Oral Microbiology Testing for Periodontal Disease Treatment

June 1, 2009 10:24 pm Published by

Periodontal disease is a multifactoral problem, and cannot always be answered by the traditional methods of mechanical debridement (scaling and root planing) and periodontal surgery. Although in most cases,  debridement and improvement of oral hygiene can do wonders, unique cases always arise which leave periodontists baffled.  What happens when you have a 30 year old patient, with no radiographic calculus or significant plaque buildup but has severe bone loss and 8mm pockets? Clearly debridement of the pockets isn’t going to work. Understanding the microbiology of periodontal disease is of increasing importance to the general dentist and working with specialized labs is vital to the successful treatment of the disease.

The Oral Microbiology Testing Service (OMTS) at Temple University School of Dentistry was designed specifically to assist dentists with identifying and treating difficult cases of periodontal disease. It is one of only 4 state and federally-licensed clinical periodontal microbiology reference laboratories in the United States.

The process:

How do you get the culture?
The dentist should first use college pliers and a cotton pellet to wipe away supragingival plaque. Then a medium cotton point should be placed into about six different sites with the deepest periodontal probing depths. The cotton point should be left in for 5 to 10 seconds and then quickly placed in the culture medium, which is then sent to the lab.

Once the lab has the culture, they incubate and culture it. This is done in a one to two week period in a special chamber that replicates the conditions of the area of the mouth in which the bacteria grows.

After the culture is grown , it is examined by microbiologists and  the types of bacteria are identified. Then an antibiotic sensitivity test is performed on all the species of bacteria that were found. The pathogens were divided into groups depending on their known associations with periodontal disease. An acceptable critical % threshold level was given for each species of bacteria. The % of cultivable microbiota for each species from the sample was then compared against the given markers. For example if the acceptable threshold level for a certain species was 2.5% but the level found in this sample was 5.6% then the conclusion would be that there were elevated proportions of that species.

Antibiotic sensitivity tests were performed for 4 major antibiotics commonly used to treat periodontal pathogens. This bodes well for the patient because specific antibiotic therapy can be given to the patient in addition to dental treatment.


Clinical Scenario:
A patient presented to Dr. Dorfman’s office recently with severe periodontal disease and acute necrotizing ulcerative gingivitis (ANUG) on the lingual aspect of #27,28. The patient was treatment planned for 4 quadrant scaling and root planning,

The patient was previously treated with amoxicillin and metrodiazanole, two commonly prescribed antibiotics for periodontal pathogens. However, the lab results showed that many of the periodontal pathogens found were resistant to both antibiotics. The head of the lab at the OMTS suggested the use of Cipro to target the gram-negative bacteria that were found to be in significantly higher levels than expected.

R.A., Columbia University School of Dental Medicine

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