1.11 Cariology

Teeth are covered by a salivary pellicle layer, consisting of __________, which facilitates the binding of the oral microbiota to the teeth and eventually the formation of dental or oral _______ (dental plaque).

proteins and glycoproteins
biofilm

The biofilm shuts off the surface enamel from the saliva and oral cavity, produces a protected ________ at the tooth surface.

microenvironment

The teeth are always covered by an ______ proteinaceous film; this is the salivary pellicle that starts to form on a cleaned tooth surface within ______

acellular
minutes

T or F: bacteria colonize directly on any hard surface in the oral cavity

false
bacteria cannot colonize directly on the surface, they colonize on the pellicle

How are bacteria able to bind to the pellicle?

Bacteria contain a recognition system on their surfaces that enables bacterial surface adhesins to bind to complementary molecules (receptors) in the pellicle.

Steps of biofilm formation

1. pellicle formation
2. attachment
3. co-adhesion, growth, and matrix formation
4. diversification
5. maturation

biofilms reach maturity by day ____.

7

Early colonizers of the plaque biofilm are:

gram positive bacteria
s. gordoni, s. sanguis, s. oralis

Late colonizers

attach to early colonizers (co-aggregation)
these bacteria tend to be gram-neg., pathogenic, and anaerobic
P. intermedia, T. denticola, P. gingivalis, F. nucleatum

Biofilm _____ is composed of bacterial polymers secreted in the external environment, including polysaccharides derived from sugar metabolism.

matrix

which 2 bacteria are believed to cause most caries

Streptococcus mutans and Lactobacilli sp.

Cariogenic bacteria
- Produce ______ as a metabolic byproduct
- prefer growing under ____ conditions
- Synthesize ____ and ____ from sucrose

acid (especially lactic acid)
acidic
intracellular and extracellular polysaccharides

T or F: if cariogenic bacteria are present in the oral flora, the patient will develop caries.

False
The known etiologic agents of dental caries are normal constituents of the oral flora. They can be found in health and in disease.

bacteria that erupt after tooth eruption

Pioneers: Streptococcus sanguinis, S.oralis, S. gordonii.
Mutans streptococci

Early colonization by _______ is a major risk factor for future caries experience.

mutans streptococci

A child should have their first dental visit within _____ or no later than _____. This is an important time for anticipatory guidance.

6 months of tooth eruption
12 months of age

Approximately ____ species of bacteria have been isolated in the mouth and an individual can have up to ____ species inhabiting their mouth.

700
200

T or F: the natural oral microflora has a symbiotic and mutualistic relationship with the host

true

Changes in the oral environment may cause a _____ shift in the microflora present. This leads to pathogenesis.

dysbiotic

the ecological caries hypothesis states that

carious lesions result from naturally occurring biological phenomenon that take place in the dental biofilm as a result of ecological disturbances to the biofilm community.

Carbohydrate rich diets increase ____ production by and _____ of pathogenic microbes. This also leads to faster _____ accumulation

acid
growth rate
plaque

Biofilm with a pH less than _____ is considered high risk.

4.5

Two theories for future prevention of cavities is a ____ and _______ therapy.

vaccine
bacterial replacement