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High quality, less bias

Sir, we enjoyed the paper by Sathorn & Parashos1 on evidence-based patient care. However, we were concerned that section 7.0 'Where can the evidence be found' missed some vital information. Specifically, section 7.1.5 on The Cochrane Library was strangely incomplete. The authors conclude that 'currently this database has little benefit, if any in the dental field'. We would like to challenge this opinion with the following information which might be helpful for the readers of the BDJ:

The Cochrane Library contains several databases and each are of considerable value to searching for evidence in dentistry. These include:

  1. 1

    Cochrane Database of Systematic Reviews (CDSR). These are Cochrane reviews and recognised as the highest quality systematic reviews in biomedicine. In the latest issue (Issue 3, 2007) there are 3,197 complete reviews and 1,744 protocols. Of these 74 reviews are in dentistry including: restorative dentistry, periodontology, implantology, orthodontics, paediatric dentistry, endodontology, oral surgery, oral medicine, oral pain, oral cancer, craniofacial anomalies and dental public health. Also included are 66 protocols for forthcoming systematic reviews in dentistry. CDSR should help to reduce duplication of effort listing existing and 'in progress' systematic reviews

  2. 2

    Database of Abstracts of Reviews of Effects (DARE). This is a unique database from the University of York and includes critically appraised non-Cochrane reviews. A simple search of 'Dentistry' OR 'Oral Health' indicates at least 70 reviews currently. The critical appraisal is helpful in guiding the reader to the potential value of the reviews

  3. 3

    Cochrane Central Register of Controlled Trials (CENTRAL). This register is the most complete database of trials and related publications as it includes the international handsearching programme from Cochrane volunteers. As a result, many trials have been found that were not originally included in other databases such as MEDLINE. In the current issue, there are more than half a million records.

Systematic reviews should be the starting point for any search for information since the hard work of finding, appraising and summarising the information has already been done. The quality of the review is crucial and several surveys have demonstrated that Cochrane Reviews are of higher quality and less biased than other systematic reviews.2,3 Readers looking for evidence in dentistry will find much of relevance to their practice in The Cochrane Library whether as Cochrane reviews or in the DARE database. If you are looking for controlled clinical trials then again CENTRAL is the most complete database including oral health. The Cochrane Collaboration and the Oral Health Group recognise that there is still a huge amount to do in producing best evidence but we also hope that the results so far will help to inform and improve dental practice and policy.


  1. 1

    Sathorn C, Parashos P . Questions and answers in evidence-based patient care. Br Dent J 2007; 203: 309–319.

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  2. 2

    Moher D, Tetzlaff J, Tricco A C, Sampson M, Altman D G . Epidemiology and reporting characteristics of systematic reviews. PLoS Med 2007; 4: e78.

    Article  Google Scholar 

  3. 3

    Glenny A M, Esposito M, Coulthard P, Worthington H V . The assessment of systematic reviews in dentistry. Eur J Oral Sci 2003; 111: 85–92.

    Article  Google Scholar 

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Needleman, I., Worthington, H., Fernandez-Gonzalez, L. et al. High quality, less bias. Br Dent J 203, 561 (2007).

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