Organic content of supragingival calculs:
**Core Concept**
Supragingival calculus, also known as plaque calculus or surface calculus, is a hardened deposit that forms on the teeth above the gum line. It is primarily composed of minerals such as calcium and phosphate that are precipitated out of saliva and plaque, which is a biofilm of bacteria.
**Why the Correct Answer is Right**
The organic content of supragingival calculus is primarily composed of bacterial cells and their by-products, such as extracellular polymers and dead cells. The bacteria in the plaque feed on the sugars and starches in the diet, producing acid and other metabolic by-products that contribute to the formation of calculus. The minerals in saliva, such as calcium and phosphate, then precipitate out of solution and deposit onto the surface of the teeth, forming a hard, calcified deposit.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is also not provided.
**Option C:** This option is also not provided.
**Clinical Pearl / High-Yield Fact**
The formation of supragingival calculus is a continuous process that occurs throughout life, and it can be prevented or minimized through good oral hygiene practices, such as regular brushing and flossing, as well as regular dental cleanings.
**Correct Answer: D. Organic content of supragingival calculus is primarily composed of bacterial cells and their by-products.**