The Complex Structure of Mature Dental Plaque Biofilms

A. Bacterial Microcolonies

1. Bacteria in biofilms are not distributed evenly. As the bacteria to attach to the surface and with each other, they all come together to form a mushroom microcolonies that are attached to the tooth surface to narrow base (Fig. 6-10).

2. Each microcolony tiny independent community with thousands compatible bacteria. Various microcolonies can contain various combinations of species of bacteria.

a. The environment within each microcolony bacteria can vary dramatically. Environmental conditions among several microcolonies may include differences in the concentration of oxygen, pH and temperature.

B. Differences in environmental conditions within biofilms means that bacterial population is very diverse, and each different species of bacteria preferring particular environment in biofilms.

1) this is a bacterial diversity helps to ensure survivability plaque biofilm in varying degrees mouth.

2) If the plaque biofilm was only one type of bacteria, it would be much more likely that a toxic substance or condition that would destroy biofilms.

B. Extracellular Layer Of Mucus

1. Extracellular mucus layer - tight protective barrier that surrounds bacterial microcolonies (Fig. 6-10).

2. The mucus layer acts as a shield that protects bacterial microcolonies from antibiotics, antimicrobials, and the body's immune system.

C. The Fluid Forces

1. The fluid forces of saliva, surrounding biofilms to influence the form plaque biofilm, and spatial arrangement of bacteria inside.

2. These fluids forces resulting in the development of extensions from the main body of biofilms. These biofilms extensions can break free and to be swallowed, expectorated, or form new biofilm colonies in other areas of the mouth.

3. Liquid force the cell to clashes bacteria in biofilms.

a. Bacterial cells clashes lead to a more rapid spread of genes among bacteria than if there were no forces acting on the fluid in biofilms.

B. This is a quick transfer of genes from bacterial cell to cell bacteria can lead to increased virulence of the bacteria and antimicrobial resistance.

c. A constant exchange of genetic material between bacteria means that the bacteria are in constant evolution. It makes bacterial biofilms very difficult to eradicate and helps to ensure the survivability of biofilms.

D. Fluid Channels

1. As plaque biofilm is developing a series of fluid channels are formed, which penetrate into the intercellular mucus layer (Fig. 6-10).

2. These fluids channels direct fluid in and around biofilms, nutrients and oxygen, bacteria and carrying bacterial waste away.

3. Liquids include everything from saliva that any drinks consumed.

E. cell-to-cell communication system

1. Direct intercellular interaction occurs among bacteria in biofilms.

2. Bacterial microcolonies to use chemical signals to communicate with each other (Fig. 6-11). 3. This cell-to-cell communication also leads to gene transfer among bacteria.

F. Bacterial Signaling

1. Bacteria in biofilms produce hundreds of proteins that are freely floating bacteria do not.

2. Some of these proteins are signaling proteins that cause events such as adhesion additional bacteria and formation of extracellular layer of mucus that surrounds bacteria.

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