Mutans Strep (ms) test:

-The current ms commercial chair side testing kits have limited use in determining caries activity when cavitated lesions are present. If the lesions are noncavitated, assessment using surface testure and appearance are best used to establish activity.  My personal assessment of the commercially available ms tests in the USA suggest the Dentocult MS is probably best.  

This test has low sensitivity--does not identify true positive very well, but has a fairly good specificity--identifies patient with low ms levels.  Thus it has a use clinically.*  

The most reliable ms test is available through bacteriological testing labs and using the commercial chairside test is of limited benefit.  Knowing ms levels is important for caries assessment and monitoring.  While we are primarily interested in the ms levels, knowing lactobacilli salivary levels is also important since they can also survive in an acid environment and can produce acid.

-MS test results are an indicator of levels of bacterial colonization on teeth.  

-For testing, chewing paraffin is used to dislodge the bacteria from the plaque into the saliva.  It has been show that salivary and tongue surface levels of ms correlate well with ms plaque levels.**

-This test uses a selective media for ms.

-Levels of ms of <100,000 CFU is normal, prefer to have closer to 10,000 CFU.

-Levels of ms of>100,000 CFU is an indicator of high caries risk levels.

-Perform test several hours after toothbrushing, eating or smoking.
-Wait 2 weeks after antibiotic treatment to perform these tests.
          -Wait 12 hours after use of an antibacterial mouthwash to perform these tests.

*Anderson, MH, Bales, DJ, Omnell, K.  Modern management of dental caries. JADA, 124:37-44, 1993.
**Tanzer, JM, Salivary and plaque microbiology tests and the management of dental caries. J.Dent Ed, 61:866-874.

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