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Tests for prediction and Activity of dental caries. Presented by : Deepti Awasthi. CONTENTS. Introduction Definition Objectives Uses for Clinician Ideal requisites of caries activity test Tests Conclusion References. INTRODUCTION. DEFINITIONS.

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tests for prediction and activity of dental caries

Tests for prediction and Activity of dentalcaries

Presented by :


  • Introduction
  • Definition
  • Objectives
  • Uses for Clinician
  • Ideal requisites of caries activity test
  • Tests
  • Conclusion
  • References
  • Caries activity
  • Caries susceptibility
  • Caries activity tests
  • Identify high risk group and individual
  • Determine need for preventive measures
  • To serve as an index of the success of the therapeutic measures.
  • To motivate and to monitor the effectiveness of education programs
  • Manage the progress of restorative procedures.
uses for clinician
Uses for Clinician
  • Determine need for caries control measure
  • Indicator of patient co-operation
  • Aid in timing of recall appointments
  • Guide to insertion of expensive restorations
  • Determine the prognosis
  • Precautionary signal to the orthodontist in placing bands
ideal requisites
  • Sound theoretical basis
  • Maximum correlation with clinical status.
  • Accuratewith respect to duplication of results.
  • Simple
  • Quickin performance
  • Inexpensive , feasible
  • Validity
  • Reliability
  • Sensitivity
  • Specificity
1 lactobacillus colony count test
  • introduced by HADLEY in 1933
  • Principle

This test measures the number of acidogenic and aciduric bacteria in patient’s saliva by counting the number of colonies on tomato peptone agar plates after inoculation with a sample of saliva.

Cariology , 3rd Ed. - Earnest Newbrun



patient chews a small piece of paraffin

before breakfast

The saliva that accumulates in the 3 minute period is collected in a sterile container

Saliva collected is shaken by a machine for 2 minutes

The saliva sample is diluted with sterile saline solution to 1:100
  • 0.4 ml of each sample is spread on the surface of an agar plate
  • The plates are incubated for 3 to 4 days at 37°C
  • The number of Lactobacillus colonies that develop are counted using Quebec counter.

Interpretation of LB colony count test

No. of organism


Symbolic designation

Degree of caries activity


Little or No

0-- 1000



1,000– 5000



5000-- 10,000



> 10,000

  • Quick and easy but results are available in days.
  • Counting colony tedious
  • complex instrument, trained personnel required
  • Not completely exclude the growth of other relatively aciduric organisms
  • Inaccurate for predicting the onset of caries
2 colorimetric snyder test
2. Colorimetric SNYDER TEST
  • SNYDER in 1951
  • Principle
  • Test measures the ability of salivary microorganisms to form organic acid from a carbohydrate medium
  • Bromocresol green indicator dye, changes colour from greentoyellowat pH 5.4 to 3.8

Essentials of Preventive and community Dentistry- Soben Peter


Salivary sample is collected after the patient chews a small piece of paraffin before breakfast.

0.2 cc of saliva is pipetted into the 10ml melted agar containing medium in a test tube at 50°C, allowed to solidify and then incubated at 37°C .

The incubation period is upto 72 hours.

  • The media contains :
  • Bactopeptone
  • Dextrose
  • Sodium chloride
  • Agar
  • Bromocresol green
  • The rate of colour change from green toyellowis indicative of the degree of caries activity.

Advantages :

  • relatively simple
  • Moderate cost

Disadvantages :

  • Time consuming
  • Sometimes color change is not very clear
  • Limited predictive value
3 the swab test
  • GRAINGER et al in 1965.
  • Principle

same as Synder test.

Cariology , 3rd Ed. - Earnest Newbrun

  • The oral flora is sampled by swabbing the buccal surfaces of the teeth with a cotton applicator,
  • subsequently incubated in the medium.
  • The change in the pH following a 48 hour incubation is read on a pH meter or the colour change is read by the use of a colour comparator.

Interpretation :

  • pH 4.1 and < 4.1 = Marked caries
  • pH 4.2 to 4.4 = Active
  • pH 4.5 to 4.6 = Slightly active
  • pH 4.6 and over = Caries inactive
4 salivary reductase test
  • measures the activity of the reductase enzyme present in salivary bacteria
  • This enzyme is involved in the reactions for the formation of products dangerous to the tooth surface.
  • Rate at which the indicator molecule , diazoresorcinol, changes from blue to red to colorless


  • Saliva is collected by chewing a special flavoured paraffin and expectorated directly into collection tubes
  • The sample is then mixed with the dye Diazo-resorcinol
  • The colour changes and the “Caries Conduciveness” reading is taken after 15 minutes


  • No incubation
  • Quick results


  • Results vary with time after food intake & after brushing
5 alban test
  • Simple modified Snyder test

Main Features:

  • softer medium that permits the diffusion of saliva and acids without melting the medium.
  • simpler sampling procedure , patient expectorates directly into tubes containing the medium

Essentials of Preventive and community Dentistry- Soben Peter


following materials are required:

  • Synder test agar
  • A small scale to measure 60 grams.
  • A 2 litter Pyrex glass to melt the medium.
  • A funnel to dispense the medium into test tubes.
  • 100 - 16 mm test tubes with screw caps

Procedure :

  • 60gms of Snyder test agar is placed in 1 litre of water &suspension is brought to a boil over a low flame.
  • When thoroughly melted the agar is distributed
  • The tubes are autoclaved for 15 minutes: allowed to cool and stored in a refrigerator.
  • 2 tubes are taken & the patient is asked to expectorate a small amount of saliva directly into the tubes.
  • incubated at 370C for upto 4 days

observe for:

  • Change of colour from bluish green (pH 5) to definite yellow (pH 4 or below).
  • The depth in the medium to which the change has occurred.
Scale for Scoring:
  • 1. No colour change = ‘3/4’
  • 2. Beginning colour change = ‘+’

(from top to medium down)

  • 3. One half colour change = ‘++’

(from top down)

  • 4. Three fourths colour change = ‘+++’

(from top down)

  • 5. Total colour changes to yellow = ‘++++’


  • Simplicity,
  • Low cost,
  • Diagnostic value when negative results are obtained.
  • Motivational value


  • More armamentarium
  • Subjective evaluation
6 salivary buffer capacity


  • Measures the no. of mls of acid required to lower the pH from 7 to 6.


  • pH meter
  • 0.05N lactic acid
  • Paraffin
  • Sterile glass jars containing small amount of oil.

Cariology , 3rd Ed. - Earnest Newbrun



  • 10ml of saliva collected under oil 1hr after eating
  • 5ml is taken into a beaker
  • pH of saliva is adjusted to 7.0
  • Lactic acid is added until pH of 6.0 is reached.
  • The no. of ml of lactic acid needed to reduce pH is a measure of buffer capacity.

Evaluation :

  • Inverse relationship
7 streptococcus mutans level in saliva
  • measures the number of Streptococcus mutans colony forming units per unit volume of saliva
  • Incubation is done on MitisSalivariusAgarwith addition of sucrose (20%) & 0.2U bacitracin /ml which supresses the growth of most non-S.Mutans colonies


The samples of organisms is obtained by the use of tongue blades

Sample then pressed against MitisSalivarius

Bacitracin Agar in special Petri dishes

incubated at 370C for 48 hrs in 95%& 5%CO2

gas mixture

Cariology , 3rd Ed. - Earnest Newbrun



  • Difficulty of distinguishing between a carrier state and cariogenic infection.
  • S. Mutans may constitute less than 1% of total flora of plaque.
  • S. Mutans tends to be located at specific sites only.
  • Not convenient for chair side
8 dip slide method
8.Dip slide method
  • Dentocult
  • Larmas ,1975
  • S.Mutans levels in saliva


Saliva is collected and poured over the agar coated slide & allowed to dry

Bacitracin disks are placed in the middle

Co2 tablet is inserted in the tube & then incubated for 48 hrs.


Colony density (small blue colonies) compared with model chart

0 - negligible

1 - <105

2 - 105 - 106

3 - > 106

9 plaque tooth pick method
9.Plaque / tooth pick method


  • Simple screening of diluted plaque sample


  • Plaque samples are collected from the gingival thirds of buccal tooth surfaces & placed in Ringer’s solution
  • Suspension is stretched across MSA plates
  • Incubation at 370C for 72 hrs

Cariology , 3rd Ed. - Earnest Newbrun

10 s mutans adherence method
10. S. mutans adherence method

Saliva inoculated in MSB broth for 24 hrs at 37°C

After growth, the supernatant removed

Cells adhering to the glass examined macroscopically

10 fosdick calcium dissolution test
10.Fosdick Calcium dissolution test


  • Measures the mgs of powdered enamel dissolved in 4 hours, when patients saliva mixed with glucose and powdered enamel.

Essentials of Preventive and community Dentistry- Soben Peter



  • Correlation reported is good
  • Disadvantages
  • Complex equipment
  • Expensive, trained personnel.
11 dewar test
  • Test similar to fosdick calcium dissolution test
  • Except that in this test the pH of the mixture is measured instead of the amount of calcium dissolved by the acid.

Essentials of Preventive and community Dentistry- Soben Peter

12 cariostat test
  • Tsutomu Shimono 1974
  • This test has been reported to significantly correlate with counts of S.mutans in children
  • uses a semisynthetic liquid containing sucrose, tryptose, a gram-negative bacteria growth inhibitor, and bromcresol green and bromcresol purple indicators.
  • The test assesses acid production by cariogenic bacteria and thus indirectly assesses caries activity

The sensitivity and specificity of a colorimetric microbiological caries activity test (Cariostat) in preschool children

13 oratest
  • Rosenberg et al. in 1989


  • The rate of oxygen depletion by micro organisms in expectorated milk samples

Under aerobic conditions the bacterial enzyme, aerobic dehydrogenase transfers electrons or protons to oxygen.

  • Once oxygen gets utilized by the aerobic organisms and an anaerobic environment is attained, methylene blue acts as an electron acceptor and gets reduced to leucomethylene blue
  • The metabolic activity of the aerobic microorganism is reflected by the reduction of methylene blue to leucomethylene blue.

Oratest: A Simple Chairside Aid for Caries Risk Assessment



  • Simple , inexpensive , less time consuming , reproducible and requiring no trained personnel.
  • Used to monitor mouth rinse regime , denture hygine , gingival inflammation and plaque levels.
  • Good educational and motivational tool for patient,school and community health programmes.
  • Vehicle for test is nontoxic (milk)
  • Anticipate the onset of caries
  • Results can provide dentist to command patient to reinforce motivation ,plaque control and behaviour


  • It does not identify a specific group of organism in a specific disease.
  • It cannot accurately differentiate between the healthy state and between initial and progressive carious lesion
  • Lack of specificity since positive observation can be obtained in gingivitis and other oral ailments.
14 salivary glucosyltransferase b
14. Salivary glucosyltransferase b
  • Gtfs play a critical role in the pathogenesis of caries and furthermore, the enzymes are present in whole saliva.
  • Therefore, hypothesized that the amount of Gtfs collectively or separately could be correlated with caries activity.
  • chair side and provide results within minutes

Salivary Glucosyltransferase B as a Possible Marker for Caries Activity-


2 ml of saliva was collected

  • saliva was clarified by centrifugation,
  • Clarified saliva was mixed in a 1:1 ratio with the coating buffer supplied in the kit and was coated onto 96-well plates
  • After washing, antibodies to Gtf B, C and D were applied
  • intensity of the color in the wells, which correlated to the amount of purified Gtf present, was read in an ELISA reader
15 cariscreen caries susceptibility test
15. CariScreen Caries Susceptibility Test
  • is done in one minute at chairside
  • ATP bioluminescence technology, which is a test for light reaction, will measure on a scale from 0 to 9999.
  • the levels of acid-producing bacteria by swabbing lingual surfaces of lower anterior teeth and then inserting the sample in the CariScreen meter to be read
  • 0 to 1500 is low risk and 1500 to 9999 is high risk
  • The ATP generates light once it reacts with luciferin, a light-emitting biological pigment/enzyme present in the CariScreen. The amount of light emission is in direct proportion to the amount of ATP and a well-known fact is that acid-producing bacteria contain 100 times more ATP than non-acid-producing strains
16 carivis
16. Carivis
  • system for assessment of caries activity relies on the unique properties of the Glowdent marker that detects actively occuring dental demineralisation
  • The amount of light emitted varies with the amount of minerals present
  • more minerals equals more light.

Advantages of the Carivis System

  • The Carivis caries assessment system marks a new approach in preventive dentistry. Its innovative design offers:

Non-invasive, one-step method

  • Caries activity assessment is possible with a single visit to the dentist
  • Extreme sensitivity and information on the extent of demineralisation
  • Access to all dental surfaces, including contacting surfaces of teeth and around restorations
  • Ease of use
  • Speed; signal collection requires less than 10 seconds
  • Cariology , 3rd Ed. - Earnest Newbrun
  • Principles & practice of pedodontics – ArathiRao
  • Dentistry for the child & adolescent – McDonald
  • Textbook of Pedodontics- ShobhaTandon
  • Textbook of Pediatric dentistry- S.G.Damle
  • Essentials of Preventive and community Dentistry- Soben Peter
  • Chair side simple caries activity test: Ora test- Bhasin S, JISPPD 2006;24:2
  • A Modified dip slide test for microbiological risk in caries assessment.BThaweboon,srosorithaweboonetal,Southeast Asian J Trop Med Public health;2006 37:2:400-04
  • Salivary Glucosyltransferase B as a Possible Marker for Caries Activity-A.M. Vacca Smith. Caries Res. 2007 November; 41(6): 445–450
  • Using a Caries Activity Test to Predict Caries Risk in Early Childhood. Michiko Nishimura, JADA
  • Oratest: A Simple Chairside Aid for Caries Risk Assessment -AroraRuchia, Lahiri. Prathik. Kb, MasihUpdes. Int. j of dental clinics 2009:1(1): 26-30
  • The sensitivity and specificity of a colorimetric microbiological caries activity test (Cariostat) in preschool children. Pediatric Dentistry: July/Aug 1994 - Volume1 6, 4