Download Cross-cultural implications of evidence based dentistry

Braz J Oral Sci . April/June 2002 - Vol. 1 - Number 1
Cross-cultural implications of
evidence based dentistry
Francesco Chiappelli 1
Edna Concepcion 1
Elaine Sunga 1
Paolo Prolo1
1
Division of Oral Biology & Medicine, UCLA
School of Dentistry
Abstract
Evidence based dentistry is a process of systematic evaluation of
the research evidence for directed implications and applications
in the day-to-day reality of clinical practice. In order to be
successful, the integration of research evidence into the practice of
clinical dentistry relies on the ability of dentists to identify
appropriately designed and conducted research, whose data are
correctly analyzed.
The current practice of dentistry must
increasingly rest on the judicious utilization of the best available
evidence. However, questions arise as to the validity of the
published research to individual clinical needs in different sociocultural environments, as to whether or not published research
can indeed be trusted, and as to what might be the most readily
protocols for the evaluation of published research evidence.
These issues are discussed herein in the context of the practical
example of the chewing sticks, often used in tropical countries as a
preventive measure for oral health and hygiene.
Key Words:
Evidence based dentistry, PICO, PIPO, CONSORT, QUORUM,
SESTA, chewing sticks, miswak
Correspondence to:
Francesco Chiappelli
UCLA School of Dentistry, CHS 63-090
Division of Oral Dentistry & Medicine
Los Angeles, CA 90095-1668
e-mail: [email protected]
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Braz J Oral Sci 1(1): 47-53
Evidence Based Dentistry The Premise
The aim of evidence based dentistry is to alert clinical
dentists to novel and improved treatment interventions
in the practice of dentistry by means of a critical process
of evaluation of the research evidence that is available in
the printed dental and biomedical literature. One
approach at defining this emerging branch of scientific
inquiry in oral biology and medicine states that evidence
based dentistry is a process “…of systematically finding,
appraising and using contemporaneous research
findings as the basis for clinical decision…"1. The goal of
this endeavor is to insure the most judicious selection of
the most appropriate treatment intervention for a given
patient.
There stands one of the critical issues in evidence based
dentistry: it lies where research significance overlaps
with clinical significance. A brief discussion of these two
domains is therefore warranted. Indeed, research
generates evidence about what the most appropriate
treatment is for a given condition. Research generally
involves groups of patients who are studied along
variables that serve either to make comparisons of
treatment outcomes, or to perform predictions about the
effectiveness of one or another treatment variable.
Optimally, at least from the viewpoint of the clinician,
research should be performed in the form of clinical
trials. From this perspective, the participants are
randomized to the treatment and the placebo groups, and
they and the nursing staff who administers the condition
are blind to group assignment (i.e., “double-blind”):
hence the terminology randomized double-blind clinical
trial (RBT).
Research is a process that rests on stringent principles of
methodology, design and data analysis, and it is not
surprising that “…research is very hard to do well…”2.
Research conclusions may be invalidated by subtle
errors in the choice of variables, sampling issues, design
allocation and statistical analysis3,4. Research generates
evidence, which is quantified and expressed as research
data. Inappropriate research methodology and design
cannot but generate erroneous and misleading data.
Well-designed and well-conducted research produces
data that, while perhaps reliable and valid, may be
incorrectly analyzed, and consequently misinterpreted.
In brief, research must be conceived as a three-level
endeavor that rests on appropriate research
methodology (i.e., choice of variables, tools of
measurements, sampling), appropriate research design
Cross-cultural implications of evidence based dentistry
(i.e., observational, experimental, clinical trial designs),
and appropriate statistical analysis of the data, lest it be
irreparably flawed.
Statistical analysis of research data rests more often than
not on characteristic behavior or responses by the group
of subjects studied. Statistical significant evidence
represents the probability that the responses of the group
of subjects are not due to a chance phenomenon, but
rather to an actual effect specific to the treatment. The
critical point here is that statistical significance relates to
the average response of the group.
By contrast, clinical significance refers to what is best for
the individual patient presently under consideration by
the dentist. Clinical significance and statistical
significance are not equivalent, nor are the two concepts
meant to be similar or associated, or even comparable. As
the one pertains to the average behavior of the group of
subjects studied, the other refers directly, specifically and
uniquely to the immediate needs of one given particular
patient3-5.
Evidence based dentistry lies as a bridge, a delicate bridge
at that, between these two disparate domains (Figure 1).
In that capacity, evidence based dentistry serves to shift
the implications of research statistical evidence to the
realm of clinical practice, and to highlight the need for
structured research in specific clinical cases and
situations.
Statistical Significance
Clinical Significance
is Distinct from
Statistical Significance
What is best
scientifically
the best?
What is best for
the patients?
Evidence-Based
Dentistry
Clinical Significance
Statistical Significance
2. Evidence Based Dentistry Across Cultural Realities
An important question immediately emerges in relation
to the validity of the published research to individual
clinical needs across a variety of socio-cultural
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Braz J Oral Sci 1(1): 47-53
environments. Indeed, available statistics inform us
that merely six of the most industrialized countries have
generated, over the past decades, over 85% of the
worldwide government expenditure on health
research6. Most of the research performed in these wellindustrialized countries pertains to patient populations,
oral pathologies and interventions, and, more generally
speaking, clinical dental needs proper to their societies,
and often hardly generalizable, to the larger world
community. This disparity contributes to the wellrecognized cross-national inequalities in health-care
research and delivery.
Ethnic differences in certain physiological and
pathological processes, are well acknowledged by the
US National Institutes for Health, and cannot be ignored
cross-nationally and worldwide. Therefore, health
practitioners in general, and dentists in particular, in
countries other than the US and their well-industrialized
cohorts, must regard the integration of research
evidence produced in the well-industrialized giants
with prudence, to say the least.
While it is fair to state that “…improvements in global
health in the second half of the twentieth century have
been enormous…”, it is also important to recognize that
they, in fact, “…remain incomplete…”7. The conclusion
that “…a global program focusing on lifting the poor out
of ill health would require extraordinary and sustained
popular and political will …(and)…would have truly
profound beneficial effect…”7 is accurate. However, if
overly globalizing, it may run the risk of ignoring the
idiosyncratic needs and peculiarities of individual
cultures, and seek to persevere the irrational notion that
what has been established in the richer countries is
absolute and must be imposed across the board to all
countries and cultures10.
This is tantamount to stating that researchers and
dentists alike, here and abroad, must be sensitive to
cross-national and cross-cultural issues. The effective
utilization of evidence based dentistry differs, and must
drastically differ in developed and in under-developed
countries, fundamentally due to differences in states of
disease, technological levels, cultural, economical and
sociopolitical circumstances11. Clearly, and as stated
elsewhere there is an “…urgent need for cooperation in
dental education and research between developing and
industrialized countries to cultivate acceptable costeffective preventative programs in countries where
caries activity (and other dental and oral pathologies) is
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Cross-cultural implications of evidence based dentistry
higher or increasing rapidly…"12. The question remains
as to how to best achieve this goal in the 21st Century.
To stand true to the premise of evidence based dentistry,
we may propose that research evidence, generated in the
well-industrialized countries and under-industrialized
countries, be evaluated by the same standards and
weighed equally. To achieve this goal, the future success
of evidence based dentistry from a cross-national
perspective may rest on the establishment of WHOsupported Evidence-Based Practice Centers, designed to
assist the socio-economical and technological dental
health-related advances expected and de facto achieved in
each country. One approach to promote the sharing of
research information on dental practice may be through
the use of technology. The Internet, for example, has
allowed, in well-developed countries, clinicians to access
databases and research papers, and to interact with other
clinicians and researchers. By focusing in the immediate
future to provide these resources to clinicians in underdeveloped countries, Evidence-Based Practice Centers
could go a long way in establishing access of clinical
dentists anywhere in the world to the critical information
needed in making evidence based decisions on dental
intervention.
In brief and from a cross-national and a cross-cultural
standpoint, evidence based dentistry must be formulated
to support the notion that research evidence needs to be
tailored for use and applications to the specific culturesensitive needs for each individual patient under
treatment within a given socio-cultural context. Dental
patients in less industrialized societies have a set of
concerns that range from oral disease to access to dental
treatment, which are quite distinct than patients in more
industrialized countries. The field of evidence based
dentistry must address these differences, lest the
disparity between under-served and well (over)-served
dental patients remain grotesquely hampering to the
establishment of the profession in a global scale.
3. Of PICO and JADAD and CONSORT and QUORUM
and SESTA
Another set of important questions that arise in the
context of evidence based dentistry from a cross-national
perspective relate to assessing whether or not the
published research can be trusted and what might be a
readily available protocol for the evaluation of published
research evidence across national and cultural
boundaries.
Braz J Oral Sci 1(1): 47-53
The answer to the first part of this query is simple: no,
most of the dental research evidence is not reliable,
valid, or exempt from flaws and deficiencies that
seriously hamper its use and utilization in the context of
clinical practice. The fact that a paper is published in a
peer-reviewed journal is not by itself a guarantee that
design, methods, data analysis and conclusions are
correct, nor that those findings can be translated
everywhere in the world into clinical practice. A recent
assessment of the quality of randomized clinical trials
published in 1999 established that most published
research in medicine or in dentistry were
“…imperfect…of overall inadequate quality…”, and
“…there is a clear need to improve the quality of trial
reporting in dental and medical research…”8. This
conclusion was echoed by another recent evaluative
report9. These concerns are further compounded by the
weak external validity of most studies, noted above,
with respect to their overwhelming lack of
generalizability beyond the local or national context of
the original research. From the perspective of crossnational and cross-cultural applications and
implications, there is a dearth of sound evidence based
dentistry.
This state of affairs leads to two principal concerns,
which must be addressed with relative urgency. On the
one hand, it is critical to the field that a better approach to
assess research be developed, evaluated and generally
adopted to insure some degree of homogeneity. This
approach must be applicable across national and
cultural boundaries. Evidence based dentistry must also
strive to apply these principles to culture-specific
situations3, 10.
The field of evidence based dentistry has endeavored to
develop strategies to evaluate research evidence. Types
of research reports3 and levels of evidence13 have been
characterized, and the essential steps of the process by
which research evidence ought to be evaluated have
been proposed. The PICO process, for instance, which
stands for identifying the clinical problem (or the target
population), the experimental intervention under test,
the comparison groups, and the outcomes, is one such
systematic approach at evaluating research evidence in
general and clinical trials in particular13. Indeed, as
noted above, whereas some research seeks to compare
groups, other research studies seek to generate
predictions. Evidently, therefore, the PICO process of
research involving comparisons must have a parallel
Cross-cultural implications of evidence based dentistry
PIPO systematic evaluative process of research that
involves predictions. The PICO (and PIPO) approach
represents “…a systematic process of asking clinical
questions…”13, whose applications and implications of
PICO (and PIPO) to the cross-national and cross-cultural
dimensions of evidence based dentistry remain to be fully
evaluated.
PICO and PIPO refer to the process by which practicing
dentists may begin to peruse the research literature about
a specific clinical question in a systematic manner. The
question, then, arises about the criteria by which the
readers can establish and determine the qualities and the
deficiencies of any given research report. Here too, the
field has striven to establish a set of strategies, which are
increasingly being accepted. Standards for reporting
clinical trials have been proposed and evaluated, and now
generally referred under the acronym CONSORT
(consolidated standards of reporting clinical trials)2,14.
Standards for evaluating clinical trials have also been
proposed (e.g., JADAD scale), and a recent report
indicates that most clinical trials reported in the research
literature suffers from one or more serious
methodological or design flaws8,15.
We noted earlier that research is a three-pronged
endeavor, which relies upon methodological issues,
design issues and data analysis issues. Therefore, it is not
surprising that guidelines have been proposed and
implemented for evaluating the quality of analysis and
reporting of meta-analyses (QUORUM
quality of
reporting of meta-analyses)2,16. Meta-analysis refers to the
comprehensive analysis of several published research
studies on one given common research question. It
represents an approach at integrating the findings
reported by several investigators, in an attempt at
generating a decisive statement of statistical significance
across the board of several independent studies.
Meta-analytical studies are most valuable for clinical
dentists; however, they are rarer, for any given research
question in clinical dentistry, than individual research
studies. More often than not, dentists have access to
primary research reports; that is, to research reports that
describe one given study, rather than a synthesis of
multiple studies. Often, clinical dentists must make an
immediate decision about whether or not to consider the
evidence presented in a given primary research report. It
is essential, therefore, as we have argued elsewhere3,4, that
a rigorous approach for the systematic evaluation of
statistical analysis (SESTA) of the data presented in
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Braz J Oral Sci 1(1): 47-53
individual reports be developed for routine use by the
clinical dentist perusing the original research literature.
The argument could be defended that cross-national
and cross-cultural concerns may become imbedded in
PICO and PIPO. By contrast, it is possible and even
probable that, due to the nature of CONSORT, JADAD,
QUORUM and SESTA, these particular strategies at
evaluating the nature and the quality of research
evidence may be somewhat immune to cultural and
national issues.
We present below a concerted effort at the utilization of
these approaches is evaluating the evidence in support
of the utilization of chewing sticks for the prevention of
periodontal disease in tropical countries.
4. Chewing Sticks and Oral Health in Tropical
Countries
The Year 2000 Consensus Report on Oral Hygiene by the
World Health Organization (WHO) presented
arguments in support of the use of chewing sticks to help
in the maintenance of oral hygiene in tropical countries.
Indeed, chewing sticks have been used for decades, if
not centuries, in tropical countries of Asia, Africa and the
Americas for dental cleaning purpose and for
preventive oral health17. Little systematic analysis of the
evidence has been done, however. The significance of
this particular body of literature stands in the strong
association between diabetes and the progression of
periodontal disease18. Poor general and oral hygiene and
preventive medicine in tropical countries may favor the
onset and progression of either diabetes and or oral and
periodontal disease.
It is possible and even probable that in many
economically deprived countries whose people are not
afforded the luxury of expensive medications and
medical advances, many diabetics suffer from an
uncontrolled state of their disease. These patients may
be more likely to suffer from oral and periodontal
disease that will likewise remain untreated. In these
areas of world, it would be advantageous to consider
low-cost preventive options to help diminish the
incidence and severity of oral and periodontal disease,
such as chewing sticks that are derived from
endogenous plants.
In many tropical countries in Asia, in Africa and in the
Americas, the use of certain plants as chewing sticks has
been a common practice for teeth cleaning for centuries.
Sticks are usually chewed at one end into a tuft, which is
51
Cross-cultural implications of evidence based dentistry
then used in a brush-like manner to clean the teeth, while
others are simply chewed on. Among the most
commonly used chewing sticks is the Miswak, which is
harvested from the plant Salvadora persica. The value of
the Miswak and of the many other plant species currently
used as chewing sticks throughout the world was
originally believed to rest solely on their mechanical
cleansing action. Recent research suggests several
additional properties of chewing sticks, including
hemostatic, analgesic, antimicrobial, buffering, and antiplaque forming activity.
We have engaged in a process of systematic examination
of the available research literature on the topic of chewing
sticks essentially by the approach outlined above. We
have examined this literature by means of the protocols
outlined above, or slight modifications thereof. The
research papers that were found to adhere to the stringent
guidelines imperative in research design are discussed
briefly below. Taken together, the research evidence on
chewing sticks supports a relationship between their use
and cleaning effectiveness, pocket depth, gingival
recession, plaque inhibition, and antibacterial activity.
One report describes the oral hygiene habits of Tanzanian
schoolchildren participating in an oral health educational
program, and who were studied by focusing on the
cleaning effectiveness of chewing sticks among habitual
users versus toothbrush users. The report provides
adequate details about the research design such that the
study is straightforwardly reproducible: 124 students
ranging in age from 10 to 13 years were selected to
participate in the study. Subjects were separated into four
groups: 2 experimental groups, one each for chewing
stick and toothbrush use, and 2 control groups also
consisting chewing stick users and toothbrush users.
Each experimental group received oral hygiene
education, while the control group did not. Each habitual
chewing stick user was randomly matched with a
toothbrush user of similar sex, age, and school. The study
conducted single blind oral examinations by one
examiner. Baseline measurements indicated chewing
stick users experienced statistically significant more
plaque, while their gingival condition was not statistically
significantly different from that of their matched
toothbrush counterparts. Three months into the study,
data analysis indicated that subjects in the experimental
groups exhibited a statistically significant reduction in
plaque, and a large, but not significantly significant
decrease in gingival bleeding in contrast to the control
Braz J Oral Sci 1(1): 47-53
group. The degree of reduction in plaque scores between
chewing stick and toothbrush experimental groups was
comparable. Chewing stick users, however, continued
to have higher plaque scores in comparison to
toothbrush users three months into the research. Taken
together, the data suggest that, with proper education,
oral hygiene can be improved regardless of the cleaning
instrument (i.e., toothbrush vs. chewing stick) used.
Data do not suggest that chewing sticks are superior to,
or equal to toothbrushes since chewing sticks users
consistently showed higher levels of plaque. However,
chewing sticks, with proper oral health instruction, may
provide an inexpensive and reasonably effective
alternative in removing plaque and improving gingival
health, when the conventional toothbrushes are not
available19.
These observations were confirmed and expanded in a
related cross-sectional study that used 236 Saudi
Arabian subjects categorized into three groups: a
chewing stick group, a toothbrush group, and a group
who reportedly used both chewing sticks and
toothbrushes in combination. All participants were
examined by two examiners: one interviewed the
patients about their oral hygiene habits, the other
performed all clinical measurements. This approach
sought to reduce examiner bias.
Upon clinical
examination, investigators assessed plaque levels,
gingival inflammation, pocket depths, attachment loss,
and gingival recession. Clinical procedures for the
examinations were clearly and thoroughly presented
such that intra-oral examinations and their appropriate
assessment would be adequately reproducible. From
the viewpoint of SESTA, data analysis was somewhat
disputable, since, for instance, measurements such as
the frequency distribution of plaque and the presence of
absence of bleeding on probing ought to have been
analyzed as categorical data, and not by the parametric
test of ANOVA. Nonetheless, valuable information on
pocket depth can still be extrapolated from this study,
and the data indicate that chewing stick users exhibit
greater pocket depths on mid-facial surfaces in
comparison to toothbrush users. Subjects who used
both chewing sticks in conjunction with toothbrushes
were reported to have deeper pocket depths than either
group. It is possible and even probable, as the
investigators suggest, that patients in this group used
the chewing sticks more frequently than the toothbrush,
and that improper or aggressive use of the chewing stick
Cross-cultural implications of evidence based dentistry
may be responsible for this type of periodontal damage20.
In an attempt to understand the mechanisms by which
plant extracts may be beneficial to oral health, extracts
were studied for their ability to inhibit the growth or
physical properties of the bacteria suspected of
involvement in the initiation and progression of
destructive periodontal diseases. The extracts, from
plants commonly used in Kenya as chewing sticks, were
tested against three strains each of the proteolytic Gramnegative organisms, Bacteriodes gingivalis and Bacteroides
intermedius and two strains of the anaerobic spirochaete
Treponema denticola. The source of plants used as chewing
sticks were obtained from a questionnaire distributed to
all primary schools in Kenya in which children were
asked to state what they used to clean their teeth and if
they used a chewing stick. At the end of a six-monthperiod, over 11,400 responses were received, of which
over 70% claimed to use mswaki (i.e., Miswak). The
plants to be used for further study were identified by a
botanist from a pool of 284 different species and
narrowed down to the five most commonly reported
species. The effects of the plant extracts on bacterial
protease activity, measured by means of sound
biochemical protocols at five different concentrations,
generated data, which were appropriately analyszed
along SESTA criteria. Taken together, the findings suggest
that extracts from plants used in chewing sticks have the
property of interfering with the pattern of growth of
certain bacteria resident in the periodontal plaque flora,
as well as their proteolytic activity. The bacteria
identified to be most sensitive to these extracts were B.
intermedius, B. gingivalis and T. denticola. The findings
also indicated that, one of the plant species tested, C.
hisitanica, is a tropical species introduced in Kenya as a
plantation tree for timber and is widespread in regions
with a high economic potential, suggesting, this plant
species may present the possibility of widespread use as
chewing sticks into countries where these sticks are not
yet readily available21.
In conclusion, the evidence suggests that chewing sticks
are not superior to toothbrushes, although their use may
be beneficial, if moderate, when conventional tools for
oral health are not available. Evidence also supports the
effectiveness of chewing sticks as oral hygiene tools.
Therefore and based on their availability, low-cost, and
cultural acceptability, the research evidence supports the
use of chewing sticks as viable tools for preventive oral
hygiene.
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Braz J Oral Sci 1(1): 47-53
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