Norlund introduced the ‘compression theory’ which stated
that constriction of the maxillary arch is related to the absence of the
lateralizing pressure of the tongue against the palate. In response to
nasal obstruction, the tongue drops and the medializing effects of the
buccal musculature is left unopposed. The effect is further enhanced
by a pressure differential across the hard palate in the absence of
nasal airflow, leading to a narrow, high- arched palate.

13. • Norlund also put forward the ‘theory of inactivity’, according to
which there is reduced growth of the nasal cavity, due to its inactivity,
as suggested by Korner (1891) and Bentzen (1903).
• The air pressure theory described by Kantorowicz (1916) and James
& Hastings (1932) holds that a change to mouth breathing causes the
normal negative pressure in the anteriorly sealed oral cavity to be
lost, and the palate thus is not carried downward with the growth of
the maxillary alveolar process.
• The excavation theory proposed by Bloch (1903) and Michel (1908)
states that an upward stream of oral airflow presses on the palate
leading to higher palatal vault.

14. • Although the literature is replete with statements that airway
impairment alters facial and dental growth, there is substantial
evidence to the contrary.
• Bushey found no relationship between nasal respiration and linear
measurements of the adenoids on lateral skull cephalograms before
and after surgical removal of the tonsils and adenoids.

15. • Kingsley (1989) noted normal craniofacial development in children
with severe nasal obstruction and Whitaker described severe palate
malformations in patients who had undergone adenoidectomy at an
early age.
• More recent findings suggest that nasal-oral breathing per se is not
necessarily harmful to craniofacial growth. However, in instances
where the nasopharyngeal or oropharyngeal airspace is small,
exaggerated postural responses in mouthbreathers may be detrimental
to craniofacial growth.

16. METHODS OF ANALYSIS
Clinical examination
• The general well-being of the child, including growth and development,
must be determined.
• Pertinent past history include birth trauma, early childhood trauma,
previous hospitalizations, medications, and surgical history.
• Physical assessment includes facial morphology, skeletal jaw
relationships, functional assessment of nostrils, the size and function of
the tongue and the anatomy of the soft palate, uvula and tonsils.

17. • Regarding facial morphology, Class II patterns due to mandibular
retrusion have smaller upper airway volumes, which is usually
associated with adenoid hypertrophy with a very short upper lip and a
thick and everted bottom lip.

18. • Swallowing difficulties may be noted.
• Voice quality (degree of nasality) and clarity, daytime
hypersomnolence, and school/behavioral difficulties should be
evaluated.
• Sleep history may often reveal loud irregular snoring, restless sleep,
abnormal sleep position and nocturnal mouth breathing.

19. • Resting mouth position is noted.
• "Adenoid facies" is characterized by an open mouth, dull facial
appearance, and short upper lip. This is nonspecific for chronic nasal
obstruction.
• Other craniofacial anomalies may be associated with these symptoms
including cleft palate, Down syndrome, etc.

20. • Tonsillar hypertrophy, macroglossia and oropharyngeal masses should
be evaluated.
• The nasal cavity was inspected for the presence of secretions, edema
and erythema of the nasal mucosa.
• The ears should be evaluated as otitis media certainly is associated
with nasal obstruction problems.
• Bony nasal anomalies, external masses, pits, etc. should be evaluated.

21. a) Functional assessment of nostrils (Duran V.) :
To do this we observe nostril response to intense inspiration, paying
special attention to the degree of collapse during the maneuver. This is
the classification obtained -
• Value 0: Dilated nostrils both at rest and in deep inspiration
• Value 1: Narrowed nostrils at rest, without functional collapse
• Value 2: Functional partial unilateral collapse
• Value 3: Functional total unilateral or bilateral partial collapse
• Value 4: Functional partial collapse of one nostril and total collapse of
the other one
• Value 5: Total functional collapse in both nostrils

22. b) Intraoral evaluation of tonsils
The tonsils are assessed according to the degree of obstruction of the
oropharynx - a reliable clinical evaluation method.
• Grade 1 - the tonsils are within their cavity
• Grade 2 - do not exceed the midline between the uvula and the anterior
pillar of the soft palate
• Grade 3 - go over the midline between the uvula and the anterior pillar
• Grade 4 - the tonsils are less than 4 mm between them.
Grades 3 or 4 represents a decrease in airway permeability

23. c) Upper airway assessment with the Mallampati score - evaluates the
risk of obstruction of the airway.
• Based on the visual assessment of the oropharyngeal structures, mainly
the distance between the tip of the uvula and the tongue base.
• Class 1 - full visibility of the tonsils, uvula and soft palate
• Class 2 - hard and soft palate, the upper section of the tonsils and uvula
• Class 3 - hard and soft palate, and the base of the uvula
• Class 4 - only the hard palate. Classes 3 and 4 are commonly present in
breathing-related sleep disorders, even after an adenotonsillectomy

24. Most Commonly Used Otorhinolaryngology
Tests For Upper Airway Assessment
a) Rhinomanometry - evaluate nasal obstruction.
• There are different types of rhinomanometry (RMM), active anterior
RMM being the one most frequently used. This evaluates nasal
airflow in inspiration and expiration by detecting potential
obstructions and/or resistance. This can be done with a face mask and
it requires full patient cooperation.
• After placing the mask, airflows are measured with the
rhinomanometer, and the data are analyzed computationally and then
graphs are designed in pressure/volume curves.

25. • The recording is repeated under the effect of a topical vasoconstrictor,
which will differentiate mechanical obstructions (which do not vary
with the vasoconstrictor), vasomotor obstructions (which fully
improve with the vasoconstrictor) and mixed obstructions (which
improve partially with the vasoconstrictor).

26. b) Acoustic rhinometry - study of the geometry of the nasal cavity.
• Based on the analysis of sound reflection and provides a calculation
of cross-sectional areas of the nasal cavity and of certain nasal
volumes.
• Done by generating an audible sound in the nostril with an adapter,
taking care not to deform the nasal vestibule. The sound wave
penetrates the cavities and is reflected on the different nasal structures
or their irregularities.

27. • MCA1 corresponds anatomically to the area at the nasal valve level
which has the greatest resistance in the normal nose. MCA2
corresponds to the area at the level of the head of the inferior
turbinate.
• As in active anterior RMM, the study can be performed before and
after applying a vasoconstrictor for the same purpose and with a
similar interpretation of the results.
• Incident wave signals are measured and
reflected according to time, which makes
it possible to determine the distance, from
the nostril, where there is a change in
acoustic impedance.
• The most interesting data are the
“minimum cross-sectional areas 1 and 2
(MCA1 and MCA2)”.

28. c) C) Nasopharyngolaryngoscopy - evaluates the anatomy of the upper
airway, soft palate, the movement of the vocal cords and the process
of deglutition.
• Performed with a flexible fiberscope which is inserted through the
nasal cavities to observe both pharynx and larynx.
• The patient is usually awake, and topical lidocaine is applied on the
nostrils.

29. • During the test, the patient may be asked to talk, cough or swallow,
depending on what is being evaluated.
• The following anatomical elements should be evaluated:
i. deviations of the nasal septum
ii. size of inferior turbinates
iii. presence and size of the adenoid tissue
iv. quantity and quality of nasal secretion
v. size of palatine tonsils & base of the tongue
vi. its relationship with the oropharyngeal cavity
vii. abduction of the vocal cords
viii. subglottic diameter
ix. presence of masses or pathological deformities at any levels

30. d) Functional Nasal Permeability (PeNaF) - assesses the independent
functional nasal permeability of each cavity.
• The performance is recorded as negative (-) when the patient
maintains nasal breathing for six inspirations at rest, and positive (+)
when the patient fails to maintain it for six inspirations.
• A study validated in Chile recommends orthodontists implement this
simple examination to rule out a possible nasal obstruction. If this is
not the case, they should request an objective assessment to check the
increase in nasal resistance

31. e) SNORT - Simultaneous Nasal Oral Respirometric Technique by
Gurley and Vig reported a enabled the direct and simultaneous
measurement of inspired and expired air, both orally and nasally.
• Using a custom fitted face mask with separate valves attached to the
nose and mouth and attached to a flow meter, air pressure transducer,
recorder and computer, it can give the nasal versus the oral
inspiration, expiration and their ratios.
• SNORT permits the objective quantification of the ratio of oral to
nasal airflow and permits a numerical determination of both normal
and pathological states of breathing mode.

32. Supplementary Examinations
a) Upper airway assessment in lateral cephalograms
• Lateral cephalometry is commonly used in clinical practice given its
relative simplicity, accessibility, low cost and low exposure to
radiation.
• Lateral cephalograms provide reliable linear measurements, can
measure the dimensions of the nasopharyngeal and retropalatal
regions, but have not proven to be reliable to measure the airway in
the back of the tongue.
• Though multiple authors have tried to standardize a method of airway
analysis on lateral cephalogram, very few methods have been widely
accepted.

33. McNamara’s Analysis (1984) –
• Two measurements are used to examine the possibility of an airway
impairment.
• The upper pharyngeal width is measured from a point on the posterior
outline of the soft palate to the closest point on the posterior pharyngeal
wall.
• This measurement is taken on the anterior half of the soft palate outline
because the area immediately adjacent to the posterior opening of the
nose is critical in determining upper respiratory patency.

34. • Apparent airway obstruction, as indicated by an opening of 5 mm or
less in the upper pharyngeal measurement - only an indicator of
possible airway impairment.
• The average upper airway measurement for adults of both sexes is
17.4 mm.
• Lower pharyngeal width is measured from the intersection of the
posterior border of the tongue and the inferior border of the mandible
to the closest point on the posterior pharyngeal wall.
• The average value for this measurement is 10 to 12 mm and does not
change appreciably with age.
• In contrast to the upper pharynx, a smaller than average value for the
lower pharynx is not remarkable. A lower pharyngeal width of greater
than 15 mm suggests anterior positioning of the tongue, either as a
result of habitual posture or due to an enlargement of the tonsils.

35. Martin’s Analysis (2006) –
The following cephalometric measurements
were made –
1. PNS-AD1: lower airway thickness;
distance between PNS and the nearest
adenoid tissue measured through the PNS-
Ba line (AD1).
2. AD1-Ba: lower adenoid thickness; defined
as the soft-tissue thickness at the posterior
nasopharynx wall through the PNS-Ba line.
3. PNS-Ba: lower airway thickness; distance
between PNS and Ba—the sum of
variables 1 and 2.

36. 4. PNS-AD2: upper airway thickness;
distance between PNS and the nearest
adenoid tissue measured through a
perpendicular line to S-Ba from PNS
(AD2).
5. AD2-H: upper adenoid thickness;
defined as the soft-tissue thickness at the
posterior nasopharynx wall through the
PNS-H line.
● Hormion (H): cephalometric point located
near the adenoidal tissue at cranial base
localized where a perpendicular to S-Ba line
crosses the sphenoid bone. The variations of
this point are minimal because it is located
far from growing sites.

37. 6. PNS-H: upper airway thickness; distance
between PNS and H—the sum of variables
1 and 2.
7. N-H: nasal fossa length; distance between
N and H.
8. S-N: anterior cranial base.
9. McNamara’s upper pharynx dimension
10.McNamara’s lower pharynx dimension

38. 11 and 12. Total adenoidal, and aerial areas: the Ba-N plane, the bispinal
plane, and 2 perpendicular lines to the bispinal plane: 1 that crosses the
more anterior point at atlas vertebra and other that crosses the PNS. The
resulting trapezoid is divided in 2 spaces (aerial and adenoid).

40. Fujioka et al. (1979) - described the adenoidal-nasopharyngeal ratio
(AN ratio).
• Relates the length of the line perpendicular to the sphenoid bone (A)
by the thickest portion of the adenoids with the distance between the
posterior nasal spine and the anterior edge of the sphenobasioccipital
synchondrosis (N).
• An AN< 0.8 is considered normal and an AN > 0.8 is considered
enlarged
• In addition, Feres, Murilo et al. in 2012 found that both parameters
had good reproducibility and a variability which was not clinically
significant.

41. • One of the most common reasons for upper airway obstruction is
hypertrophic adenoids. Before planning an orthodontic treatment, this
area is usually observed in the lateral cephalometry.
• A study was conducted to assess whether adenoidal ratio on lateral
cephalograms can be used to estimate airway volumes, using CBCT
as the validation method. They concluded that the lateral cephalogram
can provide some information about the nasopharyngeal space,
particularly in patients over 15.
• This is due to the stability reached by the tissue at this age; however,
it cannot be used as a diagnostic procedure to determine the volume
of the total airway, but rather as an assessment tool to determine the
need for a more comprehensive ENT examination.

42. b) Upper airway assessment using CBCT
• Several studies have shown that CBCT is accurate and reliable for
upper airway assessment.
• Volumetric reconstructions that may be obtained from CBCTs help
clinicians make a correct diagnosis and indicate a better treatment
plan for some pathologies of the maxillofacial area, especially those
related to the airway.

43. • For the volumetric reconstruction and visualization of the upper
airway, software programs must allow us to find the correct location
of the boundaries of the pharynx and nasal cavity (segmentation)
through a process that can be manual, automatic or semi-automatic.
• Studies comparing the commercial software programs for the study of
the airway were analyzed. They were found to have reliable
reproducible and accurate results of linear measurements, but they
lost accuracy when calculating the volume of the airway. This could
be due to the automatic segmentation of the nasal cavity, the
nasopharynx and oropharynx.

44. • The head position and the position of the patient when the CBCT is
taken must be considered to obtain accurate and repeatable upper
airway measurements and volumes.
• The position of the hyoid bone and tongue, and the dimension of the
airway would be highly reproducible using the natural position of the
head when taking lateral cephalograms.
• It has been found that individuals would be approximately 40% more
affected by the width of the airway in an upright position.
• Solow et al. determined that in an upright position or by increasing
the cervical skull angle, there is an increase in upper airway
diameters.
• Alsufyani et al. states that images must be obtained with the patient in
a sitting position so as not to affect airway diameter.

45. • Aboudara et al. stated that CBCT is a simple and effective method to
evaluate upper airway. They compared the volumetric measurements
from CBCT with known physical airway phantoms and found that the
errors ranged from 0 to 5%. They also reported a moderately high
correlation (r = 0.75) between the sagittal area and the volume when
correlating lateral cephalograms measurements with CBCT data.

46. • Two systematic literature reviews concluded that although major
progress has been made in the capture and management of CBCT
images, there is no optimized evidence-based protocol to obtain
images to analyze the upper airway.
• Several obstacles must still be overcome, such as the influence of the
position of the tongue, mandible morphology, the impact of the
respiratory phase and the definition of the anatomical boundaries of
the upper airway, as well as the lack of consistency in the
configuration of the equipment and in how images and volumetric
reconstructions are obtained.

47. AIRWAY AND SKELETAL PATTERNS
• A study conducted in New Delhi compared the reliability of lateral
cephalograms and computed tomographies to assess airways. They
compared three skeletal patterns determined by the different values of
the ANB angle, and related their linear values taken from the
cephalometries to volumetric values delivered by CT, and concluded
that the skeletal pattern had a strong association with pharyngeal
volume and its linear dimensions. They also noted that the S-shaped
soft palate can be considered high-risk for sleep apnea compared to
the leaf shape, which is more common.

48. • In contrast, Dalmau et al., found no statistically significant
differences that correlate airway with skeletal patterns or facial
biotypes.
• The recent results of Lucas Castro-Silva et al., in Brazil, found a
positive correlation of higher values of pharyngeal airway for Class
III patients.

49. • A new study by El and Palomo found that oropharyngeal airway
volumes were lower in Class II patients compared to Class I and
Class III patients. They also state that the mandibular position with
respect to the skull base has a strong impact on oropharyngeal
volume.

50. OBSTRUCTIVE SLEEP APNEA
• Definition: condition caused either by complete occlusion or partial
collapse of the upper airway despite the presence of simultaneous
respiratory effort. Cessation occurs at the level of nostrils and mouth.
• Condition is considered pathologic when the episodes last for at least
ten seconds and at a frequency of 30 times or more during 7 hrs. of
nocturnal sleep in REM and especially in non REM stages of sleep.

51. • Diagnosis is by polysomnography - Measurements are made to assess
sleep stages of breathing and gas exchange to detect sleep stages.
PSG ensures the no. of apnic episodes per hour of sleep expressed by
respiratory(Disturbance Index)measurements of chest and abdominal
efforts and oxygen saturation.
• Airway measurement by cephalometric 3D imaging – lateral
pharyngeal dimension.

52. • Treatment Options -
− Enlarging the upper airway
− Continuous positive airway pressure
− Weight loss
− Oral appliances - mandibular advancement devices
− Upper airway surgery
− Combination CPAP/ dental sleep device therapy

54. MOUTH BREATHING
• Clinical examination – ask patient to hold water in the mouth, use
double sided mouth mirror or cotton wisps
• Cephalometric Analysis: -
1. McNamara airway analysis –
• Upper pharyngeal width – the point on posterior outline on soft palate
to closest point on pharyngeal wall – 15 to 20 mm in width. Values
2mm or less indicate airway impairment. Lower pharyngeal width
from point of intersection of posterior border of tongue and inferior
border of mandible to the closet point on posterior pharyngeal wall –
11 to 14mm.
2. Vertical growth pattern, increased ANB, increased gonial angle,
decreased mandibular length, steep MP angle, over erupted upper
posterior segments

55. EFFECT OF ORTHODONTICS ON AIRWAY
1. Extraction and airway changes:
• A systematic review on the effects of bicuspid extractions and incisor
retraction on upper airway of Asian adults and late adolescents
showed that Linear airway response to incisor retraction measured on
lateral cephalograms varied substantially, while linear, cross‐sectional
and volumetric measurements of posterior airway space using CT
showed larger effect sizes and smaller variations, providing evidence
of airway narrowing with bicuspid extractions and incisor retraction.

56. • An article published in Orthodontics and craniofacial research journal
on three-dimensional pharyngeal airway changes in orthodontic
patients treated with and without extractions analysed the pharyngeal
airway for subjects treated with extractions and without extractions.
• Nasopharyngeal (NP) and oropharyngeal (OP) volumes, area of
maximum pharyngeal constriction (AMPC), and upper arch perimeter
were measured on CBCT scans.
• There were no statistically significant differences in the pharyngeal
airway values between the extraction and non-extraction groups.
• The extraction group showed a statistically significant increase for NP
and OP volumes and AMPC values. Such increase was also noted in
the non-extraction group, without statistical significance for AMPC
values.

57. • A retrospective study evaluating the airway space changes after
extraction of four second premolars and orthodontic space closure in
adult female patients with bimaxillary protrusion showed orthodontic
treatment increases the vertical airway length, which is the amount of
distance between base of the tongue and posterior nasal spine.
• A study conducted on pharyngeal airway dimensional changes after
premolar extraction in skeletal class II and class III, growing and
adult orthodontic patients showed significant increase in
nasopharyngeal airway dimension in class II and class III patients,
whereas palatopharyngeal and glossopharyngeal dimensions were
insignificantly decreased in both groups.

58. 2. Rapid Maxillary Expansion
• RME is successful in increasing the nasal permeability and reducing
airway resistance.
• Reduced airway resistance reduces negative pressure during
ventilation, with promising results in the treatment of paediatric sleep
disordered breathing, including obstructive sleep apnoea
• The effects on more distant structures include stretching of the tensor
palatine muscles by the expanding maxilla with subsequent
improvement in drainage of the Eustachian tubes, aiding in reducing
otitis media and conductive hearing loss
• Enlarged palatal space may also allow for an improved tongue
posture, which could facilitate increased airway space in the
oropharynx

59. • Donald Timms, in a study with Rapid Maxillary Expansion, reported
a 37 percent mean drop in nasal resistance with 7 mm of expansion.
• In another larger study of children with a previous history respiratory
disease treated with Rapid Maxillary Expansion, 82 percent reported
improvement in number of upper respiratory tract infections and 60
percent reported improvement of allergic rhinitis.

60. • According to Bishara and Staley -
Anatomically, there is an increase in the
width of the nasal cavity immediately
following expansion, particularly at the
floor of the nose adjacent to the
midpalatal suture. As the maxillae
separate, the outer walls of the nasal
cavity move laterally. The total effect is
an increase in the intranasal capacity. The
nasal cavity width gain averages 1.9 mm
but can widen as much as 8 to 10 mm at
the level of the inferior turbinates, while
the more superior areas might move
medially.

61. • A number of rhinologists indicate that RME, in addition to its
widening procedure, results in correction of septal deformity as a
result of the lowering of the floor of the nasal cavity.
• Hershey, Stewart, and Warren, and Turbyfill reported a reduction of
nasal airway resistance by an average of 45% to 53% with RME.
• Wertz concluded that opening the midpalatal suture for the purpose of
increasing nasal permeability cannot be justified unless the
obstruction is shown to be in the lower anterior portion of the nasal
cavity and accompanied by a relative maxillary arch width deficiency.

62. • Graber believes that the claims of improved nasal breathing
apparently as a result of RME are most likely only temporary.
Spontaneous regression of lymphoid tissues during growth
automatically improves nasal breathing, even if nothing is done to the
palate.
• Therefore, it can be concluded that the effect of RME on the nasal
airway will to a great extent depend on the cause, location, and the
severity of the nasal obstruction

63. 3. Mandibular advancement
• Mandibular repositioning is most effective in mild to moderate
obstructive sleep apnea.
• It enhances retro pharyngeal air space thereby increasing nasal airway
patency.
1. Mandibular repositioners - open the airway by moving the mandible
forward.
As the jaw is moved forward, the collapsible part of your airway is held
open by the forward movement of the tongue and other airway muscles.

64. • 2. Mandibular Advancement Devices (MADs) also improve the
strength and rigidity of the airway by increasing the muscle activity
of the tongue and other muscles of the airway.
3. Elastic Mandibular Advancement (EMA ) Appliance

65. 4. Tongue retaining devices (with airway tubes)
• Like MADs, Tongue Retaining Devices (TRDs) also work by holding the
tongue in a forward position.
• These devices pull the tongue forward, but instead of moving the jaw
forward like a Mandibular Advancement Device (MAD), TRDs directly
control the tongue itself.
• In some cases, Tongue Retaining Devices (TRDs) have decreased
therapeutic complications compared to MADs, but TRDs can also be less
comfortable and generally take several weeks or months to be worn
comfortably.

66. EFFECT OF ORTHOGNATHIC SURGERY ON
AIRWAY
• If the difference between the maxillary and the mandibular unit length
is greater than 16mm at the age of 12 in class II malocclusion and
greater than 29mm at the age of 12 in class III dysplasias, surgical
intervention is necessary.
• Surgical superior impaction of the maxilla has become an accepted
treatment for the correction of vertical maxillary excess and it does
reduce nasal resistance, but it does not increase the percentage of
nasal airflow.
• It has been speculated that this change may be associated with the
common postoperative increase in interalar width and widening of the
external nares, which result in an opening of the liminal valve.

67. • At the present time,
maxillomandibular advancement
(MMA) remains the most
effective surgical procedure in
treating patients with moderate
to severe OSA.
• Advancement of maxillofacial
skeletal structures opens the
oropharyngeal airway and places
the oropharyngeal musculature
on tension.
• MMA surgery results in a significant increase in the volume and a
morphologic airway change from a round to an elliptical f shape in the
upper airway space in patients with OSA.
• These changes are stated to reduce the collapsibility of the upper airway
during deep stages of sleep.

70. ROLE OF ORTHODONTIST
• In 1987, Weimert published a study of 1360 patients referred to
otolaryngologists by orthodontists because of suspicion of nasal
obstruction. Although it was not a solid scientific study, the findings
suggest that orthodontists can effectively screen for nasal obstruction.
• The most common reasons for referral were: dentofacial characteristics
suggestive of upper airway obstruction, inability to retain a dental
appliance, and unsatisfactory results from an orthodontic program.
• Dentists are important as both referrers and treating doctors.
• Allergies generally must be treated first, before consideration of any
surgery. The greatest number of surgical failures are in allergic patients.
• The greatest number of orthodontic relapses are in patients who have not
had their breathing problems successfully treated.

71. • Orthodontic therapy is affected by the function of the lips, tongue,
and masticatory musculature, all of which may accommodate to nasal
obstruction in ways which can effect occlusion.
• Effective orthodontic therapy may require the elimination of the nasal
obstruction to allow for normalization of the facial musculature
surrounding the dentition.
• According to Meredith, the growth of the face (excluding the
mandible) is completed at a relatively early age. 60% of craniofacial
development takes place during the first 4 years of life and 90% by
age 12. Based on these observations, any intervention to open the
airway must take place at an early age.
• As a referring doctor, one has to decide between allergist, ENT,
pediatrician or sleep lab.

74. CONCLUSION
• In spite of the long history of research between respiration and
malocclusion, only now is this aspect of diagnosis and treatment
given its due importance.
• Evaluation of children with nasal obstruction and dental abnormalities
requires a multidisciplinary approach between the orthodontists,
pediatricians, and otolaryngologists.
• The orthodontists must be familiar with the dental literature so as to
provide optimal care for pediatric patients as they have an opportunity
to examine and institute treatment to the patients at a very early age.

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