Evidence based dentistry Flashcards
What is 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 patients oral and medical condition and history, together with the
-dentists clinical expertise and
-the patients treatment needs and preferences
What are the 5 As
Ask
Align
Acquire
Appraise
Apply
What is the process of evidence based practice
How to ask the clinical questions in a focused way so that you can FIND the evidence and APPRAISE the evidence [ASK-BDS1]
Search for and retrieve evidence [ALIGN/ACQUIRE- BDS2]
-Know where to go for good evidence
-Be sure that you get all of it
-And you understand the strengths and weaknesses of different sources
Critically appraise the evidence for validity and clinical relevance [APPRAISE-BDS3/4]
-Is it good evidence?
-Is it important from a clinical point of view?
Applying this evidence to patient treatment/care [APPLY-BDS3+]
-Does it apply to my patients?
Reflection
-Can I do things differently next time?
What are some decisions and questions where evidence would be required
-Placing a stainless steel crown versus conventional restoration ?
-Analgesia before treatment to reduce post-operative pain?
-Powered versus manual tooth brush ?
-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?
What is evidence
Evidence is the available body of facts or information to show whether a belief or statement is true or valid
Study of 1000 patients treated in primary care in Australia
Looked at 22 most common conditions seen in primary care
What proportion of patients received evidence-based care for
Coronary heart disease –
Alcohol dependence –
Coronary heart disease – 90%
Alcohol dependence – 13%
Why should you practice evidence based dentistry
Professionally: It is part of your professional role and a requirement of your regulatory body (GDC)
Personally: you should be informed on how to spot a scare story/ fad/ pseudo-science to avoid you (or your loved ones) being ripped off, duped, wrongly treated, sub-optimally treated, exposed to harmful practices
What can clinicians use to make decisions
Clinical experience
Text books
Patient groups
Teachers
Healthcare research
Popular media
What do the public believe about healthcare decisions
Research funding and efforts are coordinated and prioritized
The progress of research is steady and upwards
The results of research are systematically applied to clinical practice
All clinical practice is evidence based
What is peer review
The system through which scientists/ researchers decide which research studies should be published in a scientific journal
Eg British Dental Journal; British Medical Journal; The Lancet; Nature
How does peer review work
When researchers or a team of researchers finish their work, they usually will write a “paper” presenting their methods, findings and conclusions.
This paper is sent to a scientific journal to be considered for publication
The editor decides if the topic is suitable for their journal then sends the paper to peer reviewers (other scientists working in the same area who have expertise on the topic). The peer reviewers
-Comments on the validity of the study (design, methods, results)
-Judge importance
-Judge originality
-Should the paper be published/ improved/rejected
Peer review means that to some extent the research has passed the scrutiny of other scientists, and is considered valid, important and original.
Peer review is also used to assess applications for grant funding.
What are the issues with peer review
Corruption
Cant prevent fraud, plagiarism or duplication (only in more obvious cases)
Quality of the review process
Skills of the reviewer
Time-consuming
What makes bad research
Not needed
-No more research is required as we have the answer
Poor design
-Wrong design
-Inappropriate control/ comparison group
-Biased (many issues)
Poorly reported
Not reported
How to ask the questions in a focused way so that you can FIND the evidence and APPRAISE the evidence
POPULATION
-How would I describe a group of patients similar to this one?
INTERVENTION
-What is being “done” to the patients
-Could be an exposure (eg carcinogen)
COMPARISON
-What are we comparing to?
OUTCOME
-Desired or undesired
What clinical guidelines should dental professional follow
NICE
SIGN
SDCEP
A child presents with a carious primary molar. How do you manage this?
Complete removal of carious tissue before restoring tooth?
Seal in caries?
Does the Hall Technique for sealing in caries offer long-term benefits over current GDP practice?
Population
-Children with caries in primary teeth
Intervention
-Hall technique
Comparison
-Current practice
-Removal and restoration (eg)
Outcomes
-Rate of failure
When researching for evidence we should consider, have the authors used:
Population
Intervention
Comparison
Outcome
That are relevant to your question
WHAT IS THE PICO:
A child patient requires a dental extraction via General Anaesthetic (GA). Some surgeons administer Local Anaesthetic (LA) intra-operatively to reduce post-operative pain
…but anecdotally some report this is distressing, uncomfortable, causes excessive dribbling and inadvertent lip/cheek biting
Population: Children undergoing dental general anaesthetic
Intervention: Local Anaesthetic intra-operatively
Comparison: placebo / no treatment
Outcome: post-operative pain/distress
-Bleeding
-Cardiac
-Lip biting/cheek biting
-Satisfaction
-anxiety
FORM A PICO
The common cold causes enormous morbidity worldwide and the search for simple and effective preventive or therapeutic agents has been elusive. Even if vitamin C might have modest effects in restricted population groups, that could be important from a public health point of view.
There has been 70 years of conflicting evidence around the benefit of Vitamin C in preventing the cold and in shortening the number of “sick days”. Some have suggested that high doses may be more effective
Population: In the general population (adults/children/males/females)
Intervention: Vitamin C (dosage/ frequency)
Comparison: Placebo/ No treatment
Outcome: Incidence of cold/ days sick with cold
GENERATE PICO:
A 35 year old patient attends for a routine appointment and asks you if she should purchase a powered toothbrush (~£100)- She wants to know if it will improve her oral health…
Population: In the general population (adults/children)
Intervention: powered toothbrush (different types)
Comparison: manual toothbrush
Outcome: decay/ periodontitis/ plaque/ gingivitis
What are the criticisms of evidence based dentistry
The tendency of a group of young, confident and highly numerate medical academics to belittle the performance of experienced clinicians using a combination of epidemiological jargon and statistical sleight-of-hand or
the argument, usually presented with near-evangelistic zeal, that no health-related action should ever be taken by a doctor, a nurse, a purchaser of health services, or a policy maker, unless and until the results of several large and expensive research trials have appeared in print and approved by a committee of experts.
What is risk
The chances of something happening
Can be good or bad
What is outcome
“something” that might happen
Death, heart attack, cancer diagnosis
Tooth decay/ periodontitis/ TMJD
Caries free
What are statistics
Numbers that summarize information
Based on observations of large numbers people
Useful in predicting what is likely to happen in the future
The chance that an outcome will happen
Risk statistics
Fractions
How is odds calculated
odds = number of events of interest / number without the event
How is risk interpreted
Risk of what?
-What is the outcome?
-Getting a disease? Dying from a disease
-Developing a symptom? Surviving a disease?
How big is the risk?
-What are the chances of experiencing the outcome?
-Out of how many?
What is the timeframe? Next year? Next 10 years? Lifetime?
-Out of 1000 people in the last 10 years
Does the risk information reasonably apply to me or my patient?
-Age/sex/lifestyle
How does this risk compare with other risks?
-Perspective- which risk should I do something about?
What is ARD
Absolute risk difference
What value would the RR take if the risks in both groups were equal (ie no benefit of paracetamol over placebo) ?
1
When is a case report/case series used
Used for
Identify new disease outcome
Hypothesis generation
What is a case report/case series
A report on a single patient or series of patients with an outcome of interest
No control group is involved
What are the disadvantages of case report/series
Disadvantages
Cannot demonstrate valid statistical associations
Lack of control group
What study is used:
What is the incidence of oesophageal cancer in adults?
Cohort study
What study is used to determine:
Does nystatin prevent oral candidiasis in patients receiving treatment for head and neck cancer?
Randomised controlled trial
Systemic review and meta analysis
How can we determine:
What are parents’ experiences of their child’s dental anaesthesia?
Cross-sectional study
What study is best to find:
Are teenagers with crossbites more likely to go on to develop temporomandibular joint disorders ?
Case control study
Cohort study
What study can be used to determine:
What is the prevalence of cleft lip and palate in children born in the West Coast of Scotland?
Cross-sectional study
Cohort study
How can we answer this question:
What risk factors are associated with root resorption in patients who have undergone orthodontic treatment ?
Case-control study
Cohort study
What is a confidence interval
A confidence interval tells us the range of values that a true population treatment effect (eg RR) is likely to lie
If the value of no difference is 1 and the confidence interval embraces/overlaps/contains or straddles this what does it indicate
insufficient evidence that there is a difference between paracetamol and placebo (check sample size)
If the value of no difference isnot within the CI what does it show
If this interval does not embrace/overlap/contain/ straddle 1 sufficient evidence to suggest there is a difference
Hersh 2000
63% vs 18%
63/18= 3.42
RR= 3.42
95% Confidence Interval = 1.52 to 7.73
Is there sufficient evidence that paracetamol is effective in pain relief for extraction in the population ?
There is sufficient evidence to suggest that patients in paracetamol group are 3.42 times more likely to experience pain relief than patients in placebo group. This may be as low as 1.52 or as high as 7.73 times more likely in the population. The wide CI may reflect the small sample size.
How do confidence intervals prove significance
For a DIFFERENCE between two quantities
-If two values are equal, the difference would be 0
-The “value of no difference” is 0
-There is sufficient evidence for a difference between two values in the population if the CI for the difference does not overlap 0
For a RATIO between two quantities
-If two values are equal, the ratio would be 1
-The “value of no difference” is 1
-There is sufficient evidence for a difference between two values in the population if the CI for the ratio does not overlap 1
What do obdervational uncontrolled studies look like
Researchers watch what happens to a group of people
A group of patients has disease A and is treated with drug X
The researchers observe how many get better
How believable?
What is a controlled study
Cohort or case control
Researchers observe what happens to people in different situations-without intervening
Rank the studies from most to least evidence
-Systemic reviews and meta analysis
-Randomised controlled trials
-Cohort studies
-Case-contolled studies
-Cross-sectional surveys
-Ecological studies
-Case series and case reports
-Ideas,editorialsand opinions
What is a cross-sectional study
The observation of a defined population at a single point in time (or time interval)
-Exposure and outcome are determined at the same time
When is a cross-sectional study used
Estimating prevalence of a disease
Investigate potential risk factors
What are some disadvantages of cross-sectional study
Causality
Confounding
Recall bias
What is a case-control study
The study of people with a disease and a suitable control group of people without the disease
-Looks back in time at exposure to a particular risk factor in both groups
What is a case-control study used for
Looking at potential causes of disease
What are the disadvantages of case-control study
Confounding
Recall / selection bias
Selection of controls
Time relationships (did exposure occur before disease?)
What does a case-control study look like
100 peoplewith oral cancer (who smokes, who doesnt)
100 people without oral cancer (who smokes, who doesnt)
COMPARE
What is a cohort study
Cohort Study
Establish a group of individuals in population
Measure exposures
Follow up over a period of time
Identify those that develop disease (outcome of interest)
What disadvantages does a cohort study have
Controls difficult to identify
Confounding
Blinding difficult
For rare diseases- need large samples
Very expensive/ time consuming
When is a cohort study used
Estimating incidence of disease
Investigating causes of disease
Determining prognosis
Timing and direction of events
What is a randomised controlled trial
Sometimes referred to as a Clinical Trial
RCTs considered the gold standard study design
For effectiveness and efficacy
Particularly useful for clinical studies
Provides strongest evidence on effectiveness of treatments
What study provides the strongest evidence
Randomised controlled trials
What are the 4 elements to a RCT
Specification of participants (inclusion/ exclusion criteria)
Control/ Comparison groups
Randomisation
Blinding/ Masking
What are the inclusion or exclusion criteria of a randomised controlled trial
Age
Disease severity/ diagnosis
Unambiguous
Exact definitions
What is a comparison group
Placebo (control group)
Why is a comparison group needed
To prove the treatment is the cause for the results and not just the patient getting better by themselves
Why is randomisation needed
To minimise Bias
Older patients
Patients with more severe disease
What is allocation concealment
A technique used to prevent selection bias by concealing the allocation sequence from those assigning participants to intervention groups, until the moment of assignment. Allocation concealment prevents researchers from (unconsciously or otherwise) influencing which participants are assigned to a given intervention group.
What are the advantages of RCTs
Provide strongest and most direct epidemiologic evidence for causality
BUT
Non-blinded RCTs may overestimate treatment effects eg estimates of effect from trials with inadequately concealed allocation have been 40% larger than clinical trials with adequately concealed random allocation
What are the disadvantages of RCTs
More difficult to design and conduct than observational studies
ethical issues
feasibility
costs
Still some risk of bias and generalisibility often limited
Not suitable for all research questions
What does consort stand for
Consolidation of the standards of reporting trials
What is a consort
Statement called Consolidation of the Standards of Reporting Trials (CONSORT)
Aimed to improve the standard of written reports of RCTs
