Dental info

2. Dental caries, classification and etiology
and theories of Dental Caries

3. CONTENTS
Introduction
Definition
Historical background and early
theories of caries etiology
Etiology
Histopathogenesis
Caries Activity
Caries Prediction
Caries Susceptibility tests
Conclusion
Bibliography

5. Introduction
THE ORAL
ENVIRONME
NT
The oral
cavity
Saliva
Micro-
organisms
in saliva
Microbial
deposits/
dental
plaque
Dental
caries

6. Introduction
THE ORAL
ENVIRONME
NT
The oral
cavity
Saliva
Micro-
organisms
in saliva
Microbial
deposits/
dental
plaque
Dental
caries
Entity
Several major and
minor compartments
Microenvironment
Proteinaceous film…
Composition of saliva from
the various glands differs
Various secretions mix in
the oral cavity to form
whole saliva or the “oral
fluids” + tissue fluid
1ml of whole saliva
– more than 200
million organisms –
more than 250
different bacterial
species.
All surfaces –
microbial
colonization, pattern
depends partly on
the surface
properties of the
mucous membrane/
tooth surfaces.
Dynamic process taking
place in the microbial
deposits (dental plaque
on the tooth surfaces)
which results in a
disturbance of the
equilibrium between
tooth substance and the
surrounding plaque
fluid so that, over time,
the net result is a loss
of mineral from the
tooth surface.

7. Definition
According to Shafer, Hine & Levy: It is
defined as a progressive, irreversible
microbial disease of multifactorial
nature affecting the calcified tissues of
the teeth, characterized by
demineralization of the inorganic
portion and destruction of the organic
portion of the tooth.

8. Historical background

12. Early theories –
legend of the worms
According to
ancient
Sumerian text,
5000 BC.
Toothache was caused by a
worm that drank the blood of
the teeth and fed on the roots
of the jaws.
Discovered on a
clay tablet,
excavated from
an ancient city
within the
Euphrates
valley.

13. Early theories –
legend of the worms
The idea that caries is caused by a worm
was almost universal at one time –
evidenced by writings of Homer and
popular lore of China, India, Finland and
Scotland.

14. Early theories –
legend of the worms
Guy de Cahuliac (1300-1368)
Believed that worms caused dental decay.
As a cure advocated fumigation with seeds of
leeks, onion and hyoscyamus.
Hyoscyamine – alkaloid obtained from henbane,
used as a hypnotic, sedative and smooth muscle
relaxant.
Fumigation was used by
Chinese, Egyptians in earlier
times, England in late 19th
century.

15. Early theories –
legend of the worms
The Ebers Papyrus, an
Egyptian text from 1550 BC,
mentions diseases of teeth.
Chinese (2700 BC)- treatment
for dental tissues – acupuncture
– insertion of metal needles into
selected points in the body.

17. Endogenous theory –
Humoral theory
person’s physical and mental constitution was
determined by the relative proportions of the four
elemental fluids of the body- blood, phlegm, black
bile and yellow bile
which corresponds to the four humors- sanguine,
phlegmatic, melancholic and choleric.

18. Endogenous theory –
Humoral theory
Courageous,
hopeful,
amorous
Easily
angered,
bad
tempered
Despondent
, sleepless,
irritable
Calm,
unemotional
Blood -
sanguine
Yellow
bile –
choleric
Black bile
-
melancholi
c
Phlegm –
phlegmati
c

19. Endogenous theory –
Humoral theory
All diseases,
including caries,
could be explained
by an imbalance of
these humors.
According to Galen,
‘dental caries is
produced by internal
action of acrid and
corroding humors’
“The cure must
consist in acting upon
such viscous humors
by means of local or
general medicaments
according to
circumstances and
also in strengthening
the substance itself
of the teeth by the
use of astringents
and tonic remedies”

20. Endogenous theory –
Humoral theory
Aristotle, Referred to
elements of the Greek
diet, such as figs, which
adhered to teeth and thus
contributed to decay.
Hippocrates, drew
attention to the
stagnation of food
and suggested that
both local and
systemic factors
were related to the
cause of caries.

21. Endogenous theory –
Vital theory
Dental caries – o
Clinically, well-known type of caries is
characterized by extensive penetration into the
dentin and even into the pulp, but with a barely
detectable catch in the fissure.
It is not so surprising, therefore attracted many
supporters.
riginating within the tooth itself, analogous to
bone gangrene.

23. Robertson (1835) and Regnart (1938) – showed
the effects of inorganic acids (nitric and sulfuric
acid) formed by fermentation of food particles
that caused dental decay.
Since the fermentation at this time considered
to be strictly non-vital process, the possibility
that micro-organisms were involved was not, as
yet, recognized.
Exogenous theory –
Chemical theory
Parmly
(1819) -
rebelled
Proposed – an unidentified “chymal
agent” was responsible for caries.
Stated – caries began on the
enamel surface in locations where
food putrified and acquired
sufficient dissolving power to
produce the disease chemically.

24. Parasitic or Septic
theory
Long before the demonstration of the germ
theory of disease, the possibility that
microorganisms can have toxic and destructive
effects on tissue was postulated (Dubous, 1954)
These postulations spelled the end of the vital
theory and gave rise to the idea that chemicals
can destroy teeth.

25. Parasitic or Septic
theory
Early microscope observations of scrapings from
teeth and of the carious lesions
Antoni van Leeuwenhoek (1632-1723)
maker of first powerful microscope
indicated that microorganisms were associated with
the carious process.

26. Parasitic or Septic
theory
Erdl (1843) described filamentous parasites in the
membrane removed from the teeth.
Ficinus (1847) also observed filamentous organisms
in the enamel cuticle (surface protein membrane of
teeth) and in carious lesions.

27. Parasitic or Septic
theory
Ficinus coined “Denticolae”
- filamentous micro organisms taken from
carious cavities.
- He implied that these bacteria caused
decomposition of the enamel and dentin.
An explanation of the mechanism by which
microorganisms caused decay was not
attempted until later.

28. A synthesis of ideas that acid and
microorganisms were involved in the
etiology of dental caries did not occur
until 1889
When Miller ( an American working in the
university of Berlin) published a text
entitled ‘Die Mikroorganismen der
Mundhohle’ (1890)
Chemico parasitic
theory

29. W. D. Miller
Student of Koch
Extensive studies
(oral micro-flora and relationship to
caries)
Influenced Koch and other scientists
From Koch – learned to isolate, stain
and identify bacteria.
Chemico parasitic
theory

30. This enabled Miller to assign
to oral microorganism,
the role of acid formation.
And thus assign a chemical role to flora
which is the basis of his chemico-
parasitic theory of dental caries.
Chemico parasitic
theory At this time, Pasteur had
discovered that the process
of conversion of sucrose to
lactic acid is mediated by
microorganism.

31. The microorganisms of mouth, by secretion of
enzymes or by their own metabolism, degrade the
fermentable carbohydrate food material so as to
form acids.
acid demineralizes the lime salts of the tooth.
Chemico parasitic
theory

32. The enamel is destroyed by the acid of
fermentation and the disintegrated
enamel is subsequently mechanically
removed by forces of mastication.
After penetration of the enamel, the
dissolution of dentin...
Chemico parasitic
theory

33. The final breakdown of dentin results
from the secretion of proteolytic
enzymes that digest the organic part of
dentin and form a cavity.
Chemico parasitic
theory

34. Is that he assigned an essential role to three factors in
the caries process:
• Oral microorganisms in acid production and in
proteolysis.
• Carbohydrate substrate which microorganisms
fermented.
• Acid which causes dissolution of tooth minerals.
Chemico parasitic
theory

35. Miller’s final
No single species of microorganism caused
caries but rather that the process was mediated
by multiple oral microorganisms capable of
producing acid and degrading protiens
Chemico parasitic
theory

36. Dental decay is a chemo-parasitic process
consisting of two stages:
decalcification or softening of the
tissues
dissolution of the softened residue.
Chemico parasitic
theory

37. Underwood & Miles (1881)
–
Micrococci, oval and rod-
shaped bacteria in histological
sections of carious dentin.
Chemico parasitic
theory

38. Caries to be absolutely dependent on
the presence and proliferation of
organisms;
That these organisms attack first the
organic material and feeding upon it,
create an acid which removed the lime salt;
That the only difference between
the caries and decalcification by acids
is due to the presence and operation
of germs’.
Chemico parasitic
theory

39. Emil Magitot (1867) –
Fermentation of sugars caused dissolution
of tooth mineral in vitro.
He opposed vital theory on the basis that caries
occurred in natural teeth when used in artificial
dentures.
Leber & Rottenstein (1867) –
Acids and bacteria are the causative agents
of caries.
Chemico parasitic
theory

40. Millers chemico-parasitic theory is the
back bone of current knowledge and
understanding of the etiology of dental
caries.
The criticism that follows is in the
light of present knowledge and should
not be interpreted as demerit points of
the Miller’s brilliant observations.
Chemico parasitic
theory

41. 1. Was unable to explain the predilection of
specific sites on a tooth to dental caries.
2. Initiation of caries on smooth surfaces was not
accounted for by his theory.
3. Millers theory did not explain why some
population are caries free.
Chemico parasitic
theory

42. 4. The phenomenon of arrested caries is not explained.
5. Miller believed that in some systemic conditions the
inorganic salts within a tooth could be withdrawn and that
the organic-inorganic bonds would be weakened. He did
not produce any experimental evidence that the adult
tooth is subject to such systemic influences.
Chemico parasitic
theory

43. The surface coverings found on the tooth, in grooves
and pits, are organic in nature; also, enamel contains
small but significant amounts of organic material.
These observations and the fact that carious lesions
are characterized histologically by pigmentation, a
phenomenon that was interpreted, without evidence,
as being indicative of proteolysis, led to the
development of this theory.
Exogenous theory –
Proteolytic theory

44. Classical chemo-parasitic theory has not been
universally accepted.
Instead it has been proposed that organic or
protein elements are initial pathway of invasion by
micro-organisms.
Exogenous theory –
Proteolytic theory

45. According to theory – organic component is
most vulnerable & is attacked by hydrolytic
enzymes of micro-organisms.
This precedes the loss of inorganic phase.
Exogenous theory –
Proteolytic theory

46. Gottlieb (1944) :
Initial action was due to proteolytic enzymes
attacking lamellae, rod sheaths, tufts & walls
of dentinal tubules :
Staphylococcus aureus was involved because of
yellow pigmentation that he considered
pathognomonic of dental caries.
Exogenous theory –
Proteolytic theory

47. Said acids alone produces chalky enamel
but not caries.
There no bacteriological confirmation of
his proposed link between micro-
organism & caries
Exogenous theory –
Proteolytic theory

48. A chelate results from
Inorganic metal ion
Two electron rich
functional groups in a
single organic molecule
+
The Greek word ‘Chele’ meaning claw, and refers
to compounds that are able to bind metallic ions as
calcium, iron, copper, zinc and other metals by
secondary valence bonds.
Proteolysis-Chelation
theory

49. Schatz et al [1955] – simultaneous microbial
degradation of the organic components
(proteolysis) and the dissolution of the minerals
of the tooth (chelation)
According to this theory, dental caries results
from an initial bacterial and enzymatic
proteolytic action on the organic matter of
enamel without preliminary demineralization.
Proteolysis-Chelation
theory
While proteolysis-chelation is an
important biological phenomenon, its
primary role in the etiology of dental
caries has not been corroborated.

50. Such action, produces an initial caries lesion
and the release of a variety of complexing
agents, such as amino acids, polyphosphates
and organic acids.
The complexing agents then dissolve the
crystalline apatite.
Proteolysis-Chelation
theory

51. Less than 1% of mature enamel is organic in
nature…
Also, there is no substantial experimental evidence
that the initial caries lesion stems from a
breakdown of organic matter, i.e. due to proteolytic
action.
Proteolysis-Chelation
theory

52. Pincus (1950): bacterial sulfatase
hydrolyzes the...
mucoitin sulfate – enamel
chondroitin sulfate – dentin
produces – sulfuric acid, causes
decalcification – dental tissues.
But, concentration of sulfated
polysaccharides in enamel is very small and
not readily accessible as a substrate for
enzymatic degradation....
Other theories –
Sulfatase theory

53. Lura, 1967: high bacterial utilization of
phosphate in plaque causes a local
disturbance in the phosphate
equilibrium...
Other theories - Complexing
& phosphorylating theory:
But, saliva- an abundant source of
inorganic phosphate for bacterial
utilization.
Hence it is highly improbable that
depletion of phosphate in plaque
by oral microbial metabolism
results in phosphate withdrawal
from enamel.