Showing posts with label endodontics. Show all posts
Showing posts with label endodontics. Show all posts

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?

Questions

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.

Search

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.

Implementation

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 :)

Monday, 21 May 2012

Crowns or not for root-filled teeth?





Some time ago I wrote a paper for the EBD journal looking at whether there was high level evidence (i.e. systematic reviews or randomised controlled trials) for restoring heavily-filled vital posterior teeth with crowns (1). I was unable to find a single RCT let alone a systematic review of RCTs. At the time, though, I came across a study that compared crowns versus no crown on root-filled premolars (2). It was as small study with 117 participants and a fairly low failure rate in both groups (root-filling plus composite versus root-filling plus crown) and no statistical difference between the two. My search strategy would have allowed for other trials involving root-filled teeth but there appeared to be none. 

And so, since that time, I have been discussing with students that the evidence for placing crowns on root-filled posterior teeth is poor, and that there is therefore a reasonable degree of uncertainty over whether we should place them or not. I raise this because there are known negative consequences of placing crowns: cost, time, removal of sound tooth tissue, possibly increased risk of caries due to poor margins and poor OH, and probably some more. Do the positives of preventing tooth fracture and maintaining coronal seal outweigh these?

By coincidence, this morning I have just extracted a root-filled and crowned lower left 2nd molar with the students because it was grossly carious beneath the crown, causing it to fail (only roots retained). And that was in a well-motivated patient with good OH and low sugar intake. 

The Cochrane Library - Independent high-quality evidence for health care decision making


A systematic review has just been published (3) that, funnily enough, identified just one RCT comparing crowns to no crowns on root-filled teeth - the one I described above. What was the conclusion? 

"There is insufficient evidence to support or refute the effectiveness of conventional fillings over crowns for the restoration of root filled teeth. Until more evidence becomes available clinicians should continue to base decisions on how to restore root filled teeth on their own clinical experience, whilst taking into consideration the individual circumstances and preferences of their patients."

I think I might have worded this differently and suggest that, equally, there is insufficient evidence to support or refute the effectiveness of crowns over conventional fillings but the point is still the same - we are left with personal experience and patient values to guide us (2 of the 3 components for evidence-based decision-making) but are left bereft of good research to inform this.

Given the number of crowns placed in practice and the cost of these to individuals and society, plus the cost of root-canal fillings in the first place, it seems ludicrous that those who pay for these services (the NHS, private insurance groups, patients) do not demand an RCT or two to be done. If anyone's got an idea of where to get the funding and if there's anyone in practice who wants to participate, I'm ready to run one!

Happy decision-making ;-)

References



Friday, 24 February 2012

Diagnosing pulpal pathology


Cover image for Vol. 45 Issue 3

I spend a lot of time discussing diagnosis of pain originating from the pulp with students. We have mostly been brought up on making diagnoses of irreversible or reversible pulpitis based on signs and symptoms - spontaneous pain, length of pain, reaction to thermal stimuli, percussion, electric pulp testers, ethyl chloride, bladebladebla. And what I realised a while ago was that some of those teeth - based on these criteria - that I had determined as irreversibly damaged or non-vital actually turned out to respond well to simple temporary dressings without going anywhere near the pulp i.e. the inflammation in the pulp was actually reversible.

So I was pleasantly surprised to come across a systematic review that looks at the sensitivity and specificity of signs, symptoms and diagnostic tests commonly used to make decisions about whether a pulp is alive and well or ailing.

Diagnosis of the condition of the dental pulp: a systematic review

Of 18 studies, none were high quality according to pre-specified criteria, 2 were moderate and the rest were low quality.


Regarding signs and symptoms as indicators of the inflammatory status of pulp the authors concluded: "there is insufficient evidence to determine whether the presence, nature and duration of toothache offer accurate information about the extent to which dental pulp is inflamed. The evidence base is also insufficient to assess the accuracy of other commonly used clinical markers of pulp inflammation "


and with regard to sensibility and vitality testing they conclude: "there is insufficient evidence to determine the diagnostic accuracy of tests used to assess pulp vitality".

I think this is borne out by my experience and suggests that, with plenty of discussion with the patient, we take a conservative view in deciding whether a tooth needs to be opened up or extracted. It may be that, in the absence of a clear diagnosis, we are best temporising and warning the patient the pain may get worse.

One thing, however, is that this review did not take into account the use of radiographs. We often don't see apical changes with irreversible pulpitic teeth but a tooth that does not respond to sensitivity testing and that has an apical radiolucency plus a potential cause for pulpal necrosis (deep filling, caries, fracture) may be diagnosed more confidently as being non-vital.