Evidence Based dentistry Flashcards
abstract
- Condensed version of full paper
- Structured abstracts outline important elements
- Backgrounds/aim
- Methods
- Results
- Conclusion
- Good for screening but does not replace reading full paper
background/introduction
- What do we already know?
- What is not known?
- Justification/rationale
- Aims/objectives/hypotheses
Scan
Not important critical appraisal as not on methods or results
materials and methods
- KEY for critical analysis
- Used PICO to define the research question
- Sample size estimates
- Statistical analysis
- What tests and data manipulation
- Randomised controlled trial
- Randomisation method
- Allocation concealment
- Masking (blinding)
results
know aims, methods and controls already
Tables, charts and narratives
- Study characteristics
- Table 1 – what study population look like – should be similar on both side, can see if representative to your pts
- Outcomes
- Allows reader to judge how representative study sample is of target population
In RCTs – how balanced arms are
- Do results favour intervention?
- Is intervention better?
- Estimate effect size
- Risk difference
- Risk ratio (relative risk)
- Odds ratio
- Precision of estimate - CI
discussion, conclusion and references
- Context of study, given prior research
- Implication of these results on health condition involved
- Study limitations
- The likelihood that chance, bias and confounding have influenced the findings
- What else could have caused change
- The likelihood that chance, bias and confounding have influenced the findings
- References
acknowledgment and sources of funding
- Publication bias
- Trials more likely to be published if
- They produce positive results
- They reflect well on a product
- They are funded by industry
- Do authors have a financial conflict of interests
CONSORT flow chart
Describes flow of participants through study
See consort guidelines
Evidence Based Dentistry
- An approach to oral health care that requires the judicious integration of:
- Systematic assessments of clinically relevant scientific evidence, relating to the patient’s oral and medical conditions and history, together with Dentist’s clinical expertise and the patient’s treatment needs and preferences
ADA
critical appraisal
- The process of assessing and interpreting evidence through the systematic consideration of its validity, relevance and results
- What are the studies strengths and weaknesses and can it be used to inform your practice?
why critically appraise research papers
- To gain a full and in-depth understanding of a subject.
- To see if your intended research subject has been done before and avoid duplication.
- To avoid any errors made in similar research.
- To enable you to place your study within its context (ie so that you can show how your research will add to the existing sum of knowledge).
- To provide you with information with which to compare and contrast your findings.
- To provide you with ideas to help you define or amend your own research topic.
- To make sure that your ‘on the right track’ !
what decisons need to be made of evidence based dentistry
all clinical decisions
e.g
- Placing a stainless-steel crown Vs conventional restoration (GIC, composite)?
- Analgesia before treatment to reduce post-operative pain?
- Powered versus manual toothbrush?
- Recommending flossing to your patients?
- Is there any difference in effectiveness when undertaking root canal treatment in one visit compared to over several visits?
- What are the effects on pain and complications?
- What is the optimal interval for dental check-ups?
- 6 months – but what’s the evidence
- How effective are non-pharmacological interventions to manage orthodontic pain?
- Laser irradiation; laser devices; chewing patterns; brain-wave music; text messages
Does it differ for different pt groups? E.g. elderly Vs adult Vs child Vs special needs
RCT
Randomised Controlled Trials
- For research questions about effectiveness of one treatment compared to another RCTs are considered the gold standard study design (primary)
CASP Checklist
different tools for different types of studies
checklist for critical appraisal
3 main issues to consider when critically appraising
Are the results of the trial valid?
- Focussed question (PICO)
- Conduct of study (randomization, blinding, allocation concealment, flow of participants)
What are the results?
- Effect of treatment – what has been measured? what direction? How large?
- Precision - CIs
Are the results relevant to your clinical practice?
- Generalizable – people in trial reflect your pts
- Clinically important outcome measures
- Adverse effects/ harms?
did the trial address a clearly foccussed issue?
(making it valid)
SHOULD BE CLEAR AND SPECIFIC
- Population
- Intervention
- Comparison
- Outcome
CONSORT Flow
flow participants from randomisation to results
- Want to know that those that are initially randomised into the trial have the outcome measure
Occasional drop outs OK
Need to check systematic drop outs
- e.g. deaths – check not as consequence of intervention
- Were all of the patients who entered the trail accounted for at its conclusion?*
- affect validity*
how to check if radomised groups similar at start of trial
table 1
run down of characteristics of people at start of trial
Want to be balanced – should be done by randomisation but check
affect validitiy
results - look at
difference between 2 groups results
e. g. absolute risk difference with CIs
* Need this 2:2 contingency table to get this information*
Absolute risk difference
- Difference in risk between groups
Risk in paracetamol group= 40/63= 63%
Risk in placebo group=5/27= 18%
Risk Difference = 63% - 18% = 45%
- 45% more patients experienced pain relief in the paracetamol group
*
confidence intervals
The range of values the ARD will take in the population
- 95 times out of 100 the CI will contain the TRUE population ARD
What value would ARD take if there was no benefit of paracetamol over placebo?
- 0 (value of no difference)
- So 95% CI should not overlap “0”
ARD= 45%
- 95% CI= [30% to 55%] never have to calculate this – should be given
- “Sufficient evidence”
number needed to treat
NNT
The number of patients you would need to treat to prevent one patient from developing the disease/ condition/ outcome
- Numerically:
- 1/ Absolute Risk Difference
NNT for paracetamol = 1/ 0.45 = 2.22
- Would need to treat 3 people with paracetamol post-operatively to have one person experience pain relief of >50% in 4 hours
- Compare to NNT for statins ~ 33 (paracetamol has a good NNT)
