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Oral Appliance Therapy
193
13
city of 93% [22]. The predicted degree of mandibular
advancement was effective in 86% of the cases according
to a later prospective test in a new sample [22]. Another
study described a novel auto- adjusting OAM, which
could be used for predictions as well as to continuously
optimize jaw positioning in order to secure an effective
apnea reduction [23]. These two new methods will be of
great help to nd the responders to OAM treatment as
well as reduce the time and costs for titration of mandibular positioning, provided that the equipment becomes
clinically available and has a reasonable price.
13.7.4 Pharyngeal Anatomy andPhysiology
Treatment success with OAM is more likely in patients
who have a veried widening of the upper airway during a manipulated mandibular advancement procedure
[76]. Drug-induced sleep endoscopy (DISE) can be used
to visualize such effects. In one study, a simulation bite
in a maximal comfortable advanced mandibular position
was used [77]. One hundred and thirty-ve patients with a
mean AHI of 21 who were referred for OA
therapy were
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studied. Those who had complete resolution of pharyngeal obstruction with the simulation bite were more likely
to get treatment success with OAM with an odds ratio of 5,
compared with patients who only had partial or no effect
on their pharyngeal collapse with this bite registration. In
another study using DISE, 28 patients with mild to moderate OSA were studied [78]. The anesthesiologist moved
the mandible 4–5mm forward and observed the effects on
snoring and apneas. Prediction was based on observations
that the obstructive events were less frequent or were eliminated together with an improved upper airway patency
of at least 50% at one or more sites during 3minutes. This
method predicted success in 71% of the patients, dened
as an AHI<5 or an AHI reduction of ≥50%.
Endoscopy during wakefulness has also been used to
test if the pharyngeal response to mandibular advancement could be used for prediction purposes [12, 79]. A
study, including 36 severe OSA patients, reports that
patients with a veried widening at the velopharyngeal
level in supine position predicted success with OAM, irrespective if the expansion of the airway occurred in the
antero-posterior direction or the lateral direction [12].
These ndings were later conrmed in a larger sample of
61 patients with moderate to severe OSA, where a widening at the velopharyngeal level was an independent
predictor of success together with a low AHI in a model
controlling for age and body mass index (BMI = kg/
2
) [79]. Several criteria for treatment success with OAM
m
were tested, and the ORs varied in between 1.4 and 7.3
for this predictor. A more recent study nds that it is
primarily the effect of OAM on pharyngeal collapsibility,
which may be predicted during awake endoscopy [80].
A new way of analyzing airow curves in order to
localize the site of collapse into tongue-related, isolated
palatal, lateral walls, or epiglottis has been developed
[81, 82]. This technique can be of help to predict which
patients will respond to OAM therapy, since a tonguerelated collapse has been associated with OAM treatment
success [83–85], and persistent collapse at velopharynx
and epiglottis and deeper events have been related to
failure [86, 87].
13.7.5 Non-anatomical Traits
Patients with milder OSA have less collapsible upper
airways. They might, however, differ in the occurrence
of non-anatomical traits that may cause upper airway
collapse [5, 13]. Such factors can therefore be used to
predict treatment response with OAM therapy. Patients
with less collapsible upper airways and a less sensitive
ventilatory control system are therefore more likely to
benet from OA
therapy [13, 14, 88]. In contrast, those
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with an overly sensitive ventilator control system (high
loop gain) and a low arousal threshold, which are factors that are uninuenced by OAM therapy, are less likely
to be responders.
13.7.6 Disease Severity
Patients with milder OSA are generally considered to
have a greater chance to get a sufcient AHI reduction
with OAM therapy compared with patients with more
severe disease. The success rate is fairly equal between
OA and PAP [3, 42, 46] in these patients with mild
OSA. The exact indications and large night-to-night
variability in AHI represent uncertainties in this group
of patients [89–91]. Patients might have a more severe
disease than the sleep apnea recording indicates and risk
a suboptimal treatment or no treatment.
Some patients with severe OSA can be successfully
treated with OAM [42], but PAP is more effective [3]. OAs
are therefore regarded a second-line treatment in PAPintolerant patients [3, 92].
13.7.7 Supine Dependency
A change from supine to lateral sleep position will result
in markedly improved upper airway dimensions when
the tongue base and the larynx relocate to more favorable positions [93]. The collapsibility of the upper airway
is reduced, and breathing stops occur less frequently in
the lateral sleep position compared with the supine sleep
position [94]. Some patients are highly supine position
dependent [95]. These patients with primarily supine
194
M. Marklund
13
sleep apneas have been found to have more normal
upper airway anatomy, with a wide airway in the lateral
dimension compared with patients with co- existing nonsupine sleep apneas who have lateral pharyngeal narrowing [96]. The position dependency is mainly regulated by
a tendency of the lateral walls to collapse [93], but may
also arise from a posteriorly located tongue [97].
There are several denitions of supine dependency
such as a high AHI supine and normal value nonsupine, a doubled frequency supine versus non-supine
or denitions that are specically designed to be of help
for treatment decisions [98]. Depending on the exact
denition, the prevalence of supine dependency varies
in between 20% and 60% among OSA patients [99].
Supine dependency has been identied as a predictor of success for OAM therapy [100–103] with similar
efcacy as for PAP [102], although the results vary [99,
104]. The conicting results regarding these predictors
of success can be explained by device design. A nonrandomized study report almost four times increased
responder rate controlled for baseline characteristics
with the use of elastic bands in a device that allowed
mouth opening in patients with positional OSA [68].
The efcacy of an OA
that allows mouth opening dur-
M
ing sleep is also lower than that of a xed device [55–58,
62, 64, 67] (. Fig.13.4). In experiments on rabbits, pre-
vention of mouth opening in supine position improves
the effect of mandibular advancement on upper airway
resistance [105]. The xation of the lower jaw to the
upper jaw to guarantee the intended forward repositioning is probably important, particularly in the supine
position in order to optimize the efcacy of the device
[61]. Prediction of the efcacy of devices that allows
mouth opening might therefore be unreliable compared
with prediction of the efcacy of appliances that xate
the lower jaw during sleep.
13.7.8 Anthropometric Variables
fromtheClinical Examinations
Younger and leaner patients or females have been identied to have a higher chance to receive treatment success with OA
with variable strength. Such predictors are generally less
useful in clinical practice, since the majority of OSA
patients are older and men and many are obese [108,
109].
A combination of variables reecting increased oropharyngeal crowding with the use of the Mallampati
score and BMI has been related to a large risk of failure with OA
informed about the risks with weight increase during
OAM treatment, since this might reduce the efcacy of
the device [101]. Weight gain has also been related to
therapy [18, 46, 101, 106, 107], although
M
[110]. Moreover, the patients should be
M
increased severity of obstructive events, which might
further risk the patients’ health [111].
Evaluation of craniofacial morphology in cephalometric measurements has shown that isolated variables
or combinations of such measurements are inconsistent
predictors of treatment success for OAM [112].
Few studies have specically evaluated the inuence
of age on the treatment outcome. This might be particularly important in the large geriatric population. One
retrospective study indicates that elderly people may be
satisfactorily treated with OAM [113], but there is also
some skepticism [114]. Adherence might be low according to one of these studies [114].
Patients who have had a trial with PAP can be assessed
if they are suitable for OAM therapy based on the PAP
pressures required in order to successfully improve their
airway patency. In this way, a low PAP pressure has been
found to predict treatment success with OAM [115–117].
In summary, many different factors will inuence
the chance of treatment success with OA
, where the
M
degree of mandibular advancement of the device and
patient characteristics are important factors. Overnight
titration procedures represent the most promising prediction alternative for the future. A veried widening of
the upper airway dimension can also be used to calculate
the chance of treatment success. In the future, airow
curves might be useful to predict the type of pharyngeal collapse and treatment success. A custom-made,
adjustable OAM that prevents mouth opening is primarily recommended. Prefabricated devices often have poor
retention. More knowledge is needed about predictors
of success and the inuence of OAM design on the outcome on OSA.
13.8 Eects ofOAs onSnoring andthe
Upper Airway Resistance Syndrome
Reduced or eliminated snoring is an important outcome for many patients. Many studies evaluate subjective reports and nd that snoring is reduced by OAM [2,
33, 118]. Objective measurement conrm that snoring is
reduced, but usually not eliminated by OA
few studies that compare device designs have included
measurements of snoring. Two studies report more
snoring with devices that allow mouth opening compared with xed devices [57, 58]. OAM is more effective
in reducing snoring than an intraoral placebo device [24,
29, 33, 34], while PAP is more effective than OAM [39–
41]. Persistent snoring during OA
treatment has been
M
related to insufcient apnea control and poor adherence
to treatment [40, 119].
OAM can also be used in patients who suffer from the
upper airway resistance syndrome, dened by daytime
[29, 34]. A
M
Oral Appliance Therapy
195
13
sleepiness with increased respiratory effort, but without
increased AHI [120]. The respiratory disturbance index,
arousal index, and severity of depression symptoms
decreased and sleep quality improved with OAM in this
group of patients.
In summary, less research exists on treatment effects
of OAs on snoring compared with effects on sleep apneas,
despite that many patients are primarily interested in how
to best eliminate snoring and its negative consequences
on family life [121]. Research about why and how we
sleep together, which is of importance in terms of snoring
treatments, is emerging [122]. The limited research interest in snoring might be explained by difculty measuring
sounds and that this symptom has been less related to
longer term negative health outcomes [108].
13.9 Symptomatic Eects ofOAs
Excessive daytime sleepiness affects a fraction of sleep
apnea patients in the population [108]. Still, sleepiness
is a common reason for many patients to seek treatment
for their snoring problem. Excessive daytime sleepiness is usually assessed by the ESS score where patients
report the likelihood of falling asleep in eight different situations using a scale from 0 to 3 [123]. The total
score varies in between 0 and 24, where a score of more
than 10 is dened as excessive daytime sleepiness. The
degree of excessive daytime sleepiness dened in this
way correlates poorly with AHI [108, 124–126]. A variety of symptoms have been related to OSA according
to the International Classication of Sleep Disorders
(ICSD- 3) [127]. The inclusion of more symptoms than
daytime sleepiness in the sleep apnea diagnosis highly
increases the prevalence of obstructive sleep apnea syndrome [128]. Examples of such symptoms include nonrestorative sleep, fatigue, insomnia symptoms, nightly
choking, as well as concomitant sleep apnea–related diseases such as hypertension and coronary artery disease.
Symptomatic effects of OSA treatments have mostly
focused on daytime sleepiness measured by the ESS
score. In subjects within the mildest spectrum of disease severity, effects from OSA treatments on daytime
sleepiness are uncertain [3, 27, 33, 129, 130]. Patients
often report lower ESS scores with an OA compared
with untreated conditions [2, 3], but some of these can
be explained by placebo effects [24, 28, 29, 33, 36]. Only
one cross-over study [29] of nine randomized controlled
trials found a signicant difference in the ESS score
between OA
and a placebo device [24, 26–28, 30, 31,
M
33, 36]. None of the six parallel RCT studies reported
a signicantly lower ESS score with OA
compared
M
with a placebo device [24, 26, 28, 30, 33, 36]. Milder
OSA patients, that is, those with primarily indications
for OAM therapy were included in two of these studies
with no effect on the ESS score compared with placebo devices [27, 33]. One of these two studies found
no effect on prospective reports of daytime sleepiness
measured by the Karolinska Sleepiness Scale, objective
tests of sleepiness by the Osler test or quality of life [33].
A meta-analysis reports no effect on the ESS score from
OA
compared with placebo and no difference between
M
OAM and PAP in patients with moderate sleep apnea [3].
There were no published randomized controlled studies
of mild OSA patients when that meta-analysis was published. Most likely, a number of other causes to daytime
sleepiness exist in patients with milder OSA.This might
explain why as much as one third of patients who are
treated with either PAP or OAM are still sleepy, dened
as an ESS score of above 10, despite a successful sleep
apnea reduction [131, 132]. In patients with more severe
disease, OAM reduces daytime sleepiness [3], although to
a lesser degree than PAP does. Other measures than the
ESS score might also be used in future studies to evaluate subjective complaints, such as fatigue, which gave
interesting results in one study [133].
Few other OSA-related symptoms than daytime
sleepiness have been systematically evaluated regarding treatment effect from OA
. Positive effect on symp-
M
toms of restless legs by OAM treatment versus placebo
interventions has been found in two studies [33, 134].
Some other OSA-related symptoms, such as headaches,
nasal congestion, and insomnia, were improved with
OAM treatment compared with untreated conditions in
an RCT, although there was no difference to a placebo
device [33]. Many symptoms, such as insomnia, daytime sleepiness, headaches, and restless legs, may coexist
with OSA and might require individualized treatment
approaches [135–137]. The difference in expression of
symptoms between OSA patients is exemplied in a study
that subdivided the results of the polysomnographic
sleep recordings. OSA patients who were registered to
have primarily sleep arousals more often continued with
OAM treatment compared with those who had primarily desaturations [138]. More studies of various phenotypes of obstructive sleep apnea patients are therefore
needed in order to better understand the symptomatic
effects from various treatments of this multiclausal and
multifaceted disease. A good approach in patients with
mild symptomatic OSA is to test if treatment with PAP
reduces daytime symptoms before treatment with OA
M
is initiated [90].
In summary, the effect of OAM on daytime sleepiness
is uncertain in patients with mild to moderate OSA, that
is, the group of patients for whom this type of therapy is
primarily recommended. Mild to moderate OSA probably causes less pronounced daytime sleepiness than
previously assumed, while there are a number of other
plausible causes to their daytime sleepiness. Patients
with severe disease are likely to become less sleepy with
196
M. Marklund
13
OAM treatment, although PAP is more effective. Future
studies are needed of various symptomatic effects of
OAM treatment in relation to phenotype and maybe
unknown outcomes on sleep of OSA treatment, such as
on the glymphatic system [139].
13.10 Cardiovascular Eects
Blood pressure is reduced from OAM treatment compared
with placebo interventions according to meta- analyses
[2, 140–142]. The effect is similar between OAM and
PAP in the studied samples [2, 140]. One meta- analysis
that subdivides between APAP, CPAP, OAM and control
favored CPAP in terms of blood pressure effects [141].
The results of OAM on blood pressure derive from randomized controlled trials comparing with placebo [25,
28, 143–146], PAP [25, 43, 144, 147, 148], untreated con-
trols [37, 147], or in a comparison between OA
designs
M
[55]. In between 12 to 108 mild to severe OSA patients
completed these studies that lasted in between 1 and 4
months. All but one study included patients irrespective of initial blood pressure, while one study required
baseline hypertension [143]. In addition, there are six
descriptive studies of blood pressure effects from OAM
[149–153]. The reduction in blood pressure by OAM was
signicantly associated with a reduction in AHI [143, 151,
152]. Several of the studies show that the blood pressure
effects are particularly evident in hypertensive patients
[43, 143, 150–152]. One study subdivided women and
men and found effects on blood pressure only in women
and at night [146]. Further studies are needed on possible
differences between women and men regarding effects
from sleep apnea treatments, since previous samples have
included a majority of men, 80% in average.
OAM has also been found to normalize the nightly
dips in blood pressure [25] or give a better outcome
than CPAP [144] in the studied samples. Benecial effect
on endothelial reactivity was found in one small study
[148], but the result was not conrmed in a larger randomized controlled trial in severe OSA patients [28]. A
small, descriptive study reports similar mortality rate in
patients treated with OAM or PAP as in healthy controls,
while untreated severe OSA patients had a higher mortality rate than the other groups [154].
A higher adherence to OA
treatment than with PAP
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may, to some extent, explain the fairly similar outcomes
on blood pressure from these treatments [43]. It is also
possible, that patients included in studies regarding
OAM treatment, are healthier than patients treated with
PAP, particularly those with more severe OSA.A recent
RCT comparing OA
with a placebo device in patients
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with severe OSA, did not, as a secondary aim show any
effect on blood-pressure despite good compliance and
a substantial reduction in AHI [28]. This study high-
lights the complexity of OSA and possibilities to reduce
cardiovascular risks with interventions. On the positive
side, two studies report benecial long-term effects of
OA treatment on blood pressure after 3years or more
[149, 155].
In summary, some positive effects on cardiovascular
health has been found as a result of OAM therapy. More
research is, however, needed on treatment outcomes in
this complex area of multiple illnesses.
13.11 Side Eects
The introduction of a foreign body into the mouth that
aims to stabilize the lower jaw forward during sleep may
cause discomfort with pressure on the teeth, tenderness in
the temporomandibular joint, and temporary changes in
dental occlusion. These adverse effects may prolong the
acclimatization to the device or even cause the discontinuation of treatment. With time, the initial discomfort
disappears, while more permanent bite changes become
more obvious. These side effects are well known. Their
general management relies on clinical experience rather
than scientic evidence, since there are few evaluated
methods that describe how to manage side effects [156].
13.11.1 Forces fromtheDevice
The nightly repositioning of the lower jaw to an anterior position will create forces on the teeth. Distally
directed forces will arise on the upper jaw and teeth and
anteriorly directed ones will appear on the lower jaw
and teeth. Already in the beginning of the treatment,
the patient may experience slight discomfort in terms of
a temporary changed bite with fewer occlusal contact
areas some hours after appliance removal [157, 158].
The muscle force is weaker, but returns to normal levels [157, 158]. Dose-dependent but individually variable
forces from the appliance will inuence tooth movement
and the changed dental occlusion [159]. A cut-off of
60% advancement for signicantly increased forces on
the teeth has been identied [160]. Patients with poor
oral health including an insufcient bony support of the
teeth will be more at risk for negative effects from the
forces of an OA
as well as suffer from impaired oral
M
health by wearing a device on the teeth at night.
13.11.2 Short-Term Side Eects
From treatment start, the patients may experience salivation problems, tenderness in teeth, temporomandibular joint symptoms, or bite changes [2]. Some side effects
are appliance related, since devices that are less indi-
Oral Appliance Therapy
197
13
vidualized or non-adjustable ones give more adaptation
problems [17, 63, 66, 69] and are also less efcient [59,
63, 66]. The repositioning in itself inuences the mag-
nitude of discomfort, since a device that advances and
opens the jaw more causes more side effects compared
with a control device or a device with less repositioning [33, 48, 54]. An unforeseen aspect of the risk of side
effects is visualized in a study that found more muscular
pain in the initial part of OAM treatment in patients on
statin medication than in controls [161].
PAP causes similar amount of side effects as OAM
[2], although these differ in character between the treatments [24, 32, 38, 39, 41, 44]. The PAP mask produces
pressure in different areas of the face and may cause
skin irritation, while OAM produces pressure on the
teeth and jaws that may cause tenderness or pain. PAP
more often causes dryness in the throat or nose problems, while OAM may cause either excessive salivation
or a dry mouth. Both treatments may disturb sleep [38].
Adherence problems are more common with PAP than
with OA
treatment, and side effects tend to more often
M
cause the discontinuation of treatment with PAP than
with OAM treatment [2].
13.11.5 Changes inDental Occlusion
There is a continuous progressive mesial shift in dental
occlusion with molar positions changing into a more
mesial relationship (Angle Class III) and reductions in
overjet and overbite during OAM treatment according to
measurements on dental casts and cephalograms [166–
170, 174–176, 178–189] (. Fig. 13.7). There are also
slight skeletal changes, primarily of the lower jaw, in the
same direction as those of the teeth [166, 167, 170, 178,
180, 182, 184, 187, 190, 191].
The changes in overjet and overbite are noticed
early during the rst years of treatment and thereafter continue gradually [186] (. Fig. 13.8a, b). After
5 years’ treatment, around one third of the patients
may be expected to have >1 mm change in overjet or
overbite [185]. After one decade of treatment, around
2 mm decrease in average in overjet and overbite has
13.11.3 Methods toAvoid Initial Side Eects
Prevention of muscle tenderness and TMJ pain has been
the main topic in studying methods to decrease shortterm side effects. A group of patients with diagnosed
TMD experienced less pain after performing mandibular exercises compared with a similar group of patients
who had been randomized to placebo training [162].
Similar exercises were also tested in patients without
previous TMD, and no patient experienced TMD symptoms after 1 month of OAM treatment [163].
Prevention of occlusal changes in the initial phase of
treatment has been studied using either jig exercises or
stretching in the morning, and both methods increased
the number of occlusal contacts [164].
13.11.4 Longer Term Side Eects
Salivation problems and tooth discomfort usually
decline or are less disturbing in the longer term [165–
170]. Temporomandibular joint symptoms decrease in
patients who continue treatment [168, 171, 172] and
do seldom limit OAM use [171, 173]. Instead, tooth
movement and bite changes become more and more
prevalent with time. Almost all patients will receive
more or less marked bite changes after 5 years’ treatment [174]. Only a minor part of the patients is, however, disturbed about these bite changes [169, 172,
175–177].
. Fig. 13.7 Expected bite changes during longer use of OA
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198
Rose et al. 2002 (Adjustable activator n=34)
–2.6
Rose et al. 2002 (Adjustable activator n=34)
a
b
M. Marklund
2345 7101117 years
0
-0.2
-0.4
-0.6
)mm( egnahc tejrevo egarevA
-0.8
-1
-1.2
-1.4
-1.6
-1.8
-2
-2.2
-2.4
-2.6
Bondemark 1999 (Monoblock, n=30)
Doff et al. 2013 (TAP n=29)
Fransson et al. 2004 (Monoblock, n=65)
Fritsch et al. 2001 (Herbst, Monoblock,
n=22)
Hammond et al. 2007 (Somnomed n=45)
Robertson et al. 2003 (Monoblock, n=20)
Ghazal et al. 2008 (TAP, n=24 )
Hou et al. 2006 (Monoblock, n=67)
Battagel et al. 2005 (Herbst n=30)
Ringqvist et al. 2003 (Monoblock, n=30)
Wang et al. 2015 (Silensor, n=42)
Marklund 2006 (Monoblock, n=156)
Martinez-Gomis et al. 2010 (Herbst, n=15)
Gong et al. 2013 (Monoblock, n=25)
Almeida et al. 2006 (Klearway, n=70)
Fransson et al. 2017 (Monoblock, n=60)
Pliska et al. 2014 (Klearway, n=77)
Marklund 2016 (Monoblock n=9)
2 345 71011 17 years
0
13
–0.2
–0.4
–0.6
)mm( egnahc etibrevo egarevA
–0.8
–1
–1.2
–1.4
–1.6
–1.8
–2
–2.2
–2.4
Bondemark 1999 (Monoblock, n=30)
Do et al. 2013 (TAP n=29)
Fransson et al. 2004 (Monoblock, n=65)
Fritsch et al. 2001 (Herbst, Monoblock,
n=22)
Hammond et al. 2007 (Somnomed n=45)
Robertson et al. 2003 (Monoblock, n=20)
Ghazal et al. 2008 (TAP, n=24 )
Hou et al. 2006 (Monoblock, n=67)
Battagel et al. 2005 (Herbst, n=30)
Ringqvist et al. 2003 (Monoblock, n=30)
Wang et al. 2015 (Silensor, n=42)
Marklund 2006 (Monoblock, n=156)
Martinez-Gomis et al. 2010 (Herbst, n=15)
Gong et al. 2013 (Monoblock, n=25)
Almeida et al. 2006 (Klearway, n=70)
Fransson et al. 2017 (Monoblock, n=60)
Pliska et al. 2014 (Klearway, n=77)
Marklund 2016 (Monoblock, n=9)
. Fig. 13.8 a Average overjet change during longer term use of OAM. b Average overbite change during longer term use of OA
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Oral Appliance Therapy
199
13
been reported [186, 189]. In a small group of patients
that were evaluated after 17years, the median changes
in overjet and overbite were 1–2mm [192]. Two patients
had more extreme reductions of 4–5 mm in overjet or
overbite during those years. Younger and older subjects
are affected by bite changes to a similar degree during
similar observation times, although this relationship is
sparsely evaluated and depends on the individual oral
health [113].
In the clinic, some patients complain about problems
to chew tough food because they have lost tooth contacts between their posterior teeth. Studies have conrmed that the changed bite will result in fewer contacts
between the upper and lower teeth in the posterior parts
of the dentition [168, 174, 181, 186, 193, 194]. One fth
to one fourth of the patients have posterior open bites
after 1–2 years’ treatment with OAM [172, 188]. It must
be noticed that the occlusal contacts vary largely over
time and may improve [168]. Patients also complain
about food impaction during longer term treatment,
possibly because of lost contact between teeth where the
appliance is attached [177].
The teeth might also undergo other types of positional changes in terms of crowding of teeth or the
development of interproximal open spaces [186, 188,
195, 196], but such changes are not observed in all stud-
ies [174]. The upper posterior teeth may tip distally and
the lower molars can incline mesially [178].
13.11.6 Bite Changes inRelation toInitial
Bite Characteristics
The initial type of bite is associated with the degree of
bite changes from OAM treatment. Patients with normal
bite (Angle Class I) or mesial occlusion (Angle Class III)
will be more at risk of unfavorable bite changes from
OAM treatment. On the other hand, subjects with distal deep bite and a large overjet (Angle Class II:1) can
expect favorable changes with reduced overjet and overbite [174, 185]. Such positive effects might also explain
why many patients are unaware of bite changes [177]. An
initial deep bite has been associated with a less marked
decrease in overjet [174, 185].
13.11.7 Bite Changes inRelation
toMandibular Repositioning
The larger the mandibular advancement by the device,
the greater is the risk for reductions in overbite [181] and
overjet [176, 185]. In accordance with these ndings, a
large opening increases the risk for a decrease in overbite
[185, 187].
13.11.8 Device Design andPossibilities
toPrevent Bite Changes
A few studies have compared devices in terms of dental side effects. A device with an anteriorly positioned
adjustment mechanism (. Fig. 13.4f) was associated
with more pronounced occlusal changes when compared with an OAM with a lateral adjustment mechanism (. Fig. 13.4d) [194]. There was no difference in
changes in overjet and overjet between OAM with a lateral adjustment mechanism and CPAP in that study.
Another study used a specially designed OA that lacked
material in front of the upper incisors in order to cause
less pressure on these teeth backward [191]. In the lower
jaw, there was a spring in front of the incisors in order to
prevent these teeth from moving anteriorly. No signicant change in overjet and overbite was detected after
4 years’ treatment. Another observational study compared a soft elastomeric device that covered parts of
the alveolar processes and the teeth with a hard acrylic
that was mainly xed to the teeth and found fewer
OA
M
changes in overjet and overbite with the soft elastomeric
device with alveolar extensions [185]. Finally, a rigid
full-coverage appliance was found to prevent from incisor crowding that might appear from a exible device
without incisor coverage [196].
One small randomized controlled study aimed to
specically counteract the forces from the device by
incorporating counteracting forces on the upper front
teeth [197]. The forces were designed to produce a proclination of the upper incisors by relocating them in a
plaster cast model, on which the soft elastomeric monoblock appliance was made [197]. This study reports positive effect on overjet changes compared with a control
device, but was not developed further because of the
need of using adjustable devices which are more difcult
to fabricate in soft elastomer.
13.11.9 Comparison ofBite Changes
Between PAP andOA
PAP treatment may also result in bite changes, primarily
the loss of contacts between the upper and lower posterior teeth [181, 194]. This is probably explained by the
changed lower jaw posture during PAP use. No change
in overjet and overbite was found from PAP [181, 194].
The pressure of the PAP mask on the upper jaw may
alter its form [198].
A larger mandibular advancement is generally associated with larger bite changes and a higher efcacy of
MAD [48, 199], although there is no linear relationship
[49, 50]. These progressive bite changes will successively reduce the mandibular advancement. This will
M
200
M. Marklund
13
introduce risk of impaired efcacy of the device, since
it is the teeth that move, not the jaws [200]. Higher PAP
pressure will produce more side effects in terms of leaks,
nasal irritation, and intolerance [201], but not hazard
the mechanism of that device.
In conclusion, bite changes during OAM treatment
are progressive in nature, and patients may at some time
point be disturbed about the aesthetics or have problems
with chewing. Most importantly, these bite changes will
inuence the mechanism of the device, since a forward
shift of the lower teeth compared with the upper ones
will result in a successively reduced degree of mandibular advancement by the device. Consequently, patients
must be cared for in an individual way, since they will
respond differently to a mandibular repositioning during the night. It may be important for the future to
study how often the patients have to be followed up in
order to assess bite changes in relation to the efcacy of
the device and the importance of bite changes for oral
health.
13.12 Adherence andMean Disease
Alleviation
13.12.1 Measurement ofAdherence
Most studies rely on subjective reports of adherence
to OAM treatment. More recently, compliance monitors for OAM have been incorporated in some types of
appliances and found safe [202]. These monitors have,
however, to be more supervised compared with those in
the PAP machines [203, 204]. Objective measurement
of OAM adherence has been compared with subjective
reports and found to give fairly similar results, with a
30 min overestimation of usage time in the patients’
reports [203, 204]. A few studies have now used these
monitors, which strengthen their results [28, 119, 205].
13.12.2 Denitions ofAdherence
Patients may discontinue treatment or they can adhere
to various degrees to a treatment. Adherence to OSA
treatment has mainly been identied for PAP and
described in various ways [206]. The most common
descriptions include the average hours of use per night
and the percentage of nights the treatment was used
during a specic period. A regular PAP user is identied by: ≥4hours nightly use at least 70% of the nights
[207], and a frequent user is dened even more strictly by
Pepin etal. [208] requiring more than 4hours per night
on more than 5days per week. In general, more CPAP
use is related to better outcomes, both on mortality, cardiovascular outcomes, and quality of life [201, 209].
13.12.3 Adherence
Objectively assessed adherence after 3 months’ OAM
treatment was 7hours/night in average in a group of 43
assessed patients [210]. Regular objectively measured
OAM use was found in 85% after 3months and in 82%
after 1 year [203]. More than half of patients continue
treatment after 3–4 years according to other studies
without compliance monitoring [211–213]. Comparison
between OAM and PAP demonstrates that self-reported
adherence is higher for OAM already at 1 month after
acclimatization [43]. OAM are also used around 1 hour
longer each night than PAP [2, 214].
13.12.4 Mean Disease Alleviation
A combined measurement, the mean disease alleviation, summarizes the efcacy and the adherence of the
specic therapeutic method [202, 203]. A very effective,
but less utilized treatment can in such a comparison be
considered fairly equal as another treatment that is less
effective, but more often used [4].
13.12.5 Reasons forOA Non-adherence
withOA
M
Non-adherence to OAM treatment is strongly associated with patient worries and experiences about discomfort, adverse effects on the teeth, and lack of efcacy
on snoring and apneas [119, 211, 212, 215]. Clinicians
are therefore recommended to continuously follow-up
the treatment outcome as well as factors such as device
quality and new dental restorations that may interfere
with OAM treatment [211, 212, 215].
In summary, the adherence to OA
therapy is gener-
M
ally higher than that of the more efcient treatment with
PAP, which to some extent, may equalize these treatments in some groups of patients. More than half of the
patients continue with OAM after some years, although
the adherence is dependent on a number of factors such
as oral health, side effects, and disease deterioration:
factors that are usually of less concern for PAP treatment.
40
Baseline < 18 mo 18-24 mo >2<7 yrs10 yrs17 yrs
AHI, RDI or ODI
)
Oral Appliance Therapy
35
30
25
20
15
10
201
Rose et al. 2002 n=26
Ghazal et al. 2009 n=45
Fransson et al. 2003 n=39 (ODI)
Walker-Engström et al. 2002 n=32
Gauthier et al. 2011 n=14 (RDI)
Marklund et al. 2001 n=19
Do et a. 2013 n=29
Wiman Eriksson et al. 2014 n=30 (ODI
Gong et al. 2013 n=22 (median)
Marklund 2015 n=9 (median)
13
5
0
. Fig. 13.9 Long-term efcacy of OA
M
13.13 Long-Term Outcomes
A fairly stable effect of OAM on AHI from 2 up to
10 years has been reported in ten studies of carefully followed-up patients [58, 155, 167, 213, 216–221]
Fig. 13.9). Only one small study has followed
(.
OA-treated patients even longer [192]. After 17years, all
the patients had worsened with the device and all but
two patients had increased their AHI without it. The
patients had not increased in weight, and they were not
sleepy at the follow-up. During this long treatment time,
the patients had received continuous follow-up of symptomatic effects and side effects. Regularly, the devices
had been replaced with new ones with more advancement, if needed, in order to compensate for the mesial
shift in dental occlusion. The increase in AHI at followup can be explained by the fact that patients were older
or had more comorbidities [222]. Studies show that AHI
and the durations of apneas, hypopneas, and desaturations may be expected to increase during the time when
sleep apnea treatments are ongoing [109, 223]. It must
therefore be considered in the original treatment plan
that the OSA pathophysiology in the individual patient
may change over time. In addition, a mesial movement
of the whole dental occlusion will change the intended
degree of mandibular advancement, which may reduce
the efcacy of the device.
In conclusion, the effectiveness of an OA
will
M
decrease in the longer term, since some patients discontinue treatment because of poor subjective treatment
effects or side effects. Continuing patients may risk a
poorer objective treatment effect on sleep apneas. It is
not the same patient that is treated after a number of
years, because of for instance age, comorbidities, and
bite changes. The mechanism of action of OAs is more
vulnerable than that of PAP, which makes it necessary
202
M. Marklund
13
to continuously re-evaluate the treatment outcome.
More research is needed about the long-term outcomes
of OAM therapy. In addition, it would be of interest to
better study oral health during OSA treatment, that is,
whether oral health improves or deteriorates as a result
of the treatment, and, in that case, in which patients.
13.14 OA
in Relation to Other OSA
M
Treatments
13.14.1 OA
Compared with Positional
M
Therapy
Positional therapy can be used in patients with positional OSA.This method can be subdivided into sleep
position training that use some sort of alarm or vibration in order to prevent the subjects to sleep supine and
methods that makes it uncomfortable to sleep on the
back such as the use of tennis balls or other items. Both
techniques effectively reduce the percentage of supine
sleep and AHI [224, 225]. The sleep position trainer is
preferred by the patients and gives a better sleep quality
compared with sleeping with a tennis ball or backpack
[225]. Snoring is, however, not satisfactorily reduced by
positional therapy [226].
Patients with positional OSA can be diagnosed based
on the chance of elimination of sleep apneas with positional therapy. Consequently, a normal value of the nonsupine index (non-supine AHI<5) will give a high chance
of complete treatment success [98], but patients may benet from this treatment also using other denitions.
OA
therapy and sleep position training have equal
M
short-term efcacy on AHI in patients with positiondependent OSA dened by a doubled AHI or more in the
supine sleep compared with the non-supine position [205].
In addition, both treatments remained stable in their effect
on AHI after 1 year [227]. Positional therapy must, in
accordance with OAM therapy, continue long term, since
there are no indications of a training effect in sleeping less
supine after the use of a sleep position trainer [228]. A
problem with positional therapy is that supine dependency
can vary from night to night and a more than fourfold difference is needed in order to identify supine dependency,
and this criterion was only found in men [229].
is fairly common that apneas may persist in the supine
sleep position. The prevalence of supine dependency
during OAM treatment ranges in between 18% and 34%
depending on the denition of this condition [99]. These
patients with insufcient effect in supine sleep position
during OAM treatment may be subjected to intermittent increased sleep apnea frequencies, depending on
the alternatingly preferred sleep position. A good treatment outcome in all sleep positions is important for
some of these patients, since severe supine-dependent
OSA has been related to an increased risk for cardiovascular events and mortality [230]. A combination of
both OAM and a sleep position trainer that helps the
patients avoid supine sleep is therefore a promising new
concept in order to increase the success rate of OAM
therapy [231]. The long-term outcome of this therapy
is unknown.
13.14.3 OA
Combined with PAP
M
Some patients do not tolerate PAP therapy every night,
and these patients may benet from OAM as an alternate treatment. Sleep apneas will be reduced during
periods of non-tolerance to PAP or on journeys [232],
which may reduce the risk for negative consequences of
untreated OSA.
OAM and PAP can also be used together in order to
reduce the resistance in the upper airway and reduce the
PAP pressure [233–235].
13.15 OAs asSecond-Line Treatment
Non-compliance with PAP might, to some extent, be
explained by differences in OSA phenotypes [236, 237].
For some patients who do not tolerate PAP, OAM may
constitute a less intrusive treatment alternative. Both
moderate and severe OSA patients have been found to
reduce their AHI to a substantial amount with OAM
treatment, also after 1 to 2years [92, 238]. In a group of
severe OSA patients, over half of them continued with
after 2years [238]. Half of the patients who had
OA
M
a renewed sleep apnea recording had a treated AHI of
less than 15.
13.14.2 OA
Combined with Positional
M
Therapy
The efcacy of OAM therapy differs in relation to sleep
positioning. The lateral-AHI is more often normalized
than the supine-AHI by OAM [99, 101]. Consequently, it
13.16 Guidelines
There are many published guidelines and meta-analyses
that provide clinical advice about how to conduct the best
available care for the patients [1–4, 47, 239–244]. Several
guidelines include advice for general practicing dentists to
be aware of OSA, since they can be of help to recognize