Aaron MadisonTakeaki Murakami

Alyssa MerrickAnthony Meyer

A New Front in War on Cavities

Cavities declined in the 70s and 80s and appeared to hit a low around the mid 90sAccording to data from Centers for Disease

Control and Prevention, only 24% of children had cavities in mid 90s

In more recent years, a survey has found that 28% of children had cavitiesReasons are unclear for the significant

increase, but may be due to children drinking more bottled water that doesn’t contain fluoride, and to changes in dietary habits

Scientists have found that not all mouth bacteria are harmful but they are currently trying to identify the worst pathogens and stop them

Dennis Cvitkovitch, director of the Dental Research Institute at the University of Toronto, has been probing deep into the genetics of Streptococcus mutans, which has been consistently implicated in causing cavities.

He identified S. mutans genome affects its ability to join together with other bacteria

They found that it temporarily restrains the buildup of plaque

This discovery could someday lead to a decay fighting additive for mouthwash and certain foods

So Many Places to Hide!!!Bacteria is hard to kill permanently

because it contains so many different species and crevices where they can hide.

Within three to four hours of brushing or using mouthwash, the microbes begin to multiply again.

Bacteria works in groups communicating with each other about where they have settled and ask other bacteria to join them through direct contact by sharing nutrients and by emitting small signaling molecules.

Preparing for PathogensThe first bacteria called colonizers do not

cause harm alone but they pave the way for other microbes, like S. mutans, that promote tooth decay.

When bacteria joins together with plaque they are more difficult to remove with brushing and to kill with mouthwash. There are some pathogens such as Lactobacillus Casei, that accelerate tooth decay.

Dr. Cvitkovitch’s goal is to interrupt communication among bacteria.

He hopes that will lead to a more targeted and effective way of killing the pathogens or controlling the damage they cause. His lab is working on “understanding intimate communication between bacteria and finding ways to stop plaque from binding so well.”

Virulent CharacteristicsS. mutans was chosen by scientists

because its good at converting sugars into lactic acid which eats away at tooth minerals. It also makes a sticky substance that helps form the glue that holds plaque together.

The researchers identified a small sequence of amino acids on the S. mutans DNA that encodes a peptide which appears responsible for much of the bacteria’s communication ability.

Urging Microbes to Die!!!S. mutans cells begin to die off when the

concentration of CSP, the peptide that is responsible for the communication ability, rises above a certain level.

To test their thesis that CSP could be used to influence the bacteria’s ability to form plaque, they constructed a compound that closely relates to CSP.

Although results remain unpublished, the analog appears to temporarily reduce plaque by as much as 40%.

Animal clinical trials of the CSP analog are expected to begin in the spring.

Other research efforts are focusing on other bacteria that reside in the mouth.

Some scientists are focusing on “good bacteria” and the efforts are aimed at figuring out how to promote these bacteria and prevent the environment from becoming diseased.

Some other scientists are focusing on the gum-diseasing-causing strains. They hope to learn how to jam their communication signals, disrupt their feeding and prevent their ability to attach to other bacteria.

TIPS FOR GOOD ORAL HYGIENETooth brushing

Brush twice daily with fluoride toothpaste to remove plaque on tooth surfaces

Parents should help small childrenFlossing

Floss daily to remove plaque and food between teeth and under gum line

It doesn’t matter if you brush or floss firstOther tips

Eat a balanced diet and limit snacks in between meals

Get regular professional check ups and cleaning every 6 months to reduce hard to reach plaque