Evidence-Based Dentistry: ASK

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Evidence-Based Dentistry eBook

How to Use Evidence-Based Dental Practices to Improve Clinical Decision-Making by Alonso Carrasco-Labra; Romina Brignardello-Petersen; Michael Glick; Azir Azarpazhooh; Gordon Guyatt
ISBN: 9781684470617
Publication Date: 2019-11-22
How to Use Evidence-Based Dental Practices to Improve Your Clinical Decision-Making is the definitive resource for dental students and practitioners who want to learn from leaders in the field of evidence-based dentistry (EBD); quickly conduct searches for the latest research; master the skill of critically appraising clinical studies; confidently apply the latest research to patient care; teach others how to inform their practice with the latest clinical evidence; and access everything they need to become an EBD all-star.

Background vs. Foreground Questions

There are two types of clinical questions: background questions and foreground questions. Knowing the difference between the two is useful for determining where to search for information, and whether to continue in the evidence-based dentistry process.

Type	Description	Example	Finding Information
Background Questions	Questions that ask basic or foundational information about conditions, tests, or treatments. Answers to these questions have been well-established.	What is bruxism? What is the chemical makeup of dental wax?	Consult a textbook, medical encyclopedia, or point-of-care resource/clinical summaries (i.e., Dynamed). Background questions do not need to continue in the evidence-based dentistry process.
Foreground Questions	Questions about a specific clinical problem relating to therapy, prevention, diagnosis, etiology, or prognosis to directly inform clinical decision making. Answers to these questions may not be easily found or well-established.	Is chlorhexidine effective to use in geriatric patients to treat mouth ulcers?	Search for evidence (ACQUIRE phase) usually in the form of journal articles. Foreground questions continue in the evidence-based dentistry process.

Type

Description

Example

Finding Information

Background Questions

Questions that ask basic or foundational information about conditions, tests, or treatments. Answers to these questions have been well-established.

What is bruxism?

What is the chemical makeup of dental wax?

Consult a textbook, medical encyclopedia, or point-of-care resource/clinical summaries (i.e., Dynamed). Background questions do not need to continue in the evidence-based dentistry process.

Foreground Questions

Questions about a specific clinical problem relating to therapy, prevention, diagnosis, etiology, or prognosis to directly inform clinical decision making. Answers to these questions may not be easily found or well-established.

Is chlorhexidine effective to use in geriatric patients to treat mouth ulcers?

Search for evidence (ACQUIRE phase) usually in the form of journal articles. Foreground questions continue in the evidence-based dentistry process.

Categories of Clinical Questions

Foreground questions can be categorized into types of clinical questions. Categorizing a question is helpful for determining the strongest level of evidence, or study design, that should be used to answer it. In other words, the question type determines the primary studies that are stronger and weaker to answer the question.

Categories of clinical questions

Clinical question type	Purpose	Example
Etiology/Harm	Identifying associations, risk factors and causes of a disease	Are teenagers who frequently drink soda at risk for developing dental caries?
Diagnosis	Selecting tests that accurately detect a disease	What is the best method that dentists can use to identify early carious lesions?
Therapy/Prevention	Selecting effective interventions to treat or prevent a disease	Should teenagers and young adults with asymptomatic impacted wisdom teeth have them removed?
Prognosis	Predicting the probable outcome of a disease or treatment	How long will a dental implant last in an adult patient with no periodontal disease?

Study Designs for Clinical Questions (Hierarchy of Evidence)

Study design methods for clinical question categories

Researchers select the study design to match the kind of clinical question being asked and the level of knowledge about the question that already exists. Identifying the type of question being asked and the type of research that would best answer the question will help you focus the search on the highest level of evidence.

*Please note*- When available, clinical guidelines based on meta-analyses and systematic reviews often provide the best answers to clinical questions. Meta-analyses and systematic reviews synthesize results of multiple randomized controlled trials or primary studies. It is best to look for clinical practice guidelines, meta-analyses, and systematic reviews first, before moving to primary studies. However, clinical practice guidelines, meta-analyses, and systematic reviews are not always available to answer specific questions.

Clinical Question Type	Preferred study type (in order of preference, or strength)
Diagnosis	Prospective blind controlled trial comparison to gold standard (with report of sensitivity/specificity: Randomized controlled trial (RCT) → cross-sectional study (more common in dental literature)
Etiology/Harm	RCT → cohort study → case-control study → cross-sectional study
Prognosis	cohort study → case-control study → case series
Therapy/Prevention	RCT → cohort study → case-control study → case series

Hierarchy of Evidence Explained

Always start by looking for the highest level of evidence. If a guideline is not available on a topic, look for a meta-analysis, look next for systematic reviews without statistical synthesis, next for randomized control trials, next for cohort studies, next for case control studies, etc.

Definitions of Select Study Designs

Meta-analysis

"Meta-analysis is a tool by which small, related studies are identified and, through systematic review, are combined into a common data pool for a single, larger population analysis."

Livingston M,et al.Meta-analysis: an introduction into a research process. Special Care in Dentistry 28, no. 4 (2008):125-30. UNC-CH Full Text

Systematic Reviews

"Systematic reviews summarize and synthesize the available evidence related to diagnosis, therapy, prognosis, and harm for clinicians, patients, and decision makers. Such reviews represent one of the most powerful tools to translate knowledge into action."

Carrasco-Labra A, Brignardello-Petersen R, Glick M, Guyatt GH, Azarpazhooh A. A practical approach to evidence-based dentistry: VI: How to use a systematic review. Journal of the American Dental Association. 2015 Apr;146(4):255-65.e1. UNC-CH Access

Randomized Controlled Trial (RCT)

"At the level of primary studies, RCTs represent the optimal study design to address questions of therapy. An RCT is an experiment assessing a medical treatment in patients. In an RCT, participants are allocated randomly into 2 or more groups that are treated equally except for the intervention the participants receive"

Brignardello-Petersen R, Carrasco-Labra A, Glick M, Guyatt GH, Azarpazhooh A. A practical approach to evidence-based dentistry: III: how to appraise and use an article about therapy. Journal of the American Dental Association. 2015 Jan;146(1):42-49.e1. UNC-CH Full Text

Cohort Study

"A cohort study is one in which a group of subjects, selected to represent the population of interest, is studied over time."

Levin, K. A. Study design IV: Cohort studies. Evidence-based dentistry 7, no. 2 (2006):51-52. UNC-CH Full Text

Case-Control Study

"Like cohort studies, the purpose of case-control studies is to establish association between exposure to risk factors and disease. Unlike cohort studies, however, members of the population with the disease are selected into the study at the outset and risk factor information is collected retrospectively"

Levin, K. A. Study design V: Case-control studies. Evidence-based dentistry 7, no. 3 (2006):83-84. UNC-CH Full Text

What is a PICO Question?

A well formed clinical question covers the following 4 areas identified by the acronym PICO.

Element	Questions to consider	Example
P Patient(s) / Population(s)	Who is the focus of my research question?	Patients undergoing third-molar extractions
I Intervention(s)	What is the proposed, new intervention?	Antibiotic prophylaxis
C Comparison(s)	What is the current or alternative intervention?	No prophylaxis
O Outcome(s)	What measurable outcome is affected?	Alveolar osteitis, surgical wound infection

Element

Questions to consider

Example

Patient(s) / Population(s)

Who is the focus of my research question?

Patients undergoing third-molar extractions

Intervention(s)

What is the proposed, new intervention?

Antibiotic prophylaxis

Comparison(s)

What is the current or alternative intervention?

No prophylaxis

Outcome(s)

What measurable outcome is affected?

Alveolar osteitis, surgical wound infection

Another variation of PICO is PICOT. This type of framework can be used if a clinical question has a time element or if you want to consider a specific study type.

Element	Questions to consider	Example
P Patient(s) / Population(s)	Who is the focus of my research question?	Patients undergoing third-molar extractions
I Intervention(s)	What is the proposed, new intervention?	Antibiotic prophylaxis
C Comparison(s)	What is the current or alternative intervention?	No prophylaxis
O Outcome(s)	What measurable outcome is affected?	Alveolar osteitis, surgical wound infection
T Time/Type	Is there a specific time frame that is important? What category of clinical question is being asked and what type of study design is best to answer this question?	Randomized controlled trial

Element

Questions to consider

Example

Patient(s) / Population(s)

Who is the focus of my research question?

Patients undergoing third-molar extractions

Intervention(s)

What is the proposed, new intervention?

Antibiotic prophylaxis

Comparison(s)

What is the current or alternative intervention?

No prophylaxis

Outcome(s)

What measurable outcome is affected?

Alveolar osteitis, surgical wound infection

Time/Type

Is there a specific time frame that is important?

What category of clinical question is being asked and what type of study design is best to answer this question?

Randomized controlled trial

Clinical Questions Using PICO Framework

Purpose:

To select a test that accurately detects a disease or condition

PICO:

P: Patients suspected of having interproximal caries

I: Periapical radiograph

C: Bitewing radiograph

O: Diagnostic accuracy (as assessed by sensitivity and specificity findings)

Question framework:

Are (is) _________ (I)_________(O) in diagnosing _________ (P) compared with_________(C)?

In _________(P) are/is _________(I) compared with _________(C) more accurate in diagnosing_________(O)?

Example:

Is periapical radiograph more accurate in diagnosing patients suspected of having interproximal caries compared with bitewing radiograph?

Purpose:

Identifying associations, risk factors and causes of a disease

PICO:

P: Toddlers

I: Drinking milk at night

C: Drinking water at night

O: Caries

Question framework:

Are ____ (P) who have _______ (I) at ___ (Increased/decreased) risk for/of_______ (O) compared with ______ (P) with/without ______ (C)?

Are ______(P) who have ______(I) compared with those without _______(C) at ________ risk for/of _______ (O)?

Example:

Are toddlers who drink milk at night compared to those who drink water at night at an increased risk of developing dental caries?

Purpose:

Predicting the probable outcome of a disease or treatment

PICO:

P: Patients undergoing third-molar extractions

I: Presence of diabetes

C: Absence of diabetes

O: Pain, swelling, trismus, postoperative infections

Question framework:

Does __________ (I) influence ________ (O) in patients who have _______ (P)?

In _______ (P), how does ________ (I) compared to ________ (C) influence _________ (O)?

Example:

In patients undergoing third-molar extractions, how does having diabetes compared to not influence the risk of complications?

Purpose:

Selecting effective interventions to treat or prevent a disease

PICO:

P: Patients undergoing third-molar extractions

I: Antibiotic prophylaxis

C: No prophylaxis

O: Alveolar osteitis, surgical wound infection

Question framework:

In _______(P), what is the effect of _______(I) on ______(O) compared with _______(C)?

Example:

In patients undergoing third-molar extractions, what is the effect of antibiotic prophylaxis on preventing postoperative infections compared to no prophylaxis?