Epidemiology ppt

1. 1

2. EPIDEMIOLOGY OF DENTAL
CARIES
EPIDEMIOLOGY OF
DENTAL CARIES
2

3.  CARIES: Latin word meaning ‘ROT’ or ‘DECAY’.
 “KER”: Greek word meaning DEATH.
INTRODUCTION
3

4.  “Progressive, irreversible, microbial disease
affecting the hard parts of the tooth exposed
to the oral environment, resulting in
demineralization of inorganic constituents and
dissolution of the organic constituents,
thereby leading to a cavity formation”
Definition
4

5.  Epi - among
Demos - people
Logos - study
 “The study of the distribution and
determinants of health related states or
events in specified population and the
application of this study to the control of
health problems”
-John M. Last 1988
EPIDEMIOLOGY
5

6. EPIDEMIOLOGICAL TRIAD
6
TIME

7. HOST
 “MAN”
 The characteristics of a human being that
determine how he reacts to the agents in the
environment.
7

8.  “EXTERNAL CAUSE”
 Defined as a substance, living or non-living,
or a force, tangible or intangible, the
excessive presence or relative lack of which
may initiate or perpetuate a disease process.
AGENT
8

9.  All that which is external to the individual
human host, living and non-living, and with
which he is in constant interaction.
ENVIRONMENT
9

10.  C
C
HOST
 Tooth - size, morphology, composition, position
 Saliva - composition, pH, quantity, viscosity,
antibacterial properties
 Familial hereditary
 Age
 Sex
 Socioeconomic & Behavioural variables
 Emotional disturbances
 Nutrition & Diet
AGENT
 Plaque forming streptococci & suitable carbohydrates
Nutrition
ENVIRONMENT
Fluorides
Nutrition
Climate – sunshine, temperature, relative humidity
Annual Rainfall
War
Trace elements
D
E
N
T
A
L
C
A
R
I
E
S
10

11. HOST
11

12.  Various aspects of the resistance of tooth to
dental caries can be described.
Tooth size
Tooth morphology
Tooth composition
Tooth position
Tooth surface
Risk teeth
TOOTH
HOST
12

13.  TOOTH SIZE
 Larger teeth are considered to be more caries
susceptible.
prolonged eruption time
plaque accumulation
 hinder access - mechanical plaque control
TOOTH
HOST
13

14.  TOOTH MORPHOLOGY
deep, narrow occlusal fissures or buccal and
lingual pits.
trap food, bacteria and debris
An exposed CEJ - plaque retention -root caries
TOOTH
HOST
14

15.  TOOTH COMPOSITION
• Opacities - small areas of a tooth, they will not
influence caries resistance.
• Turners teeth are caries susceptible
tooth
HOST
15

16.  TOOTH SURFACES
• Depending on age & caries prevalence
1. PIT & FISSURE CARIES
2. PROXIMAL CARIES
3. CERVICAL CARIES
4. ROOT CARIES
TOOTH
HOST
16

17.  RISK TEETH

TOOTH
•Mandibular 1st & 2nd molars
•Maxillary 1st & 2nd molars
•Mandibular 2nd premolars, maxillary central &
lateral incisors
•Maxillary canines & mandibular 1st premolars
•Mandibular central & lateral incisors,
mandibular canines
HOST
17

18.  TOOTH POSITION
Malaligned, out of position, rotated or not
normally situated .
Difficult to cleanse - favor accumulation of
food & debris.
TOOTH
HOST
18

19.  COMPOSITION
 Lesser the Ca & P levels – more caries activity.
 More the F levels – lesser the caries activity.
SALIVA
Saliva
1% Solids
Proteins
Glycoproteins
Lipids
Glucose, Urea
Electrolytes:
Na, Ca, Cl, P
99% Water
HOST
19

20.  QUANTITY
SALIVA
Normal - 0.5 to 1.5 Litres / day.
A rate < 0.1 mL/min for
unstimulated saliva
A rate < 0.7 mL/min for
stimulated saliva
HYPOSALIVATION – increased
caries risk.
HOST
20

21.  SALIVA pH
SALIVA
pH
range
6.5 – 7.4
pH of saliva -
Bicarbonate
concentration
High saliva buffer
capacity [Hco3] -
Protect against
dental caries -
Reducing
demineralization.
HOST
21

22.  VISCOSITY
SALIVA
mucin
content
HOST
22

23.  ANTIBACTERIAL PROPERTIES
SALIVA
Saliva -enhance
some bacteria
survive & reduce
others.
Lactoferrin
Lacto peroxidase
Salivary agglutinin
Immunoglobulins
Lysozyme
Reduced
caries
risk
HOST
23

24.  Race or ethnic group - important factor.
 Chinese & Negro populations - lower caries
rates than white population.
ETHINICITY
HOST
24

25. • Education plays an important role.
• The link between social class & dental caries
have been demonstrated in many studies.
SOCIOECONOMIC &
BEHAVIORAL VARIABLES
HOST
25

26.  Relationship between parents social status &
children’s dental health – demonstrated.
 Higher caries prevalence -low socioeconomic
background.
 Reasons: feeding practices, lesser parental
involvement in hygiene practices & lesser
parental knowledge & fluoride regimens
educational level, parent’s income.
SOCIOECONOMIC &
BEHAVIORAL VARIABLES
HOST
26

27.  INCIDENCE
A. INCIDENCE IN YOUNGER AGE AND ADULTS
incidence of dental caries is maximum at ages
17-24 years.
B. INCIDENCE IN ELDERLY PEOPLE
recession - root caries incidence increases as
the age advances from 70-80 years.
AGE
HOST
27

28.  PREVALENCE
 Prevalence is high in 35-44 year olds.
 This is according to WHO national survey
data in 1997.
AGE
HOST
28

29.  Higher in females - due to early eruption of
teeth.
SEX
HOST
29

30. • Dental caries varies - family to family -
inheritance of a characteristic tooth structure.
• Resemblance between identical twins.
• Environmental factors (occlusion, salivary
flow or composition)-greater influence than
genetic factors.
FAMILIAL HEREDITY
HOST
30

31. • “TRANSITORY ANXIETY STATE”
• Salivary changes depends on changes in
mental health.
• Salivary pH is low - emotional stress.
• Emotional disturbances seen in systemic
diseases.
EMOTIONAL DISTURBANCES
HOST
31

32.  Individual selects foods from array available,
& metabolizes according his normal
physiology & state of health.
 People who used refined, fermentable
carbohydrates- Increased caries.
NUTRITION
HOST
32

33.  Under nutrition - hypoplasia -increases caries
susceptibility
 Deficiency of Vitamin D - enamel hypoplasia -
increased caries
 Under nutrition leads to:
- salivary gland atrophy,
- reduced salivary flow rate
-reduced buffering capacity
INCREASE CARIES SUSCEPTIBILITY
NUTRITION
HOST
33

34.  Evidence for a relationship between diet &
dental caries comes from different types of
study:
human observational studies
human intervention studies
animal experiments
plaque pH studies
enamel slab experiments
incubation studies
EFFECT OF DIET ON
DENTAL CARIES
HOST
34

35.  C
C
HOST
 Tooth - size, morphology, composition, position
 Saliva - composition, ph, quantity, viscosity,
antibacterial properties
 Familial hereditary
 Age
 Sex
 Socioeconomic & Behavioural variables
 Emotional disturbances
 Nutrition & Diet
AGENT
 Plaque forming streptococci & suitable carbohydrates
Nutrition
ENVIRONMENT
Fluorides
Nutrition
Climate – sunshine, temperature, relative humidity
Annual Rainfall
War
Trace elements
D
E
N
T
A
L
C
A
R
I
E
S
35

36. AGENT
36

37. PLAQUE
AGENT
37

38.  The mouth - diverse resident microbial flora.
 In longitudinal studies, strong correlation
between Streptococcus mutans -development
of caries on smooth surfaces.
 2nd genus –Lactobacillus.
MICROBIAL AGENTS
AGENT
38

39.  C
C
HOST
 Tooth - size, morphology, composition, position
 Saliva - composition, ph, quantity, viscosity,
antibacterial properties
 Familial hereditary
 Age
 Sex
 Socioeconomic & Behavioural variables
 Emotional disturbances
 Nutrition & Diet
AGENT
 Plaque forming streptococci & suitable carbohydrates
Nutrition
ENVIRONMENT
Fluorides
Nutrition
Climate – sunshine, temperature, relative humidity
Annual Rainfall
War
Trace elements
D
E
N
T
A
L
C
A
R
I
E
S
39

40. ENVIRONMENT
40

41.  1916 Mc Kay and GV. Black found fluorosed
teeth are more resistant to caries.
 Dean and coworkers found the correlation
between the levels F in water supply and
caries experience.
 Study -Grand Rapids -decrease in caries levels
after 9 years of fluoridation.
FLUORIDES
ENVIRONMENT
41

42.  SUNSHINE
 East et al compared dental caries with mean
annual sunshine – significant inverse relation.
CLIMATE
Decrease in
caries levels
Increase in
annual sunshine
ENVIRONMENT
42

43. TEMPERATURE
 Acts to vary the caloric requirements & water
intake of Human beings.
 Carbohydrates food is not only a quick, but a
relatively cheap, source of caloric energy. This
indicates a way in which this disease may be
related to temperature.
CLIMATE
ENVIRONMENT
43

44. RELATIVE HUMIDITY
 The data in Australian states- higher
correlation between caries & relative humidity
than between caries & any other climatic
factor.
CLIMATE
Relative
humidity
Dental
caries
ENVIRON
MENT
44

45. Rainfall leads to leaching of essential
minerals from the soil and blocks the
sunlight.
RAINFALL
ENVIRONMENT
45

46.  During war - drastic dietary change.
WAR
Sugar
availability-
2nd world
war
Reduction
caries
ENVIRONMENT
46

47.  Geographic, cultural, or educational factors -
influence food availability.
 Selection among array of foods/availability of
certain nutrients.
 Lack of plant food in Eskimos - seek animal
food- diet of protein & fat- less dental caries.
 Civilized transport facilities- introduction of
other foods- more dental caries.
NUTRITION
ENVIRONMENT
47

48.  Selenium- increases caries
 Molybdenum- reduces caries
TRACE ELEMENTS
ENVIRONMENT
48

49.  C
C
HOST
 Tooth - size, morphology, composition, position
 Saliva - composition, ph, quantity, viscosity,
antibacterial properties
 Familial hereditary
 Age
 Sex
 Socioeconomic & Behavioural variables
 Emotional disturbances
 Nutrition & Diet
AGENT
 Plaque forming streptococci & suitable carbohydrates
Nutrition
ENVIRONMENT
Fluorides
Nutrition
Climate – sunshine, temperature, relative humidity
Annual Rainfall
War
Trace elements
D
E
N
T
A
L
C
A
R
I
E
S
49

50. LEVELS OF PREVENTION FOR
DENTAL CARIES
7/16/2022 50

51. 7/16/2022 51

52. CONCLUSION
52
HOST
AGENT ENVIRONMENT

53. Dunning JM, Principles of Dental
Public Health, 4th edition, 1986,
Harvard university press, UK
Murray JJ, Nunn JH, Steele JG.
Prevention of oral disease 4th edition
2003, Oxford University Press
Nikiforuk G. Understanding Dental
caries. 1st edition. Basel: Karger
REFERENCES

54. Newbrun E. Cariology 3rd edition
1989 Quintessence Publishing
Company, Illinois
Overman PA. Biofilm: A New View of
Plaque Journal of Contemporary
Dental Practice, 2000; 1: 1-8.
National oral health survey and
fluoride mapping. Dental council of
REFERENCES