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Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on facial soft tissue form in children

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Background Mouth breathing syndrome (MBS) is defined as a set of signs and symptoms that may be completely or incompletely present in subjects who, for various reasons, replace the correct pattern of nasal breathing with an oral or mixed pattern. Better understanding of the characteristics of MBS at each stage of growth will be helpful for the accurate diagnosis and treatment of MBS. Objective This review aimed to clarify the relevant factors affecting MBS in children and to examine the influence of an incompetent lip seal (ILS) on facial soft tissue form in preschool-aged children. Results Recent data have shown that an ILS affects MBS in children. In addition, the factors associated with MBS in preschool-aged children were not mutually unrelated, and multiple factors such as general conditions, lifestyle, and eating habits may interact with one another. Furthermore, children with an ILS already tended to have a flattened nose and an anteriorly prominent lip at 3 years of age, implying that the adverse effects of an ILS on the growth of the craniofacial region appear relatively early. Conclusions These results suggest the importance of early diagnosis and treatment of MBS. Early treatment of MBS may prevent possible dental and physical problems in the future.
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Review
Factors related to mouth-breathing syndrome and
the influence of an incompetent lip seal on facial
soft tissue form in children
Emi Inada
a,*
, Issei Saitoh
b
, Yasutaka Kaihara
c
, Youichi Yamasaki
a
a
Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences,
Kagoshima, Japan
b
Division of Pediatric Dentistry, Graduate School of Medical and Dental Science, Niigata University, Niigata, Japan
c
Department of Dental Hygiene, Ogaki Women’s College, Gifu, Japan
article info
Article history:
Received 2 October 2020
Received in revised form
8 October 2020
Accepted 13 October 2020
Available online xxx
Keywords:
Mouth-breathing syndrome
Incompetent lip seal
Factor analysis
Facial soft tissue
Children
abstract
Background: Mouth breathing syndrome (MBS) is defined as a set of signs and symptoms
that may be completely or incompletely present in subjects who, for various reasons,
replace the correct pattern of nasal breathing with an oral or mixed pattern. Better un-
derstanding of the characteristics of MBS at each stage of growth will be helpful for the
accurate diagnosis and treatment of MBS.
Objective: This review aimed to clarify the relevant factors affecting MBS in children and to
examine the influence of an incompetent lip seal (ILS) on facial soft tissue form in
preschool-aged children.
Results: Recent data have shown that an ILS affects MBS in children. In addition, the factors
associated with MBS in preschool-aged children were not mutually unrelated, and multiple
factors such as general conditions, lifestyle, and eating habits may interact with one
another. Furthermore, children with an ILS already tended to have a flattened nose and an
anteriorly prominent lip at 3 years of age, implying that the adverse effects of an ILS on the
growth of the craniofacial region appear relatively early.
Conclusions: These results suggest the importance of early diagnosis and treatment of MBS.
Early treatment of MBS may prevent possible dental and physical problems in the future.
©2020 The Authors. Published by Elsevier Ltd on behalf of Japanese Society of Pediatric
Dentistry. This is an open access article under the CC BY-NC-ND license (http://
creativecommons.org/licenses/by-nc-nd/4.0/).
*Corresponding author. Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-
1 Sakuragaoka, Kagoshima, Kagoshima, 890-8544, Japan.
E-mail address: inada@dent.kagoshima-u.ac.jp (E. Inada).
Available online at www.sciencedirect.com
Pediatric Dental Journal
journal homepage: www.elsevier.com/locate/pdj
pediatric dental journal xxx (xxxx) xxx
https://doi.org/10.1016/j.pdj.2020.10.002
0917-2394/©2020 The Authors. Published by Elsevier Ltd on behalf of Japanese Society of Pediatric Dentistry. This is an open access
article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
1. Introduction
The disease management structure in the dental field has
changed recently, and responses have shifted from a
treatment-centered approach mainly focusing on tooth resto-
ration to a treatment/management-cooperative approach
focusing on the improvement/maintenance/recovery of oral
function. Consequently, in Japan, management of oral function
according to life stage has been promoted, and functional
assessment and training is being actively conducted for chil-
dren showing poor development of oral function.
Mouth breathing in children is a manifestation of poorly
developed oral function and has negative influences not only
on the oral environment and craniofacial morphology but
also on the general condition [1e4](Fig. 1). In this context,
mouth-breathing syndrome (MBS) is defined as a set of signs
and symptoms that may be completely or incompletely
present in participants who, for various reasons, replace the
correct pattern of nasal breathing with an oral or mixed
pattern [5]. Since oral function is constantly developing in
children, it is necessary to understand the characteristics of
MBS at each stage of growth in order to diagnose and treat
MBS accurately.
This study aimed to clarify the relevant factors affecting
MBS in children and to examine the influence of an
incompetent lip seal (ILS) on facial soft tissue form in pre-
school children.
1.1. A large-scale study on MBS in children
Continuous mouth breathing during the growing period is
known to be detrimental to the oral environment, oral func-
tion, and craniofacial morphology [6,7]. Choi et al. compared
the intraoral pH and temperature of individuals who were
mouth breathing during sleep and those who were not. They
concluded that mouth breathing during sleep was related to a
lower intraoral pH in comparison with the pH associated with
nasal breathing during sleep, indicating that mouth breathing
could be a causal factor for dental erosion and caries [8]. Motta
et al. examined the relationship between bad breath and
mouth breathing in children, and concluded that the occur-
rence of bad breath was significantly associated with mouth
breathing [9]. Gulati et al. reported that the gingival index in
mouth breathers with an ILS was higher than that of normal
nasal breathers, and that mouth breathers showed a higher
prevalence of bleeding gingivitis [3]. Additionally, Hsu et al.
reported that the number of chewing strokes and the chewing
cycles in mouth breathers were significantly lower than those
in nasal breathers, and the variance in chewing cycles among
mouth breathers was significantly greater than that in nasal
breathers [10]. Many other reports have described the effects
Fig. 1 eNegative effects of mouth breathing.
pediatric dental journal xxx (xxxx) xxx2
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
of mouth breathing on the dentition and maxillofacial
morphology, which will be explained in detail later.
The physical problems caused by mouth breathing in
children have also been discussed in some literature [11]. Boas
et al. compared the physical performance of mouth-breathing
and nasal-breathing children in a six-minute walking test.
They concluded that the physical performance of mouth
breathers was poorer than that of nasal breathers because of a
significant differences between the two groups in respiratory
rate, oxygen saturation, and distance walked in 6 min [12].
Conti et al. investigated the body posture classifications and
clinical variables of mouth-breathing children, and reported
that mouth breathers exhibited a higher incidence of thoracic
respiratory patterns and unfavorable postural classifications
[5]. Furthermore, mouth breathing has been shown to be
related to allergic rhinitis, and these insights have been
documented in the Allergic Rhinitis and Its Impact on Asthma
guidelines [13].
To prevent these clinical problems, it is especially important
to clarify the interrelationships between mouth breathing and
each clinical problem. However, few reports have clearly
addressed these causal relationships. Since the functional
problems associated with mouth breathing can be attributed to
multiple factors, an adequate examination of the factors related
to mouth breathing is important for diagnosing and treating
this condition. Therefore, our research group conducted a large-
scale questionnaire study to investigate the actual condition of
MBS in children. We requested the cooperation of private dental
clinics that specialize in pediatric dentistry throughout Japan
and were members of Japanese Society of Practitioners for Pe-
diatric Dentistry (JSPP), and the study was conducted from 3
months from August to October 2014. The questionnaire con-
sisted of 44 questions that might be linked to mouth breathing
and assessed the patients’ general conditions (5 items), condi-
tion of the nose, throat, and ear (9 items), condition of the
mouth and occlusion (10 items), condition of the lips and
gingiva (11 items),and how well they consumed a meal (9 items)
(Table 1). Each item was set to answer from four choices: yes,
think so,”“do not think so,and no.
We surveyed approximately 3500 children aged 3e12 years
who regularly visited a dental clinic, and the questionnaire
was completed by the participants’ guardians. Those who
responded Yesor think soto the item Is your mouth often
open during the day?were defined as children with mouth
breathing. On the basis of the responses, 30.7% of the children
were considered to show mouth breathing (Fig. 2). The ratio of
mouth breathing children tended to significantly increase
with age from 3 years (overall, 19.0%; males, 18.1%; females,
19.8%) to 12 years (overall, 39.7%; males, 41.0%; females, 38.4%)
(Fig. 3; Cochran-Armitage trend test, p <0.001). Furthermore,
we investigated the relationship between the survey re-
sponses and mouth breathing using Pearson’s correlation
coefficient test and identified 12 of the 44 survey items that
showed a strong relationship with mouth breathing (Table 2).
Of the 12 items identified by correlation analysis, Are your
lips droopy?showed the strongest correlation with mouth
Fig. 2 eRatio of children with suspected mouth breathing.
Table 1 eQuestionnaire on conditions which might be
linked to Mouth Breathing Syndrome.
Question item
1. Do you get tired easily?
2. Are you good riser?
3. Are you good at exercising?
4. Are you a restless sleeper?
5. Do you have round shoulders?
6. Does your nose become stuffed easily during the day?
7. Does your nose become stuffed easily while sleeping?
8. Do you sneeze often?
9. Do you often have a runny nose?
10. Do you often have a nosebleed?
11. Do you often have a sore throat?
12. Do you have swollen tonsils?
13. Do you often fail to listen?
14. Are you a habitual snorer?
15. Is your mouth often dry?
16. Do people tell you that you have bad breath in the morning?
17. Do people tell you that you have bad breath during day?
18. Is your mouth often open during the day?
19. Do you sleep with your mouth open?
20. Can you keep your mouth closed for about 1 min?
21. Do you have an over bite?
22. Do you have an under bite?
23. Do you have an anterior open bite?
24. Can you talk clearly?
25. Are your lips often chapped?
26. Are your lips thick?
27. Is your upper lip turned upward?
28. Are your teeth visible between your upper and lower lips?
29. Are your lips droopy?
30. Are your lips often cracked?
31. Are your gums often swollen?
32. Are your gums easily stained?
33. Are your teeth easily stained?
34. Do you often have canker sores?
35. Do you have tartar build-up?
36. Do your meals consist of small servings?
37. Do you prefer soft food?
38. Do you drink water during meals?
39. Do you eat fast?
40. Are you a picky eater?
41. Do you chew food well?
42. Are you a noisy eater?
43. Do you keep your mouth closed when you eat?
44. Do you have food left in your mouth for a long time?
pediatric dental journal xxx (xxxx) xxx 3
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
breathing, and Do you sleep with your mouth open?also
showed a strong correlation. The positive response rates for
all 12 items tended to increase significantly with age in both
male and female participants.
These results indicate the importance of diagnosing MBS at
an early stage of age and approaching it clinically. Moreover,
the signs of MBS that can be observed on a daily basis, such as
the 12 items identified in this survey, may provide an oppor-
tunity for early dental consultation because they are easy for
parents to recognize.
1.2. An exploratory study of the factors related to MBS
in pre-school and school-aged children
A large-scale study can clarify the actual status of MBS in
children. For a more detailed analysis, we surveyed 285 chil-
dren aged 3e5 years (150 males, 135 females) attending
kindergarten as the pre-school group, and 380 children aged
6e12 years (187 males, 193 females) attending elementary
school as the school-age group. We measured the lip-closing
strength of the participants, and their guardians completed
the questionnaire described in the previous section. The
children’s lip-closing strength was measured with a digital
force gauge (Imada, Inc., Northbrook, IL). A button (24 mm in
diameter and 4 mm thick) was attached, at its center, to a
piece of string 10 cm long [14](Fig. 4-1), and the other end of
the string was attached to a digital force gauge. The partici-
pants were seated in an upright position with their eyes open.
Their natural head posture was adjusted such that their eye-
ear plane was parallel to the floor. A button was inserted
into the vestibule between the incisors and lips and held; the
force gauge was pulled parallel to the floor; and the gauge
recorded the highest tension (N) before the button was pulled
from the mouth (Fig. 4-2). Before the measurements, partici-
pants familiarized themselves with the measurement by
performing preliminary trials. The measurements were
repeated three times for each participant, and the average was
calculated as the lip-closing strength. A multiple comparison
test was used to identify significant differences in the lip-
closing strength between the age groups. For the question-
naires, we performed an exploratory factor analysis
(maximum-likelihood method and promax rotation) to
Fig. 3 eRatio of children with suspected mouth breathing by age.
Table 2 eFactors related to mouth breathing in children.
Questionnaire
item
29. Are your lips
droopy?
19. Do you sleep
with your mouth
open?
15. Is your mouth
often dry?
28. Are your teeth
visible between
your upper and
lower lips?
20. Can you keep
your mouth closed
for about 1 min?
42. Are you a
noisy eater?
Peason’s
Correlation
coefficient
0.602** 0.542** 0.385** 0.314** 0.257** 0.248**
Questionnaire
item
7. Does your nose
become stuffed
easily while
sleeping?
43. Do you keep
your mouth
closed
when you eat?
21. Do you have
an over bite?
6. Does your nose
become stuffed
easily during the
day?
17. Do people tell
you that you have
bad breath
during day?
16. Do people tell you
that you have
bad breath
in the morning?
Peason’s
Correlation
coefficient
0.237*** 0.232*** 0.213** 0.227*** 0.219** 0.209**
**:p<0.01, ***:p<0.001.
pediatric dental journal xxx (xxxx) xxx4
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
classify questionnaire items that were closely related to their
respective factors.
The lip-closing strength of the pre-school group increased
significantly with age in both male and female participants
(Fig. 5). On the other hand, the lip-closing strength in the
school-age group was significantly different only between the
1st and 5th grades, and between the 1st and 6th grades, and
was not different between the other grades (Fig. 6). Thus, the
lip-closing strength of the pre-school group increased
remarkably, whereas that of the school-age group increased
moderately.
Factor analysis of the questionnaire data identified 9 of the
44 items as MBS-related items in the pre-school group and
classified them into four factors (Table 3). Factor 1 was defined
as diseases of the nosebased on the item Does your nose
become stuffed easily (during the day, while sleeping)?. Fac-
tor 2 was defined as incompetent lip sealbased on the items
Is your mouth often open during the day?,Do you sleep
with your mouth open?, and Are your lips droopy?. Simi-
larly, based on factor loading and the content of the other
items, factors 3 and 4 were defined as eating habitsand
food preference.In contrast, 26 of the 44 items were selected
as MBS-related items in the school-age group and classified
into seven factors (Table 4). Factor 1 was defined as incom-
petent lip sealbased on the items Are your lips droopy?and
Is your mouth often open during the day?. Factor 2 was
defined as diseases of the nose and throatbased on the
strong factor loading of Does your nose become stuffed easily
(during the day, while sleeping)?and Do you often have a
sore throat?. Based on the factor loading and content of the
other items, Factors 3, 4, 5, 6, and 7 were defined as eating and
drinking habits,”“bad breath,”“problems with swallowing
and chewing,”“condition of the teeth and gums,and dry
lips,respectively [15].
These results show that incompetent lip sealis a relevant
factor affecting MBS. In addition, the factors associated with
Fig. 4 eMeasurement of lip-closing strength. Fig. 4 adapted from Reference No. 14.
Fig. 5 eLip-closing strength of pre-school children.
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Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
MBS at the pre-school age are not unrelated, and multiple
factors such as general conditions, lifestyle, and eating habits
may interact with one another. Thus, the pre-school age may
represent the early stage of MBS development because it is an
important period for the development of lip-closing strength.
These findings indicate the importance of early diagnosis and
treatment of MBS, and may also facilitate the diagnosis of
MBS.
1.3. Morphological influence of an ILS on facial soft
tissue
Lip-closing strength refers to the force of the orbicularis oris
muscle and is an important examination parameter for den-
tists because the dental arch form is determined by the bal-
ance of pressure between the lips and the tongue [16e18]. Oral
habits such as finger-sucking, tongue thrust, lip biting, and
nail biting can cause various malocclusions by disrupting this
balance, and mouth breathing is possibly as important as
these oral habits [19,20]. Cabrera et al. reported that the
overjet and upper and lower incisor angles of mouth breathers
were greater than those of nasal breathers [21]. Harari et al.
reported that mouth breathing during critical growth periods
in children was associated with a higher tendency for clock-
wise rotation of the growing mandible, with a dispropor-
tionate increase in the anterior lower vertical face height and
decreased posterior facial height [22]. Thus, mouth breathing
affects the tooth axis as well as maxillofacial morphological
growth. Saccomanno et al. advocated the importance of a
combination of orthodontic treatment and myofunctional
treatment, which involves muscle conditioning, in order to
obtain the balance needed for the stability of orthodontic
treatment in patients with oral habits [23].
As mentioned above, the pre-school age is the develop-
mental period of the lip-closing strength that is also related
to the MBS, and is the time when various symptoms of the
Fig. 6 eLip-closing strength of school-age children.
Table 3 eFactor Analysis of MBS in Pre-school children.
Factor Questionnaire item Factor loading Definition of factor Degree of importance
Factor 1 6. Does your nose become stuffed easily during the day? 0.989 Diseases of the nose
7. Does your nose become stuffed easily while sleeping? 0.613
Factor 2 18. Is your mouth often open during the day? 0.631 Incompetent lip seal
19. Do you sleep with your mouth open? 0.539
29. Are your lips droopy? 0.453
Factor 3 43. Do you keep your mouth closed when you eat? 0.717 Eating habits
42. Are you a noisy eater? 0.606
Factor 4 40. Are you a picky eater? 0.638 Food preference
37. Do you prefer soft food? 0.487
pediatric dental journal xxx (xxxx) xxx6
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
Table 4 eFactor Analysis of MBS in school-age children.
Factor Questionnaire item Factor loading Definition of factor Degree of importance
Factor 1 29. Are your lips droopy? 0.980 Incompetent lip seal
18. Is your mouth often open during the day? 0.676
28. Are your teeth visible between your upper and lower lips? 0.633
19. Do you sleep with your mouth open? 0.533
21. Do you have an over bite? 0.490
26. Are your lips thick? 0.432
27. Is your upper lip turned upward? 0.427
Factor 2 6. Does your nose become stuffed easily during the day? 0.930 Diseases of the nose and throat
7. Does your nose become stuffed easily while sleeping? 0.828
9. Do you often have a runny nose? 0.738
8. Do you sneeze often? 0.671
11. Do you often have a sore throat? 0.415
Factor 3 36. Do your meals consist of small servings? 0.930 Eating and drinking habits
39. Do you eat fast? 0.828
40. Are you a picky eater? 0.738
44. Do you have food left in your mouth for a long time? 0.671
37. Do you prefer soft food? 0.415
Factor 4 16. Do people tell you that you have bad breath in the morning? 0.975 Bad breath
17. Do people tell you that you have bad breath during day? 0.768
Factor 5 42. Are you a noisy eater? 0.935 Problems with swallowing and chewing
43. Do you keep your mouth closed when you eat? 0.688
Factor 6 33. Are your teeth easily stained? 0.756 Condition of teeth and gums
35. Do you have tartar build-up? 0.669
31. Are your gums often swollen? 0.446
Factor 7 25. Are your lips often chapped? 0.916 Dry lips
30. Are your lips often cracked? 0.628
pediatric dental journal xxx (xxxx) xxx 7
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
MBS already appear. Therefore, we investigated the influ-
ence of an ILS on the form of facial soft tissue in pre-school
children. The participants were 444 pre-school children (225
boys and 219 girls) of three different ages (3, 4, or 5 years)
who had entered kindergarten from 2009 to 2013. The images
of the participants’ facial surface were obtained with a three-
dimensional laser scanner, and the questionnaire assess-
ment was completed by the participants’ guardians. Chil-
dren for whom the question Is your mouth often open
during the day?was answered as yeswere defined as
children with an incompetent lip seal (wILS), and children
for whom this result was nowere defined as children
without an incompetent lip seal (woILS). Three-dimensional
laser scans were acquired using a Vivid®910 laser scanner
(Konica Minolta, Tokyo, Japan). During the scans, the
participants sat relaxed in a chair with their heads in a
natural head position. The participant-to-scanner distance
wassetat1.5m,andtheparticipantswereinstructedtokeep
their jaw in the intercuspal position just before the scans
were taken. During the measurement, the participants were
instructed to lightly close their lips and watch forward
(Fig. 7-1). The three-dimensional coordinates of 16 facial
landmarks were established and identified on the three-
dimensional facial image (Fig. 7-2). Ten internal angles
were calculated and were compared between the wILS and
woILS at each age. The results showed obvious differences
between the groups in the following three angles [24].
1) The NeSn-Pog angle of wILS was significantly smaller than
that of woILS in four- and five-year-olds (Fig. 8-1),
Fig. 7 eMeasurement and calculation of facial soft tissue.
Fig. 8 eMean values of facial angles of children with and without incompetent lip seal. Fig. 4 adapted from Reference No. 24.
pediatric dental journal xxx (xxxx) xxx8
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
suggesting that children with an ILS had an anteriorly
prominent subnasale or posteriorly prominent mentum.
2) The Prn-N-Sn angle of wILS was significantly smaller than
that of woILS at all ages (Fig. 8-2), suggesting that children
with ILS had an anteriorly prominent subnasale or flat nose.
3) The (Sn-Ls) - (Li-Pog) angle of wILS wassignificantly smaller
than that of woILS at all ages (Fig. 8-3), suggesting that
children with ILS had an anteriorly prominent lip.
These results show that children with ILS already tend to
have a flattened nose and anteriorly prominent lip at the age
of 3 years, implying that the adverse effects of ILS on the
growth of the craniofacial region begins relatively early.
2. Conclusion
The results of our research suggest the importance of early
diagnosis and treatment of MBS, and early treatment of MBS
may prevent possible future dental and physical problems.
We think that proper treatment based on the most likely cause
is necessary to improve the MBS.
Since the mental and physical development of children
markedly influences their future health and personality
development, clarification of MBS occurring in children
during the developmental period is extremely important. In
the future, our research group plans to increase the number
of survey participants to clarify the functional and
morphological characteristics of MBS, and to verify the out-
comes of dental therapeutic intervention. We also expect
that these studies will enable the identification of the causes
of individual MBS and facilitate accurate selection of effec-
tive therapeutic interventions.
Declaration of competing interest
The authors declare no conflict of interest.
Acknowledgement
This work was supported by a Grant-in-Aid for Scientific
Research (grant no. 16K11809 and no. 19K10408) from the
Japan Society for the Promotion of Science of Japan.
references
[1] Campanha SM, Fontes MJ, Camargos PA, Freire LM. The
impact of speech therapy on asthma and allergic rhinitis
control in mouth breathing children and adolescents. J
Pediatr 2010;86:202e8.
[2] Okuro RT, Morcillo AM, Ribeiro MA, Sakano E, Conti PB,
Ribeiro JD. Mouth breathing and forward head posture:
effects on respiratory biomechanics and exercise capacity in
children. J Bras Pneumol 2011;37:471e9.
[3] Gulati MS, Grewal N, Kaur A. A comparative study of effects
of mouth breathing and normal breathing on gingival health
in children. J Indian Soc Pedod Prev Dent 1998;16:72e83.
[4] Nascimento Filho E, Mayer MP, Pontes P, Pignatari AC,
Weckx LL. Caries prevalence, levels of mutans streptococci,
and gingival and plaque indices in 3.0- to 5.0-year-old mouth
breathing children. Caries Res 2004;38:572e5.
[5] Conti PB, Sakano E, Ribeiro MA, Schivinski CI, Ribeiro JD.
Assessment of the body posture of mouth-breathing children
and adolescents. J Pediatr 2011;87:357e63.
[6] Juliano ML, Machado MA, de Carvalho LB, Zancanella E,
Santos GM, do Prado LB, et al. Polysomnographic findings are
associated with cephalometric measurements in mouth-
breathing children. J Clin Sleep Med 2009;5:554e61.
[7] Lofstrand-Tidestrom B, Thilander B, Ahlqvist-Rastad J,
Jakobsson O, Hultcrantz E. Breathing obstruction in relation
to craniofacial and dental arch morphology in 4-year-old
children. Eur J Orthod 1999;21:323e32.
[8] Choi JE, Waddell JN, Lyons KM, Kieser JA. Intraoral pH and
temperature during sleep with and without mouth
breathing. J Oral Rehabil 2016;43:356e63.
[9] Motta LJ, Bachiega JC, Guedes CC, Laranja LT, Bussadori SK.
Association between halitosis and mouth breathing in
children. Clinics 2011;66:939e42.
[10] Hsu HY, Yamaguchi K. Decreased chewing activity during
mouth breathing. J Oral Rehabil 2012;39:559e67.
[11] Chaves TC, de Andrade e Silva TS, Monteiro SA,
Watanabe PC, Oliveira AS, Grossi DB. Craniocervical posture
and hyoid bone position in children with mild and moderate
asthma and mouth breathing. Int J Pediatr Otorhinolaryngol
2010;74:1021e7.
[12] Boas AP, Marson FA, Ribeiro MA, Sakano E, Conti PB,
Toro AD, et al. Walk test and school performance in mouth-
breathing children. Braz J Otorhinolaryngol 2013;79:212e8.
[13] Stensson M, Wendt LK, Koch G, Nilsson M, Oldaeus G,
Birkhed D. Oral health in pre-school children with asthma-
followed from 3 to 6 years. Int J Paediatr Dent 2010;20:165e72.
[14] Fukami A, Saitoh I, Inada E, Oku T, Iwase Y, Takemoto Y,
et al. A reproducibility method to test lip-closing strength in
preschool children. Cranio 2010;28:232e7.
[15] Saitoh I, Inada E, Kaihara Y, Nogami Y, Murakami D,
Kubota N, et al. An exploratory study of the factors related to
mouth breathing syndrome in primary school children. Arch
Oral Biol 2018;92:57e61.
[16] Takada JI, Miyamoto JJ, Sato C, Dei A, Moriyama K.
Comparison of EMG activity and blood flow during graded
exertion in the orbicularis oris muscle of adult subjects with
and without lip incompetence: a cross-sectional survey. Eur J
Orthod 2017;40:304e11.
[17] Frohlich K, Thuer U, Ingervall B. Pressure from the tongue on
the teeth in young adults. Angle Orthod 1991;61:17e24.
[18] Trotman CA, McNamara Jr JA, Dibbets JM, van der Weele LT.
Association of lip posture and the dimensions of the tonsils
and sagittal airway with facial morphology. Angle Orthod
1997;67:425e32.
[19] Kasparaviciene K, Sidlauskas A, Zasciurinskiene E,
Vasiliauskas A, Juodzbalys G, Sidlauskak M, et al. The
prevalence of malocclusion and oral habits among 5-7-year-
old children. Med Sci Mon 2014;20:2036e42.
[20] Reyes Romagosa DE, Paneque Gamboa MR, Almeida
Muniz Y, Quesada Oliva LM, Escalona Oliva D, Torres
Naranjo S. Risk factors associated with deforming oral
pediatric dental journal xxx (xxxx) xxx 9
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
habits in children aged 5 to 11: a case-control study.
Medwave 2014;14:e5927.
[21] Cabrera Lde C, Retamoso LB, Mei RM, Tanaka O. Sagittal and
vertical aspects of Class II division 1 subjects according to the
respiratory pattern. Dental Press J Orthod 2013;18:30e5.
[22] Harari D, Redlich M, Miri S, Hamud T, Gross M. The effect of
mouth breathing versus nasal breathing on dentofacial and
craniofacial development in orthodontic patients.
Laryngoscope 2010;120:2089e93.
[23] Saccomanno S, Antonini G, D’Alatri L, D’Angelantonio M,
Fiorita A, Deli R. Causal relationship between malocclusion
and oral muscles dysfunction: a model of approach. Eur J
Paediatr Dent 2012;13:321e3.
[24] Inada E, Saitoh I, Kaihara Y, Murakami D, Nogami Y,
Kubota N, et al. Incompetent lip seal affects the form of
facial soft tissue in preschool children. Cranio
2019;37:1e7.
pediatric dental journal xxx (xxxx) xxx10
Please cite this article as: Inada E et al., Factors related to mouth-breathing syndrome and the influence of an incompetent lip seal on
facial soft tissue form in children, Pediatric Dental Journal, https://doi.org/10.1016/j.pdj.2020.10.002
... Tis study only considered two types of NNSH, namely, thumb sucking and pacifer sucking. Other types, i.e., nail biting, mouth breathing, and bruxism, may also have a deteriorating efect on oral health [23,[28][29][30][31]. Other limitations related to the present study were that bacteria other than E. coli were not considered. ...
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... In speech, oral inhalations are probably the most frequent [4]. At rest, nasal inhalation is the default and frequent mouth breathing in children is associated with dental and craniofacial problems [5,6]. Exhalations, which in speaking are typically used in combination with phonation to produce speech, may also occur without it [4]. ...
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Introduction: Dental and maxillofacial anomalies have multiple and complex causes. Most frequent among these are poor oral habits. A large number of children present with oral malocclusions, most of which are caused by deforming oral habits. It is important to learn about risk factors for this condition in order to institute preventive measures, early detection and treatment, and identification of low- and high-risk groups. Objectives: To identify risk factors associated with deforming oral habits, which, if maintained over time, are responsible for occlusion defects, speech disorders, and can affect physical and emotional child development. Methods: A case-control study of children presenting with deforming oral habits in the municipality of Manzanillo in Granma province was conducted between January and August 2013. 540 children aged 5 to 11 were included of which 180 had deforming oral habits and were asked to fill out a survey to identify specific type of habits leading to malocclusion. The case group was composed of children with deforming habits, and the remaining 360 children without poor oral habits were the control group. Each case was randomly matched to two control cases. The children mothers were also surveyed to gather supplemental information. Results: Children with deforming oral habits were mostly female. At age 10, onychophagia was the predominant oral deforming habit. Risk factors detected for these habits were sociobiological maternal and child variables such as low and high birth weight, maternal breastfeeding inexperience, and discord in the family. Conclusions: The study identified likely risk factors associated with deforming oral habits. These are discord in the family, birth weight, and lack of breastfeeding experience.
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Unlabelled: In recent decades, many studies on mouth breathing (MB) have been published; however, little is known about many aspects of this syndrome, including severity, impact on physical and academic performances. Objective: Compare the physical performance in a six minutes walk test (6MWT) and the academic performance of MB and nasal-breathing (NB) children and adolescents. Method: This is a descriptive, cross-sectional, and prospective study with MB and NB children submitted to the 6MWT and scholar performance assessment. Results: We included 156 children, 87 girls (60 NB and 27 MB) and 69 boys (44 NB and 25 MB). Variables were analyzed during the 6MWT: heart rate (HR), respiratory rate, oxygen saturation, distance walked in six minutes and modified Borg scale. All the variables studied were statistically different between groups NB and MB, with the exception of school performance and HR in 6MWT. Conclusion: MB affects physical performance and not the academic performance, we noticed a changed pattern in the 6MWT in the MB group. Since the MBs in our study were classified as non-severe, other studies comparing the academic performance variables and 6MWT are needed to better understand the process of physical and academic performances in MB children.
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Objective: To examine whether incompetent lip seal (ILS) influences the form of facial soft tissue. Methods: Four hundred forty-four preschool children 3–5 years of age were selected. The images of the subjects’ facial surface were obtained with a three-dimensional laser scanner. Coordinates of 16 facial landmarks were established and identified on the three-dimensional facial images, and the differences between children with (wILS) and without ILS (woILS) were measured. Results: The angle of sagittal facial convexity, excluding the nose, in 4- and 5-year-old children was significantly smaller in wILS children than in woILS children. The nasal prominence angle and the protrusion angle of lips in wILS children were significantly smaller than those in woILS children, at all ages. Conclusion: Children with ILS have anteriorly prominent subnasales and lips and flatter noses. The influence of ILS on facial form begins to appear even before 3 years of age.
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Objective: Mouth breathing syndrome (MBS) is defined as a set of signs and symptoms that may be completely or incompletely present in subjects who, for various reasons, replace the correct pattern of nasal breathing with an oral or mixed pattern. It is important to identify the relevant factors affecting MBS in order to diagnose its cause since breathing obstructions can result from multiple factors. The purpose of this study is to clarify the relevant factors and the interrelationships between factors affecting MBS among children. Design: We surveyed 380 elementary school children from 6 to 12 years in age. The questionnaire consisted of 44 questions regarding their daily health conditions and lifestyle habits and was completed by the children's guardians. A factor analysis was performed to classify closely related questions into their respective factors and to examine the strength of the correlation between the newly revealed factors. Results: Twenty-six out of the 44 questions were selected, and they were classified into seven factors. Factors 1-7 were defined as "Incompetent lip seal", "Diseases of the nose and throat", "Eating and drinking habits", "Bad breath", "Problems with swallowing and chewing", "Condition of teeth and gums", and "Dry lips", respectively. There were also correlations between these factors themselves. Conclusion: MBS was categorized according to 7 major factors. Because Factor 1 was defined as "Incompetent lip seal", which was representative of the physical appearance of mouth breathers and correlated with other factors, we suggested that MBS should consist of 7 factors in total.
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The prevalence of breathing obstruction was determined in a cohort of 4-year-old children. Craniofacial morphology was studied in obstructed children and compared with data from a control group of ...