The document discusses dental caries, emphasizing the role of Streptococcus mutans in the demineralization process of tooth tissues. It outlines the stages of caries progression from white spots to pulp involvement, as well as the factors influencing caries development, including microbial presence and dietary sugars. Additionally, it highlights the importance of saliva in dental health, serving protective functions against caries.

1. *Definition:
Caries calcified tissues of the teeth are modified and dissolved. By mainly Streptococcus
mutans .
*Dental caries stages
*Demineralization And Remineralization
reach the •
tooth's pulp.
reaches into the •
dentin, where it
can spread and
undermine the
enamel.
•Enamel starts to
break down.
(Irreversible
lesion).
demineralization •
of enamel layer
by microbial
acids.
(Reversible
lesion)
1st stage
(white spots)
2nd stage
(Enamel
decay)
4th stage
(Pulp
involvement)
3rd stage
(Dentin
decay)
Caries sites
Pit-and-fissure caries Smooth-surface caries . Root caries

2. *Main Factors Involved In Dental Caries
Teeth: the microbe challenges a susceptible
surface on some areas of the tooth to attack
than other that related to many factor
position and morphology of teeth.
Microorganism : S mutans considered the
caries initiator
Diet : most cariogenic sugar is sucrose
Acidogenic bacteria
•S viridance as S
mutans.
•Lactobacillus sp.
Proteolytic bacteria
•Actinomyces sp.
•Colistridia sp.
•Pseudomonas sp.
Chromogenic
bacteria
•Asprigillus sp.
Ability to adhere
to the tooth
surface
)colonization).
Production of
glucans and other
polysaccharides to
plaque
accumulation.
Production of
acids to
Production of
acids
Tolerate the
low pH values.

3.  Adherence factors (adhesins as pili).
 Invasive factors e.g TB as the organism produces disease by invasion
of tissues.
 Ability to survive intracellularly as Neisseria sp.
 Toxic production as Dephtheria, the organism multiplies locally in
the throat but releases strong toxin diffuses to the blood.
_______________________________________________________
Important
bacteria in caries
Streptococcus
mutans.
Lactobacilli sp
Actinomyces sp.
____________________________________________________
Initial attachment
to tooth surfaces
Virulence
factors of
S mutans
Acid tolerance
Acid production
Polysaccharide
production
(1) Extrusion of H+
(2) Malolactic
fermentation
(3) Alternation of cell
(4) Production of
ammonia
 energy source
 plaque accumulation.
 metabolize a variety
of sugars,resulting in
the production of a
number of weak
acids.
 Initiators of smooth
surface caries.
There is an outer fibrillar
layer its function include :
-Attachment to salivary
pellicle.
-Adhere to colonizing
streptococci.

4. • The role of saliva in caries
Formation of
acquired enamel
pellicle.
The role of
saliva in caries
Washing effect of saliva.
Antibacterial substances.
Salivary antibodies. Buffering effect of saliva.
DONE BE :
Ghadeer Hassan