Theories &Diagnosis of Dental

caries

Lecture ( 5 )

Dr.Baha, H. AL-Amiedi

Ph.D.Microbiology

NORMAL TOOTH

Dental Caries: Dential caries can be thought of chronic

of enamal or dentine in which microbial

agents cause lesion result from the

demineralization of enamel or dentine by

acid produce by plaque microoganisms as

they metabolize dietary carbohydrate

Once the surface layer enamel has been

lost progress via dentine & with in the

pIup becoming firstly inflamed & later

necrotic.

Classification of Dental caries:

Dental caries can be classified with

respect to the site of the lesion and

diagrammatically in of lesion as

1- Bit and fissuer

2- Smooth Surface

3- Root surface

4- Recureent caries

Bacterial associated with caries type

caries type microorganisms isolate

pit and fissure S . mutans , S.sanguis

S .mitis, lactobacilli

Actinomyces

Smooth surface S. mutans

Recurrent caries lactobacilli

S. mutans

A. naeslundii

Filumentous Rods

A viscosus

Root caries A. viscosus .

A naeslundii,

A salivarius

S mutans, S sanguis

Filamentous Rods

Dental Caries

Demineralization of the tooth surface caused by

bacteria

Aetiological factors in dental caries

Major Factor involved in dental caries

1- Dental plaque( Microorganism).

2-Saliva.

3-Diet

4-Time

Minor factor involved in dental caries:

1-Morphology of the tooth.

2-position of the tooth .

3- Enemal composition

4-Immunity.

Theories of etiology of caries :

1-Early Theories :

A-Worms tooth aches caries caused by worm

B-Humors : unbalance between the humors :

( blood , black bile , yellow bile )

2-Vital Theory : origination of dental caries

with in tooth it self extensive penetration

into the dentin & into pulp

3-Chemical Theory : chemical agents

responsible for caries

4-Parasitic or septic Theory : filmentous

microorganisms caused decomposition of

the enamel and the dentin

5-Chemo - parasitic Theory (Miller 1890) : caries is

caused by acids produced by oral cavity

microorganisms of the mouth miller 1890

concluded that the process was mediated by

microorganisms produced acids and digestion

proteins .

6-Proteolytic Theory(Gottlib 1944) : it has been

proposed that the organic matrix or protein

elements of enamel are the initial pathway of

invasion by oral cavity microorganisms

7-Proteolysis – chelation Theory : this theory

considers dental caries to be bacterial destruction

of teeth where the initial attack essentially on

organic component of enamel and the end

products of proteolysis acts as a chelating- agent.

Bacterial caries susceptibility test(synder test):

Many attepts have been made to develop sutable

diagnosis test for the determination of caries

susceptibility of an individual. most of these tests

have been based on differences in type of bacteria

present in the microflora of caries & whether these

microflora of caries are capable of producing acid

when incubated with sugar, usually glucose.

There have been number of modifications of this

test in 1965 Grainger introduced a swab for the

buccal surface of teeth, the placing in semifluid

synder type medium& incubating at 37 C for 96 hr

Test reading by color comparison to standard test.

Reading of synder modification test Diffusion acid

color change to from yellow top down one fourth

or less of tube, from top down +

color change to yellow, one half of tube ++

from top down

color change to yellow, three fourths of +++

tube , from top down

color change to yellow, entire tube ++++

No color change _

Interactions among dental caries bacteria

The current approach to diagnose

The current approach to diagnose

dental caries

1-Naked eyes

2-Mechanical probing

3-X-ray

X-ray

“Gross” Visual

Examination

Mechanical Probing and X-ray

The current approach to treat

dental caries

Surgical repair

Fluoride treatment

Mechanical removal

The end