Caries activity tests

Introduction

Carious lesions are easily detected Carious lesions are easily detected by a clinical examination with a by a clinical examination with a probe, mouth mirror coupled with probe, mouth mirror coupled with bite wing radiographs.bite wing radiographs.

However, a clinical examination However, a clinical examination neither predicts caries activity nor neither predicts caries activity nor indicates a patients susceptibility indicates a patients susceptibility to dental caries.to dental caries.

OBJECTIVES

To identify some parameters related to the triad of challenge, defense and repair that will indicate impending or existent caries activity or inactivity.

To formulate the strategies for prevention of the disease.

USES

FOR A CLINICIAN: To determine the need for caries control

measures. To act as indicator of patients cooperation. To act as an aid in timing of recall appointments. As a guide to insertion of expensive restorations. To aid in the determination of prognosis. As a precautionary signal to the orthodontist in

placing bands.

FOR THE RESEARCH WORKER

As an aid in the selection of patients for caries study.

To help in the screening of potential therapeutic agents.

To serve as an indicator of periods of exacerbation and remission.

IDEAL REQUISITES

Snyder has suggested that a suitable caries activity test should:

Have a sound theoretical basis.

Show have maximal correlation with clinical status.

Be accurate with respect to duplication of results.

Be simple. Be inexpensive. Take little time. In addition a good caries-predictive test should

possess at least three characteristics: Validity Reliability Feasibility

CLASSIFICATION OF CARIES ACTIVITY TESTS

TESTS FOR EVALUATING MICROBIOLOGICAL ACTIVITY:

Lactobacillus colony counts Dip-slide method Streptococcus mutans colony counts Dip-slide method Snyder’s test Alban’s test

TESTS FOR EVALUATING SALIVA DEFENSE:

Saliva flow rate Viscosity of saliva Buffering capacity of saliva

TESTS FOR EVALUATING TOOTH DEFENSE:

Critical visual examination Fluoride levels Intra oral cariogenicity tests (ICT) Electrical resistance

Lactobacillus colony count test

Introduced by Hadley in 1933.

Principle-Estimates the no. of acidogenic and aciduric bacteria in patients saliva by counting the no. of colonies of lactobacillus appearing on tomato peptone agar plates after inoculation with a sample of saliva.

Equipment – saliva collecting bottles, paraffin, two 9ml tubes of saline, two agar plates, two bent glass rods, incubator, Quebec counter, pipettes.

Procedure –

Collection of saliva sample

Preparation of 1:10 and 1: 100 dilution saliva samples

Inoculation of saliva sample on tomato peptone agar plates and incubation at 370c for 3-4 days

No. of lactobacilli/ml No. of lactobacilli/ml saliva saliva

Caries activity Caries activity

0-10000-1000 Little or noneLittle or none

1000-50001000-5000 SlightSlight

5000-10,0005000-10,000 ModerateModerate

>10,000>10,000 MarkedMarked

Results and inference

Drawbacks

Counting of colonies is a very tedious process

Requires a qualified person to carryout the test

Need more time to get the result Relatively high cost

Dip slide method

Modifications Use of dip slide coated with lactobacillus

selective agar Use of model charts for comparison

rather than making a count

Equipments required Procedure Results and inference < 1000 = low 1000 – 10000 = medium > 10000 = high

Streptococcus mutans colony count test

Principle Equipments required Procedure Drawbacks

Dip slide method

Equipments required Procedure Results and inference

Snyder’s test

Principle Equipments required Procedure Drawbacks

Alban’s test

Principle Equipments required Procedure Drawbacks

LIMITATIONS FOR CARIES ACTIVITY TESTS:

Caries activity tests are better correlated with the prognosis/diagnosis of group outcomes rather than for individuals.

None of the caries activity tests [currently used] has been shown to satisfactorily predict caries activity.

Conclusion