PICO | Critical Appraisal - Dental Medicine: Resources for the Rutgers School of Dental Medicine

Cochrane Library

About Cochrane

The Cochrane Collaboration is an international, non-profit, independent organization that publishes systematic assessments of evidence of the effects of healthcare interventions. Cochrane systematic review authors follow a published procedure that has become the gold standard for systematic reviews of interventions.

To learn more about how the Cochrane Collaboration works see the Cochrane Collaboration Newcomer's Guide.

Cochrane Oral Health Group

The Cochrane Oral Health Group focuses on producing systematic reviews covering "the prevention, treatment and rehabilitation of oral, dental and craniofacial diseases and disorders."

Cochrane Library

The Cochrane Library provides full-text access to Cochrane protocols and reviews. Off-campus access is restricted Rutgers people with NetID's.

Cochrane Review citations are included in the ADA Evidence Database and are indexed in PubMed.

Finding Evidence by Study Type in PubMed

Log into PubMed

Finding Dental Journals

Use Journal filters, select Dental Journals.

Finding Meta-analysis

Enter search words for the clinical question
On the results page, select Meta-Analysis under Article Types in the left-hand filters sidebar

Finding Systematic Reviews

Enter search words for the clinical question
On the results page, select Systematic Reviews under Article Types in the left-hand filters sidebar

Finding Randomized Controlled Trial (RCT)

Enter search words for the clinical question
On the results page, select Randomized Controlled Trial under Article Types in the left-hand filters sidebar

Finding Cohort Studies

Enter search words for the clinical question
Add Cohort Studies[MeSH] to the search words

Finding Case-Control Studies

Enter search terms for the clinical question
Add Case-Control Studies[Mesh] to the search words

PICO
Critical appraising

What is a PICO Question

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

Patient or population or problem

Intervention or exposure or prognostic factor

Comparison (not always included)

Outcome

Applying PICO to a Sample Question

Will an adult patient with sleep bruxism find that an occlusal splint reduces jaw muscle discomfort?

Patient / population / problem: Adult with sleep bruxism

Intervention: Occlusal Splints

Comparison: No treatment

Outcome: Reduce pain

Sample Search

Clearly articulating all parts of the question will help you conduct a comprehensive search.

Make sure that words for each part of the PICO question are in the search:

Adult AND Sleep Bruxism AND Occlusal Splints AND Pain

Searching is an iterative process. The results from your first set of search terms can help you identify additional related terms:

Adult AND Sleep Bruxism AND (Occlusal Splints OR Mandibular Advancement) AND (Pain OR Headache)

Categories of Clinical Questions

Categories of clinical questions

Etiology / Harm: identifying associations, risk factors and causes of a disease

Diagnosis: selecting tests that accurately detect a disease

Therapy / Prevention: selecting effective interventions to treat or prevent a disease

Prognosis: predicting the probable outcome of a disease or treatment

Sample questions for clinical question categories

Etiology / Harm: Are teenagers who frequently drink soda at risk for developing dental caries?

Diagnosis: What is the best method that dentists can use to identify early carious lesions?

Therapy / Prevention: Should teenagers and young adults with asymptomatic impacted wisdom teeth have them removed?

Prognosis: How long will a dental implant last in an adult patient with no periodontal disease?

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.

Etiology / Harm: Randomized control trial, cohort, case-control, cross-sectional

Diagnosis: Comparison to a reference standard with report of sensitivity/specificity

Therapy / Prevention: Randomized control trial, cohort, case-control, case series

Prognosis: Cohort, case-control, case series

Critical Appraisal of Dental Research

Once you have found systematic reviews or clinical research articles related to your question you must critically evaluate the research and how it is reported. Even a Cochrane systematic review should be read critically!

Critical appraisal is the process of reading research papers with an focus on:

examining whether the results are valid and unbiased;
understanding and evaluating the report of the results;
deciding whether these results can be applied to your patient(s).

Articles about of critically appraising dental research

Critical appraisal of the dental literature: papers about diagnosis, etiology and prognosis
Sutherland SE. Evidence-based Dentistry: Part VI. Critical Appraisal of the Dental Literature: Papers About Diagnosis, Etiology and Prognosis. J Can Dent Assoc. 2001 Nov;67(10):582-5.
Critical appraisal of the dental literature: papers about therapy
Sutherland SE. Evidence-based dentistry: Part V. Critical appraisal of the dental literature: papers about therapy. J Can Dent Assoc. 2001 Sep;67(8):442-5.
Critically appraising randomized trials
Derek Richards. (2009). Critically appraising randomised trials. Evidence-Based Dentistry, 10(3), 88–90. https://doi.org/10.1038/sj.ebd.6400673
Critically appraising systematic reviews
Derek Richards. (2010). Critically Appraising Systematic Reviews. Evidence-Based Dentistry, 11(1), 27–29. https://doi.org/10.1038/sj.ebd.6400710

Definition of Study Types

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., Messura, J., Dellinger, T., Holder, R., & Hyde, J. (2008). Meta‐analysis: an introduction into a research process. Special Care in Dentistry, 28(4), 125–130. https://doi.org/10.1111/j.1754-4505.2008.00033.x

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."

Brignardello-Petersen, R., Carrasco-Labra, A., Booth, H., Glick, M., Guyatt, G., Azarpazhooh, A., & Agoritsas, T. (2014). A practical approach to evidence-based dentistry. The Journal of the American Dental Association, 145(12), 1262–1267. https://doi.org/10.14219/jada.2014.113

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, G., & Azarpazhooh, A. (2015). A practical approach to evidence-based dentistry: III - how to appraise and use an article about therapy. Journal of the American Dental Association, 146(1), 42–49.e1. https://doi.org/10.1016/j.adaj.2014.11.010

Cohort Study

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

Kate Ann Levin. (2006). Study design IV: Cohort studies. Evidence-Based Dentistry, 7(2), 51–52. https://doi.org/10.1038/sj.ebd.6400407

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., & Levin, K. (2006). Study design V. Case-control studies. Evidence-Based Dentistry, 7(3), 83–84. http://search.proquest.com/docview/68896309/

Levels of Evidence

Hierarchy of evidence for clinical questions related to therapy, prevention, etiology or harm.

Evidence Hierarchy

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

For more detailed information about the levels of evidence see the Oxford Centre for Evidence-based Medicine - Levels of Evidence (March 2009).