EPIDEMIOLOGY OF DENTAL

CARIESPRESENTED BY :-Dr SAKSHI KAUR CHHABRA2ND YEAR POST GRADUATEDEPARTMENT OF PUBLIC HEALTH DENTISTRY

DENTAL CARIESAccording 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.

EPIDEMIOLOGY Epidemiology has been defined by John

M. last in 1988 as:-

‘The study of the distribution and

determinants of health-related states or

events in specified populations and the

application of this study to the control of

health problems.’

THEORIES OF CARIES ETIOLOGY

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

[A] EARLY THEORIES OF CARIES

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.

[B] ENDOGENOUS THEORIES

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.

[C] EXOGENOUS THEORIES

[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

[D] OTHER THEORIES

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.

ETIOLOGIC FACTORS IN DENTAL CARIES

EPIDEMIOLOGICAL TRIAD

• HOST FACTOR• AGENT FACTOR• ENVIRONMENTAL

FACTOR

Dental caries is a multifactorial disease in which there is an interaction between 3 principle factors :-

[A] HOST FACTORSTOOTHSALIVA

SEX RACEAGE

FAMILY HEREDITYDEVELOPMENTAL DISTURBANCES

ECONOMIC STATUSCONCOMITANT DISEASE

ORAL HYGIENE HABITS

a. TOOTH 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.

b. SALIVAIt 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.

c. SEXMost of the studies have shown that dental caries is more common in girls than boys.

d. RACEDental caries is more common in whites compared to the blacks.

e. AGE Pit and fissure caries is more commonly seen in young age. Root caries is seen in old age (gingival recession).

f. DEVELOPMENTAL DISTURBANCES

The presence of deep pits and fissures, enamel hypoplasia and enamel defects make the tooth more prone to caries.

g. Socio-Economic status

In young primary school children dental caries decreases with

increase in Income. In adults, when income decreases there is decrease in dental caries.

h. CONCOMITANT DISEASE

Dental caries is found to be less in controlled diabetes.

i. ORAL HYGIENE STATUS

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

[B] AGENT FACTORSIt 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.

[C] ENVIRONMENTAL FACTOR[1] DIET and NUTRITION

[2] GEOGRAPHIC VARIATIONS

[3] SOIL

[4] URBANIZATION

[5] CLIMATE

[1] DIET AND NUTRITIONDEFINITIO

NSDiet 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.

Some dietary studies are :-[A] VIPEHOLM STUDY

[B] HOPEWOOD HOUSE STUDY

[C] TURKU SUGAR STUDY

[D] HEREDITARY FRUCTOSE

INTOLERANCE (HFI)

[E] TRISTAN DA CUNHA STUDY

[2] GEOGRAPHIC VARIATIONS

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

[3] SOIL

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

[4] URBANIZATION

Dental caries is said to increase with urbanization.

[5] CLIMATE

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