Epidemiology

EPIDEMIOLOGY OF PERIODONTAL DISEASES

Contents

• Introduction • History• Definition• Principles & Purpose of epidemiology• Components of epidemiology• Epidemiological triad• Epidemiological methods• Epidemiologic measures of disease• Periodontal epidemiology• Periodontal disease in India • Periodontal disease – Global overview • Conclusion• References

INTRODUCTION • Epi - among, demos- people, logos- study

• Epidemiology - well being of society as a whole rather than individuals

• Multifactorial etiology of periodontal diseases

• Measures prevalence, extent and severity of periodontal diseases

HISTORY

• Hippocrates

• CLAUDIUS GALEN (130-200A.D.)

• THOMAS SYDENHAM ‘founder of epidemiology’.

• JOHN SNOW ‘father of epidemiology’

History of Dental Epidemiology

Descriptive studies........Hippocrates

Health habits & dental status of 96 old men, all over 80 years Sir John Linchour ; Britain 1803

First dental epidemiology, studied eruption of teethEdwin Saunders; Britain 1837

Tooth mortality studyJohn Tomes; 1848

Dental status of school childrenFisher ; Britain 1885

Nation wide survey of school childrenAinsworth & Young; Britain 1925

DEFINITION

• The study of the distribution of disease or a physiological condition in human populations and of the factors that

influence this distribution Lilienfeld 1978

• Epidemiology is essentially an inductive science, concerned not merely with describing the distribution of disease, but

equally or more with fitting it into a consistent philosophy Frost 1941

• The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control health problems

Last JM,1995

PRINCIPLES OF EPIDEMIOLOGY

• Exact observation

• Correct interpretation

• Rationale explanation

• Scientific construction

PURPOSE OF EPIDEMIOLOGICAL STUDY

1. To determine the amount and distribution of a disease in a population

2. To investigate causes for the disease.

3. To apply this knowledge to control & prevent the disease.

COMPONENTS OF EPIDEMIOLOGY

1. Disease frequency: Rate or ratio

2. Distribution of disease : pattern of distribution 3. Determinants of disease : etiological hypothesis

EPIDEMIOLOGICAL TRIAD

• Agent,Host,Environment

• AGENT: “An organism, a substance or a force, the presence or lack of which may initiate a disease process or may cause it to continue”

Living - Bacteria,viruses etc Nonliving - carbohydrate ,protein Chemical Agents Physical Agents

HOST“A person or an animal that afford subsistence lodgement to a infectious agent under natural conditions”

• Demographic characteristics: Age, Gender, Race

• Biological characteristics: Genetic, Immune, Nutritional

• Socio-economic characteristics : Social class, Religion, Education, Marital status

• Life style : living habits, food habits

ENVIRONMENT Environment is the source or reservoir for the agents of disease

• Physical • Biological• Social

Tools of measurement

• Rate = No. of disease in a specified period X 1000 Population at risk of expressing the disease

• Ratio

• Proportion= No. of school children with gingivitis X 100 Total No. of children in the school

EPIDEMIOLOGICAL METHODS

1. Descriptive epidemiology2. Analytical epidemiology3. Experimental epidemiology

• Experimental studies - efficacy of preventive interventions, treatments, and drugs.

Descriptive epidemiology

Describes the pattern of occurrence of disease/conditionrelative to other characteristics of population.

Any departure, subjective or objective from a state of physical well being

morbidity: prevalence-cross sectional study incidence-longitudinal study

Cross-Sectional Studies• Disease frequency surveys or prevalence studies. • Presence or absence of disease and characteristics of subjects• Generates hypothesis regarding the etiology of a disease.

Limitation :• Only identify prevalent cases of disease. • Determining whether the characteristic preceded the disease is

not always possible

Advantages• Generally less expensive than longitudinal studies• Quicker to conduct.

Analytical epidemiology

It deals with discovering the causes of disease

2 approaches:Cohort study- from exposure to effectscase control study- from disease to cause

Cohort Studies• Strong support for an association• Exposed & unexposed groups and followed over time• Incidence in exposed group >> unexposed

Limitations• long periods of follow up & can be expensive to conduct. • Rare diseases- large numbers of subjects will need to be

followed

Case-Control Studies• In day to day…• Cases and controls• Primarily used to assess riskLimitation• The temporal relationship between the exposure & disease may

be obscured• Historical information often cannot be validated.

Advantage • Require fewer resources and conducted quickly than cohort

studies• Rapid evaluation of chronic diseases

Experimental epidemiology

The results obtained from observational studies aboutassociation & causation/benefit of a particular intervention

1.Randomised controlled trials2.Field trials3.Community trials

EPIDEMIOLOGIC MEASURES OF DISEASE

PREVALENCE:

• Prevalence is the proportion of persons in a population who have the disease of interest at a given point or period of time.

• Prevalence = No of persons with the disease X 100 No of persons in the population

Types of prevalence:• Point prevalence - ’the no of all current cases (both old &

new) of a specific disease at one point in time in relation to a defined population’.

• ‘A point in time’ can be either a day, few days or even few weeks

• Period prevalence- ‘the total no of existing cases (old &new) of a specific disease during a defined period of time in relation to a defined population’

• It is the sum of the point prevalence & the incidence.

USES

1. To estimate the magnitude of disease or health problems in community

2. To identify the potential high risk population

3. Useful in administrative & planning purposes

Limitations of prevalence rates:

• It is not the ideal measure for studying etiology of disease.(I x D)

Factors influencing prevalence

Prevalence rate increases by:

1. Longer duration of the disease.2. Prolongation of life of the patient3. Prolongation of life of patient without care e.g. periodontitis4. In-migration of cases5. Improved diagnostic facilities.

Prevalence rate decreases by:

1. Shorter duration of disease

2. High case fatality from disease

3. Decrease in new cases

4. Improved cure rate of disease

Incidence

• ‘ The number of new cases of a specific disease occurring in a defined population during a specified period of time’

• Incidence =no of new case during a given period of time x 1000 no of persons at risk

Uses of incidence rates:

• It helps with the study of distribution of disease.• It is useful in evaluating the efficacy of preventive &

therapeutic measures.• It gives clues to research into the etiology & pathogenesis of

disease.• It helps in taking action to control the disease

Scientific method

• Establishing the objective• Designing the investigation• Selecting the sample• Conducting the examinations• Analysing the data• Drawing the conclusions• Publishing the results

• Most important but complex part of dental epidemiology

• Special indices have been designed to provide objective measurement of identifiable features

• Quantitative science

PERIODONTAL EPIDEMOLOGY

Indices Used To Assess Gingival Inflammation

• Papillary-marginal-attachment index (PMA) - (Schour & Massler, 1948).

• Gingival index (GI) - (Loe & Silness, 1963).

• Modified Gingival Index (MGI)- (Lobene et al., 1986)

• Periodontal index (PI)- (Russell, 1956)

• Gingivitis component of periodontal disease index (PDI) (Ramfjord SP , 1959)

Indices used to assess gingival bleeding

• Gingival index used by the National Institute of Dental Research

(NIDR) (Miller et al., 1987)

• National Institute of Dental & Craniofacial Research (NICDR)

(NHANES III, 1997)

• Sulcus Bleeding Index (Mϋhlemann & Major, 1958)

• Bleeding Point Index (Lenox & Kopczyk, 1973)

• Ainamo’s Gingival Bleeding Index (Ainamo & Bay, 1975)

• Carter’s Gingival Bleeding Index (Carter & Barnes, 1974)

• Eastman Interdental Bleeding Index (Caton & Polson, 1985)

Indices used to assess plaque & calculus

• Plaque Index (PI) (Silness & Loe, 1964)• Plaque component of PDI (Ramfjord, 1959)• Turesky modification of Quigley Hein Index (Quigley &

Hein 1962,Turesky 1970) • Shick and Ash Modification of Plaque Criteria ( Shick & Ash

1961)

• Oral Hygiene Index-Simplified (OHI -S) (Greene & Vermillion ,1964)

• Calculus component of PDI (Ramfjord, 1959)• Calculus severity index (Ennever &Radike 1961)

Indices to measure degree of periodontal destruction

• Periodontal disease index (Ramfjord SP , 1959)

• Extent and Severity Index (ESI) (Carlos et al,1986)

Indices used to assess treatment needs

• Gingival plaque index (O'Leary et al., 1963)

• Periodontal Treatment Need System (PTNS) (Bellini & Gjermo, 1973)

• CPITN- Community Periodontal Index Of Treatment Needs (Ainamo et al., 1982)

PERIODONTAL DISEASES IN INDIA

National survey in India

National oral health survey and fluoride mapping DCI,2004• First ever national wide survey• WHO probe & CPI index used • M- F• Rural >Urban

Age group(yrs)

Periodontitis

12 57 %

15 67.7 %

35-44 89.6 %

65-74 79.9 %

Oral health in India, Govt. of india & WHO,2004• 22,400 subjects • M>F, Geriatric F>M, • Rural>urban• 65-74>>35-44 yrs

States 35-44 yr 65-74yr

Maharashtra 78% 96%

Orissa 68% 90%

Delhi 46% 85.5%

Rajasthan 33% 75%

Uttar pradesh 30% 68%

Puducherry 20% 55%

Arunachal Pradesh

15% 20%

PREVALENCE OF GINGIVITIS ACCORDING TO THE GEOGRAPHIC LOCATION

Name Year Area PrevalenceMarshal & Day 1940 North India 59.6%

Marshal,Day & Shourie 1944 Kangra,HP 81%

Mehta &Sanjana 1956 Bombay 93.7%

Greene 1960 India 96.9%

S P Ramford 1961 Bombay 100%

Dutta 1965 Calcutta 89.8%

PREVALENCE OF PERIODONTAL DISEASE ACCORDING TO THE GEOGRAPHIC LOCATION

In adult population

Name Year Area Prevalence

Marshal & Day 1940 North India 60%

Greene J.C. 1960 Bombay 90.3%

Gupta O.P. 1962 Trivandrum 96.9%

Chawla T.N. 1963 Lucknow 100%

Miglani D.C. 1965 Madras 94.9%

Ramachandra 1973 Chennai 95.5%

Anil S & Hari S 1990 Trivandrum 80%

PREVALENCE OF PERIODONTAL DISEASE ACCORDING TO THE GEOGRAPHIC LOCATION

In child population

Name Year Area PrevalenceMarshal & Day 1940 North India 60%Marshal,Day& Shourie 1947 Lahore 73.3%

Dutta A.N. 1965 Calcutta 89%

Miglani D.C. 1965 Madras 83%

Tewari 1979 Chandigarh 92.4%

Pandit K 1985 Delhi 41.7%Srivastava R P 1989 Jhansi 94%

Name Year Area PrevalenceSamant Asha 1976 Chandigarh Increased in 2nd

trimesterDixit J 1980 Lucknow Increased in 2nd

trimester

In Pregnant women

In Handicapped children

Name Year PrevalenceMehrotra AK 1982 88.5%

Shobha tendon 1986 97.3%

Recent studies

• Gingivitis : 80-85% Bhayya,2010

• Males > females (84% vs 78%)Mehta ,2010

• Periodontitis : • 35% for 35-40 yrs• 85% for 80-90 yrs• Aggressive periodontitis < 1% • Loss of attachment - 45-77% in 35-44 55-96% in 65-74

Jacob, 2010

PERIODONTAL DISEASES – GLOBAL OVERVIEW

ASIAN OVERVIEW

Gingivitis• Increased tooth brushing frequency & better oral hygiene

score were associated with lower PI scores NHANES I, 1971-74• Younger and older age groups > middle age NHANES III, 1988-1994• Most prevalent in 13-17 yrs (63%) > 45-54 yrs > 35-44 yrs NIDR,1986

Periodontitis in adults(1) periodontal disease - major, global public health problem in

35–40 years(2) gingivitis in youth- lead to periodontitis(3) age and oral hygiene Scherp 1964• Extent & severity Loe etal, Baelum et al. 1986• Probing assessments at six sites per tooth around all teeth -the

highest prevalence Susin et al. 2004

• In 480 Sri Lankan, Male tea-plantation labourers, aged 14–31 years

RP (8%) - 0.1 and 1.0 mm, MP (81%) -0.05 and 0.5 mm NP (11%) - 0.09 mm• Prevalence of gingival recession (> 1 mm) increases with age 38% - 30-39 yr 90% - 80-90 yr • Attachment loss of moderate magnitude was frequent in

elderly subjects( Beck et al. 1990; Mack et al. 2004)

Periodontal disease in children andadolescents

• In Michigan, USA 27% for 5–7-year-old children, 25% for 8–10-year-olds and

Jamison, (1963)• Presence of subgingival calculus at baseline was significantly

linked to disease progression. Clerehugh et al.

(1990) • In US ,14 013 adolescents from baseline 62% - localized periodontitis lesions 6 years later, 35% - generalized disease pattern. Brown et al. (1996)

• In Australian children (542) aged 5–12 years, 13.0% were found to display definite bone loss

Darby et al. (2005)

Prevalence of juvenile periodontitis• 0.53% LJP• O.13% GJP

NIDR ,1989• Severely affected teeth : 1st molars > 2nd molars >

incisors

• African Americans > Whites (M> F) (F> M)• South Indian : (females> males)

• Incidence: 1.5 cases per 1000 person per year at risk.Loe & Brown,1991

RISK FACTORS

• Helps in predicting ,who will get the disease

• Risk factor

• Risk assessment : to prevent disease by identifying and

modifying risk factors

• Tobacco smoking

• Systemic diseases such as Diabetes mellitus

• Pathogenic bacteria and microbial tooth deposits

Risk determinants / background factors : • Genetic factors • Age • Gender • Race

Risk indicators : • AIDS • Osteoporosis • Infrequent dental visits

CONCLUSION

REFERENCES • Newman MG, Takei HH, Klokevold PR, Carranza FA. Carranza’s

Clinical Periodontology. Saunders Elsevier;10th Edition.• Soben Peter ; Essentials of Preventive and Community dentistry , 2nd

edition• Niklaus P. Lang, Jan Lindhe . Clinical Periodontology and Implant

Dentistry. 5th ed. • Agarwal V. Prevalence of Periodontal Diseases in India J Oral Health

Comm Dent 2010;4(Spl)7-16• Shaju JP, Zade RM, Das M . Prevalence of periodontitis in the Indian

population :a literature review. J Indian Soc Periodontol, 2011,15,29-34

• Esmonde F. Corbet, K.-Y. Zee & Edward C. M. Lo . Periodontal diseases in Asia and Oceania : Periodontology 2000, Vol. 29, 2002, 122–152

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