Theories of dental caries.ppt

1. THEORIES OF DENTAL THEORIES OF DENTAL
CARIESCARIES
Rubab HaiderRubab Haider
Final year BDSFinal year BDS
FMH college of MED and DentistryFMH college of MED and Dentistry
Lahore.Lahore.

2. DENTAL CARIESDENTAL CARIES
--Progressive bacterial damage to --Progressive bacterial damage to
teeth exposed to saliva.teeth exposed to saliva.
--one of the most major causes of --one of the most major causes of
all diseases and major cause of all diseases and major cause of
tooth loss.tooth loss.
--ultimate effect-to breakdown --ultimate effect-to breakdown
enamel and dentin and open a enamel and dentin and open a
path for bacteria to reach pulp.path for bacteria to reach pulp.
Consequences-inflammation of pulp Consequences-inflammation of pulp
and periapical tissues.and periapical tissues.

3. AETIOLOGYAETIOLOGY
Four major factors involved in etiology:-Four major factors involved in etiology:-
Cariogenic bacteriaCariogenic bacteria
Bacterial plaqueBacterial plaque
Susceptible tooth surfaceSusceptible tooth surface
Fermentable bacterial substrate (sugar)Fermentable bacterial substrate (sugar)

5. THEORIES OF DENTAL THEORIES OF DENTAL
CARIESCARIES
Chemical (acid) theoryChemical (acid) theory
Parasitic (septic) theoryParasitic (septic) theory
The Acidogenic theoryThe Acidogenic theory
The Proteolytic theoryThe Proteolytic theory
Proteolysis chelation theoryProteolysis chelation theory

6. CHEMICAL (ACID) CHEMICAL (ACID)
THEORYTHEORY
In 17In 17
thth
and 18 and 18
thth
century,there emerged century,there emerged
a concept that teeth are destroyed by a concept that teeth are destroyed by
acids formed in the oral cavity by acids formed in the oral cavity by
fermentation of food particles around fermentation of food particles around
the teeth..the teeth..

7. PARASITIC (SEPTIC) PARASITIC (SEPTIC)
THEORYTHEORY
Microorganisms were associated with Microorganisms were associated with
the carious process...the carious process...

8. ACIDOGENIC THEORYACIDOGENIC THEORY
W.D Miller was the first well known scientist W.D Miller was the first well known scientist
and investigator of dental caries and and investigator of dental caries and
published his results in 1882.published his results in 1882.
According to him dental decay is a According to him dental decay is a
chemoparasitic processchemoparasitic process
It is a two stage process there is It is a two stage process there is
decalcification of the enamel which also decalcification of the enamel which also
results in the destruction of the dentin. in results in the destruction of the dentin. in
the second stage there is dissolution of the the second stage there is dissolution of the
softened residue of the enamel and dentin. softened residue of the enamel and dentin.

9. ACIDOGENIC THEORYACIDOGENIC THEORY
In the first stage there is destruction is In the first stage there is destruction is
done by the acid attack where as the done by the acid attack where as the
dissolution of the residue is carried by dissolution of the residue is carried by
the proteolytic action of the bacteria's the proteolytic action of the bacteria's
This whole process is supported by the This whole process is supported by the
presence of carbohydrates presence of carbohydrates
microorganisms and dental plaque microorganisms and dental plaque

10. PROTEOLYTIC PROTEOLYTIC
THEORYTHEORY

11. PROTEOLYTIC THEORYPROTEOLYTIC THEORY
The evidence given by the acidogenic The evidence given by the acidogenic
theory was considerable but it was not theory was considerable but it was not
conclusive, and alternative explanation conclusive, and alternative explanation
was given in the form of proteolytic was given in the form of proteolytic
theory.theory.
Workers like “Heider, Bodecker Workers like “Heider, Bodecker
(1878)and Abbott (1879) contributed (1878)and Abbott (1879) contributed
considerably to this theory considerably to this theory

12. PROTEOLYTIC THEORYPROTEOLYTIC THEORY
There has been evidence that the organic There has been evidence that the organic
portion of the tooth plays an important role portion of the tooth plays an important role
in the development of dental cariesin the development of dental caries
The are some enamel structure which are The are some enamel structure which are
made of the organic material such enamel made of the organic material such enamel
lamelle and enamel rodslamelle and enamel rods
These structure prove to be the path ways These structure prove to be the path ways
for the advancing microorganisms.for the advancing microorganisms.

13. PROTEOLYTIC THEORYPROTEOLYTIC THEORY
It has been established that enamel contains 0.56 It has been established that enamel contains 0.56
% of organic matter of which 0.18% is keratin and % of organic matter of which 0.18% is keratin and
0.17 % is a soluble protein 0.17 % is a soluble protein
Microorganisms produce proteolytic enzymes,which Microorganisms produce proteolytic enzymes,which
destroy the organic matrix of enamel,loosening the destroy the organic matrix of enamel,loosening the
apatite crystals….so they are eventually lost and apatite crystals….so they are eventually lost and
tissue collapses…tissue collapses…

14. PROTEOLYSIS PROTEOLYSIS
CHELATION CHELATION
THEORYTHEORY

15. PROTEOLYSIS PROTEOLYSIS
CHELATION THEORYCHELATION THEORY
Some of the minor flaws of the Some of the minor flaws of the
acidogenic and the proteolytic theory acidogenic and the proteolytic theory
were addressed in the proteolysis were addressed in the proteolysis
chelation theory.chelation theory.
This theory was put forward by Schatz This theory was put forward by Schatz
and his co-workers in 1955.and his co-workers in 1955.

16. PROTEOLYSIS PROTEOLYSIS
CHELATION THEORYCHELATION THEORY
CHELATIONCHELATION
It is a process in which there is It is a process in which there is
complexion of the metal ions to form complexion of the metal ions to form
complex substance through complex substance through
coordinate covalent bond which coordinate covalent bond which
results in:results in:
poorly dissociated /orpoorly dissociated /or
weakly ionized compoundweakly ionized compound

17. PROTEOLYSIS PROTEOLYSIS
CHELATION THEORYCHELATION THEORY
Example of chelation reaction:Example of chelation reaction:
Hemoglobin in which 4 pyrrole nuclei are linked to Hemoglobin in which 4 pyrrole nuclei are linked to
iron by a similar bondiron by a similar bond
Chelation is independent of the PH of the medium.Chelation is independent of the PH of the medium.
The bacterial attack on the surface of the enamel The bacterial attack on the surface of the enamel
results in the breakdown of the protein ,chiefly results in the breakdown of the protein ,chiefly
keratin and results in the formation of soluble keratin and results in the formation of soluble
chelates with calcium which decalcify enamel even chelates with calcium which decalcify enamel even
at neutral PH..at neutral PH..
Mucopolysaccarides may also act as secondary Mucopolysaccarides may also act as secondary
chelators.chelators.

18. Dental cariesDental caries
Its clinical correlationIts clinical correlation

19. TYPES OF DENTAL TYPES OF DENTAL
CARIESCARIES
Gv blanks classification of caries classGv blanks classification of caries class
I , II , III , IV , V and VII , II , III , IV , V and VI
Rampant caries Rampant caries
Recurrent cariesRecurrent caries
Arrested cariesArrested caries
Root or cemental cariesRoot or cemental caries
Baby bottle caries Baby bottle caries

20. Pits and fissure cariesPits and fissure caries

21. Proximal cariesProximal caries

22. Cervical cariesCervical caries

23. Rampant cariesRampant caries

24. Recurrent cariesRecurrent caries

25. Arrested cariesArrested caries

26. Root or cemental cariesRoot or cemental caries

27. Nursing bottle cariesNursing bottle caries

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