epidemiology of periodontal diseases new 4

8/3/2019 Epidemiology of Periodontal Diseases New 4

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Epidemiology of PeriodontalDiseases

Dr Khansa Ababneh


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What is Epidemiology? The study of the distribution and

determinants of health-related states in

populations, and the application of thisstudy to control health problems


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ImplicationsDefinition implies

1. Determining amount & distribution of disease2. Investigation of causes of disease

3. Applying this knowledge for control of disease


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Distribution of diseases Distribution of diseases/periodontal

diseases in populations is not random

Some members or subgroups of thepopulation are more susceptible

Physical, biologic, behavioral, culturaland social factors


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Epidemiology in periodonticsshould provide information about:

1. Prevalence & severity

2. Risk factors3. Effectiveness of preventive &

therapeutic measures


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Classification of Periodontal

DiseasesNumerous Classifications existed in thepast

World workshop in periodontics 1989

AAP classification 1999


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Periodontal Diagnosis Great importance

Distinguishing between Normal &Abnormal is based on thresholds

Thresholdsare derived fromepidemiological studies


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Study Designs Cross-sectional studies

Prevalence

Case-control studies Risk Indicators (rare diseases)

Cohort studies Incidence


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Definitions Prevalence

Incidence

Sensitivity

Specificity

Positive predictive value Negative predictive value


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Prevalence Proportion of persons in a population who

have the disease at a given point or period

of time

Prevalence = No of persons with diseaseNo of persons in the

population


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Incidence Average percentage of unaffected

persons who will develop the disease of

interest during a given period of time

Incidence = No of new casesNo of persons at risk


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Incidence ofperiodontal

diseases in a strict sense isalmost impossible at thepresent level of knowledge.


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Sensitivity Proportion of subjects with the disease

who test positive

Sensitivity = No of subjects who test positiveNo of subjects with disease


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Specificity Proportion of subjects without the disease

who test negative

Specificity = No of subjects who test negativeNo of subjects without disease

Sensitivity and specificity are useful in choosing the test


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Predictive Value Once the result of a test is ready: what

are the chances that it is right or wrong?

Predictive value


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Predictive Value

Positive predictive value of a test:Probability that a person with a positive

test has the disease

Negative Predictive Value:

probability that a person with anegative test does not have the disease


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True Disease Status

Test Result Disease No Disease

Positive A

True +ve

B

False +ve

Negative C

False -ve

D

True -ve

Sensitivity A/(A+C)

Specificity B/(B+D)

Positive predictive value A/(A+B)

Negative predictive value D/(C+D)


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Periodontal Indices Techniques employed in periodontal

epidemiology to quantitate clinicalconditions on a graduated scale to

facilitate comparison among populations

Complete periodontal examination is

Superior BUT

Time consuming Does not translate clinical conditions into

numerical data


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Periodontal Indices

Indices measuring the degree of gingivalinflammation

Example:

Gingival index(GI; Le & Silness; 1967)

Modified Gingival Index(Lobene et al, 1986)


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Periodontal Indices

Indices used to measure periodontaldestruction

Example:

Periodontal Index (PI, Russel; 1956)

Periodontal Disease Index ( Ramfjord, 1959)


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Periodontal Indices

Indices used to measure plaqueaccumulation

Example:

Plaque Index(Silness & Le, 1964)


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Periodontal Indices

Indices used to measure calculus

Example:

Calculus component of the PDI


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Periodontal Indices

Indices used to assess treatment needs

Example:

Community Periodontal IndexOf Treatment Needs (CPITN)

Ainamo et al, 1977


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Changing Concepts

Old concept in WHO (1961) has changed:

Gingivitis does not inevitably progress into

periodontitis

Universal susceptibility

Models for periodontal diseases

Models for pathogenesis


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Prevalence of Periodontal Diseases

National Health & Nutrition Examination Survey

NHANES I (1971-1974)

NHANES III (1988-1994)

NIDR (1985-1986)

Difficult to compare results


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Prevalence of Periodontal Diseases

Geographic distribution

More than 70% of adults have some

degree of gingivitis or periodontitis Gingivitis and calculus are more

prevalent and severe in developing

countries


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Gingivitis

At the population level

Found in early childhood

Prevalence & severity in adolescence

Prevalence of gingivitis in USA amongpopulation aged 13 and older= 54%


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Gingival BleedingNHANES III

Highest among 13-17 yr old (63%)

Declined through 35- to 44-yr-old group

Increased in 45- to 54- yr old group


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Gingivitis

In Adults First national survey in US (1962):

85% of men &79% of women

had gingivitis

??Gingivitis has declined indeveloped countries??


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Prevalence of Chronic Periodontitis

Depends on: Population &

Threshold definition

NHANES III: > 1mm prevalence=99%: > 3mm AL in at least one site of the

mouth= 53%

: > 7mm =7%

In Jordan: Prepared


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Prevalence of AggressivePeriodontitis

Differs with populations

In the US: 0.13%, 0.53% and 1%prevalence has been reported

In Jordan: Prepared


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Confusion

Confusion in interpreting data fromolder studies, due to differences in

measurement Severity of periodontitis according

to AAP

CAL (PAL; LPA)


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Incidence of Periodontitis

Longitudinal study of periodontitis on480 tea workers in Sri Lanka(Le et al 1986)

Revealed natural history of disease

Parallel Study in Norway


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Results

8% rapid progression

81% moderate progression

11% no progression beyond gingivitis GR progresses on all surfaces

In Norway; upper SES: GR buccally

Reason for CAL in both groups


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RISK


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EnvironmentalSmoking

HostSusceptibility

GeneticAcquired

Periodontal Diseases

BacteriaColonisationInvasion

Destruction


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Aetiology

Risk Factors

Susceptibilityfactors

Severity factors


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RiskIdentified in terms of:

Risk Factors

Risk Indicators

Risk predictors

(Pihlstrom, 2001)


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Risk Factors for Periodontitis Sociodemographic

characteristics

Dental Plaque

Oral hygiene

Local Factors

Systemic factors

Smoking

Nutrition

Genetic predisposition

Dental visits

BOP

Previous periodontaldisease

Stress


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Demographic risk factors

Gender and Race

Age

Socioeconomic status

Education


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Gender & Race Men have poorer periodontal health

than women, in terms ofLPA, pocketsand subgingival calculus

Women have better oral hygiene

No established differences in

susceptibility to chronic periodontitis


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GenderAggressive Periodontitis

Studies on Europeans show higher prevalenceof aggressive periodontitis in

FEMALES > MALES

Studies on Africans or African Americans:MALES > FEMALES

Gender is related to race(risk factors)


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Age

Cross-sectionalstudies: Greater prevalence & severity of LPA with

age

Does not mean greater susceptibility

Cumulative progression of lesions overtime

Sri Lankan study: 3 groups

Increased LPA with age (cumulative effect)

Increased susceptibility


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Age

Conclusion

Susceptibility determines age of onset

LPA (CAL or attachment loss)increases with age in the groupsusceptible to aggressive periodontitis


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Socioeconomic Status (SES)

Gingivitis & poor OH Low SES

Subgingival calculus Low SES

Relationship between periodontitis

& SES is less direct

Higher prevalence of attachment &

alveolar bone loss with lower SES

O l


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Oral Hygiene

Classic studies (Le et al, 1965) Plaque Gingivitis

Plaque & calculus correlate poorly with severe

periodontitis

Quantity of plaque correlates poorly withperiodontitis

Sensitive aetiologic factor insusceptible individuals


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Local Factors

Example: overhangs

Epidemiologically:

Of minor importance in

aetiology of periodontal diseases


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Nutrition

Insufficient studies

Vitamin C deficiency

Vitamin B6 & B12 deficiency

Iron deficiency


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Smoking

NHANES I: 1971-1975

Smoking Periodontal Diseaseclear association

Independent of OH, age & otherfactors


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Smoking

Higher prevalence of periodontitis amongsmokers

Smoking suppresses vascular reaction to

plaque Twice as many smokers require dentures

after age 50

93%-97% of patients with refractory sitesare smokers


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Smoking is a major

Risk Factor forPeriodontitis


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Systemic Diseases

Diabetes Mellitus

HIV infection

CVS diseases


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Diabetes Mellitus

Known risk factor for periodontitis

Periodontitis: classic complication of DM

Both types I ( IDDM) & and II (NIDDM)

IDDM patients: more gingivitis & pockets

IDDM: poorer glycemic control

greater LPA and bone loss


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Diabetes Mellitus

Periodontitis progresses more rapidly inpoorly controlled diabetics

Studies on Gila River community in Arizona :

NIDDM: Greater LPA, bone &tooth loss

Risk for periodontitis in NIDDM: 2.81

Risk for alveolar bone loss in NIDDM: 3.43


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HIV Infection

Not many controlled studies

Controversial results

High risk for LPA, bone & tooth lossAlarming signs: NUG, NUP

(not statistically)


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epidemiology of periodontal diseases new 4

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