Introduction to Evidence-Based DentistryDr Hakan ÇolakDDS, PhDIshık University School of DentistryDepartment of Restorative Dentistry

In this chapter, you will learn about:• The evolution of the dental knowledge base

• The evolution and definition of evidence-based dentistry (EBD)

• The three components of EBD: scientific evidence, the clinician’s expertise, and the patient’s needs and preferences

• Best evidence

• Applying EBD in practice

Definition• According to the ADA…

– Evidence-based dentistry (EBD) is 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.

Three Components of EBD• Is an approach to oral health

care

• Is a method to acquire, understand and apply the most current science

Evidence

Patient preferences

& needs

Clinical expertise

Evidence-Based Dentistry Is NOT….

• Cookbook dentistry

• A standard of care

• A mandate of what must be done

• A substitute for clinical judgment

How the Dental Knowledge Base Has Evolved

• The dental knowledge base is simply the collection of all that is known about oral health and disease and treatment methods and outcomes.

• Its contents comprise all of the – extant dental journal articles

– textbooks,

– the minds of all oral health practitioners.

The dental knowledge base• the foundation of the dental professions and the principal

determinant of how dentists and dental hygienists practice

• informs professional decision making, and portions of it comprise the content of predoctoral and postdoctoral dental school curricula.

The dental knowledge base

new information and understandings have been contributed by researchers, practitioners, and manufacturers.

the dental knowledge base has grown over time

The four eras in the evolution of the dental knowledge base

The age of the expert

The age of science

The age of evidence

The age of the expert• Evidence of the treatment of teeth

extends far back into human prehistory,and early writings discuss “tooth worms,” the supposed cause of toothache at that time.

• Ancient Roman, Greek, Egyptian, and Asian cultures all contain examples of dental technology related to replacing, retaining, and crowning teeth.

The age of the expert• Barber-surgeons and

toothdrawers extracted teeth for pain relief.

• The knowledge and skills underlying all of this early activity was strictly experiential; practitioners learned by doing

The age of professionalization • 18th century

• Pierre Fauchard– comprehensive textbook

– This textbook exemplified a new era in knowledge synthesis, enabled by better access to knowledge created by other

The age of science• Beginning of the 20th century,

• presaging the profession’s gradual shift from proprietary to university-based educational institutions

• Scientific studies– protocol-based

– controlled experimentation became more common,

– causes and prevention of dental diseases.

The age of science

• Synthesis of knowledge evolved from simple statements of “fact” based on an expert’s experience and opinion to

identification and consideration of the available information in the scientific literature.

The age of science• Knowledge dissemination enjoyed its most active period yet

• early rapid growth of university-based predoctoral and postdoctoral dental curricula,

• the proliferation of dental journals,

• organized continuing dental education

• congress

The age of evidence• knowledge creation in this era can be

characterized by the dominance of the randomized controlled trial (RCT), – represents the research design most likely

to produce an accurate and valid finding

The age of evidence• The hallmark of the age of evidence

is the systematic review

• represent a substantial change in the paradigm of knowledge synthesis by – ensuring inclusion of all relevant

evidence,

– de-emphasizing the role of the expert,

– minimizing bias through strict protocols demanding objectivity and transparency in the review process

How EBD Developed and How It Is Defined• EBD is a direct descendent and analog of a similar evolution

of the medical knowledge base, termed evidence-based medicine (EBM).

How EBD Developed

Personal experience of a single individual

synthesized observations of multiple practitioners

the results of simple, single research studies

synthesized results of several research studies (ie, literature review).

Evidence-based movement

Archie Cochrane David Sackett

Archie Cochrane

• Scottish physician and epidemiologist

• advocated the application of scientific methods, especially RCTs, to evaluate the effectiveness and efficiency of medical treatments.

• He is best known for his influential book– published in 1972

– Effectiveness and Efficiency: Random Reflections on Health Services

Archie Cochrane

• The principles he clearly set out in this book were straightforward:– Because resources would always be limited, they should be used to

provide those forms of health care that had been shown in properly designed evaluations to be effective.

– Evidence from RCTs, he stressed, are likely to provide much more reliable information than other sources of evidence.

The Cochrane Collaboration• The Cochrane Collaboration, named after

Archie Cochrane, is an international network of volunteers that prepares and updates systematic reviews on a broad variety of topics as well as maintains the largest collection of records of RCTs in the world

Evidence-based medicine.

• Created by Sackett

• first used at McMaster University in 1990

• describe “an attitude of enlightened skepticism toward the application of diagnostic, therapeutic, and prognostic technologies in day-to-day patient management.

Evidence-based medicine. • The term was first published in 1991 and reached widespread

visibility in 1992 with the publication of a description of the concept in the Journal of the American Medical Association.

Evidence-based medicine. • The classic definition of evidence-based medicine emerged a

few years later from the same group at McMaster University who pioneered the movement: – “the conscientious, explicit and judicious use of current best evidence

in making decisions about the care of the individual patient.”

• This definition focuses on the integration of individual clinical expertise with the best available external clinical evidence.

• This definition was refined a few years later to incorporate patient preferences and values

“An approach to oral healthcare 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.”

The three components of EBD

Scientific evidence

Patient’s needs and preferenc

es

Clinician’s

expertise

Evidence as the Hallmark of EBD• best evidence and systematic reviews

Best evidence• Not all evidence is created equal.

• Some evidence is more likely to be valid than other evidence

Best evidence• Validity

– measures how accurately the evidence reflects what is true, and it is an essential characteristic of evidence.

• Some types of evidence are more vulnerable to bias than others,

bias is the principal enemy

of validity

Best evidence• Bias is the existence of factors or processes that can influence

the results or conclusions of a trial.

• Bias occurs when there are important differences in – (1) the way in which subjects or groups of subjects are treated or

observed or

– (2) how data is measured or analyzed.

Best evidence• evolution of the

dental knowledge base

single observer

RCT

reduce the risk of bias in the information, or

evidence, that is created.

Maturation of evidance

Best evidence• EBD demands that the evidence upon which treatment

decisions are based have the lowest possible risk of bias.

Systematic reviews

Randomizedcontrolled trials

Cohort studies

Case-control studies

Case series/reports

Ideas, editorials, Expert opinion

Animal research

In vitro (test tube) research

Levels of evidence for preventive or therapeutic studies.

• RCTs or other low-bias evidence are not available to support every decision a

practitioner must make.

Best evidence• the term best evidence really means the best available

evidence based on this hierarchy of study designs.

• If higher levels of evidence are not available (ie, systematic reviews or RCTs), then one must seek studies lower in the hierarchy while at the same time acknowledging the potential for increased bias.

• In some instances, little more than expert opinion may be the best evidence currently available.

Systematic reviews

• The systematic review is quickly surpassing (exceeding) the traditional literature review as the preferred method for summarizing and synthesizing relevant research evidence.

Systematic reviews • Advantage

• providing clinically relevant information to aid in decision making– reducing the biases inherent in traditional literature reviews.

• follow strict protocols

Traditional review Systematic review

not to be well-focused on a specific problem

focus on specific clinical questions

ot including all of the relevant studies

including all of the relevant studies

Not combining the information from the studies

combining the information from the studies

Subjective objective

PICO format• identifying the problem or disease of interest,

• the intervention or treatment in question,

• the comparison treatment (usually the alternative treatment),

• the outcome through which the intervention and comparison treatments will be evaluated

Systematic review

• narrower focus permits a much more careful and complete search and selection process to identify and include all relevant studies that have addressed the question of interest.

• Because the topic is limited, the number of articles that contain information is also usually quite limited so that their careful analysis is feasible

Systematic review• Systematic review is to think of it as

a scientific study that is guided by the development of a protocol that outlines all steps in the review process

Systematic reviews

Systematic reviews are not simple surveys of the literature

systematic reviews are designed to minimize bias, they require the prior

determination of search methods, inclusion criteria, and evaluation

criteria, which reduces the chance of bias in deciding what studies to

include and in evaluating the strength of

those studies

Advantages of a

systematic review

Follow strict protocols

Require prior determination

of search methods

Reduce bias

Include only clinically relevant

information

Focus on specific clinical

questions

Have evaluation

criteria

Evaluate the strength of

the available evidence

The results of a systematic

review will represent the best, most current

evidence available that addresses a specifi c clinical

question

Implications of EBD for DentalPractice• Using EBD in clinical practice essentially involves identifying

and using the best available scientific evidence in caring for patients

• EBD also incorporates the clinician’s expertise and the individual patient’s needs and personal preferences during treatment decision making. – These decisions are ultimately made by the patient and are very

personal, and thus they will vary from patient to patient.

Implications of EBD for DentalPractice

!!!!

accessing and using current best available

evidence is at the forefront of the decision-

making process.

Fundamental steps in using EBD

• to help patients make individual decisions regarding the treatment that is right for them

1. Ask

2. Access

3. Apprais

e4. Apply

5. Assess

Step 1• Ask

– relevant to the condition of the patient.

– The clinical question is frequently described in a PICO format, as described previously

Step 2• Access

– systematically access the most current scientific evidence on the clinical question

Step 3• critically appraise the identified literature.

• provides insight into the strengths and weaknesses of the study, which is necessary when deciding if and how to use evidence from a study in practice.