Download - Epidemiology of periodontal diseases
EPIDEMIOLOGY OF
PERIODONTAL DISEASES
(CH 5 CARARANZA/11TH EDITION)
OBJECTIVES To describe the destribution and
magnitude of periodontal diseases To identify etiological factors and
pathogenesis of disease To study prognosis of the disease To provide data essential for prevention
and treatment of disease
PREVALANCE Prevalance is the proportion of persons
in a population who have the disease at a given point in a period of time
PREVALANCE=NO OF PERSON WITH DISEASE TOTAL NO OF PERSON IN POPULATION
INCIDENCE It is average percentage of unaffected
person who will develop the disease of interest during a given period of time
Incidence = no of new cases no of person at risk in
population
PERIODONTAL CONDITION TYPICALLY MEASURED CLINICALY Probing depth Bleeding on probing Gingival recession Mobility of teeth Presence of furcation involvement Clinical attachment levels Microbiological measures Gingival crevicular fluid
TRANSLATING PERIODONTAL CONDITIONS INTO TRADITIONAL EPIDEMIOLOGIC MEASURES OF DISEASE OCCURANCE 188 sites in patient that may or may not
bleed1 bleeding site or 5 bleeding site
regardless of no of teeth
ESI (extent and severity index) Consider the site where attachment loss
is more than 1mm E.g ESI(20,5.0) 20% site examined has disease Attachment loss 5mm
TRUE AND SURROGATE MEASURES True endpoint:Tangible outcomes that directly measure
how patient feel,function,or survivee.g painful periodontal abcess Surrogate endpoint: changes that are intangible to patiente.g anatomic measures…probing depth measure of inflammationMicrobiological measuresImmunological measures
CHALLENGES IN OBTAINING EPIDEMIOLOGICAL MEASUES Continuous changes in type of surrogate
data collected Diversity of measurement Paucity of information e.g probing depth from no of teeth
present leads to bias
EPIDEMIOLOGY STUDY DESIGN
STUDY DESIGN
EXPERIMENTAL OBSERVATION
ANALYTICAL
ANALTICAL DESCR
IPTIVE• COMMUNITY
INTERVENTION TRIALS• RANDOMIZED CLINICAL TRIALS• FIELD TRIALS
• CASE CONTROL• COHORT
• CROSSSECTIONAL• ECOLOGICAL
DESCRIBITIVE STUDIES..observing the destribution of disease
ANALYTICAL STUDIES… to determine etiology
Establish casual relationship between factor and disease
RANDOMIZED CONTROLLED TRIALS
Provide a probabilistic basis for making causal inference between intervention and outcome
Scaling and rootplaning in
preganent womenBiphasic calicum
phosphate cermics
Infant low birth weight
Clinical attachment
level
823
137
treatment outcome Sample size
COHORT STUDY Exposure based study design Subjects are classifed with respect to
exposure i.e smoking,diabetes
Exposure ……outcomePeriodontal disease+tooth loss …coronary heart
diseaseGingivitis…. Tooth loss
CASE CONTROL STUDY Outcome based study design Compare between case(person with condition
of interest) and control(person without condition of interest)
Case:Person in population or study group having
particular disease,health disorder and condition
Incident cases(date of diagnosis is after date of study initiation)
Prevalent cases(date of diagnosis preceed)Decedent cases(who died before date of study)
WHO IS AT RISK ? Case control
ETIOLOGY Sufficient cause: set of causes that
initiate a chronic disease smoking,delay neutrophils apoptosis,IL-1
gene defect Component cause:The element of sufficent cause are
component cause Necessary cause:A component cause which is an element
of all sufficient causes for a given disease
Fermentable carbohydrates necessary cause of dental caries
Smoking is not necessary cause of lung cancer