Monday, 16 September 2013

Presenting Evidence on Clinical Topics

How to do a presentation on EBD and Endodontics

A former student contacted me yesterday to ask if I could help provide some guidance on how to go about doing a presentation on EBD and endodontics. Where should he start, he asked and how should he go about it?

So I thought I'd blog a response in case anyone else has to do an EBD presentation on some aspect of dental care.

A little bit like doing endo itself, preparation is key to a successful outcome. So it is with a presentation on EBD. We may only have 10 or 20 minutes to present what we have found but probably several hours will be needed to deliver something that is informative and, importantly, backed by the most up to date research.

My first question back to my new colleague is how broad he would want to be in addressing the topic. Simply being asked to "present on EBD and Endo" unsurprisingly caused him to panic a little. The field is huge so what would he present on?


So, as with a research topic or any literature search, developing a clear idea of a clinical question to present evidence on would be my first step. Using the PICO structure (see a blog explaining this here and a prezi here) I would think about whether I was interested in a question about:

  • diagnosis (e.g. how sensitive are tests for non-vitality?) 
  • prevention (e.g. how effective is partial caries removal compared to full caries removal in preventing irreversible pulpal damage?)
  • treatment or interventions (e.g. is one stage endo better than two stage?)
  • prognosis (e.g. what is the success of re-treatment over 10 years?)
  • patient or practitioner experience (e.g. how did clinicians get on with using a particular technique for obturation?)
Sometimes it takes a while to decide how broad / narrow you want to be and sometimes only after you have begun to 'scope' the literature do you get a sense of how much research there is likely to be to help answer your question.

At this stage it is also worth thinking about the best type of study or studies to answer the question. For non-complex interventions a systematic review of randomised controlled trials or the trials themselves may be most appropriate. For a prognosis question a cohort study that follows patients with a particular condition over a period of time could be suitable (or indeed one arm of a controlled trial). For a question about experience and values a qualitative study design could be best. The point is that we shouldn't concentrate only on RCTs when looking for evidence as they are not always the only or best way to answer certain questions. You can find some guidance on the best types of studies to answer questions here.


The next stage, then, is to look for the research evidence. There is a growing recognition that we need to get better at recognising and being critical of non-research evidence too - particularly our own experience and the views of our patients - and of combining these in an optimal way (we're still working on it...). 

But we need to search the various medical databases and search engines to find the research evidence first. An efficient way to do this is to look first of all for summaries of evidence, such as guidelines, and systematic reviews. If we can find one that is up to date and relevant to the question we asked then we need not look for primary studies. So I would recommend beginning with the Cochrane Library for reviews or the National Guideline Clearinghouse for guidelines. You might search the EBD Journal website too to see if there are any commentaries on research there or the ADA Center for EBD.

Given the time - often a couple of years - to complete a review or guideline, anything that is more than a couple of years old is probably out of date since the most up to date research they include may by then be 4 years old. So if the review seems old, irrelevant or there simply isn't one, then we need to look for primary studies. PubMed is an open access medical database that allows this. There are a couple of helpful introduction videos by my colleagues at Oxford here and here.

As you become more familiar with PubMed you can limit the number of results you use by using filters for systematic reviews or randomised controlled trials. A video explains about this here. The advantage is that we can cut the number of articles we have to look through from hundreds or thousands to maybe dozens or less.

Of course, you could also ask the excellent library staff at the British Dental Association to do a search for you. As with your own search it's best to have a  clear question to give them or they may end up searching for things you're not interested in. This service is free to members of the association. The BDA also houses collections of papers on over 500 topics at their London site and these can be posted out to members at no charge.

Accessing the research you find

One of the biggest problems we face is that much of the research out there sits behind a pay wall and few of us are willing to fork out $25 to read a paper that may be irrelevant or of poor quality. I have blogged here about this problem. Again, the BDA can help out but at a cost of £2.50 per article. Unfortunately, my experience with Athens is that this provides minimal access to relevant journals. This is why up to date Cochrane Reviews are so valuable to us as they're free to anyone in the UK and several other countries (see here if you're not sure).

Get critical

Not all research is equal in terms of its validity. If you manage to find a systematic review there should be an indication of the quality of the primary studies included. There are various schemes for this and Cochrane now use GRADE criteria that assesses the research to be of very low to high quality. But if you're reading the primary studies yourself a checklist such as those produced by the CASP organisation are helpful to quickly get a sense of the methodological quality of a study and its usefulness to you.

My personal view is that any CPD presentation ought to indicate the quality of the evidence being presented. Normally on a course there is a mix of personal and research experience and I think that we are entitled to know which is being used. Likewise, if we are to do a presentation of the evidence-base for different topics around endo then the audience should be given a summary of how strong the evidence is. After all, why go through the cost and time of changing one's practice if the only research suggesting you should is of a very low quality? The quality of the evidence should determine whether or not we consider implementing it.


One of the areas in EBD that is most complex is how to go about implementing change based on high quality evidence. It is recognised that most of us transform research findings rather than implementing them as reported in the research. I think that in a presentation it would be helpful to discuss what the barriers are to changing practice and how we might go about reducing these. Perhaps we need to compromise on some element of the protocols suggested by the research to make it practical and cost-effective in our practice. Perhaps we need to think about forming a group to keep each other motivated as we seek to change practice as most of us are very poor at changing what we do on our own. 

I would include these in any presentation as EBD is useless unless this important step is achieved.

I won't talk about presentation skills here - there are many much more gifted in those than me but I take inspiration from Steve Jobs who rarely used script and stuck to simple messages with plenty of graphics to enthuse the Apple-lovers out there.

Happy EBD presenting :)