2. Exogenous Theories
> Legend of worm
>Chemical Theory
>Parasitic or Septic
Theory
Early Theories
Endogenous Theories
> Humoral theory
> Vital theory
3. Early
Theories
The worm theory
They believed tooth worm bore a hole through your
teeth and hid beneath the surface; drank blood of teeth
and fed on roots of jaws.
Dates back as far as 5000 BC referenced in a
Sumerian text
4. Old Theories
Chemical theory (acid theory)
Robertson 1835- opined that caries was caused by
chemical disintegration of the tooth
It was believed that putrefaction of protein led to
formation of ammonia which was subsequently
oxidized to nitric acid
Exogenous
Early
Theories
5. Old Theories
Parasitic or Septic Theory
Erdl and Ficinus 1843- filamentous microorganisms
caused decomposition of the teeth
Ficinus recognized the first organic matrix in enamel
Exogenous
Early
Theories
6. Endogenous
Old Theories
Imbalance in this 4 humors determines the person’s
physical and mental constitution
The four elemental fluid (humors) of the body- blood,
phlegm, black bile, yellow bile
Humoral Theory
Early
Theories
7. Endogenous
Old Theories
Proposed by Hippocrates, Celsus, Galen and Auicenna.
18th century.
Vital Theory
Postulated that tooth decay originated like bone gangrene
from within the tooth itself.
Early
Theories
8. New Theories
Chemico-Parasitic Theory
(Miller 1890)
Consists of 2 stages:
1- decalcification of enamel, destruction of dentin
(preliminary stage)
2- dissolution of the softened residue of enamel
& dentin (subsequent stage)
The theory said that caries is caused by
acids produced by oral bacteria following
fermentation of sugar
9. New Theories
Heider and Bodecker 1878 and Abbot in 1879
Proteolytic Theory
Said that organic portion of the tooth serves as pathways for
advancing microorganisms causing demineralization of the
teeth and therefore dental caries.
10. New Theories
Proteolytic Theory
Gottlieb in 1944
Suggested that the initial lesion of the carious process is due
to the proteolytic enzymes attacking the lamellae, rod sheaths,
tufts and walls of tubules
Believed that the yellow pigmentation characteristic of caries
was produced by the proteolytic organism (Staphylococcus )
11. New Theories
Proteolytic Theory
Pincus in 1949
Proposed that the first step in the carious process is the
breakdown of dental cuticle.
Nasmyth’s membrane and enamel proteins are acted upon
by sulfatase enzyme producing sulfuric acid. This acid plus
the calcium of hydroxyapatite crystals destroys the
inorganic component of enamel
12. New Theories
Proteolysis- Chelation Theory
Schatz 1955
This theory state that dental caries is a bacterial destruction
of organic components of enamel and the breakdown
products of this components have chelating properties
dissolving the minerals in enamel
There is simultaneous microbial degradation of organic
component by proteolysis and dissolution of inorganic part
by chelation
