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Epidemiology of periodontal disease
 Epi

= upon
 Demos = people
 Ology = science
 Epidemiology = the science which deals with
what falls upon people…..
The study of the
distribution of
disease or a
physiological
condition in
human population
& of the factor that
influence this
distrubution
Number of new cases

Incidence =
Number of persons at risk
Number of persons with the disease
Prevalence =
Number of persons in the population
Extent:

Severity:

describes how widespread the
disease is in subjects. (e.g., the %
of tooth sites with clinical
attachment loss > 2 mm)

e.g., mean CAL, mean bone loss
1.
2.

3.

4.
5.
6.
7.

To study the rise and fall of disease in population
To diagnose community problem of health and
disease by study and analysis of
incidence,prevalence and morbidity.
To estimate the individual risk and chances of
developing disease
To help in complete the clinical picture and natural
history of disease by group analysis
To identified clinical syndroms by observation of
group behavior
To evaluate the need and effectiveness of health
services and need for man power
To search for cause of disease and health by
observation of group habits,customs and model of
life.


Observational



Experimental


Cross-sectional studies



Cohort studies



Case-control studies
 The

presence or absence of disease and the
characteristics of the members of a
population are measured at a point in time.

 These

studies are useful for providing
prevalence data on a disease, comparing the
characteristics of persons with and without
disease, and generating hypotheses regarding
the etiology of a disease.


It follows subjects over time. The purpose of a cohort
study is to determine whether an exposure or
characteristic is associated with the development of a
disease or condition.



At the beginning of the study, all subjects must be free of
the disease of interest.



Subjects are classified into exposed and unexposed
groups and then followed over time and monitored for the
development of the disease.



The disadvantage of cohort study is that they can require
long periods of follow-up and can be expensive to conduct.


It provide and efficient way to investigate the association
between an exposure and a disease, especially a rare
disease.



Because case-control studies do not follow subjects over
time, they require fewer resources and can be conducted
more quickly than cohort studies.



The prevalence or incidence of a disease cannot be
determined from a case-control study because the
subjects are recruited into study based on their disease
status.



The major disadvantage is that the temporal relationship
between the exposure and the onset of disease cannot be
determined because the exposure is usually assessed when
the disease status is established.
Index

:-

is a numerical value describing the
relative status of population on graduated
scale with definite upper and lower limit
which is designed to permit and facilitate
comparison with other population classified
by the same criteria and method.
1.
2.
3.
4.

5.
6.
7.

Reliability
Validity
Quantifiability
Sensetivity
Clarity , Simplicity & objectivity
Acceptability
Practicality
Plaque index:

Gingival index:

Silness & Löe(1964)

Löe & Silness(1967)
Score
0

1

Criteria
Absence of plaque deposits

Plaque disclosed after running the
periodontal probe along the gingival
margin

2

Visible plaque

3

Abundant plaque
Epidemiology of periodontal disease
Epidemiology of periodontal disease
Score

Criteria

0

Normal gingiva

1

Mild inflammation: slight change in
color and
slight edema. No bleeding on probing.

2

Moderate inflammation: redness,
edema, and glazing. running along
soft tissue wall of gingival crevice.

3

Severe inflammation: marked
redness and edema. Ulceration,
Tendency toward spontaneous bleeding.
Epidemiology of periodontal disease
 Periodontal

index: Russell(1956)

 Periodontal

Disease lndex: Ramfjord(1959)
Epidemiology of periodontal disease
Epidemiology of periodontal disease
Code

CPI

0

TN

Healthy

1

Bleeding on probing

I . Oral hygiene instruction

2

Supra andor Subgingival
calculus Iatrogenic marginal
irritation

II . I+ calculus removal

3

4

Shallow pockets up to
5 mm

Deeper pockets from
6mm

III. I+II+ root planning

IV. I+II+ complex treatment
Epidemiology of periodontal disease
Epidemiology of periodontal disease
Epidemiology of periodontal disease

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Epidemiology of periodontal disease

  • 2.  Epi = upon  Demos = people  Ology = science  Epidemiology = the science which deals with what falls upon people…..
  • 3. The study of the distribution of disease or a physiological condition in human population & of the factor that influence this distrubution
  • 4. Number of new cases Incidence = Number of persons at risk
  • 5. Number of persons with the disease Prevalence = Number of persons in the population
  • 6. Extent: Severity: describes how widespread the disease is in subjects. (e.g., the % of tooth sites with clinical attachment loss > 2 mm) e.g., mean CAL, mean bone loss
  • 7. 1. 2. 3. 4. 5. 6. 7. To study the rise and fall of disease in population To diagnose community problem of health and disease by study and analysis of incidence,prevalence and morbidity. To estimate the individual risk and chances of developing disease To help in complete the clinical picture and natural history of disease by group analysis To identified clinical syndroms by observation of group behavior To evaluate the need and effectiveness of health services and need for man power To search for cause of disease and health by observation of group habits,customs and model of life.
  • 10.  The presence or absence of disease and the characteristics of the members of a population are measured at a point in time.  These studies are useful for providing prevalence data on a disease, comparing the characteristics of persons with and without disease, and generating hypotheses regarding the etiology of a disease.
  • 11.  It follows subjects over time. The purpose of a cohort study is to determine whether an exposure or characteristic is associated with the development of a disease or condition.  At the beginning of the study, all subjects must be free of the disease of interest.  Subjects are classified into exposed and unexposed groups and then followed over time and monitored for the development of the disease.  The disadvantage of cohort study is that they can require long periods of follow-up and can be expensive to conduct.
  • 12.  It provide and efficient way to investigate the association between an exposure and a disease, especially a rare disease.  Because case-control studies do not follow subjects over time, they require fewer resources and can be conducted more quickly than cohort studies.  The prevalence or incidence of a disease cannot be determined from a case-control study because the subjects are recruited into study based on their disease status.  The major disadvantage is that the temporal relationship between the exposure and the onset of disease cannot be determined because the exposure is usually assessed when the disease status is established.
  • 13. Index :- is a numerical value describing the relative status of population on graduated scale with definite upper and lower limit which is designed to permit and facilitate comparison with other population classified by the same criteria and method.
  • 15. Plaque index: Gingival index: Silness & Löe(1964) Löe & Silness(1967)
  • 16. Score 0 1 Criteria Absence of plaque deposits Plaque disclosed after running the periodontal probe along the gingival margin 2 Visible plaque 3 Abundant plaque
  • 19. Score Criteria 0 Normal gingiva 1 Mild inflammation: slight change in color and slight edema. No bleeding on probing. 2 Moderate inflammation: redness, edema, and glazing. running along soft tissue wall of gingival crevice. 3 Severe inflammation: marked redness and edema. Ulceration, Tendency toward spontaneous bleeding.
  • 21.  Periodontal index: Russell(1956)  Periodontal Disease lndex: Ramfjord(1959)
  • 24. Code CPI 0 TN Healthy 1 Bleeding on probing I . Oral hygiene instruction 2 Supra andor Subgingival calculus Iatrogenic marginal irritation II . I+ calculus removal 3 4 Shallow pockets up to 5 mm Deeper pockets from 6mm III. I+II+ root planning IV. I+II+ complex treatment