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Normal upper airway anatomy
Etiology & pathogenesis
Sleep Apnea (OSA) was first
described by Charles Dickens in The
Pickwick papers in 1836
1906 William Osler said “ an
extraordinary phenomenon in excessively
fat young persons with an uncontrolled
tendency to sleep
1950’s the research in sleep disorders gained
momentum after the works of Aserinsky,
Klutman and Demat who also termed the REM
and non – REM sleep
1956 Burwell first described the features of
Obesity, hypersomnolesence, decreased
alveolar ventilation and cor pulmonale, now
termed OSA, termed it as Pickwickan syndrome
1980’s research showed high incidence of
mortality and also oral appliances came into
sleep apnea syndrome-
by constellation of s/s related
to arterial oxygen desaturation & sleep
fragmentation caused by pharyngeal
obstruction during sleep.
Potentially life threatening condition
Periodic cessation of breathing during sleep
inspite of inspiratory effort.
was 1st described by Gastaut- disorder
associated with repetitive cessation of
breathing during sleep.
Sleep apnea defined as 30 or more apneic
episodes (cessation of airflow for more
than 10 sec) occurring during 7hrs of
Most common is obstructive type.
cranio-facial & soft tissue
Non-invasive modes of therapy i.e dental
appliances used in treatment of syndrome.
produced by vibration of soft
palate or oropharyngeal tissues.
Various factors related Sleep
related loss of m. tone
Certain medical condition
5 to 15 involuntary sleep episodes
occurring during activities that require little
Moderate: 15 to 30 sleep episodes during
activities that require some attention
Severe: > than 30 episodes of sleep during
conversation, walking, eating
Epidemiology of obstructive apnea syndrome
Namara found 1-9% prevalence of
Recent study by Young et al suggested
prevalence of OSAS to be at least 9% in
males & 4% in females
Lugaresi reported incidence of snoring to be
19% in adult population & increased
significantly with age
Katsantonics reported snoring 53% in men,
38% in women.
Normal upper airway anatomy
extends from external nares to
posterior nasal apertures & subdivided into
by nasal septum.
Nasal septum osteocartilagenous
plate of ethmoid
Nasal spine of frontal
Rostrum of sphenoid
Nasal crests of palatine bone
Septal process of interior nasal cartilage
part- fibro fatty tissue
covered with skin lower margin of
septum called columella.
Frontal process of maxilla
3-4 cartilages of ala
Labyrinth of Ethmoid
(superior & middle concha)
Inferior nasal concha
Perpendicular plate of palatine
Medial pterygoid plated
Decreased nasal patency may contribute to OSAS
in many ways
Nasal obstruction with closed mouth may result in
obstructed airway, resulting in arousal.
Nasal congestion may induce mouth breathing which in
turn leads to posterior positioning of mandible causing
hypo pharyngeal narrowing.
With nasal congestion there is large inspiratory pressure
drop across nose leading to sub-atmospheric pressure
within potentially collapsible pharynx.
muscular fold suspended from
posterior aspect of hard palate. Separates
nasopharynx from oro-pharynx.
soft palate- Might be contributing
factor in OSAS
posterior aspect of nasal
turbinates to soft palate
Oro-pharynx- from soft palate to base of
Laryngopharynx- from base of tongue to
Muscles of pharynx
patency can be
compromised by Local
Scarring secondary to surgery
Under development of local bony
Palatal uvular hypertrophy or edema
patency can be
compromised by Palatine
tonsil hypertrophy or
Palatal or uvular enlargements
pharyngeal patency can be
& superior displacements of hyoid
gland situated at floor of
circular bone found in midline
b/w mandible & thyroid cartilage.
Etiology & pathophysiology of OSAS
factors still debated
Syndrome can be Central
prevented by action of
pharyngeal dilator & abductor
muscles- sleep reduces activityairway resistance increases.
largest & best studied
upper airway m. Conditions that retract
mandible lead to posterior movement
of tongue & narrowing of airway- can
be overcome by moving jaw forward.
b/w pharyngeal musculature
& negative intrapharyngeal pressure of
inspiration determines patency of
upper airway. Structural narrowing of
airway- hinders muscular component
of balance even at rest.
pts with OSAS have narrowed
airway- confirmed by CT scan.
in facial morphology may also
be responsible for airway abnormality as
pharyngeal musculature intimately related
to bony structure. Eg- positive correlation
b/w OSAS & short or posteriorly displaced
mandible in many pts.
of obstruction in OSAS pts seen in
oropharynx & associated with large tongue
volumes & also mainly in obese persons
(excess peripharyngeal & subcutaneous fat)
with their jaws open- passive or active
jaw opening- triggers afferents in TMJreflexly inhibit Genioglossus m.
aberration of pharyngeal airway
&/or neurogenic failure to preserve patency
of pharyngeal airway- 2 most common
Many hereditary or acquired variables have also
been described that precipitate OSASAdenoid & tonsillar hypertrophy in children & adults
Vocal cord paralysis
Lymphoma or hodgkins ds
Upper airway radiation edema or fibrosis
Correlation of velopharyngeal incompetence in
Physiologic abnormalities predisposing to OSASPoliomyelitis, muscular dystrophies, amyotrophic
lateral sclerosis & other ds with bulbar incordination
sec. to brain stem abnormalities.
Flurazepam & other sedative hypnotic agents
Mouth breathing and OSA
tongue is no more in contact with the
anterior palate hence producing a dorsal motion
of the belly of the genioglossus that falls back
into the pharynx.
the axis of action of the genioglossus
hence decreasing the efficiency of pulling the
genioglossus out of the airway.
the pressure is now exerted across the
palate hence further narrowing the soft palate.
of the mouth by 1.5cm pushes back the
gonial angle by 1cm, which decreases the
distance between the ventral attachment of the
genioglossus and the posterior pharyngeal wall
hence decreasing the lumen by 1cm
in nasal airflow decreases the
neuroregulatory mechanism of respiration
-bringing about depression of respiration predisposing to apnea
Clinical & demographic features of OSAS
Diurnal symptom- excessive day-time sleepiness
symptoms of sleep deprivation-
Impaired concentration & impotence
spectrum of sleep apneaHeavy habitual snoring
Excessive day-time sleepiness
Short term memory deficits
Abnormal motor behavior
Other features includes
Nocturnal choking & coughing
Right sided heart failure
Systemic arterial hypertension
Short thick neck
Diagnostic Aids in OSA
Diagnostic aids in OSAS
4-5 loud snores followed by silence,
followed again by series of loud snores
Excessive day-time sleepiness
examinationExamination of the entire upper
: nasal valve examination, alar collapse
Nasal speculum examination for mucosa
changes, turbinates, DNS, pathology like
cysts and polyps.
cavity and the oropharynx:
: size , shape and the position.
High arched palate
Relation of tongue to oropharynx
presence of disproportionate anatomy:
soft palate, uvula, base of the tongue, and
retrognathic mandible and maxilla
hypo pharynx and larynx for presence
of tumors, large epiglottal folds, lingual tonsils,
vocal cords usually done with fibroptic
is best done at night with atleast 4hrs of
sleep time recorded. Most sleep studies
are conducted for atleast 2 consecutive
sleep apnea includes oxygen
saturations level below 60%, an apneic
index greater than 50, prolonged apnea
lasting more than 45 sec. & concurrent
or thoracic strain gauges
provide movement tracings during
When there is simultaneous pause of
airflow & thoracic or abdominal movement,
a central type of apnea has occurred.
airflow ceases but respiratory effort
continues, obstructive type of apnea.
then scrutinized. Duration & total no.
of apnoeic periods, oxygen saturation,
time during which oxygen saturation level
below 90%, no. of arousals, quantity of
REM sleep seen.
Obstructive apnea- upper airway obstruction causes
cessation of airflow with concomitant continuation of
thoracic breathing movements.
Central apnea- simultaneous cessation of both airflow &
thoracic breathing movements.
Mixed apnea- episodes of central apnea lasts 10 sec or
longer followed by obstructive apnea.
Apnea – cessation of airflow for more than 10 sec.
Hypoapnea – reduction in tidal volume accompanied by
fall in blood oxygen saturation, lasting more than 10 sec.
To diagnose OSA
or more apnoeic episodes within a course of
7hrs of sleep, resulting in excessive sleepiness
during waking hrs.
episodes of apnea or hypo apnea must occur
make diagnosis & access severity of ds
determine need & urgency of treatment.
Epworth sleepiness scale
questionnaire designed to assess how likely
person would doze off in 8 specific situations Sitting
As a passenger sitting in car for an hr
Sitting inactive in public place
Lying down to rest in afternoon
Sitting & talking to someone
Sitting quietly after lunch, without having consumed
As a driver of a car, stopped for a few min in traffic.
– no chance
1 – low likelihood
2 – moderately possible
3 – high chance
score above 12 indicates subject is
more sleepy than normal individual.
invasive scanning technique
Confines radiation to plane of interest
Permits visualization of small variations in
3 dimensional description of airway, tongue &
other associated structures.
But it is time consuming procedure &
Study in AJO 1986
et al- large tongue , soft palate &
reduced airway volumes. Majority of
constriction occurred in oropharynx
Hapnik et al- reduced cross sectional areas of
nasopharynx, oropharynx & hypopharynx.
Subjects with severe OSA- larger tongue &
smaller airway surface volume.
More obese subjects- large tongue surface
areas & smaller airway surface areas.
high resolution images without use of
ionizing radiation & yields both transverse & sagittal
sections of pharynx.
Ideally suited in assessing conditions with increased
tissue water content.
Horner et al – used MRI to assess upper airway in
obese pts showed an excess on fat deposition in soft
palate, tongue & surrounding collapsible segment of
value in location site of obstruction in
Particular emphasis is on the base of tongue,
its position & its forward movement on
protrusion pf jaws.
m. activity in OSA
Timing relationship b/w genioglossus
inspiratory effort is of physiologic importance
in pathogenesis in OSA
et al showed following hard & soft tissue
morphological characteristics in pts. with OSA Hard tissue featuresSmall mandible which is retropositioned
Increase in anterior facial ht
Enlarged occlusal & mandibular plane angle
Over erupted maxillary & mandibular molars
Steep occlusal plane
Posteriorly positioned maxillae & mandible
Inferior position of hyoid bone
tongue, soft palate & pharyngeal lt
Thickened soft palate
Decreased A-P pharyngeal space at superior,
middle & inferior levels
Enlarged cross-sectional areas of tongue &
Decreased cross-sectional areas of
oropharynx & hypopharynx
and Kronstad also documented similar
craniofacial features. Also noticed that in all their
patients the hyoid bone was inferiorly positioned
(usually at junction of C3 and C4) had shifted
much lower to C4, C5, C6 suggesting it could
be pushed down by the tongue.
deposits of submental and
Study in angle 1996
available easily performed, no radiation,
performed sitting or supine, Muller’s maneuver can
be performed possibility of predicting the outcome
of UPPP depending on the site of obstruction
Invasive and requires nasal anesthesia, evaluate
only the airway lumen and not surrounding soft
tissue and patient is usually awake.
Management of OSA
etiology not precisely understood so
diversity of treatment options.
Treatment of OSA depend on –
Magnitude of clinical complications
Etiology of upper airway obstruction
accepted options as outlined by
J.M Battagel Wt
Elimination of aggravating factors
ENT assessment plus any necessary
Elimination of aggravating factors
obstructive airway ds
such medical conditions that may 1 st
loss in wt. can result in
significant decrease in apneic episodes in
obese pts suffering from OSA.
Recommended as 1st form of therapy in
mild to moderate cases.
suggested that change in sleep
posture from supine posture to a lateral
decubital position can reduce tendency for
In supine position especially during REM
sleep, gravity & reduced tone of
genioglossus m. increase the possibility of
has been used in an effort
to diminish obstructive apneas during
sleep by acting as respiratory stimulant to
airway, diaphragm & intercostals.
beyond clinical obstruction site can
have positive effect in OSA pts.
Continuous positive airway pressure (CPAP)
by Collin Sullivan in Sydney
Continuous stream of air under pressure is
filtered & delivered to pharynx via a nasal mask.
Act as pneumatic splint.
This constant flow enough to prevent airway
from collapsing but yet not enough to prevent
periodic expiration. So to be secured firmly in
Should be worn 6hrs at night, 7 days a week.
common & successful treatment for OSA
Subject no longer dozes off
Sleeps well & feel less irritable
by Clark et al found 10-20% of subjects found
it extremely uncomfortable & discontinued it.
Overall long term compliance with this device60-70%
Quite well tolerated by pt.
tongue in a more forward
Reposition mandible forward (nocturnal
airway potency appliance NAPA, snore
guard, herbst, mandibular positioner)
To lift soft palate or reposition the uvula
Approach to patient
Evaluate for periodontal health, dental restorations,
occlusion, TMJ function, mandibular movement and
craniofacial skeletal type
Enough teeth must be present – at least 6 teeth in each
arch and one good posterior teeth in each quadrant.
patient should be able to protrude the mandible at least 5
mm without discomfort
A patient with deep palate, long soft palate and steep
mandibular plane may not be a good candidate, though
there is no set criteria.
After insertion and final adjustment a PSG must be done
to evaluate the efficiency and a base line Ceph, must
have been obtained.
32 commercial appliances
advancement devices (MAD) and
Tongue repositioning devices.
by Cartwright & Samelson in
To keep tongue in forward position- places
it into cup or bubble positioned in the
anterior region with surface adhesion
holding tongue in position.
Jaws to be kept in partly open position.
not always held in forward
position- surface adhesion lost
Forces nasal breathing- may be
troublesome in some pts.
Tongue may get irritated becoz of lack of
be used in edentulous patients,
Will not loosen restoration as they do not
Minimal or no adjustment and no sensitivity to
Offset fluctuation of the genioglossus muscle.
et al 1996- TRD most
successful in pts who are less than 50%
above ideal wt & in whom OSA is worse
when they sleep in supine position.
Clark et al 1989- TRD effective in 75% of
mild to moderate cases compared to
CPAP, more easily tolerated.
TRD & genioglossus m. activity
et al 1982- altered
genioglossus m. activity significantly
improved with TRD.
Ono et al 19962
tongue retaining devices made for each
subjects- TRD A & TRD B
TRD A- no anterior bulb
TRD B- has bulb
TRD A & B- reduced apnea-hypoapnea
index (AH index)
TRD A- activation of genioglossus m. activity by
creating passive jaw opening- TMJ receptors
send information to CNS regarding jaw rotation
which affects tongue protrusion by genioglossus
TRD B- normalized time lag b/w peak inspiratory
genioglossus m. EMG activity & max. inspiratory
effort. Also normalized amplitude of peak
genioglossus m. EMG activity that fluctuated
during AH episodes while used TRD A.
tongue position with TRD
alleviates narrowing of upper airway that
produces more positive pressure during
inspiration. OSA pts otherwise will suffer
from scarcity of negative pressure-driven
reflex during sleep.
Anterior mandibular positioning devices
2 consistent features Moves
mandible forward several mms
Maintains jaw in forward position even though
pt is asleep
be 1 piece appliance or 2 piece
appliance with tube & rod attachment
2 piece appliance
constant forward position of tongue
Can be designed to allow continued oral breathing
More esthetically pleasing
effect such as TMJ remodeling &
Occlusal change- proclination or crowding of lower
Nocturnal airway patency appliance
by George 1987
Designed to keep airway open during
sleep by Posturing
tongue more anteriorly
Inhibiting wide jaw opening
Assuring adequate air intake through mouth
whenever nasal obstruction occurs.
Snoring decreased or completely
Daytime somnolence diminished markedly.
Does produce some discomfort at night but
pts get used to it.
Mandibular advancement splints
Like CPAP, mandibular advancement splints are a nonInvasive and therefore reversible form of treatment, and
are worn only during sleep.
Many designs have been described, but essentially
these resemble a functional appliance: full coverage
upper and lower splints are constructed to a protrusive
To be effective, the appliance must have good retention
to both upper and lower teeth, sufficient protrusion to
prevent pharyngeal collapse in the supine position and
as little vertical opening as possible.
An anterior space between upper and lower segments of
the splint is helpful for those who are mouth breathers.
per cent of maximal protrusion has
Furthermore, the amount of protrusion must be
tolerated by the individual. Since tolerance
increases with time, splints which are capable of
incremental advancement would seem to have
Suitable designs include cribbed activator,
vacuum formed devices & removable herbst.
attractive force b/w magnets was
Intermagnetic distance 0.6-1mm, which
reduce force magnitude for mandibular
advancement to 5-6.5N.
Clasps for additional retention provided.
It is seen decrease in day time sleepiness
& nocturnal snoring. Blood saturation level
improved in some pts. No effect on TMJ.
To Marklund et al therapeutic efficacy
of activator is optimal when pts had A-H
index less than 10 events/hr.
Results showed- respiratory parameters
significantly improved, decrease snoring &
day time sleepiness. A-H index increased.
by Emil Herbst in 1905 &
reintroduced in 1970’s by Hans Pancherz.
et al in 1993 evaluated the effect of herbst
type of anterior mandibular positioning device in
24 OSA pts. Results were satisfactory & follow
up investigation 3 yrs later showed appliance to
have been used successfully & continually used
in 52% of the sample.
remodeling & dysfunction
Occlusal changes like lower incisor crowding
If not protruded by 75% it did not work.
of vinyl and repositions the
mandible in a “neuromuscular balanced
position” determined by “myomonitor
(TENS)”, incorporating “equalizing tubes”
which are believed to “decrease the
negative pressure in oropharynx” during
70 – 75% of maximum forward
positioning of the mandible
Kept so for a week and if symptoms do not
subside then further advancement at a
rate of .25mm per week till symptoms
subside or TMJ limitations start to show
Recalls at every 2 weeks; 1 month; 6
of the posterior teeth
Forward movement of the lower teeth
Feeling of fullness
TMJ sensitivity and sensitivity of teeth
Shows good prognosis in mild to moderate cases.
Many showed immediate symptomatic
Base of the tongue was advanced and dorsal
surface appeared more superior
Hyoid bone positioned anteriorly and cross section
of oropharynx increased from 41.6 mm to 92.3
Airway volume increased by 27.6% and tongue
volume decreased by 17.6% due to the forward
and superior tongue posture.
& Nakano 1989 described 2 devices
to have an effect at reducing snoringLabial shieldPrevent mouth breathing & forces nasal
Maintains patency b/w soft palate & pharynx
Palatal liftStop soft palate vibration so reduces snoring.
Surgical management of OSA
surgical techniques used-
Osteomy (anterior sagittal) with hyoid myotomy &
Maxillary, mandibular & hyoid advancement.
Radiofrequency volumetric shrinkage of soft palate &
Tongue base suspension sutures
reported as treatment of OSA in 1969 by
Guilleminault et al.
sleepiness with severe familial & socioeconomic impact
Severe cardiac arrhythmias with sleep apnea.
A high apneic index (>60)
Notable oxygen desaturation level during sleep i.e
No improvement of clinical symptoms or
polysomnographic findings after medical trials.
may result in sec. local & general
acute & subacute complications.
But on long term basis pts were completely
relieved of clinical symptoms.
by Ikematsu in 1964 & introduced by
Fujita et al in 1981.
Resect posterior margin of the soft palate &
redundant lateral pharyngeal wall mucosa.
Soft palate resection ranges from 8-15mm
stopping short of thick muscular part of the
Lateral pharyngeal wall treated by resecting
redundant mucosa & developing a flap along the
is advanced & sutured to anterior tonsillar
When sites of obstruction included excessive
pharyngeal tissues combined with low-arched
palates response rate is increased.
Complications of UPPP Pharyngeal
Loss of taste
laser assisted uvulo
dioxide laser at 20 watts (continuous
Reports success rates comparable or better
than convectional UPPP.
Inferior sagittal osteotomy of the mandible with
hyoid myotomy & suspension
reported by Riley et al 1984
He treated 55 pts 67%
33% non responders
Supra hyoid myotomy: to elevate the redundant lateral
pharyngeal tissues sometimes accomplished with
Maxillary, mandibular & hyoid advancement
I osteotomy & sagittal split osteotomy
Gives more predictable results
Best alternative to Tracheostomy.
with normal skeletal development & severe OSA
Morbidly obese pts
Severe skeletal deficiency
Other modes of treatment failed.
prevalence of OSA has only been recently
appreciated in part becoz s/s of chronic sleep
disruption are often overlooked inspite of
Challenge to clinician is to routinely consider the
diagnosis & to incorporate several basic
questions in the historical review of symptoms
regarding daytime or inappropriate sleepiness.
s/b aware of the role of
orthodontists in prevention & treatment of
sleep disorders by various orthodontic
Team approach for management of such
pts with OSA currently includes support of
pulmonologist, neurologist, sleep lab
technician, oral surgeon &
recently consistent use of ceph
analysis has been recommended to aid in
diagnosis & treatment planning for OSA
This coupled with new & promising
treatment alternative of the orthodontic
appliances, would suggest that the
orthodontist could contribute to team
management of these pts.
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