In the second of their series of articles, Niall McGoldrick and Derek Richards explain where to find the evidence and how to assess its quality. 

Authors: Niall McGoldrick BDS, MFDS RCPS(Glasg), Derek Richards BDS, FDS, MSc, DDPH,FDS(DPH)

Questions and answers

In the first article we explored how to establish a research question using the PICO (Population, Intervention, Comparator and Outcome) method and discussed the hierarchy of evidence. At this point in the search for evidence to support our practice, we know the question we need answered and also understand how different types of research can help to answer our questions.

We now need to think about where to find the evidence and how to assess the quality of what we find.

First let’s revisit the five steps to an evidence-based approach.

Establishing an evidence-based approach has five steps:

1. Asking answerable questions (ASK)
2. Searching for the best evidence (ACQUIRE)
3. Critically appraising the evidence (APPRAISE)
4. Applying the evidence (APPLY)
5. Evaluating the outcome (ASSESS).

This article will explore points 2 and 3 of establishing an evidence-based approach to healthcare.

Question 2: Searching for the best evidence (ACQUIRE)

The search for evidence

There are a number of databases that can be used to find the evidence. Which database you choose to search depends on what type of resource or evidence you require. In this section we will introduce and explore the use of databases that host most of the information required in day-to-day practice. Three of the most commonly used databases are included in Table 1 on the opposite page.

There are other databases available for searches of more specific topics that can be accessed through the knowledge network; for example, PsychINFO is a good database to search for psychology and behavioural science-related topics. You can see the full list of databases on offer at www.knowledge.scot.nhs.uk

Searching for systematic reviews and guidelines

It is always a good idea to start your search for evidence at the top of the evidence pyramid. As we discussed previously, systematic reviews and randomised control trials are the level of evidence we would require in order to think about changing our practice. At the end of our first article, we briefly discussed guidance documents. The guidance produced by SDCEP, NICE and SIGN are all evidence-based and the groups will have come to their recommendations after a thorough process.

SDCEP methods

Dr Doug Stirling is Programme Manager of the Guidance Development Group, Scottish Dental Clinical Effectiveness Programme, NHS Education for Scotland. Here he tells us more about the work of the SDCEP team and the methods they use.

Who is involved in guidance development? What is the skill mix in a guidance team?

The SDCEP team operates within NHS Education for Scotland’s Dental Directorate. Each guidance project is assigned an SDCEP project lead, who manages the project and is responsible for the methodology employed, and an administrator who helps to co-ordinate the project. For each project we also convene a Guidance Development Group comprising external individuals who are representatives of groups with a particular interest in the topic. Typically this will include various relevant branches of the dental profession and patients, and may also include other healthcare discipline relevant to the topic.

How rigorous is the process of appraising the evidence?

Each guidance project aims to answer a number of questions. SDCEP identifies the latest evidence that is relevant to these questions, focusing on systematic reviews and other evidence-based guidelines. To assess the quality of evidence in systematic reviews, SDCEP now uses GRADE (Grading of Recommendations, Assessment, Development and Evaluation), which is a widely accepted system for grading both evidence and recommendations in clinical guidelines. More information on the GRADE system can be found on their website.

We appraise guidelines using the AGREE II checklist, again an internationally recognised tool for assessing guideline quality and reliability. Find out more at www.agreetrust.org

Recommendations in SDCEP guidance result from a rigorous consideration of not only relevant research evidence, but also other factors, including, the balance of risks and benefits, patient’s views and preferences, practitioner perspectives and the practicalities.

The process SDCEP uses to develop its guidance has now been accredited by NICE (the National Institute for Health and Care Excellence), which should give users added confidence in the reliability of the guidance as an aid to their decision-making.

How does the SDCEP guidance apply to a general dental practitioner?

The vast majority of dental care is delivered in primary care practice. Recognising this, most SDCEP guidance is primarily directed towards dentists and their teams working in general dental practice. However, the guidance is also likely to be of interest to those in training, dental educators, and secondary care and public health practitioners.

Do we always need to follow the guidance?

Healthcare staff have the right, and indeed the duty, to make decisions that are in the best interests of their patients with their consent. SDCEP guidance is provided to inform some of these decisions. There is no obligation to follow a recommendation in the guidance if a health professional feels that it is in the best interests of an individual patient not to do so.

However, it would be advisable to document a departure from recommended practice in the patient’s clinical notes, including the reason for this.

Further information about SDCEP guidance development: www.sdcep.org.uk or to find out more about GRADE.

TRIP database

TRIP (Translating Research Into Practice) is a useful resource for searching for the results of systematic reviews, randomised controlled trials and guidelines. You might think of it as a high-quality Google for health-care research. It is an online database that has a few very useful search tools. You can do a single-word search, which is similar to a Google search, but you can be more specific and use the search function established around a PICO question. Shown in Figure 1 below. The database displays results and categorises the level of evidence in a hierarchy. It is similar to the hierarchy of evidence discussed in the first article. This makes it easy to identify what type of evidence the study is before you spend time reading it.

Searching for journal articles

TRIP will also produce results from primary research but another useful database that you should understand how to use is PubMed.

PubMed is a search engine that searches the online database MEDLINE. It includes more than 27 million records. Here you will find a range of evidence. As we demonstrated in the first article, the results can be confusing at first and the searches can result in a lot of irrelevant material.
We will discuss how best to use the search function later but will first look at the fundamentals of searching scientific databases.

PubMed can be accessed here.

Free text searching and Boolean connectors

Having a systematic approach to your search will make finding relevant papers a lot easier and quicker. Most of the pointers demonstrated in this section can be broadly applied in other online searches.

You could decide to free text the search tab as you might use a search engine such as Google. This approach can often result in a large amount of unfiltered results, similar to a search for a hotel room without any information on location, standard or length of stay.

If you know the title of the exact paper you are looking for, then you could simply type this into the search box at the top of the page.

You can tailor the search; for example, if you only have some of the information about a specific paper, such as the author.

A better way to search, and the best way to get the most out of the search engines, is to use Boolean search methods.

This approach still uses free text in the search but introduces AND, OR and NOT. The AND, OR and NOT are known as Boolean connectors. They all have specific functions and can help to widen or narrow your search.

Let’s use our example in article 1 to explore the Boolean connectors. Our original question was about whether or not fluoride varnish has an effect on caries rate in children. The formulation of a PICO question resulted in this:

• Population, patient or problem: Children
• Intervention or treatment: Fluoride varnish
• Comparison: No treatment
• Outcome: Caries.

Using AND

To construct a search for Pubmed we could use the following:

Children AND “Fluoride varnish” AND Caries

This would produce results from papers that contain all three search terms. This is a method for narrowing a search.

Phrase searching and using speech marks

You may also have noticed that the words “fluoride varnish” have speech marks either side of them. This is another useful way of narrowing a search for a specific phrase. The speech marks instruct the search engine to only include studies that have the entire phrase. If we had searched without the speech marks then we would have papers returned that include fluoride as a standalone word from varnish and not specific to our question.

Using OR

Using OR can help to widen a search. For example, if we were interested in fluoride treatments other than fluoride varnish we might search the following:

Children AND (“Fluoride varnish” or “Fluoride mouthwash”) and Caries

This would produce results from papers that contain all our original three search terms but also include studies that look at fluoride mouthwash. Again, note the use of the speech marks to search for the entire phrase.

Truncation

Truncation is useful when you want to expand a search. An example might be in periodontics. By using the trunk of the word Periodont and then adding * to the end will return results for Periodontist, Periodontal, etc.

Controlled language searches

A more advanced way of searching the database is to use controlled language searches. MEDLINE uses Medical Subject Heading, known as MeSH. Those studying for higher level degrees may wish to use this method in their searches. Speaking to the university librarian or doing a short course would be the best way to learn more on this topic. A useful tip about PubMed is that you can register for a free account and save your searches as you go. You can also access the free online tutorials that will help you understand how to get the most out of the database.

Subscriptions/access to resources

Guidelines produced in the UK by groups such as SDCEP, SIGN and NICE are free and open access. They are readily available online. The Cochrane library is also free and open access in the UK and other countries who contribute to it, while it is also available in some developing countries. Some journal articles may be free but most will be only be available through subscription to the journal itself or via an institution of which you are a member.

All NHS employees are entitled to free registration on OpenAthens, which will give you access to The Knowledge Network that is maintained by NHS Education for Scotland. That includes general dental practitioners with an NHS contract. It is a gateway platform to accessing full text articles. If you register then you can access most articles that are returned in searches on PubMed; then you simply enter you username and password once the pay wall appears.

You can register at the Athens website.

Royal College Library

If you are a member of a royal college then you have an entire library service at your disposal. Royal colleges offer members the services of a librarian who can help with literature searches and also source books that may be relevant to your search. Be sure to explore this service that is part of your membership subscription.

Specialist societies and unions

Many specialist societies have subscription services for their members. The BDA also has an extensive library and journal service for use by members which can be accessed remotely through their website.

Question 3: Critically appraising the evidence (APPRAISE)

Not every article published in a journal is a game changer. Sometimes this is easy to spot when reading an article, but other times it may be less clear as authors try to convince you about their work. Understanding the hierarchy of evidence and having some basic skills in critical appraisal will help you when trying to decide how seriously to take a new recommendation or proposed change in practice. Having critical appraisal skills can have wide-reaching benefits beyond the surgery.

At this point we have defined our search question and found the papers we think are relevant. We know about the hierarchy of evidence, but how do we decide which ones to use? Do they all meet the same standard? Are the results valid? Do they apply to the patients I see on a day-to-day basis? Do the results include the negative outcomes of the treatment?

These questions are important to consider, as how we act on the evidence will affect our patients.

Using a systematic approach to appraising the evidence in front of you is always the best way. There are a range of appraisal tools available and some are available for free download from the Centre of Evidence-based Dentistry website.

The best way to understand critical appraisal is to practice it. If you are brand new to it, then there are number of ways you can get help to get started. This could be by attending face-to-face or online courses, reading a book or attending a journal club.

Online e-modules and tutorial videos

Terry Shaneyfelt is a teacher of evidence-based medicine; he has produced a number of YouTube videos that are useful when trying to get your head around critical appraisal. Simply search YouTube for ‘Terry Shaneyfelt’ and click on his playlists where you will see the critical appraisal section.

If you wanted to spend some time and do an online e-module then you can access one provided by the Critical Appraisal Company. There is a cost associated and the course takes six to eight hours, but it gets good reviews.

Journal clubs

Most dentists in core or specialist training will have access to a journal club in their place of work. If there isn’t one, why not take the lead and get one started over a lunchtime once a month? There are other journal clubs that anyone can attend, such as the Edinburgh Dental Journal club that meets regularly at the Royal College of Surgeons of Edinburgh. Search for them on Facebook^© to find out when the next meeting is.

Conclusion

Hopefully after reading these first two articles you now have a basic understanding of the skills needed to practice evidence-based dentistry. We have introduced you to a range of resources that can help you to further develop your skill and knowledge. The best way to get better at using databases for searching and critical appraisal is to get on and do it. Look out for your local journal club or go online and make the most of the many free resources there are to hand.

The next and final article will focus on applying the evidence and evaluating outcomes in your practice.

 

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Verifiable CPD questions

Aim: Objectives:

• To demonstrate the process of using a online scientific database to search for evidence
• To explain how to use Boolean language in search strategies
• To share details on the process of developing evidence-based guidelines
• To highlight how dentists can gain access to the literature base
• To highlight the importance of critical appraisal.

Learning outcomes

After reading this article you should be able to:

• Operate an online scientific database to obtain evidence to answer clinical questions
• Describe some of the process of developing evidence-based guidelines
• Identify means of gaining access to the literature base
• Find resources to aid you in critical appraisal

GDC Development outcomes covered: C-Maintenance and development of knowledge and skill within your field of practice.

How to verify your CPD

Click here to take our online CPD quiz.