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Evidence Based Dentistry: Steps 1 & 2: Assess & Ask

Assess & Ask Steps


  • You have a research topic that your professor has assigned.
  • You want to learn about a disorder that your cousin has.
  • You have a patient who has come to the clinic and you are deciding how to treat her.

Each of these scenarios is an opportunity to use EBP.  You have just assessed that you need more information about a topic.


Background or Foreground Questions

When formulating your research question, the first step is to decide whether you are asking a background question or a foreground question.  The background question is usually asked because of the need for basic information. It is not normally asked because of a need to make a clinical decision about a specific patient and will not require the same type of search strategy that a foreground question will.

  • Background
    • Descriptive
    • Broad
    • Basic or background information
    • Answers can often be found in textbooks or encyclopedias
    • Often has 2 variables
      • Patient (Who/What)
      • Outcome
    • Does not require PICO Question - Move to step 2
  • Foreground
    • Analytic
    • Focused
    • May inform decisions about a patient or treatment
    • Requires basic knowledge of the topic
    • Answers can often be found in journals and conference materials
    • Has multiple variables (see PICO/PICOT below)


Creating a research question is a simple idea, but can be a complicated task.  A well-built question is neither too broad nor too narrow.  One method is to create a PICO or PICOT question.  You may not have all of the information available when you start, but you should at least have the P and I before you start searching for information.  The worksheets linked below can be valuable when determining this information.  The answers to these questions can help you formulate your keywords for your search strategy.

P - Patient population (What differentiates your population?  age, sex, race, ethnicity, disease process, comorbidities)

I - Intervention (What action do you want to take with the population?  What has this population been exposed to that you wish to examine?)

C - Comparison (What are you comparing your intervention against - The control group?  The gold standard treatment?)

O - Outcome (What will be improved?  What is the desired outcome?)

T - Time (Does timing matter?  When should the patient follow up?  Is it day or night?  Is there a drug administration schedule?)

  • If the outcomes will be determined a while after the intervention, you may be conducting a cohort study or a prospective study
  • If the outcomes will be determined at the time of the intervention, you may be conducting a cross sectional study
  • If the outcomes are determined prior to the intervention, you may be conducting a case-control study

Hall, H. R., & Roussel, L. A. (2016). Evidence-based practice. Jones & Bartlett Publishers

Types of Clinical Questions

Clinical Questions typically fall into one of four main categories:

1. Etiology (or harm/risk factors): What causes the problem?

Are teenagers who frequently drink soda at risk for developing dental caries?
2. Diagnosis: Does this patient have this particular problem? What is the best method that dentists can use to identify early carious lesions?
3. Therapy: What is the best treatment for this problem? Should teenagers and young adults with asymptomatic impacted wisdom teeth have them removed?
4. Prognosis: What will the outcome of the problem be? How long will a dental implant last in an adult patient with no periodontal disease?

Best Evidence per Clinical Question Type

Different study design methods are used in clinical research.  Identifying the type of question being asked and the type of research that would best answer the question will help you focus your search on the highest level of evidence.

  • Etiology/Harm: Randomized control trial, cohort, case-control, cross-sectional
  • Prevalence: Cohort studies
  • Diagnosis: Prospective study with independent, blind comparison
  • Therapy/Prevention: Randomized control trials, cohort, case-control, case series
  • Prognosis: Cohort, case-control, case series

PICO Example

Sample Question

In children with dental caries will fluoride varnish, as compared to no fluoride varnish, result in a decreased incidence of caries?


children w/ dental caries
Intervention fluoride varnish
Comparison no varnish
Outcome decrease in incidence of caries


Sample Search Strategy

children AND fluoride varnish AND dental caries AND prevention

PubMed Search Example

An image of a search details box in PubMed displaying the search: (Fluorides, Topical"[Mesh] AND "Dental Caries/prevention and control"[Mesh] ) AND "Child, Preschool"[Mesh[

Searching with PICO

Applying PICO to your Search:

Types of Studies: