SEJ_2-2017_Articol_Roulet

DENTAL EDUCATION
HOW TO SET UP, CONDUCT AND REPORT A SCIENTIFIC STUDY
Original Articles
Jean-François Roulet1a*
1
Department of Restorative Dental Sciences, College of Dentistry, University of Florida, Gainesville, FL-32610, USA

Dr med dent., Dr hc, Prof hc, Professor, Director of Center for Dental Biomaterials
a

Received: March 27, 2017
Revised: April 24, 2017
Accepted: May 24, 2017
Published: May 29, 2017

Academic Editor: Adrian Podoleanu, Eng, PhD, Professor, FInstP, FOSA, FSPIE, Professor of Biomedical Optics, Head of the Applied Optics
Group, School of Physical Sciences, University of Kent, Canterbury, Kent, UK

Cite this article:
Cite this article: Roulet J-F. How to set up, conduct and report a scientific study. Stoma Edu J. 2017;4(2):90-101.

ABSTRACT DOI: 10.25241/stomaeduj.2017.4(2).art.1

This continuing education paper gives some guidelines on how to write a scientific paper. A good
paper begins with a high quality experiment! Therefore, based on an idea, authors should first
inform themselves by reading the literature, refine their idea and convert it into a scientific question.
This is all laid down in the first draft of the “Introduction” of the future paper.
The authors must seek for ways to answer the scientific question stated above, which is done by
describing it in detail in the “Material & Methods” section of the paper. This may require a pilot
study. Once the experimental design, the parameters to be measured and the materials involved
are known, it is good practice to consult a statistician in order to determine the statistical method to
be used for analyzing the results.
The execution phase is dominated by meticulously applying the methods described above and
documenting everything in detail. Once results are obtained, they should be first displayed in a
descriptive manner to determine the final quantitative analysis, which leads to tables and figures
showing the significant differences.
What is left at this point is to write a “Discussion”, which should be well structured and then to
compile the whole manuscript in the format required by the journal of choice to submit to.
Finally some hints are given how to successfully deal with reviewers.
Conclusion: Following the recommendations given, the probability to obtain acceptance of a paper
may be quite good.
Keywords: experimental design, scientific writing, publishing.

1. Introduction An analysis of successful and failed projects reveals
Performing a scientific study is basically the same several general patterns1 (Fig 1).
as running a project. Therefore all rules regarding A plot of resources spent versus times revealed
project management apply to scientific studies that most of the effort in successful projects is
as well. Most projects, especially larger and more spent at the beginning of the process.1
complex ones are run by teams. In teams the This means that the information is properly
individual players which are unified to achieve the collected, the objectives are well defined,
same common objective (successful completion of everything has been thought through as well as
the given task) give up some of their individuality possible based on the actual knowledge and the
and at the same time bring in their competence. To task ahead is well defined. Then the “machine” can
guarantee the well functioning of the team, each be started and the project runs as perceived in the
member should comply to commonly defined creative phase. During the execution phase usually
rules. Most of these rules govern compliance and the effort diminishes and the preplanned tasks can
communication. For me the most basic rule is the be accomplished without surprises. In product
following: “I say what I think and I do what I say”. development I have learned that following a well
In scientific projects usually a multitude of players thought and structured scaffold is a good strategy
are involved, especially in a teaching institution. for success. On the other hand, projects that have
Researchers interact with other researchers, failed show a pattern that is quite different. With
with students, lab technicians, statisticians, a brilliant idea the project is just started with the
administrators, and industrial partners or grant anticipation that it will work. So the start is nice,
administrators etc. Therefore, to be successful, because without too much effort the project is
open and straightforward communication is moving forward, usually with lots of enthusiasm.
indispensable as well as the establishment of a However, when the project is usually on its way,
framework in which the team is able to perform. unanticipated problems arise that require more

*Corresponding author:
Dr med dent., Dr hc, Prof hc, Professor, Jean-François Roulet, Director of Center for Dental Biomaterials
Department of Restorative Dental Sciences, College of Dentistry, University of Florida, 1395 Center Drive, Room D9-6, PO Box 100415, Gainesville FL-32610-0415, USA
Tel / Fax: +1 352 672 2599, e-mail: jroulet@dental.ufl.edu

90 Stoma Edu J. 2017;4(2): 90-101 http://www.stomaeduj.com
HOW TO SET UP, CONDUCT AND REPORT A SCIENTIFIC STUDY

If you just search the internet (e.g. google.com)

Original Articles
the yield is much better. However there is no
way to validate and verify the information.3 This
becomes obvious, when you search a topic that
you know yourself well. There comes the peer
review process, which will be discussed later.
This is a mechanism, which, if well done, should
lead to a better report, enhanced in several of its
categories, as contributed to by those performing
the review. While many of the statements made
remain the responsibility of the author, there is the
expectation that the review paper guarantees that
it is correct and does not contain methodological
errors or biases. Andreas Lindhe, the Editor of
the Scandinavian Journal of Dental Research has
once stated in a continuing education: ”Nothing
is scientifically “shown” or “proven” before it has
been published in a SCIENTIFIC journal subject to
peer review, so one can critically judge WHAT has
Figure 1. Effort time plot of successful (green) and failed (red) been done, HOW it has been done and evaluate
projects. HOW SOLID it is!”.3 This is very true, but only if the
peer review was performed well.3 Unfortunately in
input in effort and resources. Due to the lack the last 10-15 years more and more so called open
of knowledge or good strategy, this process is access journals have been created pursuing the
usually repeated multiple times with increasing idea that knowledge should be publicly available
effort and resources to be consumed (with budget for free – in itself a very noble idea.4,5 Publishing is a
amendments), until a point is reached, where the big business, and targeting profit has undermined
success point has moved into the distant future the solidity of the peer review process.6
and the required resources cannot be estimated One experiment had shown this quite clearly. A
anymore. This is usually the moment where there researcher had constructed a scheme which he
is a danger that the management or the team modified in order to create 304 fake studies which
involved may decide to abort the project. had built in several faults, and it was expected that
Before anyone engages into a scientific study, the a reviewer should have detected this. Then the
reasons and objective should be clearly stated. researcher invented author names and universities
There are many reasons that motivate people to and departments in cities placed mainly in
conduct research, such as: the upcoming world. These manuscripts were
• obtain a title submitted at a rate of 10/week to open access
• obtain/maintain a position journals, with the result that 157 manuscripts (52%)
• apply for grant money were accepted, and only 98 manuscripts were
• become rich rejected (32%).7
• know more In dentistry and medicine the information should
• target an academic career be, if possible, evidence based, which makes
• change the world! a lot of sense. Clinicians treat patients and the
It is important to be personally very clear about quality of the treatment should be based on
the objectives, since sooner or later the task will clinical studies. This has generated the evidence
become tougher and this may require extra efforts. based approach8,9 and a hierarchy of the quality
This means that more motivation is required to of evidence putting expert opinion at the bottom
continue the research project.2 It requires more and systematic reviews of prospective randomized
than motivation to stimulate the researcher to double blinded clinical studies on the top10,11 (Fig.
spend night after night above the microscope 2). Unfortunately there are errors and dangers of
while other team members, not involved in the bias clearly present here as well.12,13
research, may go partying to have a good time in An infrastructure is needed to perform research.
the local bars. Researchers need a laboratory, access to a clinic
Once you are clear with yourself about the task at or a dental office as well as access to regulatory
hand to run your research project the next step is institutions (e.g. institutional review board), and
very important. The question why to publish must to literature. As described above, the first step is
have been deeply understood by the researchers. a literature search done via internet. However it
A research project is only completed, once it is is highly recommended to complement this with
published. Why? If the outcome of an experiment a manual search, which requires access to a good
is not published, no one will ever know it. “L’art library.
pour l’art” is the most stupid thing I have ever seen Finally for young researchers having a mentor
– it is a waste of time and effort. Let other people is essential and for the researcher this should be
know what you have found and hopefully your beneficial. It is a good idea to check out potential
activity will improve the way we treat our patients. mentors, which should be competent in the field
However publishing is not equal publishing. If you of the potential research. It is important to know if
have a question, the modern way to approach it is the mentor has enough time to deal and consult
to search the internet. If the question means to find the mentee. A good mentor should always be
a publication, then there are powerful data bases accessible and available to read every document/
such as pubmed or google scholar, which can draft submitted within a rather short time (better
guide you quickly to a high number of references. days than months) and return feedback with

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Original Articles
Highest
EVIDENCE
Meta
Analysis
Systematic Review
Random
Controlled Trial

Cohort Study

Case Control Study

Cross Sectional Study

Case Reports and Series

Animal Research

In Vitro Research
Lowest
EVIDENCE Opinion of Experts

Figure 2. Pyramid of Evidence.

detailed comments. It would be beneficial for the because if poor results occur it is important to
mentee, if the mentor could provide guidelines, know exactly what has been done. This is the only
instructions for use and templates. On the other way to improve the material or the procedure.
side the mentee cannot expect from the mentor
that he/she would do the work. All he/she can do 3. Creative phase
is to consult, open doors and provide connections. The creative phase is usually the most thrilling
As a mentor I like it very much, when the mentee part but usually the most difficult as well. It starts
comes up with his/her own idea for a project. with an idea, which most of the time is quite
vague. Therefore the first step is to write it down
2. Structure of a scientific paper as precisely and clearly as possible. “An idea that
A scientific paper always has the same structure:2 cannot be put on paper is not a good idea”.1
After the title with the authors and their affiliations The next step is to collect information about this
and contributions usually the paper should start idea. See if someone else had exactly that idea
with an “Abstract”. The body of the paper is opened or a similar idea. Determine what is really new
with an “Introduction”, followed by “Materials & with the idea and where from the idea can be
Methods”. Then a chapter “Results” should be developed further. The answers to these questions
followed by a “Discussion” and “Conclusions”. lie somewhere in the world literature. Therefore
Finally a “Literature” list should complete the a literature search is unavoidable. The literature
paper. This basic framework can be modified found should flow into the personal data bank of
depending on the type of publication. In a thesis the researcher. Modern computer programs like
the introduction serves more than introducing the Endnote are very helpful, because they allow easy
reader into the topic. The other purpose is that insertion of literature quotes into a manuscript.
the author must demonstrate his/her competence Usually such a search starts on the internet and
in the field. Therefore the “Introduction” includes may yield much more papers that one can read.
usually an extensive literature review, that may Therefore the search strategy may be refined,
be structured as a subchapter. Also “Materials & which usually parallels refinement of the idea.
Methods” is usually more detailed than in a paper Once an overseeable number of papers has been
published in a scientific journal. If a thesis deals with found, the articles must be checked whether they
multiple experiments it is highly recommended to are within the scope of the idea, which is usually
treat every experiment like a single publication and done by reading the abstracts. The ones that
use a general “Introduction” at the beginning and were positively selected should be read. Most
an allover “Discussion” with conclusions at the end information can be extracted from the chapters
as a big clasp to keep the whole project together. “Materials & Methods” as well as from the “Result”
Finally Industrial Reports have slightly different section. However reading the “Introduction”
objectives. Usually the manufacturer wants an may reveal more information about the topic of
answer to a specific question, such as the in vitro interest and the “Discussion” may contain helpful
wear rate of a material and/or the failure rate thoughts to refine the own question. If the search
and reasons after a specific clinical service time. has found review papers it is a very good start. The
The “Introduction” of an Industrial Report can be next step is a manual search by scanning through
very brief, because one must be assured that the the literature lists at the end of the read papers.
financing partner has done its homework before This may reveal more useful sources. Some of
agreeing to spend money on a study. On the other them may not be available on the internet, which
hand, the chapter “Materials & Methods” cannot requires the physical presence of the researcher in
be detailed enough. This is important to realize, a good scientific library.

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HOW TO SET UP, CONDUCT AND REPORT A SCIENTIFIC STUDY

The above mentioned search of the literature has accepted. An example for a null hypothesis would

Original Articles
two functions: one to acquire information and two, be: "All tested composites showed equal wear
to trigger the brain to think more about the original rate".
idea. This is the moment to start with writing the Writing an introduction means scientific writing
Introduction of the planned scientific study. A good which is full of traps, pitfalls and difficulties,
way to organize the thinking process is to generate especially for a less experienced writer. What is
a “mind map” which is a graphical display with most important is the clarity of the content. Scientific
textboxes, key words or symbols with lines and language does not mean complicated language,
arrows that symbolize connections (Fig. 3). the contrary is true. The simpler the formulation,
This mind map should be the backbone or skeleton the better the understanding. A handicap for
of the Introduction since it helps to fulfill the task of most authors of scientific papers is that usually
informing the reader that never has the idea of the they must be written in English which usually is
planned study been approached before, about not their mother tongue. The nomenclature of
what it is. Beginning very wide and narrowing it technical terms must be correct and metric units
down towards more and more specific contents is should be employed14 (Tab. 1 a-d). Furthermore
focusing more and more towards the own project. abbreviations should be explained the first time
By definition the last sentence of the Introduction they are introduced and synonyms should never
should start with the words: “The objective of be used for the same thing. The impersonal form
the present study is….”. Once the researcher has is preferred (“it was done” rather than “I did”) and
reached that point usually the originally vague the use of tempora is clearly defined. Everything
idea has become crystal clear and even more that was in the past (results from other researchers,
has morphed into a precise scientific question. things the authors did etc.) is put in the past
This question should be the logical consequence tense (e.g. Van Meerbeeck et al reported that self
of the content of the text above. A very common etching adhesives yielded a thinner hybrid layer
error is that the research tool used is part of the than etch & rinse adhesives) and only things that
objective. This may never be the case. First there are generally accepted should be written in the
is the question/problem. Only in the next thought present tense (eg. saliva is a buffer or chloroform is
a solution is looked for, which is then described in a solvent). Every statement in an introduction must
“Materials & Methods”. In experimental papers the be backed with a literature quote. At this stage
formulation of the objective should be followed by it is recommended to put the literature quotes
a null hypothesis, which later on can be rejected or in parentheses with just the author names and

Fact (sales) amalgam is
substituted by composites

Question: composites better than amalgam?
l
ota
ecd

M dhes itro
an

pr ech ion
A v

es al
erti ic
In

op an

Wear, handling
recurrent caries
Answer

But!
Longevity?
Clinical controlled
prospective randomized
studies do NOT

{
represent clinical reality

Systematic review

Look also for data from

!
practice based research
and clinicians
Add world wide survey

Figure 3. Mind Map. The present format is only for better readability set in the computer. Mind maps are dynamic and should be done
by hand on a note pad or a black board. The content of this mindmap is hypothetical, its purpose is to show the principle only.

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text fragments from other articles (even your own!)
Original Articles into your own paper without putting the text in “”
and quoting the source. Finally not acknowledging
work of your competitors and quoting only your
own papers is not an error per se, but a fact that
sheds a bad light on your person.
Once the objective is clear, the author must
provide a way to solve the problem. This is
described in “Materials & Methods”. What to do
must be described to the smallest detail BEFORE
the experimentation begins and once it has been
defined it may NOT be changed, because the
situation most likely occurs that the results cannot
be correlated to the investigated parameters
anymore; the change has introduced another
variable. This is big trouble.
If a standard method is used, it is sufficient to
describe it and to refer to its source. Furthermore
it is highly advisable to practice it before it is
Figure 4a. Graphical display of experimental design (Courtesy
used for the experiment. If this is ignored, bias is
of Dr. Uwe Blunck, Berlin). introduced, because the inevitable learning curve
is included into the results produced. Very often
the year. If the same author has published more some new equipment or procedures are used to
than one quoted paper in the same year, then the address a research question and the usefulness
specific article may be identified with letters: a, b, is not known. Therefore in these situations usually
c, etc.). This leads to the question what should be a pilot study should be performed. It should be
quoted and listed? dealt with identically to the real experiment, but
• Earlier work in the area with a substantially smaller sample size (feasibility
• Methodology used study). The outcome of the pilot study may lead to
• Other publications of importance modifications of the “Materials & Methods” of the
• ONLY publications actually used in text! main study.
Common errors are that the literature search has The report of a pilot study may either be inserted
failed to find relevant papers to the topic. Often after the “Introduction” reporting its “Materials &
secondary literature is quoted instead of the Methods” and “Results”, or the pilot study may be
original source (e.g. Roulet described the use just mentioned in the discussion.
of Silane in composite formulations in his thesis, Writing “Materials & Methods” usually begins
referring to Pluddemann et al as the inventers of with describing the experimental design. This is
Silane. An author uses Roulet as a reference for the phase where the most intellectual power and
Silane). Another error is quoting a paper for a creativity enter into play. The experimental design
certain fact that was not described in the quoted must be set in order to, without any doubt, be able
paper and finally the quote of opinion instead of to answer the research question. Therefore it is
experimentally based facts is not correct as well. important to eliminate all known confounders that
Today more and more publishers use software to may cloud your data. (A confounder is a variable
detect plagiarism. This reveals yet another common that is not measured, but influences the outcome
error: that of the simple use of copy paste to insert that is measured). Furthermore randomization is

Figure 4b. Graphical display of balanced experimental design.

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HOW TO SET UP, CONDUCT AND REPORT A SCIENTIFIC STUDY

always a good thing to do, because it may allow be taken in order to document what was done as

Original Articles
for generalization of the results, because the well. This will be useful in the reporting phase.
sample used was representative for the population Once data are produced, it is recommended as a
of interest. A figure of the experimental design first step to test if they are normally distributed.17
would be helpful for the reader to understand This will determine which statistical tests must be
what was done (Fig. 4a and b). The materials used used, as well as which form of graphic display of the
(incl. composition, manufacturer and lot #) are data would be most suitable (normal distribution:
best summarized in a table. Then the experimental mean ± SD, not normally distributed: box plots
groups must be described in detail including with median and 25th and 75th percentile).18 To
the # of samples. The procedures/group must preliminary check the data, it is recommended
be described as detailed so in case the author to display them graphically in order to recognize
quits, the person that takes over can continue the where there are differences. Then a first statistical
experiment under identical conditions. This means analysis should be performed to determine
that ingredients must be described precisely (e.g. where significant differences are found. This
concentration with upper and lower limits, times, is the moment to decide, if groups should be
batch numbers and decision rules, when to accept pooled (remember: this is only correct if there
or reject the outcome of a process). Not only are no significant differences between the pooled
how samples are made and what is done to them groups).
(e.g. fatigue test or exposure to any agent or cell Once the statistical analysis has been finished
cultures etc.) must be described in detail, but also the outcome should be carefully interpreted. In
how the outcome is measured. a balanced design the best possible outcome is
Also in this phase all legal requirements must be to report main effects (e.g. if you looked at sales
clear and accounted for. This is very important; of wine as a function of the bottle shape and its
because some may lead to a not publishable position on the shelf, a main effect is, if, regardless of
manuscript and may put the author in big trouble the shape, bottles on the top shelf sell the best and
(e.g. Editors of most medial journals have agreed regardless of the position cylindrical bottles sell the
not to publish any clinical study that was not best as well). In the ANOVA this is reflected by not
registered with www.clinicaltrials.gov). Every having significant interactions (Fig. 5). If significant
experiment involving human subjects or animals interactions occur, then only comparisons between
is regulated by institutional review boards (IRB) single cells may be done, which is performed with
in order to make sure that the declaration of post hoc tests (Bonferoni, Scheffee or Tukey).19
Helsinki is observed.15 Therefore IRB approval is Usually the level of significance is set before the
mandatory before ANY action is started. Working analysis e.g. p<0.05. If this level is not met the
with dangerous bacteria or viruses requires differences observed are NOT significant, this
formal training and permission as well as using means that the observed differences cannot be
radioactive materials. Finally the planned statistical accounted for due to the experimental conditions,
analysis must be outlined in the chapter “Materials but are random. Therefore it is not correct to talk
& Methods”. The type of test and the software used about a trend, when the significance level has
should be mentioned. Therefore it is a very good slightly been missed.
idea to consult a statistician in this phase of the 4.1. Reporting phase
project. Now that results are available it is time to think
where to publish. The best chances for acceptance
4. Execution phase are if the scope of the Journal of choice is
Once everything is clear and written down, congruent with the topic of the paper to be
the experimentation can begin. The written submitted. The first step should be to read the
chapter Materials and Methods must be used guidelines for authors. Most Journals require that
as an instruction set for the experimentation. the text is on a separate file and require specific
Furthermore it would be a good idea to prepare fonts and line spaces (e.g. 1.5). Figures and
templates for inserting and collating results and Tables should be on separate files and there are
having them in the correct format for the statistical minimum requirements for the resolution of the
evaluation. Such templates can easily be created figures. Usually Legends are required to be on a
using excel spread sheets. separate file as well. A submitted manuscript must
During the experimentation, documentation is the comply to a 100% to these guidelines. If it does
most important thing. Samples must be labelled not follow them meticulously, then the chance
in a way that they cannot be mistaken for another of outright rejection before the review process
one. Furthermore the identifiers must be physically is high. All the recommendations given above to
indestructible. Physical engraving is superior write the “Introduction” and “Materials & Methods”
to “permanent” marker, since the latter can be apply of course. There are a few more however.
erased by a passage through alcohol! Furthermore The working title must be now converted into the
what ever is done must be protocolled in written final title of the publication. Some journals limit the
(The GMP (Good manufacturing practices) number of words. A title is the first thing a potential
mantra is: ”What is not written down has never reader sees. Therefore it should be appealing and
happened”).16 Therefore maintaining a record of motivate the reader to continue. The title should:
steps in a scientific diary is highly recommended. • Be concise, precise
If something goes wrong, the only way to decide • Adequately represent the contents of the article
if the data are still useful, is to exactly know what • May not promise something it can not deliver
has been done. It is recommended as well to • Must specify animal species/clinical,
document redundantly, eg. using more than one in vivo/in vitro, methodology
of the paper and computer protocols, photos Key words must be assigned to the paper.
stored in data base and printed etc. Photos should The authors sequence is a topic that often raises

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Original Articles

Figure 5. Analysis of Variance (ANOVA) of flexural strength of Zirconia specimen bars as influenced by surface grinding (surface) and
heat treatment (heat). Note that heat has not a significant influence but surface condition has. There are no significant interactions.

Figure 6a. Example of reporting parametric data as bar graphs with standard deviation. Tensile strength of composite bonded to two
ceramics after different cleaning procedures of saliva contaminated ceramics.

conflicts, despite the fact that the rules about who a difficult task for many reasons. Very often the
should be where are obvious.20 Only persons journal guidelines restrict its number of words
who have contributed to a significant degree and imply a specific structure. The abstract
scientifically/intellectually to the paper are must summarize in a very condensed form the
included in the author line. Other contributions objective, what was done, how it was done and the
can be accounted for in the Acknowledgements at results. Usually a conclusion is the final point of an
the end of the paper. Each author should know the abstract. It is important to include the statistics and
article and be able to take on scientific responsibility hard numbers of the results.
for it. Who had the most scientific/intellectual input If a reader has been drawn into the paper by
should be the first author. Conflicts may occur in the title, then the abstract is the next thing he/
mentor-student situations. My personal view here she will look at. Therefore it is important that the
is that the amount of contribution of the student abstract is well done and informative, because it
should determine whether he/she is first author or will then motivate the reader to continue reading.
not. If the idea came from the student, the mentor Furthermore abstract, title and keywords are
helped and advised, the student performed the extremely important for the paper to be found in
experiment and wrote the manuscript (even with databases, since only these are used to index the
help of the mentor), then it is clear that the student paper.21, 22, 23
is the first author. On the other hand, if the idea The chapters "Introduction" and "Materials and
and the experimental design are from the mentor, Methods" are already done, so in the phase of
the student performed the experiment, but the writing the first version of the manuscript, they can
mentor wrote the manuscript, then the mentor be taken with only slight modifications. So the next
should deserve the first place in the author’s list. chapter is "Results". Here the results are displayed
To avoid conflicts more and more journals require in form of tables and figures. Examples are shown in
disclosure of the contribution of every author. Tab 2, Fig. 6a and b. The text can be short and should
The next thing to write is the "Abstract". This is mention the outcome of the statistical analysis as

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analysis, where the computer calculates as many

Original Articles
digits after the dot as instructed thus suggesting a
precision which does not reflect the data (5,79438
± 3,22459 instead of 5,8 ± 3,2). The graphic
display of the data should correspond with the
type of analysis: bar graphs with mean and SD for
results of parametric tests and box-plots for non
parametric tests. It is not recommended to use 3D
graphics unless there is a need for (displaying the
relationship of 3 parameters in one graph). And
finally table and graphics must contain information
about the statistical analysis, the minimum being
the p value and showing where the significant
differences are.
The “Discussion” is the only place, where
interpretations, explanations and maybe
speculations are allowed. Very often discussions
Figure 6b. Example of reporting non parametric data as box
are difficult to follow because the reader is not as
plots. Margin quality (% of excellent margin) of six different
adhesives (c=control).
familiar with the topic as the authors and, on top of
it all, there is a lack of structure. It is recommended
to discuss first “Materials & Methods”: Why were the
well which can be printed as a table. Furthermore materials used, why was the used method selected
the text should point to the reader some specifics and which are its advantages/disadvantages or
of the results and highlight important outcomes. limitations. Compare your method with methods
No explanations and interpretations should be of other investigations etc. Only then in a second
given in the chapter “Results”. Common errors are subchapter must the results be discussed: Here
that the data are directly copied from the statistical the null hypothesis can be accepted or rejected

Table 1a-d: SI Units (Taylor and Thompson 2008)

Table 1a. SI Base Units.

Base quantity SI base unit

Name Symbol Name Symbol

length l, x, r, etc. meter m
mass m kilogram kg
time, duration t second s
electric current I, i ampere A
thermodynamic temperature T kelvin K
amount of substance n mole mol
luminous intensity Iv candela cd

Table 1b. Examples of coherent derived units in the SI expressed in terms of base units.

Derived quantity SI base unit

Name Symbol Name Symbol

area A square meter m2
volume V cubic meter m3
speed, velocity v meter per second m/s
acceleration a meter per second squared m/s2
wavenumber σ, ṽ reciprocal meter m-1
density, mass density r kilogram per cubic meter kg/m3
surface density rA kilogram per square meter kg/m2
specific volume v cubic meter per kilogram m3/kg
current density j ampere per square meter A/m2
magnetic field strength H ampere per meter A/m
amount concentration,(a) c mole per cubic meter mol/m3
concentration
mass concentration r,g kilogram per cubic meter kg/m3
luminance LV candela per square meter cd/m2
refractive index(b) n one 1
relative permeability(b) mr one 1

(a) In the field of clinical chemistry this quantity is also called "substance concentration"
(b) These are dimensionless quantities, or quatities of dimension one, and the symbol "1" for the unit (the number "one") is
generally omitted in specifying the values of dimensionless quantities

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Original Articles Table 1c. Coherent derived units in the SI with special names and symbol.

SI coherent derived unit(a)

Expressed Expressed
in terms of other in terms of
Derived quantity Name Symbol SI units SI base units

plane angle radian(b) rad 1(b) m/m
solid angle steradian(b) sr(c) 1(b) m2/m2
frequency hertz(d) Hz s-1
force newton N m kg s-2
pressure, stress pascal Pa N/m2 m-1 kg s-2
energy, work, amount of heat joule J Nm
power, radiant flux watt W J/s m2 kg s-3
electric charge, coulomb C sA
amount of electricity
electric potential diference,(e) volt V W/A m2 kg s-3 A-1
electromotive force
capacitance farad F C/V m-2 kg-1 s4 A2
electric rezistance ohm W V/A m2 kg s-3 A-2
electric conductance siemens S A/V m-2 kg-1 s3 A2
magnetic flux weber Wb Vs m2 kg s-2 A-1
magnetic flux density tesla T Wb/m2 kg s-2 A-1
inductance henry H Wb/A m2 kg s-2 A-2
Celsius temperature degree Celsius(f) ºC K
luminous flux lumen lm cd sr(c) cd
illuminance lux lx lm/m2 m-2 cd
activity reffered to a becquerel(d) Bq s-1
radionuclide(g)
absorbded dose, specific gray Gy J/kg m2 s-2
energy (imparted), kerma
dose equivalent, sievert(h) Sv J/kg m2 s-2
ambient dose equivalent,
directional dose equivalent,
personal dose equivalent
catalytic activity katal kat s-1 mol

(a) The SI prefixes may be used with any of the special names and symbols, but when this is done the resulting unit will no
longer be coherent.
(b) The radian and steradian are special names for the number one that may be used to convey information about the quantity
concerned. In practice the symbols rad and sr are used where appropiate, but the symbol for the derived unit one is generally
omitted in specifying the values of dimensionless quantities.
(c) In photometry the name steradian and the symbol sr are usually retained in expressions for units
(d) The hertz is used only for periodic phenomena, and the becquerel is used only for stochastic processes in activity reffered
to a radionuclide.
(e) Editors' note: Electric potential difference is also called "voltage" in the United States and in many other countries, as well
as "electric tension" or simply "tension" in some countires.
(f) The degree Celsius is the special name for the kelvin used to express Celsius temperatures. The degree Celsius and the
kelvin are equal in size, so that the numerical value of a temperature difference or temperature interval is the same when
expressed in either degrees Celsius or in kelvins.
(g) Activity referred to a radionuclide is sometimes incorrectly called radioactivity.
(h) See CIPM Recommendation 2 (CI-2002), p. 78, on the use of sievert (PV, 2002, 70, 205).

based on the results. Give reasons for the outcome, more than 2x the wear volume of the universal
explain why significant differences were found or composite”. Avoid bringing in wishful thoughts
not, compare your data with the outcome of other into the conclusions!
studies and explain why there are differences, if At the very end of the text there is space for
indicated. If possible give explanations about the “Aknowledgements”. Here usually the authors
possible impact to clinical dentistry of the results should include data on sponsors, agencies,
and finally, it is helpful if indications about further industry that supported the costs of the studies (if
research based on the results of the present study supported by a grant, it's # must be mentioned)
is given. Having said all of the above, one must be and thanks to collaborators that helped to
careful in the formulation. It should be very clear accomplish the task.
which are facts from the study or other studies, Finally under “Literature” all the papers, books
which are interpretations of these facts and which and reports that were quoted in the text are listed
are hypotheses one could come up based on the with their proper source either in the sequence of
findings. their first appearance in the text or alphabetically,
At the end of the “Discussion” conclusions should depending on the instructions for authors of the
be drawn. They must be strictly limited to the facts respective journal.
of the findings in the present study and should Once the first version of the manuscript is
be formulated as briefly as possible (e.g. “the in completed, it should go through language
vitro wear volume of the glass ionomer tested was editing, if the authors do not have English as a

98 Stoma Edu J. 2017;4(2): 90-101 http://www.stomaeduj.com
HOW TO SET UP, CONDUCT AND REPORT A SCIENTIFIC STUDY

Original Articles
Table 1d. Examples of SI coherent derived units whose names and symbols include SI coherent derived units with special
names and symbols.

SI coherent derived unit

Expressed in terms of SI base
Derived quantity Name Symbol units

dynamic viscosity pascal second Pa s m-1 kg s-1
moment of force newton meter Nm m2 kg s-2
surface tension newton per meter N/m kg s-2
angular velocity radian per second rad/s m m-1 s-1 = s-1
angular acceleration radian per second squared rad/s2 m m-1 s-2 = s-2
heat flux density, irradiance watt per square meter W/m2 kg s-3
heat capacity, entropy joule per kelvin J/K m2 kg s-2 K-1
specific heat capacity, joule per kilogram kelvin J/(kg K) m2 s-2 k-1
specific entropy
specific energy joule per kilogram J/kg m2 s-2
thermal conductivity watt per meter kelvin W/(m K) m kg s-3 K-1
energy density joule per cubic meter J/m3 m-1 kg s-2
electric field strength volt per meter V/m m kg s-3 A-1
electric charge density culomb per cubic meter C/m3 m-3 s A
surface charge density culomb per square meter C/m2 m-2 s A
electric flux density, culomb per square meter C/m2 m-2 s A
electric displacement
permittivity farad per meter F/m m-3 kg-1 s4 A2
permeability henry per meter H/m m kg s-2 A-2
molar energy joule per mole J/mol m2 kg s-2 mol-1
molar entropy, joule per mole kelvin J/(mol K) m2 kg s-2 K-1 mol-1
molar heat capacity
exposure (x and g rays) coulomb per kilogram C/kg kg-1 s A
absorbed dose rate gray per second Gy/s m2 s-3
radiant intensity watt per steradian W/sr m4 m-2 kg s-3 = m2 kg s-3
radiance watt per square meter steradian W/(m2 sr) m2 m-2 kg s-3 = kg s-3
catalytic activity concentration katal per cubic meter kat/m3 m-3 s-1 mol

mother tongue. It is important to understand made if it should be sent into the review process.
that a dental publication uses some specific Most Journals use a blind review performed by
professional language. Therefore it is not sufficient at least two reviewers. The main purpose of the
to find someone proficient in English, the person review process is to improve the paper, therefore
proofreading must also be knowledgeable on if reviewers find detrimental flaws in “Materials
the dental technical language (dentist or dental & Methods”, this is usually a reason for rejection,
technician or dental hygienist). So the best choice since the paper cannot be salvaged. On the other
would be a dentist with English as a mother tongue hand, if the authors were not able to explain what
or at least a Dentist that has studied/practiced for was really done in “Materials & Methods”, then the
many years in an English speaking country. A good reviewer does not understand it and recommends
alternative for such proof reading is to seek the help rejection as well. Many reviewers do a simple test
of professional scientific editorial services (e.g. by computing the number of cells as described in
www.oleng.com.au, contact@savantproofreading. the experimental design and compare it with the
com, http://oakfortressproofreading.com). total # of samples produced (e.g. 3 materials x 2
Omitting this last step may be detrimental and may shades and 3 treatments = 3x2x3= 18 cells; if the
lead to the rejection of the manuscript, since in my author reports that 200 samples were made, then
personal experience the most frequent complaint 200/18 = 11,11 ergo something is wrong, since
of reviewers is about poor language. n can be 11 or 12 only). If the resulting n is not a
Before submission every author must read the single number then something is wrong and the
final version and approve it. This is necessary, paper in the best case goes back to the authors.
because being on the author line, every author Many papers get rejected outright, very few are
takes scientific/intellectual responsibility for the accepted without modifications/revisions. This
manuscript! means they are sent back to the authors with
4.2. The review process comments and requests for modifications. This
The standard mode for submission is the internet. causes frustration at first glance and the authors
Most editors/publishers provide templates to may get emotional, since they had tried to do the
guide authors through the submission process. best. But remember the objective of the reviewers
Usually the first step is that the editor/publisher is to improve the paper, therefore authors should
checks if the manuscript complies with the not object to the reviewer’s comments unless really
formalism. Many are very careful about the justified and return the manuscript with minimal
question if the content is new and original (high revisions only. I have personally experienced
probability to be published) or if the content is many cases where the revised paper was sent the
new, but basically confirming existing knowledge second time to the reviewers and came back with
(high risk of being rejected). Then the decision is the recommendation “reject” and the comment

Stomatology Edu Journal 99
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Original Articles Table 2. Example how results should be presented: Tensile bond strength of ceramics contaminated with saliva after
different cleaning procedures.

After contamination cleaned with

Control Water spray H3PO4 gel polishing paste Cleaner
Ceramic 1 55.9±9.2ab1 21±13.6c1 40.6±10.7b1 29.7±15.2c1 54.2±8.8ab1
Ceramic 2 52.1±10.9a1 15.8±16.1 26.7±11.8 21.9±14.2
c1 c2 c1
46.3±7.9a1

ANOVA, Tukey post hoc test p<0.01. superscript letters show same statistical groups in rows,
superscript numbers show same statistical groups in columns

Table 3. Comments of reviewers, actions taken by authors and comments of authors for the reviewers.

that authors did not follow the recommendations
for improvement. Therefore the recommendation References
is that the authors compile all comments of the
reviewers into a table with one line per comment. 1. Biedermann M. Projekte managen. ATW Verlag, Buchs
Then they should add two more columns. In the SG, Switzerland; 2009.
2. Roulet J-F, Viohl J. Der Weg zum Doktorhut. Quintessenz
first they should address the comments and let Berlin 2. Auflage; 2006.
the reviewer know what they did or give reasons 3. Roulet JF. Why Peer Review? Stoma Edu J. 2014;1(1):6.
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5. ***Budapest Open Access Initiative 2003. [Internet:
This approach may further speed up the review available http://www.budapestopenaccessinitiative.org/
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Scientific Thriller. J Adhes Dent. 2013;15(6):503-504. doi:
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bearings (deciding what the paper is about). BMJ. 2017. [Internet: available http://www.gmppublications.

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Regulations. 21 CFR Parts 210 & 211. GMP Publications

Jean-François ROULET
DDS, PhD, Dr hc, Prof hc, Professor Chair
Department of Restorative Dental Sciences
College of Dentistry, University of Florida
Gainesville, FL, USA

CV
Jean-François Roulet, DDS, Dr med dent, PhD, is the former chair and current professor of the Department
of Restorative Dental Sciences at the University of Florida. Professor Roulet is author/coauthor of more than
180 papers, edited/contributed to 27 textbooks and mentored more than 150 theses. He is a renowned
international lecturer with over 800 appearances to date. Dr. Roulet is a member of many professional
organizations, has won numerous awards, and holds four patents. He is editor of Prophylaxe Impuls and
Stomatology Edu Journal. His areas of interest include minimally invasive dentistry, dental materials (ie,
composites and ceramics), adhesive dentistry, esthetic dentistry, and application concepts in preventive
dentistry.

Questions
There are many reasons why people do research. What reason should not exist:
qa. Obtain a title;
qb. Obtain/maintain a position;
qc. Obtain grant money;
qd. “L’art pour l’art”.
The “Material and Methods” section contains:
qa. Explanations why the materials were used;
qb. Explanations why the used method was selected;
qc. Reasons for the outcome;
qd. Tables and figures.
What should a mentor not do?
qa. Provide guidelines;
qb. Provide instructions for use;
qc. Provide templates;
qd. Do the work.
What part is not in the structure of a scientific paper:
qa. Introduction;
qb. Material and methods;
qc. Results;
qd. Acknowledgements.

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