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RESEARCH ARTICLE
Assessment of the ergonomic risk from
saddle and conventional seats in dentistry: A
systematic review and meta-analysis
Giovana Renata GouvêaID
1☯
*, Walbert de Andrade Vieira
2☯
, Luiz Renato Paranhos
3☯
, I
´talo
de Macedo Bernardino
4☯
, Jaqueline Vilela Bulgareli
1☯
, Antonio Carlos Pereira
1☯
1Department of Community Dentistry, School of Dentistry of Piracicaba, University of Campinas, Piracicaba,
SP, Brazil, 2Department of Dentistry, University of Sergipe, Aracaju, SE, Brazil, 3Department of Preventive
and Community Dentistry, School of Dentistry, Federal University of Uberla
ˆndia, Uberla
ˆndia, MG, Brazil,
4Postgraduate Program in Dentistry, State University of Paraı
´ba, Campina Grande, PB, Brazil
☯These authors contributed equally to this work.
*gigouvea@hotmail.com
Abstract
Objective
This study aimed to verify whether the saddle seat provides lower ergonomic risk than con-
ventional seats in dentistry.
Methods
This review followed the PRISMA statement and a protocol was created and registered in
PROSPERO (CRD42017074918). Six electronic databases were searched as primary
study sources. The "grey literature" was included to prevent selection and publication
biases. The risk of bias among the studies included was assessed with the Joanna Briggs
Institute Critical Appraisal Tool for Systematic Reviews. Meta-analysis was performed to
estimate the effect of seat type on the ergonomic risk score in dentistry. The heterogeneity
among studies was assessed using I
2
statistics.
Results
The search resulted in 3147 records, from which two were considered eligible for this review.
Both studies were conducted with a total of 150 second-year dental students who were start-
ing their laboratory activities using phantom heads. Saddle seats were associated with a sig-
nificantly lower ergonomic risk than conventional seats [right side (mean difference = -3.18;
95% CI = -4.96, -1.40; p <0.001) and left side (mean difference = -3.12; 95% CI = -4.56,
-1.68; p <0.001)], indicating posture improvement.
Conclusion
The two eligible studies for this review provide moderate evidence that saddle seats provided
lower ergonomic risk than conventional seats in the examined population of dental students.
PLOS ONE | https://doi.org/10.1371/journal.pone.0208900 December 17, 2018 1 / 14
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OPEN ACCESS
Citation: Gouvêa GR, Vieira WdA, Paranhos LR,
Bernardino I
´dM, Bulgareli JV, Pereira AC (2018)
Assessment of the ergonomic risk from saddle and
conventional seats in dentistry: A systematic
review and meta-analysis. PLoS ONE 13(12):
e0208900. https://doi.org/10.1371/journal.
pone.0208900
Editor: Fabian Huettig, Eberhard-Karls-Universitat
Tubingen Medizinische Fakultat, GERMANY
Received: April 23, 2018
Accepted: November 26, 2018
Published: December 17, 2018
Copyright: ©2018 Gouvêa et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: All relevant data are
within the paper and its Supporting Information
files.
Funding: This work was supported by
Coordenac¸ão de Aperfeic¸oamento de Pessoal de
Nı
´vel Superior (CAPES) - process # 1595065, and
by Conselho Nacional de Desenvolvimento
Cientı
´fico e Tecnolo
´gico (CNPq) - process #
157080/2014-5.
Introduction
Occupational health has been extensively investigated in dentistry [1–4], considering that den-
tists are professionals highly vulnerable to musculoskeletal diseases [5,6], especially in the cer-
vical and lumbar spines [7]. Working posture is the main risk factor for developing
musculoskeletal disorders [8–9].
The sitting posture is the body position that dentists use most frequently [10]. The dental
stool has an influence on such posture [11–13], because it induces the use of certain postural
patterns to find a more comfortable and/or functional position [11–13]. In addition, the curva-
ture of the spine, as well as the location and correct position of the head and pelvis are crucial
for the biomechanics of the sitting position [14–16].
There is evidence that the 90˚ sitting posture (knee angle and hip angle) increases the pas-
sive tension of hamstring muscles, causing a posterior pelvic rotation and resulting in a
kyphotic sitting posture of the lumbar spine [17–18]. However, ergonomic recommendations
[19], radiographic studies [17–18], and analyses from physical therapists [20] and laypersons
[21,22] indicate that a sitting posture with a slight anterior tilt of the lumbar spine and a slight
lumbar lordosis of the lumbar spine reduces the incidence of low back pain most efficiently.
Aiming to reduce postural problems in dentistry, scientific studies have been performed to
elucidate the impact of different types of seats on the posture of students and trained profes-
sionals [16,23], as well as the importance of ergonomic seat interventions [14] in reducing
musculoskeletal symptoms [15]. However, the literature does not yet provide a consensus on
whether the saddle seat is a superior alternative to the conventional seat for maintaining opti-
mal posture.
Thus, the present study aimed to answer the following guiding question (based on the
PICO strategy): “Does the saddle seat (intervention) provide lower ergonomic risk (outcome)
to dentists and/or dental students (population) when compared with conventional seats (com-
parison)?” The authors have tested the hypothesis that using the saddle seat will promote lower
ergonomic risk than the conventional seat.
Methods
Protocol and registry
This systematic review was performed following the PRISMA (S1 PRISMA Checklist) state-
ment (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) [24] and the
Cochrane guidelines [25]. The systematic review protocol was registered in the PROSPERO
database under number CRD42017074918 (https://www.crd.york.ac.uk/PROSPERO/).
Study design and eligibility criteria
The review included only randomized controlled trials that compared the working posture of den-
tal students and/or dentists in conventional seats without ergonomic changes and in ergonomic
saddle seats. There were no restrictions of year, language, or publication status (ahead of print).
The following were excluded: 1) Studies not related to the topic; 2) Reviews, letters to the
editor, personal opinions, book/book chapters, didactic material, reports, abstracts, and pat-
ents; 3) Qualitative or prevalence studies; and 4) Studies that used other types of seats or modi-
fied seats.
Sources of information and research
The primary sources of research were the electronic databases Embase, Latin American and
Caribbean Health Sciences (LILACS), PubMed (including MedLine), SciELO, Scopus, and
Assessment of the ergonomic risk in dentistry
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Competing interests: The authors have declared
that no competing interests exist.
Web of Science. OpenThesis and OpenGrey were used to collect the “grey literature”, avoiding
selection and publication biases. A manual search was also performed through a systematic
analysis of the references of the eligible articles.
Two eligibility reviewers conducted the research independently (GG and WAV). The DeCS
(Descriptors in Health Sciences– http://decs.bvs.br) and MeSH (Medical Subject Headings–
https://www.ncbi.nml.nih.gov/mesh) resources were used for keyword selection. The Boolean
operators “AND” and “OR” were applied to enhance the search strategy through several com-
binations (S1 Table). The bibliographical research was developed and performed in August
2017. The search strategy included the following MeSH, DeCS, and Emtree terms: ‘Dentists’,
‘Posture’, ‘Human Engineering’, ‘Odontologia’ [Portuguese], ‘Postura’ [Portuguese] associated
with the entry terms: ‘Dental students’, ‘Student of dentistry’, ‘Undergraduate student of den-
tistry’, ‘Seated Position’, ‘Sitting Position’, ‘Saddle chair’, ‘Saddle seat’. The records obtained
were exported to the software EndNote Basic/Online, desktop version (Thomson Reuters,
New York, USA) and duplicates were removed.
Selection of studies
The studies were selected in three stages. In stage 1, two reviewers (GG and WAV) performed
a systematic analysis of the titles, independently. The articles whose titles met the objectives of
the study were selected for stage 2, when both reviewers (GG and WAV) also performed a sys-
tematic analysis of the abstracts. At this time, the studies not related to the topic, reviews, let-
ters to the editor, personal opinions, book/book chapters, didactic material, reports, abstracts,
patents, qualitative or observational studies, and studies that used other types of seats or modi-
fied ones were excluded. The articles whose titles met the study objectives, but had no abstract,
were fully reviewed.
In the third stage, the full texts of the preliminary eligible studies were obtained and evalu-
ated to verify whether they met the eligibility criteria. When both reviewers could not reach an
agreement, a third reviewer (LRP) was consulted to make a final decision. Rejected studies
were recorded separately along with the explicit reasons for exclusion.
Process of data collection and extraction
After the selection, two authors (MSS and WAV) analyzed the studies, which data were
extracted for the following information: article identification (author, year, study location),
sample characteristics (number of patients in each study, mean age, sex distribution, school
year), type of intervention (seat type, training time, evaluation start time), and methods for
obtaining the results (methods used for posture evaluation, image analysis, and calibration
time). Any disagreement was discussed and a third reviewer (LRP) was consulted when
necessary.
Individual risk of bias of the studies
The risk of bias in the studies selected was assessed using the Joanna Briggs Institute Critical
Appraisal tools for use in JBI Systematic Reviews for Randomized Controlled Trials [26]. Two
authors (WAV and LRP) independently assessed each domain for the potential risk of bias.
The following questions were used for the assessment: 1) Was true randomization used for
assigning the participants to treatment groups? 2) Was the allocation to treatment groups con-
cealed? 3) Were treatment groups similar at baseline? 4) Were participants blind to treatment
assignment? 5) Were those delivering treatment blind to treatment assignment? 6) Were out-
come assessors blind to treatment assignment? 7) Were treatment groups treated identically
other than the intervention of interest? 8) Was follow-up complete, and if not, were differences
Assessment of the ergonomic risk in dentistry
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between groups in terms of their follow-up adequately described and analyzed? 9) Were partic-
ipants analyzed in the groups to which they were randomized? 10) Were outcomes measured
in the same way for treatment groups? 11) Were outcomes measured in a reliable way? 12)
Was appropriate statistical analysis used? 13) Was the trial design appropriate, and were any
deviations from the standard RCT design (individual randomization, parallel groups)
accounted for in the conduct and analysis of the trial? The risk of bias was categorized as High
when the studies reached up to 49% of “yes” score, Moderate when they reached 50% to 69%
of “yes” score, and Low when the studies reached more than 70% of “yes” score. Studies cate-
gorized as either high risk of bias or low methodological quality were eliminated.
Outcome measures and data analysis
The meta-analysis for continuous outcome was performed to estimate the effect of seat type on
the ergonomic risk score in dentistry [25]. The mean difference was used for pooling effects.
Heterogeneity among studies was assessed using I
2
statistics and classified as follows: low (I
2
<
25%), moderate (I
2
= 50%), and high (I
2
>75%) [27]. The random-effects model was selected
to minimize the effect of heterogeneity among studies [28]. Publication bias was not assessed
because there was not a sufficient number of studies to group in a funnel plot. The software
Review Manager, version 5.3 (RevMan, Cochrane Collaboration) was used to perform all sta-
tistical analyses.
Confidence in cumulative evidence
The Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) tool
[28] assessed evidence quality and grading of recommendation strength. This assessment was
based on study design, methodological limitations, inconsistency, indirectness, imprecision,
and other considerations. Evidence quality was characterized as high, moderate, low, or very
low [29].
Results
Selection of studies
The bibliographical research was developed and performed in August 2017. During the first
stage of study selections, 2993 records were found in six electronic databases. After removing
the repeated/duplicated records, 1918 articles proceeded to the analysis of titles and abstracts.
A total of 154 studies from the “grey literature” was found through the search strategy,
although only one was related to the objectives of the present review. After the analysis of titles
and abstracts, only three studies were eligible for full-text analysis. The references of the ini-
tially eligible studies were carefully assessed to verify potential articles that were absent from
the main search strategy. However, from the three studies included in this stage, one of them
was excluded for being a thesis from which an eligible article was produced. Therefore, two
articles proceeded to the analysis of results. Fig 1 reproduces the process of search, identifica-
tion, inclusion, and exclusion of articles.
Characteristics of the studies
Both eligible studies [11–12] commented on the research ethical criteria and explained the use
of consent forms for research subjects. None of the studies presented either sample calculation
or study power. The analysis resulted in a total sample of 150 dental students and there were
no studies with professional dentists. The studies were performed in the United Kingdom [11]
in 2007 and in India [12] in 2014. One study compared the Salli Saddle Chair and a
Assessment of the ergonomic risk in dentistry
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conventional chair with and without back rest and flat surface [12], and the other compared a
Bambach Saddle Seat and a conventional chair with back rest and flat surface [11]. Both studies
[11–12] were performed with second-year dental students, who were starting their laboratory
activities using phantom heads.
The participants of the eligible studies [11–12] received training as to correct posture and
use of each seat type. The evaluation was performed after 10 [11] or 12 [12] weeks so the stu-
dents would get used to the seats. Table 1 presents a summary of the main characteristics of
these studies.
Fig 1. Flowchart of the process of searching and selecting the literature, adapted from the PRISMA statement.
https://doi.org/10.1371/journal.pone.0208900.g001
Assessment of the ergonomic risk in dentistry
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Risk of bias in the studies
Both studies included in this review [11–12] presented low risk of bias in the Joanna Briggs
Institute Critical Appraisal tool [26]. Table 2 shows detailed information on the risk of bias of
the studies included.
Results of individual studies and meta-analysis
The studies selected used the RULA (Rapid Upper Limb Assessment) method [30], which ana-
lyzes the overload concentrated in the neck and upper limbs during work and assesses the
static muscle work and the forces exerted by the segments analyzed. The calibration time set
by the studies ranged from 10 [11] to 15 [12] minutes so that the students could focus on their
work and be evaluated afterwards. In both studies, the students prepared a mandibular tooth
in a mannequin.
In the study by Gandavadi et al. [11], photographs were taken of both left and right sides,
while in the study by Dable et al. [12], the analysis was performed from static images captured
from videos. The results showed lower scores for the ergonomic seats (Salli Saddle Chair and
Bambach Saddle Seat) than for conventional seats. In the study by Dable et al. [12], the authors
also used image magnification lenses to compare the groups, showing even lower scores with
such system.
Table 1. Summary of the main characteristics of the eligible studies.
Author, year,
and country
Seat type Sample (n) School
period
Location Procedure
performed
Training
time
Time of
assessment
Evaluation
method
Analysis
method
Calibration
time
Gandavadi
et al., 2007,
United
Kingdom
Bambach Saddle
Seat (BSS)
Conventional
Seat (CS)
Bambach Saddle
Seat: 30
Conventional
Seat: 30
2
nd
year Preclinical
laboratory
Cavity
preparation of
mandibular teeth
in a mannequin
10 weeks 2 weeks RULA�Photos 10 minutes
Dable
et al.,2014,
India
Salli Saddle
Chair (SSC)
Conventional
chair with back
rest (CC1)
Conventional
chair without
back rest (CC2)
Salli Saddle
Chair: 30
Conventional
chair with back
rest: 30
Conventional
chair without
back rest: 30
2
nd
year Preclinical
laboratory
Cavity
preparation of the
first mandibular
premolar in a
mannequin
12 weeks 3 days RULA�Videos 15 minutes
�RULA: Rapid Upper Limb Assessment.
https://doi.org/10.1371/journal.pone.0208900.t001
Table 2. Risk of bias assessed by the Joanna Briggs Institute Critical Appraisal Tools for use in JBI Systematic Reviews for Randomized Controlled Trials” [26].
Authors Q.1 Q.2 Q.3 Q.4 Q.5 Q.6 Q.7 Q.8 Q.9 Q.10 Q.11 Q.12 Q.13 %yes/risk
Gandavadi et al., 2007 p p p —p—p p p p p p p 84.6%/Low
Dable et al., 2014 p p p —p—p p p p p p p 84.6%/Low
1) Was true randomization used for assigning the participants to treatment groups? 2) Was the allocation to treatment groups concealed? 3) Were treatment groups
similar at baseline? 4) Were participants blind to treatment assignment? 5) Were those delivering treatment blind to treatment assignment? 6) Were outcome assessors
blind to treatment assignment? 7) Were treatment groups treated identically other than the intervention of interest? 8) Was follow-up complete, and if not, were
differences between groups in terms of their follow-up adequately described and analyzed? 9) Were participants analyzed in the groups to which they were randomized?
10) Were outcomes measured in the same way for treatment groups? 11) Were outcomes measured in a reliable way? 12) Was appropriate statistical analysis used? 13)
Was the trial design appropriate, and were any deviations from the standard RCT design (individual randomization, parallel groups) accounted for in the conduct and
analysis of the trial? NA = Not Applicable; p= Yes; “–” = No.
https://doi.org/10.1371/journal.pone.0208900.t002
Assessment of the ergonomic risk in dentistry
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Fig 2 presents the forest plots. The mean differences in ergonomic risk score and their
respective 95% confidence intervals are represented by squares for the individual studies. The
S2 Table shows the risk score of individual studies. The diamonds at the bottom represent the
pooled mean ergonomic risk score with 95% confidence interval. The meta-analysis results
showed that saddle seats are associated with significantly lower ergonomic risk scores when
compared with conventional seats [right side (mean difference = -3.18; 95% CI = -4.96, -1.40;
p<0.001) and left side (mean difference = -3.12; 95% CI = -4.56, -1.68; p <0.001)], indicating
posture improvement. The overall mean difference in ergonomic risk score was -3.16 (95%
CI = -4.02, -2.30; p <0.001). Between-study heterogeneity was high (I
2
= 95%; p <0.001).
Confidence in cumulative evidence
Overall, the quality of evidence from the outcomes evaluated by the GRADE system [29] was
assessed as moderate (Table 3).
Discussion
This study aimed to compare the ergonomic risk of saddle and conventional seats used in
work practices of dentists and/or dental students. Both eligible studies [11–12] were performed
with a convenience sample (dental students). Studies with trained professionals may result in
Fig 2. Effect of seat type (saddle versus conventional) on ergonomic risk score in dentistry, assessed usingthe RULA scale.
https://doi.org/10.1371/journal.pone.0208900.g002
Table 3. Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) summary of results table for the outcomes of the systematic review
and meta-analysis [29].
Quality Assessment Summary of Results Importance
Number of
studies
Study Design Methodological
Limitations
Inconsistency Indirectness Imprecision Publication
Biases
Number of participants General
Quality
Intervention Comparison
2Randomized
controlled trials
X
1
p p p p 60 60 +++
MODERATE
Critical
GRADE factors: = p, no serious limitations; X, serious limitation. General quality of evidence: +, very low; ++, low; +++, moderate; ++++, high.
1
Absence of blinding of outcome assessors and participants.
https://doi.org/10.1371/journal.pone.0208900.t003
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bias due to the different situations of the clinical routine. Forming a control group for this type
of study, paired with the experimental group for age and time of profession, would represent
another challenge. These variables may reflect especially in existing musculoskeletal diseases
and in the resistance for changing usual postural practices [31–32]. Thus, the results of the
present meta-analysis with studies performed with dental students significantly favor saddle
seats over conventional seats, which confirms the initial hypothesis.
In both eligible studies [11–12], dental students were instructed to prepare a cavity in the man-
dibular teeth of a mannequin, at the preclinical laboratory. It is known that a procedure performed
in a dental mannequin does not reproduce the actual reality of a dentist’s routine. This is because a
real patient presents variables such as age (elderly people or children), anatomical structures (ton-
gue, cheek, and mouth opening limitation), special care (physical and/or mental disabilities),
altered psychological states (fear and/or anxiety), obesity, and pregnancy, which may change and
complicate the operational procedure. However, in the preclinical laboratory during procedures in
mannequins, students experience the first body postures, adapting their body to seat, static posture,
reduced field of vision, dental procedure, precision of fine movements, and especially to the fear
and insecurity of dealing with something new [33].
One of the methods for verifying ergonomic risks is the Rapid Upper Limb Assessment
(RULA) [30], which is the most cited in the literature and used in both eligible studies [11–12]
of this review. In this method, the positions of individual body segments are observed and
assessed with increasing scores according to the growing deviation of the neutral posture [30].
Different studies [30–34] have assessed the validity and reliability of the RULA, which is con-
sidered an adequate method to assess the body posture of dentists [35] and dental students
[36]. The observations of evaluators regarding the static image may be associated with the
uncertainty regarding camera angle [37].
Gandavadi et al. [11] observed the working postures of both right and left sides using digital
photographs. Dable et al. [12], in turn, used videos that were paused at every postural position and
at every body movement of both right and left sides. However, the assessment and final score of
both studies [11–12] were based on a static image. The assessment of the body posture images of
the research participants started after 10 to 15 minutes in a familiar environment. Given the long
time for capturing the images, the participants were likely focused on the activity proposed and
kept the postural habits of their usual routine, which canceled the Hawthorne effect [38]—a phe-
nomenon in which participants change their behavior when they are aware of being watched.
In this study, the ergonomic risk was assessed in groups that used conventional and saddle
seats. The results indicated an intermediate to high score for ergonomic risk in the group
using the conventional seat, which is consistent with other studies [36,39]. Over the last
decade, research has been intensified, designing the effects of different seats on the clinical
practice of dentists and dental students [11–13,40–42]. Among such studies, three have investi-
gated the ergonomically modified stool [40–42] and three have investigated the saddle seat
[11–13]. All studies showed an improvement in the experimental group when compared to the
control group, especially for presenting a lumbar lordosis seated posture [11–13].
There is a consensus among several studies [17–21,43–49] that the lumbar lordosed seated
posture is optimal for favoring a neutral lumbar posture, minimizing the painful symptomatol-
ogy of low back pain. It is also associated with high muscular activity and the increase in spinal
load due to the posterior pelvic tilt, which is then balanced by muscle contractions in the dorsal
spine, representing a dynamic posture [50]. This posture is obtained by positioning the lower
lumbar spine in a slight forward tilt and slight lumbar lordosis, while maintaining the relaxa-
tion of the muscles surrounding the thoracic spine [20].
In occupational science, a static body posture is defined as a posture held for more than
four seconds [51–52]. Static work procedures prevent the blood flow required for tissue
Assessment of the ergonomic risk in dentistry
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recovery. Other significant factors are the frequency of occurrence, the pauses during move-
ment, and the duration (time component) for maintaining a static body posture [53]. Conse-
quently, several dental tasks are performed in static postures with the prolonged flexion and/or
rotation of the trunk, presenting a potential risk for the musculoskeletal system [53].
The interdisciplinarity between bioengineering and health sciences improves clinical rele-
vance and research [19,54–56]. Dynamic seats [57–58] with a slight forward inclination
[54,56–59], with or without a low backrest [57] to support the ischia [19,60], are the challenges
of novel seat designs. However, it is worth noting that adopting a good posture and using the
correct furniture are not enough to reduce the overload on the osteomyoarticular tissues of
dentists [61–62]. Besides seat design, the human, occupational, and organizational factors also
play an important role in terms of load conditions in the human body [63–65]. Psychosocial
factors are also major risk factors for persistent low back pain in workers, and they should be
considered along with the physical labor requirements, reducing the disability related to lum-
bar pain [66]. Such pain is also directly associated with depression and somatization [67]. Psy-
chosocial interventions may reduce the impact of low back pain in the workplace [68,69].
Four-handed dentistry, equipment organization in the workspace, correct positioning of
patients, illumination, and auxiliary components should be observed and controlled in the
dental clinical practice [61–62]. The musculoskeletal stress of a dental professional is quantifi-
able, comparable, and especially rather variable, considering that musculoskeletal disorders
may be reduced by improving the ergonomic positioning of the patient and the practitioner
[70]. Positioning should maintain the natural curves of the lumbar spine (cervical lordosis,
thoracic kyphosis, lumbar lordosis, and sacral kyphosis), allowing a neutral sitting posture
[7,59] so that muscles and intervertebral discs may alternate between relaxation and loading.
Correct positioning is beneficial for nourishing muscles [71] and intervertebral discs [72] and
for potentially reducing ergonomic risks.
The present review is original, and it has contributed to develop the scientific knowledge
from two main points. Primarily, it is the first systematic literature review to investigate the
influence of seat type on ergonomic risk among dental students. Second, the low risk of bias
observed in the eligible studies allows drawing more consistent and reliable conclusions from
the data obtained, producing major implications for the academic dental clinical practice.
Limitations
The present study is limited by the presence of only two clinical studies on the subject, with no
sample calculation or study power. In addition, the student population included only dental stu-
dents working on phantom heads and it was not sex-specific. In both studies included, the data
were collected only at the end of follow-up. It is worth noting that short-term investigations of the
sitting posture may not completely represent the biological time-dependent responses. Further
studies should be performed to determine whether the effectiveness of a saddle seat intervention is
maintained in the long-term, especially concerning the neutral lumbar posture. In addition, both
eligible articles used static images to represent the average posture of a person, which does not fit
the reality. Therefore, further studies need to employ state of the art posture measurement equip-
ment that automatically record the posture continuously. A combination of posture and Electro-
myography (EMG) measurement would provide additional insight.
Conclusion
The two eligible studies for this review provide moderate evidence that saddle seats provided
lower ergonomic risk than conventional seats in the examined population of dental students.
Follow-up studies are required to confirm this result by addressing the limitations of the
Assessment of the ergonomic risk in dentistry
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studies. For example, follow-up studies should employ state of the art posture measurement
equipment and examine whether saddle seats also provide lower ergonomic risk in a popula-
tion of professional dentists treating real patients.
Supporting information
S1 PRISMA Checklist. PRISMA checklist.
(DOC)
S1 Table. Strategies for database search.
(DOCX)
S2 Table. Main results of eligible articles.
(DOCX)
Author Contributions
Conceptualization: Giovana Renata Gouvêa, Luiz Renato Paranhos, Jaqueline Vilela Bulgareli,
Antonio Carlos Pereira.
Formal analysis: Giovana Renata Gouvêa, I
´talo de Macedo Bernardino.
Investigation: Giovana Renata Gouvêa, Luiz Renato Paranhos.
Methodology: Giovana Renata Gouvêa, Walbert de Andrade Vieira, Luiz Renato Paranhos,
Jaqueline Vilela Bulgareli, Antonio Carlos Pereira.
Resources: Giovana Renata Gouvêa.
Supervision: Giovana Renata Gouvêa, Jaqueline Vilela Bulgareli, Antonio Carlos Pereira.
Writing – original draft: Giovana Renata Gouvêa, Walbert de Andrade Vieira, Luiz Renato
Paranhos, I
´talo de Macedo Bernardino, Jaqueline Vilela Bulgareli, Antonio Carlos Pereira.
Writing – review & editing: Giovana Renata Gouvêa, Walbert de Andrade Vieira, Luiz Renato
Paranhos, I
´talo de Macedo Bernardino, Jaqueline Vilela Bulgareli, Antonio Carlos Pereira.
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