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Tests for prediction and Activity of dental caries

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

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  1. Tests for prediction and Activity of dentalcaries Presented by : DeeptiAwasthi

  2. CONTENTS • Introduction • Definition • Objectives • Uses for Clinician • Ideal requisites of caries activity test • Tests • Conclusion • References

  3. INTRODUCTION

  4. DEFINITIONS • Caries activity • Caries susceptibility • Caries activity tests

  5. Objectives • 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.

  6. 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

  7. 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

  8. Various caries activity tests

  9. 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

  10. Procedure 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

  11. 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.

  12. Interpretation of LB colony count test No. of organism CFU/ml Symbolic designation Degree of caries activity + Little or No 0-- 1000 Slight ++ 1,000– 5000 Moderate +++ 5000-- 10,000 Marked ++++ > 10,000

  13. Disadvantages • 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

  14. 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

  15. Procedure 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.

  16. . • 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.

  17. INTERPRETATION

  18. Advantages : • relatively simple • Moderate cost Disadvantages : • Time consuming • Sometimes color change is not very clear • Limited predictive value

  19. 3. THE SWAB TEST • GRAINGER et al in 1965. • Principle same as Synder test. Cariology , 3rd Ed. - Earnest Newbrun

  20. Procedure • 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.

  21. 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

  22. 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

  23. Procedure • 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

  24. COLOUR CHANGES

  25. Advantages • No incubation • Quick results Disadvantages • Results vary with time after food intake & after brushing

  26. 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

  27. 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

  28. 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

  29. 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.

  30. 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 = ‘++++’

  31. Advantages: • Simplicity, • Low cost, • Diagnostic value when negative results are obtained. • Motivational value Disadvantages: • More armamentarium • Subjective evaluation

  32. 6. SALIVARY BUFFER CAPACITY Action • Measures the no. of mls of acid required to lower the pH from 7 to 6. Equipment • pH meter • 0.05N lactic acid • Paraffin • Sterile glass jars containing small amount of oil. Cariology , 3rd Ed. - Earnest Newbrun

  33. Procedure • 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

  34. 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

  35. Procedure 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

  36. Interpretation : Levels of Streptococcus Mutans > 10 5/ ml of saliva = unacceptable,

  37. Disadvantages • 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

  38. 8.Dip slide method • Dentocult • Larmas ,1975 • S.Mutans levels in saliva Procedure 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.

  39. Colony density (small blue colonies) compared with model chart 0 - negligible 1 - <105 2 - 105 - 106 3 - > 106

  40. 9.Plaque / tooth pick method Action • Simple screening of diluted plaque sample Procedure • 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

  41. 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

  42. 10.Fosdick Calcium dissolution test Principle • 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

  43. Advantages • Correlation reported is good • Disadvantages • Complex equipment • Expensive, trained personnel.

  44. 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

  45. 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

  46. Interpretation of Cariostat test

  47. 13.Oratest • Rosenberg et al. in 1989 Principle • The rate of oxygen depletion by micro organisms in expectorated milk samples

  48. 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

  49. Advantages • 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

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