Malocclusion prevention through the usage of an orthodontic pacifier compared to a conventional pacifier: a systematic review

Abstract

Aim: This was to investigate the occurrence of malocclusion traits among children who were users of orthodontic or conventional pacifier by means of a systematic review.
Methods: Search for articles involved five electronic databases: Latin American and Caribbean Health Sciences (LILACS), PsycINFO, PubMed (including MedLine), Scopus and Web of Science. Grey literature was partially assessed. Observational studies with children aged 6–60 months who had used orthodontic or conventional pacifier were included. The risk of bias among included studies was assessed through the Joanna Briggs Institute Tool.
Results: From the 607 initially-identified papers only three were included after the selection process. All presented moderate risk of bias. Although an anterior open bite and accentuated overjet were identified among conventional users of pacifier in one study, no differences were identified in the other two selected studies. Posterior crossbite frequency was not different in any of the included studies. There was also no difference regarding frequency and duration of use, except in the study that showed higher occurrence of open bite malocclusion in conventional pacifier users.
Conclusions: The currently available evidence is insufficient to support the concept that the usage of orthodontic pacifiers is able to prevent malocclusion traits when compared to the usage of conventional pacifiers.

Full text

Vol.:(0123456789)
1 3
European Archives of Paediatric Dentistry
https://doi.org/10.1007/s40368-018-0359-3
SYSTEMATIC REVIEW
Malocclusion prevention throughtheusage ofanorthodontic pacifier
compared toaconventional pacifier: asystematic review
R.Medeiros1· M.Ximenes2· C.Massignan1· C.Flores‑Mir3 · R.Vieira1· A.L.Porporatti4· G.DeLucaCanto3,4
Received: 3 October 2017 / Accepted: 16 May 2018
© European Academy of Paediatric Dentistry 2018
Abstract
Aim This was to investigate the occurrence of malocclusion traits among children who were users of orthodontic or conven-
tional pacifier by means of a systematic review.
Methods Search for articles involved five electronic databases: Latin American and Caribbean Health Sciences (LILACS),
PsycINFO, PubMed (including MedLine), Scopus and Web of Science. Grey literature was partially assessed. Observational
studies with children aged 6–60months who had used orthodontic or conventional pacifier were included. The risk of bias
among included studies was assessed through the Joanna Briggs Institute Tool.
Results From the 607 initially-identified papers only three were included after the selection process. All presented moderate
risk of bias. Although an anterior open bite and accentuated overjet were identified among conventional users of pacifier in
one study no differences were identified in the other two selected studies. Posterior crossbite frequency was not different in
any of the included studies. There was also no difference regarding frequency and duration of use, except in the study that
showed higher occurrence of open bite malocclusion in conventional pacifier users.
Conclusions The currently available evidence is insufficient to support the concept that the usage of orthodontic pacifiers is
able to prevent malocclusion traits when compared to the usage of conventional pacifiers.
Keywords Malocclusion· Pacifier· Systematic review· Primary teeth
Introduction
Non-nutritive sucking is a natural reflex for infants; it can
be an important first step in the infant’s development of
self-regulation and ability to control emotion (Adair etal.
1992; Casamassimo 1996; Pinkham etal. 1999; Ponti etal.
2003). The use of a pacifier is a common habit existent in
children, and it is supported by American Academy of Pedi-
atrics (AAP 2015) due to beneficial effects during the first
6months of life (Sexton and Natale 2009). Pacifiers have a
tranquilising effect, and promote pain relief (Nelson 2012).
However, their excessive usage may cause changes to the
primary dentition occlusion that may last into the permanent
dentition (Warren etal. 2000; Duncan etal. 2008; Varas
etal. 2012; Nihi etal. 2015).
Evidence suggests that pacifiers may be an important a
etiological factor for developing malocclusions, due to inter-
ference on the physiological movements of perioral muscles
(Sousa etal. 2014). Among pacifier users, approximately
27% of children aged 2–5years old may develop some
type of malocclusion (Nihi etal. 2015). Among infants,
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s4036 8-018-0359-3) contains
supplementary material, which is available to authorised users.
* M. Ximenes
marcosximenes@hotmail.com
1 Departamento de Odontologia, Universidade
Federal de Santa Catarina, UFSC, Campus
Universitário, CCS-ODT-Trindade, Florianopolis,
SantaCatarina88040-900, Brazil
2 Departamento de Odontologia, Universidade doSul de
Santa Catarina - UNISUL, Cidade Universitária, Palhoça,
SantaCatarina88137-270, Brazil
3 University ofAlberta, 5528 Edmonton Clinic Health
Academy, Edmonton, Canada
4 Departamento de Odontologia, Brazilian Centre
forEvidence-based Research, Universidade Federal de Santa
Catarina, UFSC, Campus Universitário, CCS-ODT-Trindade,
Florianopolis, SantaCatarina88040-900, Brazil

European Archives of Paediatric Dentistry
1 3
the prevalence of anterior open bite ranges from 17 to 96%.
Posterior crossbite presents rates from 27 to 88%, but for
children with no sucking habits these rates reach only 11%
(Lima etal. 2016). The presence of increased overjet is diag-
nosed in 52% of pacifier users, and almost in 33% of non-
users (Lima etal. 2016). In contrast, among children who
did not use pacifiers, only 3% presented malocclusion (Nihi
etal. 2015; Lima etal. 2016).
Studies have suggested that a malocclusion associated
with pacifier usage is influenced by its frequency, duration
and intensity (Modéer etal. 1982; Lima etal. 2016). The
longer the duration, the greater the malocclusion frequency,
and the greater the intensity of the sucking habit, the greater
the chance of developing a malocclusion (Modéer etal.
1982; Bishara etal. 2006; Abrahão etal. 2009). The usage
of a pacifier beyond the age of 3years may also influence the
development of a malocclusion (Poyak 2006).
There are two different types of pacifiers classified
according to their anatomical form (conventional pacifier
and orthodontic pacifier). A conventional pacifier (CP) is
also known as “cherry” nipple, which have a trunk that
becomes ball-shaped. They have no right way up and are
not considered “orthodontic”. The orthodontic pacifier (OP)
are made with a flattened nipple to simulate mothers’ nipple
anatomy aiming to reduce the risk of malocclusion due to
the tongue positioning during sucking and acceptable lip
seal (Adair etal. 1995; del Zardetto etal. 2002; Mesomo
and Losso 2004; Lima etal. 2016).
Although pacifiers are largely used and marketed with
a nipple-like design to reduce the risk of malocclusion
there is only a small number of studies that have compared
the two types of pacifiers. A systematic review published
which included four studies concerning interference of con-
ventional and orthodontic nipples in the stomatognathic
system reported that there was no possibility of identifying
the existence of differences regarding the consequences of
the usage of different shapes of pacifiers (De Castro Corrêa
etal. 2016). That previous systematic review did not include
parameters such as frequency and duration of pacifier usage.
In addition, new studies in the topic have been published
since the previous review, in July 2014. Therefore it was
proposed to review, the latest data aiming to answer the fol-
lowing question: “In children between 6–60months, is there
a difference in the occurrence of malocclusion between the
types of the pacifiers (conventional or orthodontic) used?”.
Methods
The Preferred Reporting Items for Systematic Reviews
and Meta-Analysis (PRISMA) Checklist was followed
in this systematic review (Moher etal. 2015). This pro-
tocol was completed and registered at the International
Prospective Register of Systematic Reviews (PROSPERO
CRD42016045826) (PROSPERO 2017).
Eligibility criteria
To be included, the selected articles had to be observational
studies performed with children aged 6–60months who had
used an orthodontic or a conventional pacifier. All aspects
associated with pacifier usage were accepted: any evaluation
of frequency, duration or intensity described in the studies.
Articles published and unpublished, in all languages, with
no publication’s time restriction were included.
Exclusion criteria
The exclusion criteria followed the PECOS (Needleman
2002) strategy: (P—participants) (1) studies in which sam-
ple included children with genetic syndrome (e.g., Down’s
syndrome, craniofacial anomalies, neuromuscular disorders,
etc.); (2) studies in which a sample included children pre-
senting malignancies, malnutrition and chronic diseases;
(3) studies in children with other non-nutritional sucking
habits, or tongue throat, or enlarged adenoids, or respiratory
problems; (4) studies in which children with history of use
of orthodontic appliances; (5) studies conducted in children
over 60months; (6) studies in which the sample included
maxillofacial surgery; (E—exposure): (7) studies that did not
measure pacifier usage characteristics; (8) in children who
used both models of pacifiers simultaneously (orthodontic
and conventional) or did not differentiate groups by types
of pacifiers; (C—comparison) studies: (9) without an active
control group (conventional pacifier); (S—types of Stud-
ies) (10) duplicated references with the same sample; and
(11) reviews, letters, personal opinions, case reports, book
chapters and conference abstracts. Those studies identified
in the search and selected for the full-text reading however
were not available, were registered under the number (12)
article not found.
Information sources andresearch strategies
An electronic search was conducted on May 5th 2016, with
an update on Aug 27th 2017. Detailed individual research
strategies for each of the following electronic databases
were performed: Latin American and Caribbean Health
Sciences (LILACS), PsycINFO, PubMed (including Med-
Line), Scopus and Web of Science. A partial grey litera-
ture research was taken using Google Scholar and the data-
base System for Information on Grey Literature in Europe
(OpenGrey). Dissertations and theses were searched using
the ProQuest Dissertations and Theses database. In addi-
tion, hand searching of the reference lists of selected studies
was performed. The research terms were developed with

European Archives of Paediatric Dentistry
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the aid of an experienced health sciences librarian and were
comprehensive to include studies reporting on orthodontic
or conventional pacifier usage and malocclusion, under a
range of other synonyms (Online Reource 1). References
were managed by referenced manager software EndNote®
Basic (Thomson Reuters, New York, EUA) and duplicated
results were removed.
Study selection
Articles where selected in two phases. Two reviewers (RM
and MX) independently examined the titles and abstracts
of all references to eliminate obviously irrelevant studies in
phase-1. In phase-2, full-texts were independently reviewed
by the same reviewers (RM and MX), and screened accord-
ingly. Disagreements were settled by discussion and a third
reviewer (CM) was consulted if necessary to make a final
decision.
Data collection process
One reviewer (RM) performed data extraction and a second
reviewer (MX) crosschecked all the retrieved information
with any disagreement resolved by consensus. A third author
(CM) was involved when required to make a final decision.
Data items
The following data were extracted: study characteristics
(author, year, country, design, setting), population char-
acteristics (sample size, age), and outcome characteristics
(main results). Attempts were made to contact the authors
to retrieve any pertinent unpublished information in case the
required data were not complete or clear.
Risk ofbias inindividual studies
The Meta-Analysis of Statistics Assessment and Review
Instrument (MAStARI) from the Joanna Briggs Institute was
the risk-of-bias tool used (Institute Joanna Briggs Institute
Reviewers’ Manual 2014). Two reviewers (RM and MX)
independently categorised methodological quality of the
selected studies as high risk of bias when the study reached
up to 49% score “yes”, moderate 50–69% score “yes”, and
low for more than 70 percent score “yes”. Inconsistencies
in ratings were resolved by consensus when possible or a
third reviewer (CM) made the final decision. The RevMan
Software (Review Manager, version 5.3 software, Cochrane
Collaboration, Copenhagen, Denmark) was used to generate
the risk-of-bias summary with adaptation for the nine ques-
tions of MAStARI.
Summary measures
Presence of a malocclusion trait was considered the main
outcome. The assessed malocclusions traits were: increased
overjet (> 2mm); anterior openbite (absent: presence of
overbite or anterior end-to-end bite or present); posterior
crossbite (absent: normal transverse relationship between the
maxillary and mandibular posterior teeth or present: one or
more maxillary posterior teeth abnormally for palatal rela-
tive to the antagonist). Posterior crossbites were assessed
unilaterally or bilaterally.
Synthesis ofresults
A meta-analysis of proportion was planned for this study,
however, due to the small number of studies finally included
and methodological differences among the included studies,
this was not done.
Results
Studies selection
The search found 607 articles across five databases. Dupli-
cates were removed and 444 studies were screened. Fur-
thermore, additional studies were identified: Google scholar
(17), Opengrey (2), Proquest (1), and reference lists (2).
From these, only one study met the inclusion criteria. After
titles and abstracts reading, 119 papers were selected for
the second phase (full-text reading). According to exclu-
sion criteria, 116 studies were excluded and four studies
were suitable for answering the review question. However,
two studies presented data from the same sample, so the
preliminary study was excluded. Thus, three studies were
finally included in this systematic review. Figure1 shows a
flowchart describing the process of identification, inclusion,
and exclusion of studies and the reasons for exclusion are
compiled in a comprehensive list (Online resource 2).
Study characteristics
Among the three studies, two were cross-sectional studies
(Adair etal. 1995; del Zardetto etal. 2002) and one retro-
spective cohort (Lima etal. 2016). Selected studies were
carried out in Brazil (two studies) (del Zardetto etal. 2002;
Lima etal. 2016), and United States of America (USA) (one
study) (Adair etal. 1995) with papers published in 1995
(Adair etal. 1995), 2002 (del Zardetto etal. 2002) and 2016
(Lima etal. 2016). The sample ages ranged in months from
24 to 60 (Adair etal. 1995; Lima etal. 2016) and 36 to 60
(del Zardetto etal. 2002) months, and sample size was 61
(del Zardetto etal. 2002), 220 (Lima etal. 2016) and 218

European Archives of Paediatric Dentistry
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(Adair etal. 1995) children. Table1 summarises the descrip-
tive characteristics of the included studies.
Risk ofbias withinstudies
According to MAStARI, three studies presented with a
moderate risk of bias (Adair etal. 1995; del Zardetto etal.
2002; Lima etal. 2016). The moderate risk was associated
to the uncertainty of sample randomisation; they all were
convenience samples. In relation to confounding factors,
the authors excluded: children with other non-nutritive
sucking habits; mouth breathers and children with lin-
gual interposition. Although questionnaires were used
WEB OF SCIENCE
n=67
SCOPUS
n=160
PUBMED
n=154
Full-text arcles assessed for eligibility
n= 119
PSYCINFO
n=1
Studies included in qualitave and quantave
synthesis
n=3
Records aer duplicates removed
n=444
Full arcles excluded with reasons
(n=116)
1- Genec syndromic paents(n=0)
2- Presenng malignancies, malnutrion
and chronic diseases (n=0)
3- Other non-nutrional sucking habits or
lingual interposion or enlarged adenoids or
respiratory problems (n=1)
4- Use of orthodonc appliances (n=0)
5- Children over 60 months (n=3)
6- Sample included maxillofacial surgery
(n=0)
7- Did not measure pacifier usage
characteriscs (n=2)
8- Used both models of pacifiers or not
differenate groups by types of pacifiers
(n=100)
9- Withoutan acve control group
(convenonal pacifier) (n=1)
10-Duplicated references with the same
sample (n=2)
11-Reviews, leers, personal opinions, case
reports, book chapters and conference
abstracts(n=1)
12-Arcles not found(n=6)
Records screened from databases
n= 118
Idenficaon
Screening
Reference
lists
n=0
EligibilityIncluded
Records screened from ProQuest
n=0
Records idenfied through database searching
n=607
Reference
lists
n=2
ProQuest
n=1
Updated
search
n=1
Updated
search
n=0
Records screened from
OpenGrey
n= 0
OpenGrey
n=2
Google Scholar
n=17
Records screened from Google Scholar
n=1
LILACS
n=225
Fig. 1 Flow diagram of literature search and selection criteria. Adapted from PRISMA

European Archives of Paediatric Dentistry
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Table 1 Summary of descriptive characteristics of included articles (n = 3)
CP conventional pacifier, OP orthodontic pacifier, h/d hours per day, AO accentuated overjet, AOB anterior open bite, PCB posterior crossbite
Study Population Outcomes
Author, year,
country
Study design Setting Age (months) Total n OP Total n CP Prevalence (%)
OP
Prevalence (%)
CP
Frequency Duration
(mean
months)
Main conclusion
Adair etal.
(1995), USA
Cross-sectional Daycare centres
and dental
clinics
24–59 82 38 AOB = 13.4
PCB = 15.9
AOB = 23.7
PCB = 13.2
OP = 6.7h/d
CP = 6.5h/d
OP = 15.4
CP = 19.8
There appeared to
be no advantage
to OP over CP
del Zardetto etal.
(2016), Brazil
Cross-sectional Schools 36–60 20 14 AO = 58
AOB = 50
PCB = 10
AO = 64
AOB = 50
PCB = 14
OP = 68% (sleep-
ing)
CP = 71% (sleep-
ing)
OP = 43
CP = 45
The prevalence and
degree of some
alterations were
lower in the OP
group than in
the CP
Lima etal. (2016),
Brazil
Cohort Private
Maternity, hos-
pitals
24–36 50 50 AO = 41.8
AOB = 63.6
PCB = 5.4
AO = 56.3
AOB = 80
PCB = 9
OP = 67.3% (day/
nighttime)
CP = 78.2% (day/
nighttime)
OP = 25
CP = 27
The use of CP was
associated to
severe anterior
open bite and
overjet compared
to use of OP

European Archives of Paediatric Dentistry
1 3
regarding the frequency and duration of the habit, parents/
guardians may have had difficulty to rememeber the facts.
A summarized assessment that considered risk of bias
can be found in Fig.2. Detailed results on the use of the
MAStARI tool in selected studies can be found in Online
Resource 3.
Results ofindividual studies
All selected studies analysed the presence of anterior open
bite, increased overjet, and posterior crossbite (Adair etal.
1995; del Zardetto etal. 2002; Lima etal. 2016).
Anterior open bite
Anterior open bite was greater in current users of pacifiers
(3.6mm) than recent (2.0mm) or early (2.2mm) discontinu-
ers of them, though these differences were not statistically
significant.
Overjet
del Zardeto etal. (2002) and Lima etal. (2016) used the
same selection criteria to determine increased overjet
(> 2mm), while Adair etal. (1995) used ≥ 4mm. del Zard-
eto etal. (2002) showed statistically significant difference
in increased accentuated overjet between groups, 58% in
OP and 64% in CP. However, Lima etal (2016) found no
significant difference in overall overjet (41.8% for OP and
56.3% for CP). Although they also measured overjet in
mm and it was higher in CP (3.38mm) compared to OP
(2.54mm). The 0.84mm difference was considered statisti-
cally significant.
Posterior crossbite
There was a significantly higher percentage of posterior
crossbite (21.1%) among those who had used pacifiers for
A Cohort Study. B Cross-sectional Studies.
Fig. 2 Summary of the risk of bias assessment according to the Meta-Analysis of Statistics Assessment and Review Instrument (MAStARI)—
figure performed with the aid of RevMan (Review Manager, version 5.3 software, Cochrane Collaboration, Copenhagen, Denmark)

European Archives of Paediatric Dentistry
1 3
more than 15.5months compared with those who had the
habit for less than 15.5months (6.1%) (Adair etal. 1995).
Amount ofusage factors
Concerning frequency, Lima etal. (2016) observed that
approximately 78.2% of the children in CP and 67.3% of
the children in OP used pacifiers day and night, and this
difference was not significant. Similarly, del Zardetto etal.
(2002) found that 71% of users of CP and 68% of users of
OP had the habit while sleeping—a difference that also was
not significant. Adair etal. (1995) showed differences in
reported hours (mean) of use per day, CP pacifier was used
6.5 and OP 6.7h/day (p = 0.74).
Regarding duration, Lima etal. (2016) recorded no sig-
nificant difference between groups (CP 27months and OP
25months). Adair etal. (1995) and del Zardeto etal. (2002)
found also no statistically difference. The mean time of
usage (months) ranged from 19.8 to 45.0 in CP and from
15.4 to 43.0 in OP.
Current users constituted 50% of all crossbite cases, while
those who discontinued recently or early made up 27.7 and
22.2% of crossbite cases, respectively (Adair etal. 1995).
Only one study (Lima etal. 2016) verified the intensity by
means of contracting the muscles (“made faces”) or “made
noises” while sucking the pacifier. In both groups intensity
was similar, 81.8% of the children in CP, and 74.5% of the
children in OP were described as not making any sucking
effort.
Discussion
This systematic review evaluated the differences in the
occurrence of malocclusion in children that used an ortho-
dontic pacifier or a conventional pacifier. The results indi-
cated that there are only a very few studies that compared
these pacifier types. In addition, these studies presented
limitations that compromised categorical conclusions. It
was observed that factors such as duration and frequency of
use of any type of pacifier shape were more associated with
the development of malocclusion and the main malocclusion
traits associated with pacifier usage were mostly limited to
changes in the position of the incisors such as an anterior
open bite, overjet and posterior crossbite (Adair etal. 1995;
del Zardetto etal. 2002; Lima etal. 2016).
Two of the three studies included in this review showed
no significant differences on the prevalence of malocclu-
sion comparing users of pacifiers. Only one study, with
moderate risk of bias, indicated that an open bite and over-
jet (both p = 0.001) were more frequent in children who
used conventional pacifiers when compared to children
that used orthodontic pacifiers. The difference between
results may be due to the small sample size and age range.
Adair etal. (1995) evaluated 120 children and delZard-
etto etal. (2002) 34 and both investigated up to 59 and
60months respectively. On the other hand, Lima etal.
(2016) reported a sample up to 36months in sample size
of 100 children. Although this single study identified sig-
nificant difference in anterior open bite and overjet, the
measurements in millimeters indicated that this difference,
3 and 4mm respectively, could be clinically significant.
It is important to emphasise that studies have shown
that auto-correction of anterior open bite may occur after
cessation of the habit in children between 4 and 6years of
age (Heimer etal. 2008), which may also have occurred
in the studies of delZardetto etal. (2002) and Adair etal.
(1995).
The studies showed that occlusal changes deformities
associated with oral habits depend on the intensity, dura-
tion and frequency of the habit (AAPD 2009). However,
parameters were measured differently. In one study, the
authors measured frequency in hours per day of use (Adair
etal. 1995), whereas other two articles evaluated in day-
time and/or nighttime (del Zardetto etal. 2002; Lima etal.
2016). Nevertheless, the frequency was similar between the
groups of conventional and orthodontic pacifier. The average
hours of usage per day shown in the studies was the quantity
considered by the literature as a factor of alteration in the
dental arch (Nelson 2012). The number of hours of usage
is an important variable for the initiation of a malocclusion,
4–6h of use per day is considered to facilitate malocclu-
sion development (Warren etal. 2000). The literature inves-
tigated showed most of the children used a pacifier during
their sleeping time. The recommendations of pacifier usage
report that it should be used when the infant is sleeping and
not reinserted if the child lets it drop during sleep (Chair-
person etal. 2005).
Concerning duration of the habit, independently of the
shape of the pacifier, although the design of the cross-sec-
tional study does not allow estimation of cause and effect
as the participants were evaluated at the same time, a study
suggested was that there is association with malocclusion,
especially in anterior open bite and posterior cross bite
(Adair etal. 1995).
In general, the duration of use was greater in CP users;
however, there was no difference in number of months of
pacifier usage between the two types of pacifier. Studies sug-
gested the usage of more than 36months interferes in occlu-
sion and the longer the duration in months, the greater the
chance of this interference. It seems that malocclusion may
be more related to the length of time of use than the design
of the pacifier (Abrahão etal. 2009; Sousa etal. 2014). A
study suggested that transverse occlusal relationship should
be evaluated between 2 and 3years of age mainly in young
pacifiers users (Bishara etal. 2006).

European Archives of Paediatric Dentistry
1 3
Although the literature has supported that pacifier use
interferes with the occlusion in children (Martins etal.
2003; Góis etal. 2008; Melink etal. 2010; Ize-Iyamu and
Isiekwe 2012; Dimberg etal. 2013; Germa etal. 2016),
there is no indication for prohibiting its use (Sexton and
Natale 2009). Besides being of great value to cherish the
infant and helping the parents to calm the crying it could
possibly act as an analgesic (Nelson 2012).
Although no randomised clinical trials supporting this
evidence have been found (Psaila etal 2017), research
suggests beneficial effects to the child’s health, such as
reducing the risk of sudden infant death syndrome (Alm
etal. 2016). The American Academy of Pediatrics and
the American Academy of Family Physicians (Sexton and
Natale 2009) recommend the usage of a pacifier in the first
month and limit it’s usage from the second to the sixth
months of life to reduce the risk of otitis media (Niemelä
etal. 2000). The Canadian Paediatric Society (2004) rec-
ommends that until further research leads to more conclu-
sive evidence on adverse outcomes, health care profession-
als should recognize pacifier usage as a parental choice
determined by the needs of their newborn or infant.
There are perceived harmful effects during the usage
of pacifiers, especially malocclusion trait’s development,
as there are increasing indications that the adverse effects
are related to the non-rational use, i.e. the indiscriminate
use without proper guidance of the pacifier indication by a
health care professional (Nelson 2012). The rational prac-
tice would be for sleeping and for less than 4–6h per day
(Warren etal. 2000).
Notwithstanding the effort to minimize bias across stud-
ies in this systematic review, the following limitations
could be pointed out: failure of parents to retrospectively
identify the type of pacifier used (Wagner and Heinrich-
Weltzie 2016); genetic factors and facial growth pattern
of the children were not assessed; lack of standardisation
of ages across studies and use of different parameters to
measure intensity, duration and frequency (Lima etal.
2016). In addition, most of the studies did not use the
same measures to define malocclusion traits.
Other relevant factor not considered would be dental
eruption timing, whether late or not. Most of the children
began using the pacifier before 6months of age, thus,
probably before tooth eruption, which can influence the
occlusal alteration as to the duration of the habit reported
by the parents (del Zardetto etal. 2002).
Despite the controversies, the usage of pacifiers may
bring benefits to a child (AAPD 2009; AAP 2015).
Therefore, the radical behaviour against using it should
not be indicated. It is important to make parents aware
of its rational usage, in order to avoid malocclusion and
bring the expected benefits. When indicating a pacifier
shape, be conscious that the anatomy of the pacifiers is
not a determinant to protect the occlusion compared to
frequency and duration.
Conclusions
There is not sufficient evidence to support concept that there
are differences in occurrence of malocclusion traits between
children that used orthodontic or conventional pacifiers.
Although, it was observed that there is a higher prevalence
of malocclusion among children that used pacifiers than in
children without pacifier sucking habit, independently of
the pacifier shape. Further high-quality investigations are
required to support orthodontic pacifier as a recommenda-
tion to prevent malocclusion trait’s development.
Author contributions RM: Worked on study conceptualization,
design, data collection, data analysis, drafted the initial manuscript.
MX: Worked on data collection, data analysis, reviewed and revised
the manuscript, and approved the final manuscript as submitted. CM:
worked on data analysis, critically reviewed the manuscript, and
approved the final manuscript as submitted. CFM: worked on study
conceptualization, design, data analysis, critically reviewed manuscript,
and approved the final manuscript as submitted. RV: revised the manu-
script, and approved the final manuscript as submitted. ALP: worked
on study conceptualization, design, data analysis, critically reviewed
manuscript, and approved the final manuscript as submitted. GDLC:
worked on study conceptualization, design, data analysis, critically
reviewed manuscript, and approved the final manuscript as submit-
ted. All authors have made substantive contribution to this manuscript.
Funding No funding was secured for this study.
Compliance with ethical standards
Conflict of interest The authors have no financial relationships relevant
to this article to disclose and have no conflicts of interest to disclose.
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