The impact of rapid palatal expansion on children's general health: A literature review

Abstract

The original indication for rapid palatal expansion was to treat skeletal maxillary constriction. As positive effects were clinically proven, the number of indications for rapid palatal expansion has continuously grown. The purpose of the present article was to review the literature and to evaluate the effect of rapid palatal expansion on nose breathing, natural head position, obstructive sleep apnoea syndrome, nocturnal enuresis and conductive hearing loss.
It can be concluded that rapid palatal expansion is predominantly recommended in children with maxillary constriction. In those with normal occlusion, maxillary expansion can be considered as the really last choice of treatment when other treatment options in patients with nose breathing, obstructive sleep apnea syndrome (OSAS), nocturnal enuresis and conductive hearing loss (CHL) have failed. Therefore, collaboration between paediatricians, otolaryngologists, paediatric dentists and orthodontists will lead to the best treatment outcomes in the future.

Full text

EuropEan Journal of paEdiatric dEntistry vol. 15/1-2014 67
M. Eichenberger, S. Baumgartner
Department of Orthodontics and Paediatric Dentistry
University of Zürich, Switzerland
e-mail: Stefan.Baumgartner@zzm.uzh.ch
abstract
Aim The original indication for rapid palatal expansion was
to treat skeletal maxillary constriction. As positive effects
were clinically proven, the number of indications for rapid
palatal expansion has continuously grown. The purpose
of the present article was to review the literature and to
evaluate the effect of rapid palatal expansion on nose
breathing, natural head position, obstructive sleep apnoea
syndrome, nocturnal enuresis and conductive hearing loss.
Conclusion
It can be concluded that rapid palatal
expansion is predominantly recommended in children
with maxillary constriction. In those with normal occlusion,
maxillary expansion can be considered as the really last
choice of treatment when other treatment options in
patients with nose breathing, obstructive sleep apnea
syndrome (OSAS), nocturnal enuresis and conductive
hearing loss (CHL) have failed. Therefore, collaboration
between paediatricians, otolaryngologists, paediatric
dentists and orthodontists will lead to the best treatment
outcomes in the future.
The impact of rapid
palatal expansion
on children’s general
health: a literature
review
Introduction
In the extensive literature of lateral maxillary
expansion with midpalatal suture opening, often
referred to as rapid maxillary expansion (RME) or
rapid palatal expansion (RPE), the earliest commonly
cited report is that of E.C. Angell, published in the
Dental Cosmos in 1860 [Angell, 1860]. After initially
falling to disrepute because of impeded oral hygiene
and uncontrolled force application, the technique was
reintroduced in the middle of the last century and
made widely popular by Andrew Haas [1961, 1965]. He
extensively studied clinical short-term effects of rapid
expansion on patients treated only with an expansion
appliance during the late mixed and permanent
dentitions, as well as repercussions on the craniofacial
complex. As a consequence of improvements in the
development of dental materials, the application of
force could be specified, and the appliance’s size
reduced. After scientific evidence of positive clinical
effects [Biedermann, 1968, Mossaz-Joelson and
Mossaz, 1989] was proved, RPE was established in
orthodontics. Today RPE with various modifications and
designs is routinely used and generally accepted as a
relatively simple and predictable orthodontic therapy to
treat patients with maxillary constriction and posterior
crossbites. All potentially negative impact of placing
palatal expanders, including pain and discomfort,
disruption of speech production, and chewing and
swallowing problems are discussed as mild, transitory,
and independent of appliance design, sex, or age [De
Felippe et al. 2010]. Remarkable adaptation to the
devices can be expected by the end of the first week. In
addition, the patients’ speech acceptability is reported
to be better after than before treatment [Stevens et
al., 2011]. Because of various positive side effects on
patients’ general health, the number of indications for
RPE has continuously grown.
The aim of this literature review was to evaluate the
impact of rapid palatal expansion on nose breathing,
natural head position, obstructive sleep apnoea
syndrome (OSAS), nocturnal enuresis and conductive
hearing loss (CHL).
Search methodology
In order to identify relevant studies about the impact
of rapid palatal expansion on children’s general health,
a computerized database search was conducted using
the Medline database (Medline/Pubmed). The search
covered the period up to February 2013. The terms used
in the search were ‘rapid palatal or maxillary expansion’
in combination with ‘general health’, ‘breathing’, ‘head
posture’, ‘OSAS’, ‘OSA’, ‘nocturnal enuresis’, ‘conductive
hearing loss’ and ‘speech’. A total of 120 references
were retrieved from the database search, among them
6 duplicate references. Both authors screened the
publications found in the database. Agreement whether
the publications were relevant to the topic of this review
was reached.
The retrieved studies with the highest available
evidence were finally included in the literature review
(Table 1).
Keywor ds
Conductive hearing loss; Enuresis; Nose
breathing; OSAS; Rapid palatal expansion.

EichEnbErgEr M. and bauMgartnEr S.
EuropEan Journal of paEdiatric dEntistry vol. 15/1-2014
68
Review of the literature
Nose breathing and natural head position
Nasal respiration is needed for ideal development
of the nasomaxillary complex and it provides the
preparation of the air before reaching the lungs by
adjusting the temperature, humidification and removing
particles. It can be constrained by respiratory infection,
cold, asthma, allergic rhinitis, enlarged tonsils and other
possible reasons for nasal obstruction. Nasal obstruction
inducing mouth breathing results in different tongue
and lip positions, in an open mouth posture, constricted
upper dental arch, downward and backward rotated
mandible and higher incidence of posterior crossbite
[Behlfelt et al., 1990; Corruccini et al., 1985]. RPE is a
recommended therapy to treat constricted upper dental
arches and posterior crossbites in growing patients.
The maxillary bones form the anatomical base of
the nasal cavity. Therefore, expansion of the maxilla
also affects the geometry of the nasal cavity. The
maxillary width and the nasal cavity width increase as
the maxillary halves separate during RPE. Baratieri et al.
[2011] qualified in their systematic review the evidence
of long-term effects of RPE on airway dimensions and
functions. Only the eight following articles met their
inclusion criteria and were of moderate methodological
quality. In these studies, airway dimensions were either
measured two-dimensionally using posterioanterior or
lateral cephalometric radiographs or three-dimensionally
using a CBCT. Cameron et al. [2002] found a significant
increase in nasal cavity width which remained stable
five years after RPE. Baccetti et al. [2001] demonstrated
a larger increase in the early treatment group (cervical
vertebral stage 1-3) compared to the late treatment
group (cervical vertebral stage 4-6) and recommended
treatment before the pubertal peak to achieve more
effective long-term changes. Other studies [Tecco et
al., 2007; Compadretti et al., 2006; Monini et al., 2009]
using a two-dimensional measurement method revealed
also a significant increase in nasopharyngeal airway
adequacy, but two of these studies did not include a
control group.
Investigating the craniocervical angle on lateral
radiographs, McGuinness and McDonald [2006]
concluded that nasal airflow increased and nasal
respiration improved one year after maxillary expansion.
TABLE 1 Summary of the
included studies.
Positive side effect of RPE Level of evidence
Yes Unclear No High Moderate Low
Nose breathing
Baccetti et al. 2001 x x
Cameron et al. 2002 x x
McGuinness et al. 2006 x x
Compadretti et al. 2006 x x
Tecco et al. 2007 x x
Monini et al. 2009 x x
De Felippe et al. 2009 x x
Zhao et al. 2010 x x
Obstructive sleep apnea syndrome (OSAS)
Cistulli et al. 1998 x x
Pirelli et al. 2004 x x
Villa et al. 2007&2011 x x
Nocturnal enuresis
Timms et al. 1990 x x
Kurol et al. 1998 x x
Schütz-Franson&Kurol 2008 x x
Usumez et al. 2009 x x
Conductive hearing loss (CHL)
Laptook et al. 1981 x x
Ceylan et al. 1996 x x
Taspinar et al. 2003 x x
Villano et al. 2006 x x
Kilic et al. 2008 x x

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In contrast to these two-dimensional findings, Zhao
et al. [2010] used CBCT as a three-dimensional
measurement method and did not find any significant
differences in airway volume between treatment and
control group. Functional measurement methods such
as rhinomanometry and acoustic rhinometry revealed
improved nasal breathing that remained stable after
RPE [Compadretti et al., 2006]. In contrast, De Felippe
et al. [2009] did not find any significant differences
in improvement of nasal breathing between test and
control group.
Baratieri et al. [2011] concluded in their systematic
review that there is a low to moderate evidence that
RPE improves the conditions for nasal breathing and
that the results can be expected to be stable for at least
11 months. Because of the ambiguous findings in the
literature, RPE cannot be recommended to treat patients
having breathing problems with normally developed
maxillary arches.
Natural head posture is influenced by nasal breathing
function. Children with nasal obstruction show an
increased craniocervical angulation. Wenzel et al.
[1983] evaluated the effect of topical steroids on nasal
respiratory resistance and head posture in children with
nasal obstruction and asthma. Rhinomanometric and
cephalometric analyses were performed to compare
the treatment group with the placebo group. After one
month of treatment, nasal resistance and craniocervical
angulation significantly decreased in the treatment
group. In a randomised clinical trial by Tecco et al.
[2005] analysing 55 mouth breathing girls with maxillary
constriction, RPE led to a significant decrease in the
craniocervical angulation, to a significant increase of the
cervical lordosis angle and to a significant flexion of the
head. This can be expected to be stable in the 12-month
follow-up [Tecco et al., 2007]. But it is uncertain if these
changes in natural head posture are clinically relevant.
On the contrary, Yagci et al. [2011] could not find a
significant difference in natural head position when the
test subjects after RPE were compared to the control
group without RPE.
Obstructive sleep apnoea syndrome (OSAS)
OSAS is common, affecting approximately 2-3%
of children [Lumeng and Chervin, 2008]. Its highest
incidence occurs between 2 and 8 years of age,
probably due to the relative size of lymphoid tissue to
airway diameter. Its prevalence is expected to increase
with rising obesity in children and adolescents. OSAS
is described by upper airway collapse during sleep as a
consequence of an imbalance between upper airway
structural load due to factors such as adenotonsillar
hypertrophy or obesity, and upper airway neuromotor
tone [Marcus et al., 2005]. Untreated OSAS is associated
with significant morbidity such as growth failure,
systemic and pulmonary hypertension, and endothelial
dysfunction [Gozal et al., 2007; Marcus et al., 2005;
Miman et al., 2000]. Therefore, untreated OSAS can
result in a significant health burden for patients.
Contrary to popular belief, a meta-analysis of the
current literature demonstrates that paediatric sleep
apnoea is often not cured by tonsillectomy and
adenoidectomy [Friedman et al., 2009]. A success rate
of 66.3% indicates that a large number of children
have residual disease. Although complete resolution
is not achieved in most cases, tonsillectomy and
adenoidectomy still offer significant improvements in
apnoea-hypopnoea index, making it a valuable first-
line treatment for paediatric OSAS. Villa et al. [2007]
assessed the impact of RPE on OSAS children with high
and narrow palate. A significant decrease in the apnoea-
hypopnea index, hypopnoea obstructive index, arousal
index and a decrease of the subjective symptoms were
found. In the three-year follow-up [Villa et al., 2011],
the hypopnoea index remained stable and the clinical
symptoms resolved. As the studies by Villa et al. [2007,
2011] included only a treatment group of 14 and 10
patients respectively without a control group, these
studies represent low evidence and must be considered
with caution. Other studies [Cistulli et al., 1998, Pirelli
et al., 2004] reported a general improvement of the
nasopharyngeal function and a new tongue posture.
However, because of low patient numbers and missing
control groups, these studies represent a low level of
evidence.
Nocturnal enuresis
Nocturnal enuresis is common in children below
the age of five years, but persistent bedwetting must
be considered abnormal. The prevalence of persistent
nocturnal enuresis is reported to be 10% in six years
old patients and 5% at the age of ten [Neveus et al.,
2000]. Different treatment methods are recommended
for children suffering from nocturnal enuresis: wetness
alarm, fluid restrictions, medication (antidiuretics) and
others. Different studies referred nocturnal enuresis as a
symptom among children having breathing problems due
to large tonsils, adenoidal hypertrophy or anterior nasal
stenosis. Tonsillectomy and adenoidectomy have been
recommended to improve bedwetting as a side effect
[Guilleminault and Stoohs, 1990; Weider and Hauri,
1985]. Since constriction of the nasal area can be partly
reduced by RPE, different studies investigated the effect
of RPE on nocturnal enuresis. Timms [1990] reported
in his retrospective study an association between RPE
and a decline in nocturnal enuresis. Kurol et al. [1998]
evaluated in their prospective study the effect of RPE
on palatal width, airway obstruction and nocturnal
enuresis. RPE was used in ten patients, expanding 3 to 5
mm, although nine patients showed a normal occlusion
before treatment. Nocturnal enuresis improved in seven
patients. Similar results were shown by Usumez et al.
[2003]. In their follow-up study, Schütz- Fransson and
Kurol [2008] evaluated the long-term effects: 50%

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of the treated patients showed an improvement of
nocturnal enuresis after RPE which remained stable
at the 10-year follow-up. The overexpanded arches
relapsed to normal transversal occlusion within one year.
The cause of the partial treatment success in children
with nocturnal enuresis who are resistant to medical
therapy is still unknown. An improvement in airflow due
to the widening of the upper dental arch and the nasal
structures, higher oxygen saturation, shorter periods of
deep sleep due to the irritating orthodontic appliance
or a placebo effect are discussed. Schütz-Fransson
and Kurol [2008] recommend a certain sequence of
treatment approaches: The first choice of treatment in
patients with bedwetting is medication after examination
of urinary function; the second treatment approach
would be to evaluate the indication for tonsillectomy
or adenoidectomy and the last choice of treatment
would be orthodontic expansion. Nevertheless, this
recommendation is based on low to moderate evidence.
Conductive hearing loss (CHL)
Hearing loss can be divided into two categories
depending on the site of disease in the auditory system:
conductive and sensorineural hearing loss. The degree
of the conductive hearing loss greatly depends on the
severity and the type of the physical changes imposed
on the mechanical system of the outer or middle ear. It
is known that transversal maxillary deficiency and high
palatal arches have close relationship with conductive
hearing loss [Rudolph, 1977, Laptook, 1981]. For
example, Rudolph [1977] reported that Eustachian tube
malfunctions were found more frequently in children
with high palatal arches and malformations of the palate
and nasopharynx that may predispose them to otitis
media. Braun [1966] stated that palatal constriction was
one cause of nasal stenosis and oral respiration and that
the aberration from normal breathing pattern could
even affect the Eustachian tube and the middle ear, and
result in hearing loss.
Both short and long-term studies evaluated the effect
of RPE on CHL. Short-term studies reported improved
hearing levels in young patients after treatment with
tooth-borne expanders [Laptook, 1981; Timms, 1990,
Ceylan et al., 1996]. Patients suffering from recurrent
serous otitis media and CHL showed functional
improvement after treatment and retention of RPE. In all
of these studies, tooth-borne RPE appliances were used
to expand the maxillary arch.
Ceylan et al. [1996] found that hearing levels were
significantly improved during the active maxillary
expansion period, although some relapse in hearing
levels occurred during the retention period. Such relapse
was also found by Taspinar et al. [2003]. In a long-term
study of Kilic et al. [2008], RPE was performed with
tooth-tissue-borne appliances. Hearing levels and middle
ear functions were improved after an active expansion
period, and remained relatively stable during the long-
term observation period. The function of the Eustachian
tube in patients with transverse maxillary deficiency
and CHL was improved after RPE. In another study
performed on 25 subjects having recurrent serous otitis
media and CHL, Villano et al. [2006] found a functional
improvement in all patients at the end of the retention
period of 8 months.
Based on low to moderate evidence, hearing levels
and middle ear function can be improved in patients
with constricted maxillary arches.
Conclusion
It has been well accepted in the literature that
rapid palatal expansion has positive skeletal and
dental effects. Positive side effects on patients’
general health are often reported, but controversially
discussed. As there are only a few studies with high-
level evidence on the impact of RPE on general health,
their results have to be considered with caution. RPE
should predominantly be considered in patients with
maxillary constriction. In those with normal occlusions,
maxillary expansion can be considered as the really last
choice of treatment when other treatment options in
patients with nose breathing, OSAS, nocturnal enuresis
and conductive hearing loss (CHL) have failed. As a
consequence, collaboration between paediatricians,
otolaryngologists, paediatric dentists and orthodontists
will lead to the best treatment outcomes in the future.
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