Evidence-based decision making

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Aims and objectives

The aim of this article is to explore the types of written literature that offer sufficient substantiated data and consider how to find evidence-based journal articles. On completing this CPD session, the reader will:

• Understand that evidence-based dentistry is globally accepted as the ‘gold standard’ in healthcare delivery

• Understand the hierarchy of evidence

• Understand the use of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool to help search for high-quality research papers

• Understand how to use PICO to formulate a clear question as required by GRADE

• Understand how others have used search terms to achieve trustworthy results in the creation of analyses.

Evidence-based decision making

Given the importance of clinicians basing their care on high-level evidence-based findings, this article will explore the types of written literature that offer sufficient substantiated data and consider how to find evidence-based journal articles.

As the General Dental Council’s ‘Standards for the Dental Team’ document states: ‘You must provide good quality care based on current evidence and authoritative guidance’.1 In addition, evidence-based dentistry (EBD) is globally accepted as the ‘gold standard’ in healthcare delivery.2

The first challenge, then, is to understand what constitutes evidence-based dentistry, to allow dental healthcare professionals to make informed decisions in their pursuit of best practice. The Oxford Dictionary of Dentistry defines evidence-based dentistry as: ‘A system of practice that integrates clinically relevant scientific evidence, clinical experience, and the patient’s treatment needs and preference, taking into account the patient’s oral and medical condition and history. The strength of the scientific evidence available can be ranked in a hierarchical order and should be taken into account when assessing its validity.’3 (See Figure 1 for the hierarchy of evidence.)

Introducing GRADE

As touched upon in the definition on evidence-based dentistry, ‘…evidence alone is not enough to support clinical decision making from an EBD perspective; decision making should rely on the integration of evidence with clinical expertise and patients’ needs and preferences. The success of an intervention that has proven to be effective in a clinical study depends on the ability of a clinician to use the intervention in an appropriate clinical setting. In other words, clinical expertise is key to determining whether and how the evidence can be applied to a specific patient’s case.’4

Brignardello-Petersen and colleagues (2014a) further highlighted the importance of considering issues such as the potential negative aspects of any proposed treatment and its costs, ensuring that patient preference and beliefs are taking into consideration during the decision-making process.4

To this end, Grading of Recommendations Assessment, Development and Evaluation (GRADE) may serve as a helpful tool.5 Adding to this belief, there is an intention that in the next ‘Delivering better oral health: an evidence-based toolkit for prevention’ produced by Public Health England, the evidence will be reclassified using the GRADE system.6

In practical terms, the GRADE system begins with the formulation of a clear question (see below for further details), followed by the identification of all the desired outcomes, rated according to importance.5 It is only then that judgment should be made about the quality of the evidence in terms of the outcome sought.5 Then the clinician may make a recommendation specific to the patient’s needs based on, ‘…the strength of evidence and net benefit’.5

Kiriakou and colleagues (2014) present GRADE as a robust way in which to assess evidence, stating: ‘It provides a structured process for developing the strength of recommendations, and its explicit and comprehensive approach ensures the transparency of the judgments made.’5

The importance of PICO

When considering the GRADE system, it may be a challenge to meet the first criteria – to formulate a clear question. PICO-formed questions may well offer a solution:

• ‘Population: which populations of patients are we interested in? How can they be best described?

• Are there subgroups that need to be considered?

• Intervention: which intervention, treatment or approach should be used?

• Comparators: what is/are the main alternative(s) to compare with the intervention being considered?

• Outcome: what is really important for the patient? Which outcomes should be considered? Examples include intermediate or short-term outcomes; mortality; morbidity and quality of life; treatment complications; adverse effects; rates of relapse; late morbidity and re-admission; return to work, physical and social functioning; resource use. ’7

Brignardello-Petersen and colleagues (2014b) provided a number of examples to help form PICO questions, such as:8

PICO framework Nature of the question Example Population Intervention (exposure or diagnostic test) Comparison (or reference standard) Outcomes
PICO questions Therapy or prevention What is the effectiveness of antibiotics in preventing complications such as post-operative infections after third molar extractions? Patients undergoing third-molar extractions Antibiotic prophylaxis No prophylaxis Alveolar osteitis, surgical wound infection
    Simple search strategy Third molar Antibiotic prophylaxis Not applicable Post-operative complications
    Complex search strategy Third molar AND adults Amoxicillin OR (clavulanic acid) OR metronidazole Placebo Pain OR swelling OR trismus OR (surgical wound) infection OR dry socket

The authors concluded: ‘Knowing how to formulate structured clinical questions and to search for the best current evidence to inform a clinical decision are vital skills for the practice of EBD. Familiarity with the many types of resources that have been developed to facilitate efficient searching is a fundamental requirement for EBD practice.’8

Finding best evidence

The next question then is where can you search for the best current evidence? The Cochrane Oral Health Group, for example, describes itself as comprising: ‘…an international network of healthcare professionals, researchers and consumers preparing, maintaining, and disseminating systematic reviews of studies in oral health.’9

As we know from the hierarchy of evidence,3 a systematic review of randomised controlled clinical trials is the highest possible level of evidence, which means the Cochrane Library at offers significant opportunities for high-quality evidence upon which dental healthcare professionals may choose to base some of their clinical decisions.

For their meta-review, Van der Weijden and colleagues (2015) chose to search The Cochrane Library, MEDLINE-PubMed and the evidence database of the American Dental Association (ADA) Center for Evidence-based Dentistry.10

The authors asked the following PICO question: ‘What is the effect of mouthwashes and their various chemical ingredients for plaque biofilm control in managing gingivitis in adults based on evidence gathered from existing systematic reviews’?10 The group searched for:

• {[MeSH Terms] Mouthwashes OR [text words] Mouthwashes OR Mouthwash OR mouthwash OR mouthrinses OR mouthrinse}

• Used filter/limits: systematic review OR meta-analysis.10

This led to the identification of a total of 306 unique articles, of which 17 articles were obtained in their entirety and examined to confirm suitability.10

Araujo and colleagues (2015), meanwhile, conducted a search, ‘…to evaluate the combined effectiveness of mechanical methods with essential oil- containing mouthrinses (MMEO) versus mechanical methods (MM) alone in achieving site-specific, healthy gingival tissue and reducing plaque and gingivitis’, accessing 32 published and unpublished randomised, long-term clinical trials for their meta-analysis.11 All 32 studies had been designed to meet the requirements of the American Dental Association and the US Food and Drug Administration.11

Deeming 29 to meet the criteria of the meta-analysis, the authors then had access to data gathered from over 5,000 people experiencing early signs and symptoms of periodontal disease, but who were otherwise healthy.11 The studies considered unsuitable were judged so for a number of reasons, including:

• Lack of ADA approval

• Inconsistent measurement scales

• Failure to include a placebo group

• Absence of a single summary level clinical site dataset for use by external researchers.11

This should provide the reader with some idea of the pains authors may choose to go to, to create work of a high quality. Indeed, one of Araujo and colleagues (2015) aims was to ‘…help clinicians to better choose a preventive approach.’11

In clinical terms, Arauajo and colleagues (2015) determined that: ‘The results of the responder analyses suggest that after 6 months of use, clinicians could expect that approximately […] 37% of participants would have at least 50% of sites without plaque (PI = 0 or 1). In addition, the implementation of a long-term oral care routine that provides 7 times greater odds for plaque-free sites […] can be compelling information for the clinician when educating patients on the appropriate oral care routine.’11

Boyle (2014) also investigated mouthwash use and the prevention of plaque, gingivitis and caries.12 To this end, they presented a number of systematic reviews with meta-analysis of mouthwash use.12 Their search involved literature published in English, without a time restriction. MeSH keywords were:

• « mouthwash » and « gingivitis »

• « mouthwash » and « dental plaque »

•« mouthwash » and « prevention and control ».12

Searches were conducted with and without limits set for « clinical trials ».12 Articles related to eligible or apparently eligible articles were also explored.12 In addition, manual searches were undertaken in reference lists of review papers.12

Adhering to specific criteria, the authors were able to conclude that quantitative assessment of data exploring mouthwash use and the risk of common oral conditions supports the use of mouthwash in preventing dental plaque.12 They also suggested that over a period of less than three months, mouthwashes containing chlorhexidine are the most effective of the preparations considered, resulting in a reduction of dental plaque. When used for 6 months or longer, however, essential oil mouthwashes equalled or exceeded the effect of chlorhexidine in controlling plaque as an adjunct to standard care.12

Integrated care

As Brignardello-Petersen and colleagues (2014a) concisely stated: ‘Scientific evidence constitutes one of the fundamental tenets of dental practice. Evidence-based dental practice integrates the use of the best available evidence, clinicians’ expertise and patients’ needs and preferences to inform decision making in clinical practice.’4




  1. Standards for the dental team. General Dental Council 2016

  2. Kishore M et al. Evidence based dental care: integrating clinical expertise with systematic research. Journal of Clinical and Diagnostic Research 2014; 8(2): 259-262

  3. Ireland R (ed). A dictionary of dentistry. OUP Oxford; 1st edition, 2010

  4. Brignardello-Petersen R et al. A practical approach to evidence-based dentistry. Understanding and applying the principles of EBD. JADA 2014a; 145(11): 1105-1107

  5. Brignardello-Petersen R et al. A practical approach to evidence-based dentistry. Understanding and applying the principles of EBD. JADA 2014a; 145(11): 1105-1107

  6. Kiriakou J et al. Developing evidence-based dentistry skills: how to interpret randomized clinical trials and systematic reviews. Progress in Orthodontics 2014, 15: 58-65

  7. Delivering better oral health: an evidence-based toolkit for prevention. Public Health England, 2014

  8. Accessed 8 February 2018

  9. Accessed 8 February 2018

  10. Brignardello-Petersen R et al. A practical approach to evidence-based dentistry: How to search for evidence to inform clinical decisions. JADA 2014b; 145(12): 1262-1267

  11. Accessed 8 February 2018

  12. Van der Weijden FA et al. Can chemical mouthwash agents achieve plaque/gingivitis control? Dent Clin N Am 2015; 59: 799-829

  13. Van der Weijden FA et al. Can chemical mouthwash agents achieve plaque/gingivitis control? Dent Clin N Am 2015; 59: 799-829

  14. Araujo MWB et al. Meta-analysis of the effect of an essential oil-containing mouthrinse on gingivitis and plaque. JADA 2015; 146(8): 610-622

  15. Boyle P et al. Mouthwash use and the prevention of plaque, gingivitis and caries. Oral Diseases, 2014; 20(1): 1-76