Periodontal diseases are highly prevalent globally and their distribution is influenced by factors like age, gender, geography, and oral hygiene habits. Gingivitis is the most common form of periodontal disease and prevalence surveys show that it affects a large portion of all populations. The prevalence of periodontitis increases with age, from 35% in 35-40 year olds to 85% in 80-90 year olds. Risk factors for periodontal diseases include tobacco use, diabetes, poor oral hygiene leading to dental plaque and calculus buildup, and specific pathogenic bacteria. Epidemiological studies are important to understand the distribution and determinants of periodontal diseases in populations in order to guide prevention and control efforts.

1. EPIDEMIOLOGY OF
PERIODONTAL DISEASES

2. 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

3. 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

4. HISTORY
• Hippocrates
• CLAUDIUS GALEN (130-200A.D.)
• THOMAS SYDENHAM ‘founder of epidemiology’.
• JOHN SNOW ‘father of epidemiology’

5. 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 teeth
Edwin Saunders; Britain 1837
Tooth mortality study
John Tomes; 1848
Dental status of school children
Fisher ; Britain 1885
Nation wide survey of school children
Ainsworth & Young; Britain 1925

6. 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

7. • 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

8. PRINCIPLES OF EPIDEMIOLOGY
• Exact observation
• Correct interpretation
• Rationale explanation
• Scientific construction

9. 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.

10. COMPONENTS OF EPIDEMIOLOGY
1. Disease frequency: Rate or ratio
2. Distribution of disease : pattern of distribution
3. Determinants of disease : etiological hypothesis

11. 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

12. 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

13. ENVIRONMENT
Environment is the source or reservoir for the agents of disease
• Physical
• Biological
• Social

14. 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

15. EPIDEMIOLOGICAL METHODS
1. Descriptive epidemiology
2. Analytical epidemiology
3. Experimental epidemiology
• Experimental studies - efficacy of preventive interventions,
treatments, and drugs.

16. Descriptive epidemiology
Describes the pattern of occurrence of disease/condition
relative 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

17. 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.

18. Analytical epidemiology
It deals with discovering the causes of disease
2 approaches:
Cohort study- from exposure to effects
case control study- from disease to cause

19. 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

20. Case-Control Studies
• In day to day…
• Cases and controls
• Primarily used to assess risk
Limitation
• 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

21. Experimental epidemiology
The results obtained from observational studies about
association & causation/benefit of a particular intervention
1.Randomised controlled trials
2.Field trials
3.Community trials

23. 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

24. 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.

25. 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)

26. Factors influencing prevalence
Prevalence rate increases by:
1. Longer duration of the disease.
2. Prolongation of life of the patient
3. Prolongation of life of patient without care e.g. periodontitis
4. In-migration of cases
5. Improved diagnostic facilities.

27. 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

28. 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

29. 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

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

31. • Most important but complex part of dental epidemiology
• Special indices have been designed to provide objective
measurement of identifiable features
• Quantitative science
PERIODONTAL EPIDEMOLOGY

32. 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)

33. 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)

34. 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)

35. Indices to measure degree of periodontal
destruction
• Periodontal disease index (Ramfjord SP , 1959)
• Extent and Severity Index (ESI) (Carlos et al,1986)

36. 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)

37. PERIODONTAL DISEASES IN INDIA

38. 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 %

39. 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%

40. PREVALENCE OF GINGIVITIS ACCORDING TO THE
GEOGRAPHIC LOCATION
Name Year Area Prevalence
Marshal & 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%

41. 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%

42. PREVALENCE OF PERIODONTAL DISEASE ACCORDING TO THE
GEOGRAPHIC LOCATION
In child population
Name Year Area Prevalence
Marshal & 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%

43. Name Year Area Prevalence
Samant Asha 1976 Chandigarh Increased in
2nd trimester
Dixit J 1980 Lucknow Increased in
2nd trimester
In Pregnant women
In Handicapped children
Name Year Prevalence
Mehrotra AK 1982 88.5%
Shobha tendon 1986 97.3%

48. 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

49. PERIODONTAL DISEASES – GLOBAL OVERVIEW

50. ASIAN OVERVIEW

54. 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

55. 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

56. • 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)

57. Periodontal disease in children and
adolescents
• 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)

58. • In Australian children (542) aged 5–12 years, 13.0% were
found to display definite bone loss
Darby et al. (2005)

59. 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

60. 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

61. Risk determinants / background factors :
• Genetic factors
• Age
• Gender
• Race
Risk indicators :
• AIDS
• Osteoporosis
• Infrequent dental visits

62. CONCLUSION

63. 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

64. THANK YOU