Lesson 5: Dental Plaque

Image: Plaque adhering in the fissure of a molar.

Although John’s gingivae and teeth look healthy, we can’t forget about plaque.

Dr. Lee to John: "You have missed a little bit of plaque. The hygienist will educate you on proper oral hygiene and better ways to reach these areas. To help you remember to brush regularly, you may want to listen to my explanation of plaque, to understand its connection to inflammation."

Plaque is a dense, soft mass of microbial colonies attached to teeth and tissues of the oral cavity, or mouth, that consists of a nonmineralized mass containing over 700 species of bacteria in a gel matrix.

Plaque adheres to the teeth and other surfaces, like in the fissure of this molar, in the oral cavity that is both above (supragingival) or below the gum line (subgingival). Supragingival plaque and subgingival plaque need to be removed regularly.

Over time, plaque hardens into a mineralized substance known as calculus, which is also covered with nonmineralized bacterial plaque. The lay term for calculus is tartar.

Dr. Lee to John: "Did you know there are hundreds of bacteria present in your mouth? This image is a magnified close-up view of calculus, commonly called tartar, on the lingual surfaces of the lower front teeth."

Although a great number of bacteria are found in each person’s oral cavity, there is a distinctive bacterial flora found in a healthy mouth compared to one with disease.

Image: Magnified close-up view of calculus on the lingual surfaces of lower front teeth.