Operative dentistry aje qualtrough, jd satterthwaite la morrow, pa brunton

IDENTIFYING EVIDENCE
There are a number of sources of information a health professional
can turn to in order to find the answer to a question. For example, they
may draw upon their own clinical judgement or past experience, they
may turn to colleagues for advice, read relevant textbooks or journal
articles, search electronic bibliographic databases (e.g. MEDLINE or
EMBASE) or secondary sources of information (e.g. The Cochrane
Library, The Journal of Evidence Based Dental Practice, Evidence-based
Dentistry). All of the available sources of information have advantages
and disadvantages (Table 8.1).
The ability to carry out quick and reliable searches to identify 
relevant research evidence is one of the key skills required when 
practising evidence based dentistry. Before starting to search for
research evidence, it is necessary to consider what type of evidence
would be most appropriate to answer your research question.
Different clinical research questions require evaluation through 
different study designs. The ceramic inlay example deals with the
effectiveness of a treatment option and would be best answered by a
randomised controlled trial (RCT) or, ideally, a systematic review of
RCTs. However, it must be noted that although RCTs and systematic
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Chapter 8
reviews of RCTs may well be the ‘gold standard’ upon which to base
decisions on the effectiveness of interventions, they are not necessar-
ily appropriate, or ethical, to answer all questions. For example, you
may be interested in the prognosis of endodontic treatment in patients
with diabetes mellitus. An RCT would obviously not be helpful in
answering this question. For questions regarding prognosis such as
this, cohort studies would be more appropriate. Table 8.2 illustrates
the types of studies designs most suitable for different types of
research questions arising in endodontics. The most appropriate
source of information will depend upon the type of study design
being sought.
For questions regarding the effectiveness of healthcare inter-
ventions, the best place to start looking for information is The 
Cochrane Library: http://www.cochrane.org/reviews/clibintro.htm
The Cochrane Library is recognised as the best single source of 
systematic reviews and controlled clinical trials, covering all aspects
of healthcare. It is available through many university libraries 
and postgraduate centres. It is also freely available to all resid-
ents in many countries including the British Isles (a full list of 
countries with free access is available at
http://www.update-software.com/cochrane/provisions.htm).
For questions not focusing on the effectiveness of interventions,
other study designs will need to be sought, for which MEDLINE can
Disadvantage
May be biased
May be out of date
Quickly out of date
Difficult to access/identify
relevant information
Can be difficult to search
Databases are not
comprehensive in their
coverage of published
journals
Can be difficult to search
Do not cover all topics
Advantage
Quick response
Easy to access
Full text of recent research
Available online
Access to large amounts 
of information
Sometimes links to full 
text online
Provide summaries of 
relevant research evidence 
Aim to be unbiased 
and up to date