Epidemiology of Periodontal & Gingival Diseases

Epidemiology of Periodontal
& Gingival Diseases
 
Learning objectives
Need for classification
previous  classification
1999 AAP classification
new classification 2017
 
 
Epidemiology
, derived from Greek word
epi
, meaning "upon, among",
demos
, meaning "people, 
 
logos
, meaning "study,
What is Epidemiology?
The study of the distribution and
determinants of health-related states in
populations, and the application of this
study to control health problems
Basic Science of Public Health
 
Public Health    deals with  health of Community
group or population
Clinical practice deals with  health of an individual.
Epidemiology
Definition implies
1.
Determining amount & distribution of disease
2.
Investigation of causes of disease
3.
Applying this knowledge for control of disease
 
The final purpose of Epidemiology is to
apply the knowledge gained through
studies to
Promote Health
Protect Health
Restore Health
Distribution of diseases
Distribution of diseases/periodontal
diseases in populations is not random
Some members or subgroups of the
population are more 
susceptible
Physical, biologic, behavioral, cultural
and social factors
 
Epidemiology in periodontics
should provide information about:
1.
Prevalence & severity
1.
Risk factors
1.
Effectiveness of preventive &
therapeutic measures
Classification of Periodontal
Diseases
 
Numerous Classifications existed in the
past
World workshop in periodontics 1989
AAP classification 1999
Periodontal Diagnosis
Great importance
Distinguishing between “Normal” &
“Abnormal” is based on 
thresholds
Thresholds
 
are derived from
epidemiological studies 
Study Designs
Cross-sectional studies
Prevalence
Case-control studies
Risk Indicators (rare diseases)
Cohort studies
Incidence
Definitions
Prevalence
Incidence
Sensitivity 
Specificity
Positive predictive value
Negative predictive value
Prevalence
Proportion of persons in a population who
have the disease at a given point or period
of time
  Prevalence = 
   
No of persons with disease
  
      
No of persons in the population
Incidence
Average percentage of unaffected
persons who will develop the disease of
interest during a given period of time
   Incidence  =  
   
No of new cases 
   
  
  
         
No of persons at risk
 
Incidence
 of 
periodontal
diseases
 in a 
strict sense
 is
almost 
impossible
 at the
present level of knowledge.
Sensitivity
Proportion of subjects with the disease
who test positive
 Sensitivity  =  
 
No of subjects who test positive
  
        
No of subjects with disease
 
Specificity
Proportion of subjects without the disease
who test negative
 Specificity = 
 
No of subjects who test negative 
 
     
  
  
  
      
No of subjects without  disease
  Sensitivity and specificity are useful in choosing the test
Predictive Value
Once the result of a test is ready: what
are the chances that it is right or wrong?
Predictive value
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 a
negative test does not have the disease
True Disease Status
Periodontal Indices
Techniques employed in periodontal
epidemiology to quantitate clinical
conditions 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
Ideal Index
Simple & quick to use
Accurate
Reproducible
Quantitative
Indices
Gingival health/bleeding
Plaque
Calculus
Attachment loss
Radiographic bone loss
Treatment needs
Periodontal Indices
Indices measuring the degree of gingival
inflammation
  Example:
  
Gingival index
 
(GI; Löe & Silness; 1967)
  
Modified Gingival Index
 
(Lobene et al, 1986)
Periodontal Indices
Indices used to measure periodontal
destruction
 
Example:
 
Periodontal Index 
(PI, Russel; 1956)
 
Periodontal Disease Index 
( Ramfjord, 1959)
Periodontal Indices
Indices used to measure plaque
accumulation
 
Example:
 
Plaque Index
 
(Silness & Löe, 1964)
Periodontal Indices
Indices used to measure calculus
 
Example:
 
Calculus component of the PDI
Periodontal Indices
Indices used to assess treatment needs
 
Example:
 
Community Periodontal Index
Of Treatment Needs 
(CPITN)
 
Ainamo et al, 1977
Prevalence of Periodontal Diseases
National Health & Nutrition Examination Survey
NHANES I     (1971-1974)
NHANES III   (1988-1994)
NIDR            (1985-1986)
Difficult to compare results
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
Gingivitis
 
At the population level
Found in early childhood
  Prevalence & severity in adolescence
Prevalence of gingivitis in USA among
population aged 13 and older= 54%
Gingival Bleeding
NHANES III
Highest among 13-17 yr old (63%)
Declined through 35- to 44-yr-old group
Increased in 45- to 54- yr old group
Gingivitis
 
In Adults
First national survey in US (1962):
 
85% of men
 & 
79% of women
 
had gingivitis
??Gingivitis has declined in
developed countries?? 
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%
 
Prevalence of Aggressive
Periodontitis
Differs with populations
In the US: 0.13%,  0.53% and 1%
prevalence has been reported
Confusion
Confusion in interpreting data from
older studies, due to differences in
measurement
Severity of periodontitis according
to AAP
CAL (PAL; LPA)
Incidence of Periodontitis
Longitudinal study of periodontitis on
480 tea workers in 
Sri Lanka
 
(Löe et al 1986)
Revealed natural history of disease
Parallel Study in 
Norway
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
RISK
 
 
 
 
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          Genetic
         Acquired
Periodontal Diseases
 
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Aetiology
Risk Factors
Susceptibility
factors
Severity factors
Risk
Identified in terms of:
Risk Factors
Risk Indicators
Risk predictors
  
   
(Pihlstrom, 
2001
)
Risk factors
Identified through Longitudnal studies
Examples
1.
Tobacco Smoking
2.
Diabetes
3.
Pathogenic Bacteria
4.
 Microbial tooth deposits
Risk Determinants
Also called Background Characteristics
Cannot be modified
Examples
1.
Genetic factors
2.
Age
3.
Gender
4.
Socioeconomic status
5.
Stress
Risk Indicators
Are probable risk factors that have been
identified in Crossectional studies but
not in longitudnal studies
Examples
1.
HIV/AIDS
2.
Osteoporosis
3.
Infrequent dental visits
Risk markers/ Predictors
Are associated with increased risk for
disease but do not cause disease
Identified in Crosssectional and
longitudnal studies
Examples
1.
Previous history of Periodontal disease
2.
Bleeding on probing
Gender & Race
Men have poorer periodontal health
than women, in terms of 
LPA
, 
pockets
and subgingival 
calculus
Women have better oral hygiene
 
No established differences in
susceptibility to chronic periodontitis
Gender
Aggressive Periodontitis
Studies on Europeans show higher prevalence
of aggressive periodontitis in
 
 
FEMALES  >  MALES
Studies on Africans or African Americans:
MALES  >  FEMALES
Gender is related to race
 
(risk factors)
Age
  
Cross-sectional
 
studies
:
Greater prevalence & severity of CALwith
age
Does not mean greater susceptibility
Cumulative progression of lesions over
time
Sri Lankan study:  3 groups
Increased CAL with age (cumulative
effect)
Increased susceptibility
Age
Conclusion
Susceptibility determines age of onset
 (CAL or attachment loss) increases
with age in the group susceptible to
aggressive periodontitis
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
Oral Hygiene
        Classic studies 
(Löe et al, 1965)
Plaque               Gingivitis
Plaque & calculus correlate poorly with severe
periodontitis
Quantity of plaque correlates poorly with
periodontitis
 
Sensitive aetiologic factor in
susceptible individuals
Local Factors
Example: overhangs
Epidemiologically
:
  
Of minor importance in
  aetiology of periodontal diseases
Nutrition
Insufficient studies
Vitamin C deficiency
Vitamin B
6
 & B
12 
 
deficiency 
Iron deficiency
Smoking
NHANES I: 1971-1975
Smoking               Periodontal Disease
   
clear association
   Independent of OralHygiene , age &
other factors
Smoking
Higher prevalence of periodontitis among
smokers
Smoking 
suppresses vascular reaction
 to
plaque
Twice as many smokers require
 dentures
after age 50 
93%-97% of patients with 
refractory
 sites
are smokers
 
 
Smoking is a 
major
Risk Factor for
Periodontitis
Systemic Diseases
Diabetes Mellitus
HIV infection
CVS diseases
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
Diabetes Mellitus
Periodontitis progresses more rapidly in
poorly controlled diabetics
Studies on Gila River community in Arizona :
NIDDM: Greater 
CAL
, 
bone
 & 
tooth loss
Risk for periodontitis in NIDDM: 2.81
Risk for alveolar bone loss in NIDDM: 3.43 
HIV Infection
Not many controlled studies
Controversial results
High risk for CAL, bone & tooth loss
Alarming signs: NUG, NUP 
 
(not statistically)
T
HANK
YOU.
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Epidemiology is the study of disease distribution and determinants in populations for effective control and prevention. It plays a crucial role in understanding the prevalence, risk factors, and effectiveness of preventive measures for periodontal and gingival diseases. Classification systems and the application of epidemiological data contribute to promoting, protecting, and restoring oral health.


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  1. Epidemiology of Periodontal & Gingival Diseases

  2. Learning objectives Need for classification previous classification 1999 AAP classification new classification 2017

  3. Epidemiology, derived from Greek word epi, meaning "upon, among", demos, meaning "people, logos, meaning "study,

  4. What is Epidemiology? The study of the distribution and determinants of health-related states in populations, and the application of this study to control health problems Basic Science of Public Health

  5. Public Health deals with health of Community group or population Clinical practice deals with health of an individual.

  6. Epidemiology Definition implies Determining amount & distribution of disease Investigation of causes of disease Applying this knowledge for control of disease 1. 2. 3.

  7. The final purpose of Epidemiology is to apply the knowledge gained through studies to Promote Health Protect Health Restore Health

  8. Distribution of diseases Distribution of diseases/periodontal diseases in populations is not random Some members or subgroups of the population are more susceptible Physical, biologic, behavioral, cultural and social factors

  9. Epidemiology in periodontics should provide information about: 1. Prevalence & severity 1. Risk factors 1. Effectiveness of preventive & therapeutic measures

  10. Classification of Periodontal Diseases Numerous Classifications existed in the past World workshop in periodontics 1989 AAP classification 1999

  11. Periodontal Diagnosis Great importance Distinguishing between Normal & Abnormal is based on thresholds Thresholds are derived from epidemiological studies

  12. Study Designs Cross-sectional studies Prevalence Case-control studies Risk Indicators (rare diseases) Cohort studies Incidence

  13. Definitions Prevalence Incidence Sensitivity Specificity Positive predictive value Negative predictive value

  14. Prevalence Proportion of persons in a population who have the disease at a given point or period of time Prevalence = No of persons with disease No of persons in the population

  15. Incidence Average percentage of unaffected persons who will develop the disease of interest during a given period of time Incidence = No of new cases No of persons at risk

  16. Incidence of periodontal diseases in a strict sense is almost impossible at the present level of knowledge.

  17. Sensitivity Proportion of subjects with the disease who test positive Sensitivity = No of subjects who test positive No of subjects with disease

  18. Specificity Proportion of subjects without the disease who test negative Specificity = No of subjects who test negative No of subjects without disease Sensitivity and specificity are useful in choosing the test

  19. Predictive Value Once the result of a test is ready: what are the chances that it is right or wrong? Predictive value

  20. 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 a negative test does not have the disease

  21. True Disease Status Test Result Disease No Disease Positive A B True +ve C False -ve A/(A+C) False +ve D True -ve Negative Sensitivity Specificity B/(B+D) Positive predictive value A/(A+B) Negative predictive value D/(C+D)

  22. Periodontal Indices Techniques employed in periodontal epidemiology to quantitate clinical conditions 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

  23. Ideal Index Simple & quick to use Accurate Reproducible Quantitative

  24. Indices Gingival health/bleeding Plaque Calculus Attachment loss Radiographic bone loss Treatment needs

  25. Periodontal Indices Indices measuring the degree of gingival inflammation Example: Gingival index (GI; L e & Silness; 1967) Modified Gingival Index (Lobene et al, 1986)

  26. Periodontal Indices Indices used to measure periodontal destruction Example: Periodontal Index (PI, Russel; 1956) Periodontal Disease Index ( Ramfjord, 1959)

  27. Periodontal Indices Indices used to measure plaque accumulation Example: Plaque Index (Silness & L e, 1964)

  28. Periodontal Indices Indices used to measure calculus Example: Calculus component of the PDI

  29. Periodontal Indices Indices used to assess treatment needs Example: Community Periodontal Index Of Treatment Needs (CPITN) Ainamo et al, 1977

  30. Prevalence of Periodontal Diseases National Health & Nutrition Examination Survey NHANES I (1971-1974) NHANES III (1988-1994) NIDR (1985-1986) Difficult to compare results

  31. 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

  32. Gingivitis At the population level Found in early childhood Prevalence & severity in adolescence Prevalence of gingivitis in USA among population aged 13 and older= 54%

  33. Gingival Bleeding NHANES III Highest among 13-17 yr old (63%) Declined through 35- to 44-yr-old group Increased in 45- to 54- yr old group

  34. Gingivitis In Adults First national survey in US (1962): 85% of men & 79% of women had gingivitis ??Gingivitis has declined in developed countries??

  35. 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%

  36. Prevalence of Aggressive Periodontitis Differs with populations In the US: 0.13%, 0.53% and 1% prevalence has been reported

  37. Confusion Confusion in interpreting data from older studies, due to differences in measurement Severity of periodontitis according to AAP CAL (PAL; LPA)

  38. Incidence of Periodontitis Longitudinal study of periodontitis on 480 tea workers in Sri Lanka (L e et al 1986) Revealed natural history of disease Parallel Study in Norway

  39. 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

  40. RISK

  41. Bacteria Colonisation Invasion Destruction Host Environmental Smoking Susceptibility Genetic Acquired Periodontal Diseases

  42. Aetiology Risk Factors Susceptibility factors Severity factors

  43. Risk Identified in terms of: Risk Factors Risk Indicators Risk predictors (Pihlstrom, 2001)

  44. Risk factors Identified through Longitudnal studies Examples 1. Tobacco Smoking 2. Diabetes 3. Pathogenic Bacteria 4. Microbial tooth deposits

  45. Risk Determinants Also called Background Characteristics Cannot be modified Examples 1. Genetic factors 2. Age 3. Gender 4. Socioeconomic status 5. Stress

  46. Risk Indicators Are probable risk factors that have been identified in Crossectional studies but not in longitudnal studies Examples 1. HIV/AIDS 2. Osteoporosis 3. Infrequent dental visits

  47. Risk markers/ Predictors Are associated with increased risk for disease but do not cause disease Identified in Crosssectional and longitudnal studies Examples 1. Previous history of Periodontal disease 2. Bleeding on probing

  48. Gender & Race Men have poorer periodontal health than women, in terms of LPA, pockets and subgingival calculus Women have better oral hygiene No established differences in susceptibility to chronic periodontitis

  49. Gender Aggressive Periodontitis Studies on Europeans show higher prevalence of aggressive periodontitis in FEMALES > MALES Studies on Africans or African Americans: MALES > FEMALES Gender is related to race (risk factors)

  50. Age Cross-sectional studies: Greater prevalence & severity of CALwith age Does not mean greater susceptibility Cumulative progression of lesions over time Sri Lankan study: 3 groups Increased CAL with age (cumulative effect) Increased susceptibility

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