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Course Structure. Certificate year Diploma year Mandatory modules Clinical practice---clinical cases Orthognathic systems 20 CAT assignment Optional Quality in practice and risk assessment 20 CAT assignment Occlusion 20 CAT assignment Research and Critical Appraisal 20 CAT assignment
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Course Structure • Certificate year • Diploma year • Mandatory modulesClinical practice---clinical casesOrthognathic systems 20 CAT assignment • OptionalQuality in practice and risk assessment 20 CAT assignmentOcclusion 20 CAT assignmentResearch and Critical Appraisal 20 CAT assignment • M Sc year60 CAT dissertation40 CAT dissertation plus 20 CAT module
John HallAssociate ProfessorClinical Director Post Graduate Education Critical Appraisal
Be critical • Not all papers that appear in refereed journals are good
Leading European periodontologists concluded:This supplement provides clear evidence that essential oil mouthwashes can be a beneficial safe component of daily oral health routines • RefJournal of Clinical Perodontology
A review by the Food and Drug Administration and American Dental Association found that supporting evidence is inconsistent and contradictory
ARCHIE COCHRANE • - 1988 LUNG SPECIALIST EPIDEMIOLOGIST Cardiff
Cochrane Collaboration • Established 1992 • Up to date systematic reviews • 15 centres world wide
Cochrane principles • Are the results valid? • What are the results? • Will the results help locally?
Are the results valid? • Did the trial address a clearly focussed issue? • Was the assignment of patients to treatment randomised? • Were all the patients accounted for? • Were groups similar at the start of the trial?
What are the results? • How large was the treatment effect?What outcomes were measured • How precise was the estimate of treatment?What are the confidence limits
Will the results help locally? • Can the results be applied to the local population? • Were all the clinically important outcomes considered? • Are the benefits worth the harms and costs?
Adjunctive systematic and locally delivered metronidazole in the treatment of periodontitis: a controlled clinical study
Are the results of the trial valid? • Did the trial address a clearly focussed issue • Yes
Are the results of the trial valid? • Was the assignment of patients randomised
Are the results of the trial valid? • Were all the patients who entered the trial properly accounted for at its conclusion
Are the results of the trial valid? • Were the patients, health workers and study personnel “blind” to treatment
Are the results of the trial valid? • Were the groups similar at the start of the trial
Are the results of the trial valid? • Aside from the experimental intervention were the groups treated equally
What are the results? • How large was the treatment affect • What outcomes were measured
What are the results? • How precise was the estimate of the treatment effect
Florida Probes • Disagreement between papers about intra examiner variability • One reference felt that Florida probes les reliable than conventional probes • J Periodontol. 1998 Jan;69(1):19-25J Periodontol. 1992 Apr;63(4):283-9J Periodontal Res. 1996 Jul;31(5):330-6
Can the results help locally? • Can the results be applied to the local population
Can the results help locally? • Were all clinically important outcomes considered
Can the results help locally? Are the benefits worth the harms and costs
Publication • What is the source of the publication? • Is it a refereed source? • BDJ • American Dental Journal
Introduction • What the paper is about • Aims clear • Trial relates to general practice • Is it an important problem
Materials and methods • Population sample • How large? • Is it representative? • Blind study • Can the study be repeated?
Materials and methods • What was measured • Are the appropriate indices valid • Were examiners trained and calibrated
Results • Are the results clearly explained? • Are the tables easy to comprehend? • Do the tables or graphs accurately reflect the results?
References • Are the references up to date? • Are the references representative of the trial?
Discussion and conclusion • Are the statements in the conclusion drawn from the results? • Do the results establish cause and effect? • Can the results be applied to general practice?
Null Hypothesis • No relationship exists between the variables in a study • Does cigarette smoking cause lung cancer • Null hypothesis would be that cigarette smoking and lung cancer are linked purely by chance
Type I error • Null hypotheses rejected when it is actually true • There is a significant difference between the samples when none exists
Type II error • Null hypothesis is accepted when it is actually false • Failing to find a significant difference between the samples when one exists • Power of a study guards against this
Probablity • P<0.05 • Only 1/20 of this occurring by chance
SensitivityHow good is the test at picking up patients who have the condition.The proportion of those patients with the condition whom the test correctly identifies • SpecificityHow good is the test at excluding patients without the conditionThe proportion of those patients without the condition whom the test identifies
Sensitivity • Are all patients with a scalloped tongue Bruxists
Specificity • If a patient has a tongue without scalloping does this mean that they are not Bruxists
Anecdotal case report • Cross sectional survey • Case series without a control • Case control observational study • Cohort study with literature control • Analyses using computer databases • Cohort study with historical control group • Unconfirmed randomised controlled clinical trial • Confirmed definitive randomosed controlled clinical trials • Systematic review of randomised controlled clinical trials
SIGN • Scottish Intercollegiate Guidelines NetworkA Guideline Developer’s Handbook, SIGN Publication No50 Edinburgh: SIGN, 2001
High quality meta analysis grade A • Systematic review grade A • Random controlled trials B • Well conducted cohort studies B • Non analytic studies eg case studies C • Expert opinion D
Cohort study • A prospective cohort study of a clip-on fixed functional appliance • Michael J. F. Read BDS, FDS, D.Orth, Consultant orthodontist ,Scott Deacon BDS, MFDS, Graduate student and Kevin O'Brien FDS, D.Orth, MSc, PhD, Professor and chairAmerican Journal of Orthodontics and Dentofacial Orthopaedics Vol 125 Issue 4 April 2004 Pages 444-449