The Usual Suspects- Bacteria

This post is part of a 4-part series from Dr. Kim Kutsch on CAMBRA, risk assessment, and the usual suspects that are causing this disease. If you would also like to watch the video, click here.


An early obstacle to dentists trying to adopt CAMBRA theory in their practices was how complicated CAMBRA seemed to be in the early days. It was hard for people to understand CAMBRA, and dentists were hesitant to make it a central principle of their patient care. As the principles of CAMBRA were better understood, it became clear that it didn’t have to be so complicated. Relatively few factors, referred to here as the usual suspects, were causing the majority of problems.


Bacteria is one of those usual suspects. Bacteria is the primary cause of caries in 46-51% of patients. In general, bacterial driven caries will occur in patients who self report having a lot of plaque buildup and/or who have a high CariScreen score. A patient who is having caries largely in the areas of plaque buildup and in the gingival area probably has a serious bacterial problem.


As we continue to study the action of bacteria in general and the action of specific bacteria in caries disease, we are learning more about which bacteria are associated not only with diseased conditions, but also which bacteria are more prevalent in healthy, caries free mouths.

While at one time, Strep Mutans and Lactobacillus were likely to get the blame for all caries, the reality of the situation is more complicated. The biofilm is complex, and research has uncovered a number of agents at play, both in healthy and unhealthy oral environments.

Fusobacteria were likely to be found on healthy tooth surfaces in a study that examined both healthy and caries diseased mouths. Lactobacillus was found in abundance in the mouths with active caries. Another similar study found that the ratio between S. Sanguinis and S. Mutans was predictive of children’s caries disease. Leptotrichia also was found in a case study to be a previously unsuspected bacteria associated with dental caries.


More than one study has suggested that, in the future, it may be beneficial to examine the ratio between healthy and unhealthy bacteria when assessing the risk of dental caries. The idea that certain bacteria are negatively associated with dental caries and how to incorporate this knowledge into dental practice is an area for further research and development.

New research has also shown that candida is a major player in caries disease. The candida fungus is highly aciduric, and the low pH, acidic environment it thrives in is known to be unhealthy for tooth enamel.  In fact, a study measuring microhardness in enamel blocks, blocks coated with a candida containing biofilm, experienced the greatest amount of mineral loss.


Bacterial risk factors in patients are generally marked by high plaque buildup and/or a high CariScreen score.

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