CHETAN BASNETBDS IV YEAR

ROLL NO: - 02

EPIDEMIOLOGY OF GINGIVAL &

PERIODONTAL DISEASES

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 population2. To investigate the causes of disease3. To apply this knowledge to the control of disease

EPIDEMIOLOGIC MEASURES OF DISEASE

• Prevalence• Incidence

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 1000The population at risk

It is of two types 1. Episode incidence2. Cumulative Incidence

PREVALENCEThe 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 prevalence2. 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

EPIDEMIOPLOGIC STUDY DESIGNS

Cross-Sectional Study DesignCohort StudyCase –Control Studies

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.

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 casesThe person without disease are considered controls.

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.

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

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.

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.

RISK VS PROGNOSIS

Risk:The likelihood that a person will get a disease ia a specified time

period is riskRisk 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.

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.

GINGIVAL DISEASE

GingivitisIT 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.

Measurement of GingivitisGingivitis 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.

Gingival indices measures one of the following:1. Gingival color2. Gingival contour3. Gingival bleeding4. Extent of gingival involvement5. Gingival cerviculartfluid flowVarious numbers like 0,1,2,3,… are assigned that represents the extent and severity of gingival condition.

Indices Gingival Index Modified Gingival Index Gingival Bleeding Index

Gingival Index

Gingival IndexIt 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 dentitionSelected teeth basis

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

Scoring Criteria:

Calculation:Gingival index for individual teeth=

Note: max score=3

Interpretation:

Total of gingival index of each toothNo. of teeth present

Score Condition0.1-1.0 Mild Gingivitis1.1-2.0 Moderate gingivitis2.1-3.0 Severe gingivitis

MODIFIED GINGIVAL INDEX [ MGI ]

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.

SCORING CRITERIAScore

Criteria

0 Absence of inflammation1 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

CONCLUSIONFrom 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.

Oral Hygiene Index-SimplifiedOHI-S

Oral Hygiene IndexOral 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]

Instruments required:1. Mouth mirror2. Explorer

Index Teeth:

NOTE: If the index tooth is missing, then next distal tooth is considered for examination.

Tooth Surface16 Upper Rt. 1st molar Buccal11 Upper Rt. CI Labial26 Upper Lt. 1st Molar Buccal36 Lower Lt. 1st molar Lingual31 Lower lt.CI Labial46 Lower rt. 1st Molar Lingual

Debris Index Simplified [DI-S]Scoring criteria:

Score Criteria0 No debris present1 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

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 Good0.7 – 1.8 Fair1.9 – 3.0 Poor

Calculus Index Simplified [DI-S]Scoring criteria:

Score Criteria0 Calculus absent1 Supra gingival calculus covering less then 1/3 of tooth

surface2 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

Calculation:Readings of 6 index teeth are obtained and calculated

CI-S = Total score No of teeth (6)

Interpretation:Score Condition0.0 – 0.6 Good0.7 – 1.8 Fair1.9 – 3.0 Poor

OHI-S = DI-S +CI-SInterpretation:

Score Condition0.0 – 1.2 Good1.3 – 3.0 Fair3.1 – 6.0 Poor

CHRONIC PERIODONTITIS

PeriodontitisIt 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.

The various measurements of Periodontitis are:

1. Periodontal Index [Russell’s ]2. Community Periodontal Index of Treatment

Need [CPITN]3. Community Periodontal Index

RUSSELL’S PERIODONTAL INDEX (PI)

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 MirrorNon-Calibrated Probe

Selection of Teeth:Whole mouth basis

SCORING AND CRITERIA FOR PIScore Criteria0 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 availlable6 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

Calculation:PI score= Sum of individual scores

No. of teeth presentRussell’s rule: When in doubt assign the lesser score

INTERPRETATION

PI Score Clinical Condition Stage of Disease0 - 0.2 Clinically normal supportive

tissuesNormal

0.3 - 0.9 Simple gingivitis Reversible1.0 - 1.9 Beginning of destructive Pdl

diseaseReversible

2.0 - 4.9 Established destructive Pdl disease

Irreversible

5.0 - 8.0 Terminal disease Irreversible

Community Periodontal ndex of Treatment Need [CPITN]

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 MirrorCPITN Probe

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.

Types of CPITN Probe1. CPITN-E: Epidemiological probe with markings of 3.5-5.5mm2. CPITN-C: Clinical probe with additional marking of 8.5-11.5mm

Selection of TeethIndex teeth(aged up to 19 yrs.): 16,11,26,36,31,46Index teeth(aged up to 20+ yrs.): 17,16,11,26,27,36,31,46,47

Scoring Criteria

Code Criteria0 No Pdl disease1 Bleeding observed on probing2 Supra or sub gingival calculus felt while probing3 Pathological pocket 4-5mm in depth. Gingival margin on black

band of probe4 Pathological pocket 6mm+ in depth. Black band of probe not

visible

x Excluded sextant (less than 2 teeth present)9 Not recorded

Treatment Needed depending upon Code

Treatment Need CodeTN-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

COMMUNITY PERIODONTAL INDEX (CPI)

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

Loss of AttachmentInformation 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.

SCORING CRITERIA

Score Criteria0 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)

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.

2. Diabetes Mellitus is another factor for increased periodontal disease.

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:

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.

Refrences• CARRANZA’S- CLINICAL PERIODONTOLOGY

-Tenth edition• SOBEN PETER- Community and Preventive Dentistry• Internet Sources

Google Wikipedia

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