It is the “study of the distribution and determinants of health related states or events in a specified population, and the application of this study to control of health problems.” -John M. Last(1988)

1. C H E T A N B A S N E T
B D S I V Y E A R
R O L L N O : - 0 2
EPIDEMIOLOGY OF GINGIVAL
&
PERIODONTAL DISEASES

2. EPIDEMIOLOGY
It is the “study of the distribution and determinants of health related
states or events in a specified population, and the application of this study to
control of health problems.”
-John M. Last(1988)
As the definition implies , EPIDEMIOLOGY has three purposes:
1. To determine the amount and distribution of a disease in a population
2. To investigate the causes of disease
3. To apply this knowledge to the control of disease

3. EPIDEMIOLOGIC MEASURES OF
DISEASE
• Prevalence
• Incidence

4. INCIDENCE
It is defined as the number of new cases of a specific disease occuring in a
defined population during a specified period of time.
Incidence=No. of new caqses of a specific disease during a given period X 1000
The population at risk
It is of two types
1. Episode incidence
2. Cumulative Incidence

5. PREVALENCE
The term disease prevalence is used to indicate all current cases (both old & new)
existing in a given population at a given point in time or over a period of time.
It is of two types:
1. Point prevalence
2. Period prevalence
Point Prevalence=total no. of cases(old&new) of specific disease at a given point in time
X 100
Estimated total population at a same point in a time
Period Prevalence Prevalence=total no. of existing cases of a specific disease during a
given given period of time X 100
Estimated mid-population at risk

6. EPIDEMIOPLOGIC STUDY DESIGNS
Cross-Sectional Study Design
Cohort Study
Case –Control Studies

7. CROSS-SECTIONAL STUDY DESIGN
It is a type of study in which the presence or absence of disease and
the characteristics of the member of a population are measured at a point of
time.
The studies are performed to :
• to provide prevalence data on prevalence of disease
• Comparing to person with or without disease
• Generating hypothesis regarding the etiology of diseases
It is also called as descriptive study or disease frequency survey or prevalence
studies.

8. CASE-CONTROL STUDY
It is a type of study providing efficient way to investigate the
association between an exposure and a disease.
The persons with diseases are considered cases
The person without disease are considered controls.

9. COHORT STUDY
It is a type of analytical study i.e. observational study which is
undertaken to obtain an additional evidence to refute or support the existence
of an association between suspected cause and disease.

10. DIAGNOSIS
For epidemiologist to study a disease in population or for clinician to care for
an individual patients, they must be able to identify individuals with or
without disease.
Various diagnostic tests are used for making correct diagnosis of diseases.
They are:
• Sensitivity & Specificity
• Predictive Value

11. SENSITIVITY & SPECIFICITY
When a diagnostic tests for a disease or condition gives a positive result, the
result can be correct(true positive) or incorrect (false negative).
When a test gives a negative result the result can be true(true negative) or
false(false negative).
The sensitivity of a test is the proportion of subjects with the disease who test
positive.
The specificity of a test is the proportion of subjects without the disease who
tests negative.

12. PREDECTIVE VALUE
The probability that a person with a positive test has the disease is Positive
predictive value of the test.
The probability that a person with a negative test does not have the disease
is Negative predictive value of the test.

13. RISK VS PROGNOSIS
Risk:
The likelihood that a person will get a disease ia a specified time
period is risk
Risk Factor:
The characteristics of a individuals that place them at increased risk
for getting a disease is risk factors.
Risk Assessment:
The process of predicting an individual probability of a disease is risk
assessment.

14. Prognosis:
it is the prediction course or outcome of the disease.
Prognostic Factors:
The characteristics or factors that predict the outcome of a disease
once disease are present are prognostic factors.
Prognostic Assessments:
The process of using prognostic factors, to predict the course of
disease is prognostic assessments.

15. GINGIVAL DISEASE

16. Gingivitis
IT IS THE INFLAMMATION OF THE GINGIVA.
Accn to literature:
It is the inflammation of the gingiva in which the
junctional epithellium remains attached to the tooth at its
original level.

17. Measurement of Gingivitis
Gingivitis is measured by gingival indices.
INDICES:
Indices are the devices to find out the incidence,
prevalence, and severity of the disease; based on which the
preventive programs can be adopted.
Gingival indices are used in epidemiological studies to
compare the prevalence of gingivitis in population.
In clinical studies it is used to test the efficacy of therapeutic
agents or devices.

18. Gingival indices measures one of the following:
1. Gingival color
2. Gingival contour
3. Gingival bleeding
4. Extent of gingival involvement
5. Gingival cerviculartfluid flow
Various numbers like 0,1,2,3,… are assigned that represents the
extent and severity of gingival condition.

19. Indices
 Gingival Index
 Modified Gingival Index
 Gingival Bleeding Index

20. Gingival Index

21. Gingival Index
It was developed by Loe & Silness in 1963 for the
purpose of assessing the severity of gingivitis.
Purpose:
to assess the severity of gingivitis based on its color,
consistency and bleeding on probing.
Instruments Required:
 Mouth Mirror
 Probe
Selection of teeth:
Whole mouth basis- entire dentition
Selected teeth basis

22. Procedure:
The index teeth are:
The tissue surrounding each index tooth are divided into
four gingival scoring units i.e.
16 12 24
44 32 36
Disto-facial
papillae
Facial margin Mesio-facial
papillae
Lingual gingival margin

23. Scoring Criteria:

24. Calculation:
Gingival index for individual teeth=
Note: max score=3
Interpretation:
Total of gingival index of each tooth
No. of teeth present
Score Condition
0.1-1.0 Mild Gingivitis
1.1-2.0 Moderate gingivitis
2.1-3.0 Severe gingivitis

25. MODIFIED GINGIVAL INDEX [ MGI ]

26. MODIFIED GINGIVAL INDEX{MGI}
There are two important changes to the gingival index i.e.
 Elimination of gingival; probing to assess the presence or absence of
bleeding
 Redefinition of the scoring system for mild and moderate
inflammation.
Note : probing was eliminated coz it could disturb plaque and irritate
gingiva
The MGI is the most widely used index in clinical trials of therapeutic
agents. As, with its predecessors, MGI doesn't assess the presence of
periodontal pockets or attachment loss, thus these indices cannot
identify gingivitis in absence of periodontitis.

27. SCORING CRITERIA
Score Criteria
0 Absence of inflammation
1 Mild Inflammation; slight change in color; little change in texture
of any portion of but not the entire marginal or papillary gingival
unit
2 Mild Inflammation: criteria as above but involvingentire marginal
or papillary gingival unit
3 Moderate inflammation: glazing redness edema and/or
hypertrophy of marginal or papillary gingival unit
4 Severe inflammation: marked redness, edema, and/or
hypertrophy of the marginal or papillary gingival unit;
spontaneous bleeding, congestion or ulceration

28. CONCLUSION
From various experimental and epidemiological study the
microbial plaque was found to be the direct cause of gingivitis.
The relation between plaque and gingival inflammation was
demonstrated by Loe et al in his classic study which consists of 12
individual i.e. 9 dental students, 1 instructor and 2 laboratory
technicians. They were asked to abstain all oral hygiene measures as a
result dental plaque began to form quickly and subsequent amount of
increased in plaque was seen with gingival inflammation. For around
10-21 days. BUT once Oral Hygiene measures were administered the
inflammation subsided within 1 week time period.
Hence bacterial plaque was considered to be the root for cause of
gingival inflammation.

29. Oral Hygiene Index-Simplified
OHI-S

30. Oral Hygiene Index
Oral hygiene index was first developed by Greene and Vermillion
in 1960. In the original index the whole mouth is divided into six
segments and both labial and lingual surfaces of one tooth with heaviest
deposits (in each segments) were graded and scored. In 1964, same
authors simplified the index and known as Greene and Vermillion “Oral
Hygiene Index- Simplified (OHI-S)”.
The OHI-S has two components:
1. Debris Index Simplified [DI-S]
2. Calculus Index Simplified [CI-S]

31.  Instruments required:
1. Mouth mirror
2. Explorer
 Index Teeth:
NOTE: If the index tooth is missing, then next distal tooth is considered for
examination.
Tooth Surface
16 Upper Rt. 1st molar Buccal
11 Upper Rt. CI Labial
26 Upper Lt. 1st Molar Buccal
36 Lower Lt. 1st molar Lingual
31 Lower lt.CI Labial
46 Lower rt. 1st Molar Lingual

32. Debris Index Simplified [DI-S]
Scoring criteria:
Score Criteria
0 No debris present
1 Soft debris covering not more then 1/3 of the tooth surface or
presence of extrinsic stains without other debris regardless of
surface area covered
2 Soft debris covering more then 1/3 , but not more than 2/3 of the
exposed tooth surface
3 Soft debris covering more then 2/3 of the exposed tooth surface

33. Calculation:
Readings of 6 index teeth are obtained and calculated
DI-S = Total score
No of teeth (6)
Interpretation:
Score Condition
0.0 – 0.6 Good
0.7 – 1.8 Fair
1.9 – 3.0 Poor

34. Calculus Index Simplified [DI-S]
Scoring criteria:
Score Criteria
0 Calculus absent
1 Supra gingival calculus covering less then 1/3 of tooth surface
2 Supra gingival calculus covering more then 1/3 of tooth surface or
presence of individual flecks of sub-gingival calculus around the
cervical portion of the tooth or both
3 Supra gingival calculus covering more then 2/3 of tooth surface or sub-
gingival continuous band of calculus around the cervical portion of
the tooth

35. Calculation:
Readings of 6 index teeth are obtained and calculated
CI-S = Total score
No of teeth (6)
Interpretation:
Score Condition
0.0 – 0.6 Good
0.7 – 1.8 Fair
1.9 – 3.0 Poor

36. OHI-S = DI-S +CI-S
Interpretation:
Score Condition
0.0 – 1.2 Good
1.3 – 3.0 Fair
3.1 – 6.0 Poor

37. CHRONIC PERIODONTITIS

38. It is the inflammation of the periodontium that extends beyond the gingiva and
produces destruction of the connective tissue attachment of the teeth.
It is considered to exists in three different forms:
• Chronic
• Aggressive
• As manifestation of systemic disease
Methods to measure periodontitis and the amount of disease vary widely across studies.

39. The various measurements of Periodontitis are:
1. Periodontal Index [Russell’s ]
2. Community Periodontal Index of Treatment Need
[CPITN]
3. Community Periodontal Index

40. RUSSELL’S PERIODONTAL INDEX
(PI)

41. RUSSELL’S PERIODONTAL INDEX (PI)
It is one of the most widely used PI in epidemiological
studies. It assesses destructive marginal periodontitis and is scored
according to the stages of periodontal disease which progresses in the
following sequence viz. gingival inflammation and its severity, pocket
formation, bone loss, decreased function i.e. increased tooth mobility,
tooth loss.
Purpose:
To assess periodontal disease status of the population.
Instruments Required;
Mouth Mirror
Non-Calibrated Probe
Selection of Teeth:
Whole mouth basis

42. SCORING AND CRITERIA FOR PI
Score Criteria
0 Negative: there is neither overt inflammation in the investing tissue
nor loss of function caused by destruction of supporting tissues.
1 Mild gingivitis: There is an overt area of inflammation in the free
gingiva but this area does not circumscribe the tooth.
2 Gingivitis: Inflammation completely circumscribes the tooth but there
is no apparent break in the epithelial attachment.
4 Used only when radiograph are availlable
6 Gingivitis with pocket formation: the epithelial attachment has broken
and there is pocket. There is no inference with masticatory function
the tooth is firm in its socket and has not drifted
8 Advanced destruction with loss of masticatory function: The tooth
may be loose may be drifted, sound dull on percussion with metallic
instruments, and may be depressible in its sockets

43. Calculation:
PI score= Sum of individual scores
No. of teeth present
Russell’s rule: When in doubt assign the lesser score

44. INTERPRETATION
PI Score Clinical Condition Stage of Disease
0 - 0.2 Clinically normal supportive
tissues
Normal
0.3 - 0.9 Simple gingivitis Reversible
1.0 - 1.9 Beginning of destructive Pdl
disease
Reversible
2.0 - 4.9 Established destructive Pdl
disease
Irreversible
5.0 - 8.0 Terminal disease Irreversible

45. Community Periodontal ndex of
Treatment Need [CPITN]

46. Community Periodontal ndex of Treatment Need
[CPITN]
The CPITN was developed for the joint working committee of World
Health Organisation [WHO] and Federation Dentaire International [FDI] by
Ainamo et al in 1982. CPITN index is the most widely recommended system for
establishing Periodontal Treatment Need.
Purpose: To survey and evaluate periodontal treatment need.
Instrument Required:
Mouth Mirror
CPITN Probe

47. CPITN Probe:
 It was described by WHO in 1978.
also called WHO Probe.
 Used for measurement of pocket
depth.
 It has light weight i.e 5 gms
 It has ball tip of 0.5 diameter for
easy detection of sub-gingival
calculus.
 Pocket depth is measured through
colour coding of black mark
starting at 3.5mm-5.5mm.

48. Types of CPITN Probe
1. CPITN-E: Epidemiological probe with markings of 3.5-5.5mm
2. CPITN-C: Clinical probe with additional marking of 8.5-11.5mm
Selection of Teeth
Index teeth(aged up to 19 yrs.): 16,11,26,36,31,46
Index teeth(aged up to 20+ yrs.): 17,16,11,26,27,36,31,46,47

49. Scoring Criteria
Code Criteria
0 No Pdl disease
1 Bleeding observed on probing
2 Supra or sub gingival calculus felt while probing
3 Pathological pocket 4-5mm in depth. Gingival margin on black band of
probe
4 Pathological pocket 6mm+ in depth. Black band of probe not visible
x Excluded sextant (less than 2 teeth present)
9 Not recorded

50. Treatment Needed depending upon Code
Treatment Need Code
TN-O No Pdl treatment Code O
TN-1 Improvement in oral hygiene Code 1
TN-2a Scaling, Improvement in oral hygiene Code 2
TN-2B Scaling and root planning; Improvement in oral hygiene Code 3
TN-3 Deep scaling, root planning and more complex surgical
procedures
Code 4

51. COMMUNITY PERIODONTAL INDEX (CPI)

52. COMMUNITY PERIODONTAL INDEX (CPI)
CPI index is a modification of CPITN index. The modification is done
by inclusion of “loss of attachment “ and elimination of “Treatment Need”
category.
Instruments Required:
• Mouth mirror
• CPI probe
Selection of Teeth
Index teeth(aged up to 19 yrs.): 16,11,26,36,31,46
Index teeth(aged up to 20+ yrs.): 17,16,11,26,27,36,31,46,47

54. Loss of Attachment
Information about loss of attachment is collected from index
teeth. The most reliable way is recording immediately after determining
CPI score. The highest score for CPI and Loss Of Atachment may not be
necessarily found on the same tooth in a sextant.
When CEJ is not visible and highest score for the sextant is
less than 4 (probing depth less than 6 mm), the attachment loss for
sextant is estimated to be less than 4 mm (i.e. loss of attachment=0). The
extent of loss of attachment is recorded using following criteria.

55. SCORING CRITERIA
Score Criteria
0 LOA 0-3mm (CEJ not visible and CPI score 0-3)
If the CEJ is not visible and the CPI score is 4,or the CEJ is visible
1 LOA 4-5 mm (CEJ within the black band)
2 LOA 6-8mm (CEJ between upper limit of black band and 8.5 mm ring )
3 LOA 9-11mm (CEJ between 8.5-11.5 mm ring )
4 LOA 12mm/+ (CEJ beyond 11.5 mm ring)
X Excluded sextant (less than 2 teeth present)
9 Not recorded (CEJ neither visible nor recorded)

56. Various epidemiological research has been focused on identification of
environmental and host factors involved in initiation and progression of
periodontal disease
1. Cigarette Smoking is considered as one of the most important factors.
Evidence for role of smoking in periodontitis include:
• A higher prevalence of disease among smoker in cross-sectional studies
• A higher incidence of periodontitis in smoker in longitudinal studies
• a statistically significant association even after controlling for other risk factors.
• Increased prevalence and incidence of disease with increased amounts of smoking
• Biologically plausible mechanism that can explain how smoking involved in destruction
of periodontal tissues.
1. Diabetes Mellitus is another factor for increased periodontal disease.

57. Several other characteristics have been investigated as possible risk factors for
periodontitis. The following lists are adapted from Page and Beck:
2. Nutrition: major nutritional deficiencies and imbalance has effect on
periodontal tissues.
3. Low-socioeconomic and educational status:
4. Osteoporosis: longitudinal data are scarce and multivariate analysis produce
inconsistent results.
5. HIV Infection and AIDS: elevate risk for periodontitis
6. Infrequent Dental Visits:

58. 8. Bacteria:
9 Bleeding on Probing: It is an indicator of active inflammation and likely to
be predictor of attachment loss rather than causal.
10 Previous periodontal disease
11. Genetic factors: Genetic factors are strongly associated with aggressive
forms and, to a lesser extent with chronic periodontitis.
12. Stress:
In addition Obesity has also been added as one factors for causinf periodontal
disease.

59. Refrences
• CARRANZA’S- CLINICAL PERIODONTOLOGY
-Tenth edition
• SOBEN PETER- Community and Preventive Dentistry
• Internet Sources
 Google
 Wikipedia

60. THANK YOU