Evidenced Based Dentistry Flashcards
How should we process evidence
- Ask questions in a focussed way so you can find the evidence
- Search for and retrieve the evidence (align/acquire)
- Critically appraise the evidence for validity and relevance (appraise)
- Apply the evidence to px tx (apply)
What is PICO and what is it used for
To help understand and critically appraise evidence
* Population = who is the population that is being treated in the research e.g children?
* Intervention = what are they being exposed to
* Comparison = what is this new intervention being compared to
* Outcomes = what is the rate of failure
What are the evidence levels from most to least reliable
- Systematic reviews/metaanalysis
- RCT
- Cohort studies
- Case-control studies
- Cross sectional surverys
- Ecological studies
- Case series and case reports
- Ideas and editorials and opinions
What is a randomised controlled trial
Gold standard study design
Has 4 design elements
* Specification of participants (inclusion/exclusion criteria)
* Control/comparison groups
* Randomisation
* Blinding/Masking
What is a cohort study
Establish a group of individuals in the population
Measure exposures
Follow up over a period of time and identify those that developed the disease
What is a case control study
Study of people with a disease and a suitable control group without the disease
Looks back in time at exposure to a particular risk factor
Used for looking at potential causes of disease
What is a cross sectional survey
Observation of a defined population at a single point in time
What is a case series and case report
Report on patients with an outcome of interest
No control group involved
What are the different calculations that can be useful in EBD
- Risk = number of events of interest/total number of observation
- Odds = number of events of interest/number without the event
- Absolute risk difference = risk in exposure group – risk in control group (0 = value of no difference)
- Risk ratio = risk of effect in exposure group: risk of effect in control group (1 = value of no difference)
- Odds ratio = odds of effect in exposure group: odds of effect in control group (1 = value of no difference)
How do you critically appraise randomized controll trials
- Did the trial address a clearly focussed issue (we assess this using PICO)
- Was the assignment of treatments to patients randomized
- Were all of the patients who entered the trial account for at the conclusion
- Were patients, health workers and study personnel ‘blind’ to treatment
- Were the groups similar at the start of the trial
- Aside from the experimental intervention, were the groups treated equally
- How large was the treatment effect?
- How precise was the estimate of the treatment effect
- Can the results be applied to the local population?
How are systematic reviews carried out
- Well formulated question
- Comprehensive data search
- Unbiased selection and abstraction process
- Assessment of papers
- Synthesis of data
What is meta analysis
Meta-analysis is the process of using statistical methods to combine results of a different studies
