Epidemiology of dental caries

According to SHAFER, It is defined as
the irreversible ‘microbial’ disease of
the calcified tissues of the teeth,
characterized by the demineralization
of the inorganic portion and
destruction of the organic substances
of the tooth.

 There is no universally accepted opinion of
the etiology of dental caries.
[A] EARLY THEORIES OF CARIES FORMATION
[B] ENDOGENOUS THEORIES
[C] EXOGENOUS THEORIES
[D] OTHER THEORIES

 THE LEGEND OF THE WORM
The earliest reference to tooth decay and toothache came
from the ancient Sumerian text known as ‘The Legend of
the Worm’.
It was obtained from the Mesopotamian areas which dates to
about 5000 BC.
This theory is supported in the ancient literature of INDIA,
CHINA, FINLAND, SCOTLAND and the writing of humor.

1. HUMORAL
THEORY
 The four humors of the body were blood, phlegm, black bile and yellow bile.
 According to the Galen, the ancient Greek physician and philosopher, ‘dental caries is
produced by internal action of acrid and corroding humors.
 According to the Hippocrates, the father of medicine, also referred to the accumulated
debris around teeth and their corroding action. He also stated that stagnation of juices
in the teeth was the cause of toothache.

2. VITAL
THEORY
Proposed during the 18th century.
According to this theory, it is postulated that tooth decay
originated like bone gangrene, from within the tooth itself.

 [A] CHEMICAL (ACID)THEORY
 In the 17th and 18th century, there emerged the concept that teeth were destroyed by
acids formed in the oral cavity by fermentation of food particles around teeth.
 On the basis of findings of Robertson, this theory proposed that tooth decay was caused
by the fermentation of food particles around the teeth.

[B] PARASITIC (SEPTIC)
THEORY
 Earlier Antoni Van Leeuwenhock (1632-1723) stated that the micro-organisms were
associated with the carious process.
 In 1954, Dubos postulated that micro-organisms can have toxic effects on tissue.

[C] Miller’s Chemicoparasitic (ACIDOGENIC) THEORY
 This theory was proposed by W.D. Miller in 1890.
 The micro-organisms found in the oral cavity
produced
enzymes
demineralization (enamel) that act upon the
fermentable carbohydrates
to produce acids like
Enamel of the tooth lactic acid, butyric acid, formic and succinic acid.
These acids acts upon the
DENTAL CARIES

[D] PROTEOLYTIC
THEORY
 This theory was proposed by Gottileb in 1934.
 According to this theory, the organic matrix would be attacked before the mineral
phase of the enamel.
 Oral bacteria liberate Proteolytic enzymes destroy organic matrix of enamel
whole structure collapse Loosening apatite crystals

[E] PROTEOLYSIS -
CHELATION THEORY
 This theory was originated by Schatz and Martin in 1955.
 This theory suggested that demineralization of the enamel could arise without acid
formation.

PROTEOLYTIC BREAKDOWN OF THE ORGANIC
PORTION OF THE ENAMEL MATRIX TAKES
PLACE
CHELATING AGENT IS FORMED BY THE
COMBINATION OF PROTEOLYTIC
BREAKDOWN PRODUCTS, ACQUIRED PELLICLE
AND FOOD DEBRIS.
TOOTH DECAY

AUTO – IMMUNE THEORY
 This theory was given by Burch and Jackson (1966).
 This theory analyzed caries epidemiological data and suggested that genes, partly
inherited and partly mutational, determine whether a site on a tooth is at risk.

• HOST FACTOR
• AGENT FACTOR
• ENVIRONMENTAL
FACTOR
Dental caries is a
multifactorial disease
in which there is an
interaction between 3
principle factors :-

 Morphological characterstics of tooth have been suggested as
influencing the initiation of caries.
 Presence of deep and narrow occlusal fissures or deep buccal and
lingual pits
which tend to trap food, bacteria and debris.
 Caries may develop in these areas.

It helps in removal of
bacteria and food debris
by its flushing action.
So when saliva is
swallowed, any bacteria
contained therein are
removed from the oral
cavity.
 A no. of different enzymes have been isolated from saliva. They
are derived from extrinsic and intrinsic sources.
 Urease is an enzyme derived from oral micro – organisms.

 pH of the saliva is determined by the bicarbonate concentration. The saliva pH
increases with flow rate. Saliva may be slightly acidic as it is secreted as
unstimulated flow rates but it may reach a pH of 7.8 at high flow rates.
 As it is exposed to the atmosphere, carbon dioxide will diffuse out & pH will rise,
often to 9 or more in saliva present as thin film.
 Other salivary components contributing to the ability of saliva to neutralize acid
are salivary phosphate, salivary proteins, ammonia, urea and statherin.

 Sialin is an arginine peptide which is pH rise factor present in saliva which rapidly
clears glucose from plaque, increases base formation and elevates pH in the plaque.
 The quantity of saliva secreted normally is 700-800 ml/day. The quantity of saliva
may influence caries incidence as is especially evident in cases of salivary gland
aplasia and xerostomia in which salivary flow may be entirely lacking, with rampant
dental caries the typical result.

Most of the studies have shown that dental
caries is more common in girls than boys.
Dental caries is more common in whites
compared to the blacks.

 Pit and fissure caries is more commonly seen in young age.
 Root caries is seen in old age (gingival recession).
The presence of deep pits and fissures, enamel hypoplasia and
enamel defects make the tooth more prone to caries.

 In young primary school children dental caries decreases with
increase in Income.
 In adults, when income decreases there is decrease in dental caries.

Dental caries is found to be less in
controlled diabetes.

Dental caries is found to be
less among those who
maintain good oral
hygiene.

It consists of dental plaque forming streptococci (streptococcus mutans).
ROLE OF MICRO-ORGANISMS IN DENTAL
CARIES
• They are prerequisite for caries initiation.
• A single type of micro organism is capable of inducing caries.
• Acid production is prerequisite for caries.
• Streptococcus strains produce extracellular dextrans or levans.
• Organisms vary greatly in their capacity to induce dental
caries.

PROPERTIES OF CARIOGENIC PLAQUE IN
DENTAL CARIES:-
[1] The rate of sucrose consumption was higher.
[2]Synthesize more intracellular
polysaccharides.
[3] More lactic acid is formed.
[4]Twice as much as extracellular polysaccharide
is formed.
[5] Higher levels of Streptococcus mutans.
[6]Lower level of Streptococcus sangius and
Actinomyces.

[1] DIET and NUTRITION
[2] GEOGRAPHIC VARIATIONS
[3] SOIL
[4] URBANIZATION
[5] CLIMATE

DEFINITIONS
Diet is defined as the types and amounts of food
eaten daily by an individual.
Nutrition is defined as the sum of the processes
by which an individual takes in and utilizes
food.

[A] VIPEHOLM STUDY
[B] HOPEWOOD HOUSE
STUDY
[C] TURKU SUGAR
STUDY
[D] HEREDITARY
FRUCTOSE
INTOLERANCE (HFI)
[E] TRISTAN DA CUNHA
STUDY

DMFT is found to be
decreasing in developed
countries and increasing in
developing countries

SELENIUM is said to increase
dental caries whereas
MOLYBDENUM and
VANADIUM are said to
decrease dental caries.

Dental caries is said to
increase with urbanization.

Sunlight is said to decrease
caries whereas rainfall is
said to increase dental
caries.

Epidemiology of dental caries

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