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CONTENT
DENTAL
CARIES:
It is an irreversible progressive disease of multifactorial nature
affecting the calcified tissues of the teeth characterized by
demineralization of inorganic portion
& destruction of organic portion of the tooth.
CARIES
ACTIVITY:
Caries activity is a measure of speed of
progression of a carious lesion.
CARIES
SUSCEPTIBILITY:
Refers to the inherent tendency of the host & the target tissue
, the tooth to be affected by the
carious process .
Caries
activity test facilitates:
1.Need & extent of personalized preventive measures.
2.Serves as an index of success of the therapeutic measures.
3.Motivates & monitors the effectiveness of education programs relating
to dietary & oral hygiene procedures.
4.Manages the progress of restorative procedures.
5.
Identify
high risk groups & individuals.
1.LACTOBACILLUS COLONY COUNT TEST:
Introduced by Hadley in 1933
Axn:
Estimates the no: of acidogenic
& aciduric bacteria in the patients saliva by counting the no: of colonies
appearing
Procedure
1. Saliva is
collected by having the subject chew paraffin before breakfast & then
collecting the saliva in a bottle
2. Specimen is
shaken to mix it
3. A 1:10
dilution is prepared by pipetting 1ml of saliva sample into a 9ml tube of
sterile saline solution
4. This is shaken
& a 1:100 dilution is made by pipetting 1ml of 1:10 dilution into another
9ml tube of sterile salt solution.
5. 0.4 ml of each
dilution is spread on the surface of an agar plate
No. of lactobacilli per ml saliva
|
Caries activity
|
0-1000
|
Little
|
1000-5000
|
Slight
|
5000-10000
|
Moderate
|
>10000
|
Marked
|
. CALORIMETRIC SNYDER TEST
It measures the ability of
salivary micro organisms to form organic acids from a carbohydrate medium. The
medium contains an indicator dye , Bromocresol green. This dye changes color from green to
yellow in the range of pH 5.4 to 3.8
Procedure
1. Saliva is
collected before breakfast by having the subject chew paraffin
2. A tube of
snyder glucose agar is melted & then cooled to 50 deg C
3. The saliva
specimen is shaken vigorously for 3 min
& 0.2 ml of saliva is pipetted into the tube & incubated at 37
deg C
4. The color
change of the indicator is observed after 24, 48, 72 hrs of incubation by
comparison with an uninoculated tube
against a white background.
When incubated Glucose Agar
medium with bromocresol green
indicator and 0.2cc of saliva at
37ºc shows colour changes as the time passes
Colour
24 hours
|
48 hours
|
72 hours
|
If yellow
Marked caries susceptibility
|
If yellow
Definite caries susceptibility
|
If yellow
Limited caries suceptibilty
|
If green continue to incubate & observe at 48 hours
|
If green continue to incubate & observe at 72 hours
|
If green caries inactive
|
ALBANS TEST
It is a
modified snyder test
Procedure
1. At the time of
test 5ml tube of semi solid agar is removed from the refrigerator but is not
heated.
2. The patient is
asked to spit unstimulated saliva directly into the tube
3. The tube is
incubated at 98.6 deg c for upto 4 days.
4. Change of
color from green to yellow shows caries susceptibiltiy
. STREPTOCOCCUS MUTANS LEVEL IN SALIVA
This measures the number of
streptococcus mutans colony forming units per unit volume of saliva
Procedure
The sample of
organisms are obtained by using a tongue blade which are then pressed against
Streptococcus mutans selective MSB agar in special petri dishes.
Intrepretation
Levels of S Mutans > 105 /ml
of saliva =unacceptable
Disadvantage
- Difficulty in distinguishing
between a carrier state & cariogenic infection.
- S.mutans may constitute less than
1% of total flora of plaque.
- S.mutans tends to be located at
specific sites only.
THE SWAB
TEST
Developed by Grainger
Advantage:
No
collection of saliva is necessary so it is valuable in evaluating caries
activity in very young children
Procedure
The
oral flora is sampled by swabbing the buccal surface of the teeth with a cotton
applicator , which is subsequently incubated in the medium.
The change in the pH following a 48 hour
incubation is read on a pH meter or color change is read by the use of a color
comparator
Interpretation
pH 4.1 & < 4.1 = Marked
caries activity
pH 4.2 to 4.4 = Active
pH 4.5 to 4.6 =Slightly active
pH 4.6 & over= Less active
.SALIVARY REDUCTASE TEST
This test
measures the activity of the reductase enzyme present in salivary bacteria.
Procedure
Saliva is collected in a plastic
container .The sample is then mixed with the dye Diazoresorcinol ,the color
changes & caries conduciveness reading is taken after 15 min . No
incubation procedures are required
SALIVARY
BUFFER CAPACITY
The volatile
bicarbonate anion is an important component of the salivary buffer system &
collection & titration of saliva in this test must be carried out under a
layer of paraffin oil to prevent loss of this anion .
1. 2ml of saliva
collected under paraffin oil is added to
2. 4ml of
distilled water under a paraffin seal
3. The amount of
0.5 N HCL required to bring the saliva to pH 5.0 is measured
4.
Saliva samples requiring less than 0.45 ml of
standard HCL in this test have lower buffer capacity .Those requiring 0.45ml or
more have high buffer capacity.
v The
saliva of individuals whose mouth contain considerable amount of carious
lesions frequently have lower acid buffering capacity than the saliva of those
who are relatively caries free.
ENAMEL
SOLUBILITY TEST
Glucose
+saliva+powdered enamel= organic acids
These in turn
decalcify the enamel resulting in an increase in the amount of soluble Ca in
the saliva
The extent of
increased Ca is supposedly a direct measure of the degree of caries
susceptibility
BIBILOGRAPHY
o TEXTBOOK OF PEDODONTICS SHOBA TENDON
o TEXTBOOK OF PEDODONTICS ARATHY RAO
o TEXTBOOK OF PEDODONTICS MACDONAD
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