Evidence-based practice and the evidence pyramid: A 21st century orthodontic odyssey

Abstract

Organized evidence-based practice is said to have started in the medical field in the late 20th century. Its principles and usage eventually spread to other health sciences, including orthodontics. Although the conceptual foundations and basic tenets of evidence-based orthodontics are based on the classical approach of testing medical interventions, differences unravel as we encounter the ground realities in orthodontics, which are unique due to the length, complexity, and diversity involved in orthodontic treatment and research. How has this led to the evolution of evidence-based orthodontics and changes in its applications? Is it being translated to better clinical answers, treatment strategies, patient satisfaction, and information for orthodontists? What more needs to be done, considering the rapidly changing orthodontic scenario? This article aims to explore these questions to evaluate how evidence-based orthodontics has played itself out so far, so that it can continue to grow strong and stand up to the challenges of 21st century orthodontics.

Full text

Evidence-based practice and the
evidence pyramid: A 21st century
orthodontic odyssey
Priti Subhash Mulimani
Melaka, Malaysia
Organized evidence-based practice is said to have started in the medical field in the late 20th century.
Its principles and usage eventually spread to other health sciences, including orthodontics. Although the concep-
tual foundations and basic tenets of evidence-based orthodontics are based on the classical approach of testing
medical interventions, differences unravel as we encounter the ground realities in orthodontics, which are unique
due to the length, complexity, and diversity involved in orthodontic treatment and research. How has this led to
the evolution of evidence-based orthodontics and changes in its applications? Is it being translated to better clin-
ical answers, treatment strategies, patient satisfaction, and information for orthodontists? What more needs to
be done, considering the rapidly changing orthodontic scenario? This article aims to explore these questions to
evaluate how evidence-based orthodontics has played itself out so far, so that it can continue to grow strong and
stand up to the challenges of 21st century orthodontics. (Am J Orthod Dentofacial Orthop 2017;152:1-8)
Dentistry as a profession has evolved through the
ages of the expert, professionalism, and science
and brought us currently into the age of
evidence.
1
Evidence-based orthodontics (EBO) is consid-
ered to be an important contributor to the rapidly
changing scenario of orthodontic practice in the 21st
century.
2
Over the past 2 to 3 decades since its inception,
concerted efforts have been made to implement EBO
and change the perception and practice of orthodontics
from just an art to an art and a science grounded in
scientific foundations able to withstand the tests of
scientific rigor and scrutiny. From exhortations in
leading orthodontic journals, creating awareness
through specialty conferences and meetings by
professionals and orthodontic societies, to inculcating
it into orthodontic education and training, all have
played an important role.
3-6
EBO is still in its early
stages, and the evolution, development, and
organization of the orthodontic evidence base is
constantly being shaped and redefined by challenges
of clinical applications and practical issues, an
overview of which is provided in this article by
following the trajectory of EBO from its origins to its
most recent developments.
Genesis of EBO and the evidence pyramid
Evidence-based practice emerged as an alternative to
“expert-based,”“eminence-based,”or “opinion-based”
orthodontics. Its modern day origin can be traced to
the medical field, where the urgent need for testing effi-
cacy, safety, and suitability of drugs for clinical applica-
tion and formalizing rules for grading quality of
evidence arose consequent to medical disasters such as
the thalidomide tragedy and deaths from the application
of untested procedures, products, or hypotheses in clin-
ical practice.
7
As evidence-based medicine started gain-
ing popularity in the 1980s, its principles spread to
dentistry and orthodontics. The term “evidence-based
dentistry”was first used in the article by Richards and
Lawrence
8
in 1995. Although the first randomized
controlled trial (RCT) in orthodontics on Class II maloc-
clusion was reported by Jakobsson
9
in 1967, the begin-
ning of the evidence-based orthodontic era is mostly
associated with the National Institute of Dental and
Craniofacial Research funding trials on the same topic
in the late 1980s.
10
A fundamental tool for evidence-based practice has
been the evidence pyramid, which depicts the hierarchy
Department of Orthodontics, Faculty of Dentistry, Melaka Manipal Medical Col-
lege, Melaka, Malaysia
The author has completed and submitted the ICMJE Form for Disclosure of
Potential Conflicts of Interest, and none were reported.
Address correspondence to: Priti Subhash Mulimani, Department of Orthodon-
tics, Faculty of Dentistry, Melaka Manipal Medical College, Bukit Baru, Melaka
75150, Malaysia; e-mail, mulimanipriti@gmail.com.
Submitted, October 2016; revised and accepted, March 2017.
0889-5406/$36.00
Ó2017 by the American Association of Orthodontists. All rights reserved.
http://dx.doi.org/10.1016/j.ajodo.2017.03.020
1
GUEST EDITORIAL

or levels of evidence from lowest to highest (Fig 1). The
levels of evidence were originally described by the Cana-
dian Task Force on the Periodic Health Examination
11
in
1979 to develop recommendations based on evidence in
the medical literature. Sackett
12
developed these further
into the evidence pyramid.
13
Levels of evidence are ar-
ranged in increasing order of internal validity (rigor or
freedom from bias) from bottom to top, with in-vitro
and animal studies placed at the lowest level, followed
by opinions, case reports, observational studies, RCTs,
systematic reviews, and meta-analyses at the tip, repre-
senting the highest level of available evidence (Fig 1).
Evidence pyramid: beyond traditional hierarchy
The evidence pyramid with its origin in evidence-
based medicine gives the highest importance to the
RCT study design as the best method to generate
reliable and unbiased evidence. The discrete and
well-delineated axis of disease-pathogenic agent / pro-
cess-pharmacologic intervention in medicine lends it-
self well to the RCT study design. However, in
orthodontics, the etiology of malocclusion is complex
and multifactorial; treatment modalities are multiple,
appliance-driven, and operator-dependent; and treat-
ment effects are simultaneous, cumulative, and
gradual. These create concerns of complexity, ethics,
length of time required to complete orthodontic treat-
ment, posttreatment follow-up, impracticality, and
cost. Hence, it is not possible to conduct RCTs for all
questions in orthodontics. This has led to the explora-
tion of more pragmatic models; one of them is the “hi-
erarchy of quality in the evidence for clinical outcomes
in orthodontics”of Proffit
14
(Fig 2), which departs from
the traditional hierarchy in 2 important ways: by giving
greater recognition and weight to good retrospective or
nonrandom prospective studies, and by questioning the
validity of poorly conducted systematic reviews.
Consideration of nonrandom study designs
Calls for integrating evidence from study designs
other than RCTs and reducing overemphasis on RCTs
have been made in literature by Bondemark and Ruf,
15
Meikle,
16
Johnston,
17
Baumrind,
18
and Ionnaidis
et al.
19
Indiscriminate inclusion of nonrandom study de-
signs increases uncertainty and decreases confidence in
the resulting evidence. Hence, for nonrandom study de-
signs to be considered as sources of reliable evidence,
they need to fulfil the 3 criteria for good quality studies:
(1) have well-defined patient groups with selection
based on pretreatment characteristics and receiving spe-
cific treatments, rather than a variety of treatments; (2)
account for all patients included in the study for analysis
and reporting and not just the successful ones; and (3)
use appropriate methodology and statistics.
14
As the extraction-nonextraction pendulum has
swung in orthodontic history, it seems so is the
randomized-nonrandomized studies pendulum swing-
ing in the present. RCTs and nonrandomized or retro-
spective studies are not to be viewed as mutually
exclusive, incompatible, or invalidating of each other.
Studies at every level engender their own utility and
Fig 1. The pyramid of evidence: systematic reviews,
meta analyses, RCTs. SR, Systematic reviews; MA,
meta-analyses.
Fig 2. Hierarchy of quality in the evidence for clinical out-
comes in orthodontics.
14
Reproduced with permission.
2Guest Editorial
July 2017 Vol 152 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics

contribute to scientific knowledge, either by guiding
further studies at higher levels or by providing evidence
that higher-level studies failed to generate. Voudouris
20
highlighted the importance of in-vitro studies in ortho-
dontics, suggesting that they be placed above expert
opinion in the proposed modified pyramid called
“iceberg of evidence,”in which the clinical application
represented as the visible tip of the iceberg is supported
by the submerged inverted pyramid of “academic find-
ings”(Fig 3). The broadest and topmost levels of the
submerged part are assigned to systematic reviews,
meta-analyses, and RCTs followed by less rigorous study
designs that progressively taper toward the bottom and
farther from the clinical application zone. Orthodontic
products are straightaway released commercially unlike
medical products that are mandated by strict regulatory
guidelines to demonstrate efficacy and safety standards
before being released for public use. Hence, the impor-
tance attributed to orthodontic in-vitro studies to inves-
tigate biologic interactions, properties, behavior, and
safety of biomaterials.
Walach et al
21
proposed the “circle of methods”as an
alternative to the hierarchy model, where evidence from
every study design is used to counterbalance the
strengths and weaknesses of individual studies and
generate evidence that is closer to the realities of clinical
applications as opposed to the strictly controlled
environment of an RCT (Fig 4). Thus, the upper half of
the circle is represented by the experimental method
(RCTs) to test efficacy; these studies are then
complemented by observational, nonexperimental
methods (lower half of the circle) that are more descrip-
tive and somewhat reflect real-life effects and applica-
bility, such as retrospective audits and
prospective studies. However, Ionnaidis et al
19
cautioned
that although using nonrandomized studies may be
justified in certain situations, these alternative
Fig 3. Iceberg of evidence for viable clinical applications.
20
Reproduced with permission.
Fig 4. Circle of methods for generating evidence.
21
Re-
produced with permission.
Guest Editorial 3
American Journal of Orthodontics and Dentofacial Orthopedics July 2017 Vol 152 Issue 1

approaches should not be misused to bypass the require-
ment of scientific rigor in evidence-based practice and
undermine the efforts to promote RCTs, so as to obtain
easy answers from nonrandomized designs. RCTs should
be the first choice wherever it is feasible to conduct
them.
Technology usage and digitization have brought us
the current hot topic of “big data”analysis in health
research. Also known as “data mining,”it refers to the
analysis of patient data recorded in electronic databases
of practices, institutions, or companies.
22
One such
example is a study where a retrospective analysis of
more than 5000 patients was done using an electronic
health records system; the authors found no relationship
between obstructive sleep apnea and premolar extrac-
tions.
23
By providing data that enormously exceed tradi-
tionally available resources, big data appears promising.
However, its pitfalls include the possibility of generating
false-positive results consequent to multiple compari-
sons and launching “fishing expeditions”to explore
data without biologically plausible underlying theoret-
ical models that may give rise to misleading results.
24
Contributions from big data analysis to the traditional
evidence base may well be a future trend in orthodontic
research, but as it is usually with newer methods, it must
be tried, tested, critically evaluated, and appropriately
applied.
Poorly conducted or inconclusive systematic
reviews
The validity of systematic reviews that are poorly
focused, potentially misleading, and confusing compared
with well-conducted clinical trials has been questioned.
Systematic reviews, no matter how extensive or methodo-
logically accurate, are said to be of no use to clinicians if
they do not provide clinical answers,
14
also reflected in a
survey of 1517 orthodontists by Madhavji et al,
25
in which
59% of them found literature to be conflicting and unam-
biguous. Cochrane Systematic Reviews are highly valued
for their methodologic rigor, objectivity, and critical
appraisal. As of October 2016, the Cochrane Oral Health
Group had 22 full reviews on orthodontic interventions,
of which 17 reviews had the conclusion that either
evidence was insufficient, further RCTs were required, or
evidence was of too low quality to make any recommen-
dations.
26
No matter how methodologically accurate a
systematic review, it cannot provide answers if studies to
address the question do not exist. Hence, the adage that
a systematic review or meta-analysis cannot be better
than its included studies allow.
27
Therefore, the onus shifts to improving and stan-
dardizing the quality of primary research so that, no
matter which part of the world a study is conducted
in, the methodology is valid, and its results can be
compared with other similar studies, thus making it
more useful, relevant, and additive to existing knowl-
edge. Nonstandardized, disconnected research contrib-
utes to health research waste, which has become an
increasingly important global concern, since research
operates from limited resources. It is estimated that
85% of all health research is “wasted”because of impor-
tant outcomes for patients and clinicians not being as-
sessed or reported, underreporting or overreporting of
studies, exclusion or suppression of adverse effects,
and failure to use or build on existing research findings
(Fig 5).
28,29
An international orthodontic registry for ongoing
and completed studies and collective, multicentered
efforts to pool patient data can address the issues of
delay and scarcity in generating clinical research
data, arising due to the long duration of orthodontic
treatment and follow-up. Often systematic reviews
can neither make treatment recommendations since
the quality of included studies is questionable, nor
compare different treatment modalities since diverse
methods and outcomes are used by authors for the
sametreatmentapproach.Aspartofenhancing
research quality, RCTs should have adequate sample
sizes based on power calculations, appropriate
randomization with allocation concealment, blind
outcome assessment, and completeness of follow up.
To facilitate comparisons, studies need to use stan-
dardized diagnostic criteria and outcome assessments;
an initiative to establish the same is under way with
the Core Outcome Measures in Effectiveness Trials
(COMET) project. Uniform implementation of guide-
lines such as CONSORT and PRISMA enhance
appraisal and conduct of research, further reducing
wastage.
To address issues of uninformative systematic re-
views for complex interventions, Pawson
30
proposed
“realist reviews”to provide a middle ground between
meta-analyses and narrative reviews. These can be
used to either substitute or supplement systematic re-
views of qualitative research when it is more meaning-
ful to understand how the outcome of an intervention
may vary with the context: in other words, to detect
“what works, how, for whom, and in what circum-
stances and to what extent.”
31
Such formats are suit-
able to explain patient-reported outcomes and
patient-related issues such as perceptions of dental es-
thetics, reasons for seeking orthodontic treatment, ex-
pectations from treatment, treatment satisfaction, and
compliance.
4Guest Editorial
July 2017 Vol 152 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics

User-friendly and accessible EBO for day-to-day
practice
When evidence-based practice was introduced in the
early years, it was generally assumed that, just by
providing accurate, evidence-based information, indi-
vidual clinicians would automatically uptake this infor-
mation, become adept at interpreting the original
scientific literature, and apply the results of their
appraisal to clinical practice.
1
Clinicians were taught
the “5 A's”of evidence-based practice—ask, acquire,
appraise, apply, and audit.
32
In reality, however, it was
found that most orthodontists still rely on expert opin-
ions, and the redressal system for discussing issues
when faced with treatment uncertainties was “consul-
ting colleagues,”since their understanding of
evidence-based practice, terminology, and concepts
was poor.
25
Practice pressure, patient workload, and
time constraints are real issues that hinder seeking and
searching for evidence by clinicians, while navigating
through the highly technical methodology and jargon
of evidence-based literature.
The need to address these issues is seeing the rise of
“preappraised evidence,”whereby experts proficient in
the semantics of evidence-based practice collate all
available evidence, critically evaluate it, and then deliver
it in a filtered, condensed, more clinically usable format.
This facilitates a faster and easier evidence-based deci-
sion-making process for the clinicians. There are
multiple sources for preappraised evidence as Alpers
and Haynes
33
(Fig 6) depicted in their pyramid 5.0. At
the lowest level are preappraised or filtered synopses of
original studies in sources such as the Journal of the
American Dental Association,Journal of Evidence-
Based Dental Practice, evidence-based abstraction jour-
nals such as Evidence-Based Dentistry Journal,and
Web sites such as Dental Elf. Synthesis and summariza-
tion of evidence from these original studies constitute
“systematic reviews”disseminated by sources such as
PubMed, Embase, Cochrane Database of Systematic Re-
views, Database of Abstracts of Reviews of Effects, and
various specialty journals. These in turn act as the foun-
dation on which “systematically derived recommenda-
tions or guidelines”are built and provided by bodies
such as the National Guideline Clearinghouse for all
health specialties.
34
Overarching 1-stop access to multi-
ple sources of both appraised and unappraised evidence
is provided by “federated”search engines such as SUM-
Search2, Turning Research into Practice, and Epistemo-
nikos.
A bridge between research and clinical application is
“synthesized summaries or reviews for clinical refer-
ence”; an example of this is Cochrane Clinical Answers,
which summarizes, curates, and filters data and then
presents the most clinically relevant aspects of the
reviews to practitioners. The most advanced and
integrated source of evidence is “systems”where
Fig 5. Stages of waste in the production and reporting of research evidence.
28
Reproduced with
permission.
Guest Editorial 5
American Journal of Orthodontics and Dentofacial Orthopedics July 2017 Vol 152 Issue 1

individual electronic health records of patients are auto-
matically linked to evidence-based solutions, guidance,
or recommendations derived from all layers, best suited
to that particular patient's problems, thus eliminating
the need for practitioners to “search.”These are known
as clinical decision support systems; although such sys-
tems have not yet been developed in orthodontics, in the
medical field, evidence-based medicine electronic deci-
sion support is implemented at sites in several European
countries.
33
With all the advantages of preappraised ev-
idence—quick, time saving, and easy—it has the disad-
vantage of having a time lag between the appearance
of new evidence and integrating it into the existing
evidence-based answer pool, because of the time needed
to appraise it. Also, syntheses, synopses, or summaries
generated by different platforms may disagree with
each other; then original sources must be searched for
resolution.
35
The American Dental Association has been providing
such evidence-based dentistry related information,
mainly through its Center for Evidence-Based
Dentistry.
36
The American Association of Orthodontists
also provides evidence-based orthodontic research links
to members. With 82% of orthodontists citing peer-
reviewed journals as the best source of evidence and
91% of them reading scientific journals at least
monthly,
25
having a section dedicated to critical sum-
maries of studies, reviews, and research by experts to
guide readers who are not adept at critiquing research
or grasping its finer nuances, would be a great value
addition to orthodontic journals.
“Experts”and “evidence”: not mutually exclusive
but symbiotic
The American Dental Association has defined
evidence-based dentistry as “an approach to oral health
care that requires the judicious integration of systematic
assessments of clinically relevant scientific evidence,
relating to the patient's oral and medical condition
and history, with the dentist's clinical expertise and the
patient's treatment needs and preferences.”
36
In spite
of highlighting clinicians' roles in the definition,
evidence-based dentistry was dismissed at 1 point as
an academic, theoretically driven, cookbook model of
practice, threatening to sabotage the autonomy, free-
thinking ability, and expertise of clinicians.
37,38
Such
thinking was part of the perception that evidence-
based dentistry undermined practitioners' abilities, was
an affront to their experience, and amounted to
intruding in their practices. However, as Keim
5
put it,
evidence-based practice is not a division or debate be-
tween “evidence-based”and “experience-based”
Fig 6. Evidence-based health care pyramid 5.0: sources of preappraised evidence for clinical
decision-making guidance.
33
Reproduced with permission.
6Guest Editorial
July 2017 Vol 152 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics

practice but, rather, a mutually beneficial continuum be-
tween the 2 philosophies. The symbiosis between them
becomes apparent in the words of Sackett
39
:“without
clinical expertise, practice risks becoming tyrannized
by evidence, for even excellent external evidence may
be inapplicable to or inappropriate for an individual pa-
tient. Without current best evidence, practice risks
becoming rapidly out of date, to the detriment of pa-
tients.”With time, attitudes seem to have changed.
Most orthodontists, even though they lack a sense of
guidance in implementing EBO, have expressed interest
in knowing more.
25
Dental school graduates now show a
greater appreciation of evidence-based practice than did
students in earlier decades, with 84.1% of them
believing that it improves patient care and 74% viewing
evidence-based dentistry as a routine part of profes-
sional growth.
40
Emphasis on EBD instruction laid by
the Commission on Dental Accreditation (CODA) as
part of Accreditation Standards for Dental Education
Programs is thought to be one of the reasons behind
this positive change among the future generation of
dentists.
41
Because evidence-based dentistry was touted earlier
as a means of answering vexing clinical questions, the
frequent absence of definitive answers led to frustra-
tion and loss of trust among clinicians.
1
Not all an-
swers are available, and treatment uncertainties are
part of day-to-day practice. Hence, it is a necessity in
EBO to develop the skill to practice it with limited
available evidence and sometimes even in the absence
of it. In the June 2016 editorial in American Journal
of Orthodontics and Dentofacial Orthopedics, Rolf
Behrents
42
wrote about “Buridan's paradox,”the prin-
ciple of which is to suspend judgment as to the best
course of action until more is known. In orthodontic
parlance, this translates into applying evidence where
it exists and where it does not exist, using clinical
expertise to select the best option, and explain the
same to the patient.
43
Until more and better research
is conducted to generate evidence about new products
or techniques or even old techniques with lack of evi-
dence, our treatment choice should be determined not
by our biases but instead be based on sound scientific
principles and the patient's best interest and prefer-
ence. In the meantime, it is critical to propel orthodon-
tics to the next level of EBO practice, through the 3
steps of developing evidence by improving research,
translating or disseminating evidence through effective
evidence-based information services, and implement-
ing the evidence by provision of guidance and tools.
44
The 21st century has brought its own unique chal-
lenges. With the speed, breadth, and penetration of
the Internet today, it is a matter of seconds for news
to go viral. The seamless, all-pervasive, and omnipresent
access to the Internet makes it a no-brainer to spread
both information and misinformation, along with un-
founded claims, misconceptions, and scare mongering.
Even as orthodontic treatment is promised to
be delivered to the doorstep of the patients
45
and
do-it-yourself orthodontics poses dangers to users
46
an era of rapidly changing dynamics between orthodon-
tic services and patients is emerging. This makes it all the
more crucial for orthodontists to step up to the challenge
and equip themselves with biologically sound scientific
rationale and evidence-backed facts to face the
Google-equipped and informed patients and their
interrogations. Hence, reinventing EBO to continue
being the providers of the best, safest, most scientific,
and latest orthodontic care to patients has never been
more important for orthodontists.
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8Guest Editorial
July 2017 Vol 152 Issue 1 American Journal of Orthodontics and Dentofacial Orthopedics