Dental Calculus Overview

Questions and Answers

What is a primary characteristic of the inorganic composition of subgingival calculus compared to supragingival calculus?

Higher calcium concentration

Lower magnesium content

Lower phosphate ratio

Higher sodium content (correct)

What is not one of the modes of attachment for dental calculus to the tooth surface?

Organic pellicle attachment

Mechanical locking into surface irregularities

Mechanical bonding through adjacent tissues (correct)

Close adaptation to cementum surface

What happens to dental plaque in the initial stages before it converts to calculus?

It contains a small amount of inorganic material (correct)

It becomes fully mineralized within 24 hours

It remains unchanged for 14 days

It is coated with a protective film

How long does calcification of plaque generally begin after plaque formation?

Within 4 to 8 hours Signup and view all the answers

Which source primarily mineralizes supragingival calculus?

Saliva Signup and view all the answers

What is a characteristic of plaque that does not develop into calculus?

It reaches a maximal mineral content plateau in 2 days Signup and view all the answers

What is one of the reasons for the difficulty in removing dental calculus from the tooth surface?

Mechanical locking into surface irregularities Signup and view all the answers

Which mineral element's concentration in plaque is notably higher than in saliva?

Calcium Signup and view all the answers

What is the characteristic color of supragingival calculus?

White or whitish-yellow Signup and view all the answers

Where is supragingival calculus most commonly located?

Buccal surfaces of the maxillary molars Signup and view all the answers

What describes subgingival calculus?

Dark brown or greenish-black in color Signup and view all the answers

What can influence the color of supragingival calculus?

Contact with tobacco and food pigments Signup and view all the answers

What is a common effect after the removal of supragingival calculus?

It recurs quickly, especially in certain areas Signup and view all the answers

How is the extent of subgingival calculus typically assessed?

Dental instrument examination like an explorer Signup and view all the answers

What is true regarding the relationship between supragingival and subgingival calculus?

Both generally occur together but one can be present without the other Signup and view all the answers

Which of the following statements about subgingival calculus is incorrect?

It is always visible during a clinical exam Signup and view all the answers

What percentage of the inorganic component of dental calculus is typically composed of calcium phosphate?

76% Signup and view all the answers

Which crystal form is most commonly found in supragingival calculus?

Hydroxyapatite Signup and view all the answers

What is the primary component of the organic content in dental calculus?

Salivary proteins Signup and view all the answers

In what form does lipids exist as a part of the organic component in dental calculus?

Cholesterol and phospholipids Signup and view all the answers

Which inorganic component has the lowest percentage in dental calculus composition?

Calcium carbonate Signup and view all the answers

Which two crystal forms are typically found together in the majority of supragingival calculus samples?

Hydroxyapatite and octacalcium phosphate Signup and view all the answers

What is the approximate percentage of carbohydrates in the organic content of dental calculus?

Between 1.9% and 9.1% Signup and view all the answers

Which of the following elements is NOT typically found in the inorganic composition of dental calculus deposits?

Lead Signup and view all the answers

What is the primary location where mineralization of plaque begins?

Extracellularly around microorganisms Signup and view all the answers

Why is distinguishing between calculus and plaque effects on gingiva difficult?

Calculus is covered with a nonmineralized layer of plaque Signup and view all the answers

What is the relationship between calculus and gingivitis?

There is a positive correlation, but less than plaque and gingivitis Signup and view all the answers

Which of the following statements about calculus is true?

Calculus retains bacterial plaque close to the gingiva Signup and view all the answers

Which organisms are identified as periodontal pathogens found within calculus?

Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola Signup and view all the answers

What is the composition of materia alba?

Microorganisms, epithelial cells, and salivary proteins Signup and view all the answers

What is a key characteristic of dental stains?

They appear as pigmented deposits on the tooth surface Signup and view all the answers

How does materia alba irritate the gingiva?

Due to the presence of bacteria and their products Signup and view all the answers

Study Notes

Calculus Overview

Mineralized bacterial plaque on teeth and prostheses.
Supragingival calculus is above the gum line, visible, usually white or whitish-yellow.
Subgingival calculus is below the gum line, not visible without instruments, often dark brown or greenish-black.
Common supragingival locations: buccal surfaces of maxillary molars and lingual surfaces of mandibular anterior teeth.
Both types of calculus may coexist but can occur independently.

Composition of Calculus

Inorganic content constitutes 70-90% of calculus, primarily calcium phosphate (76%).
Other inorganic components include calcium carbonate, magnesium phosphate, and trace elements like sodium and zinc.
Four primary crystal forms: Hydroxyapatite (58%), Magnesium whitlockite (21%), Octacalcium phosphate (12%), Brushite (9%).
Organic content includes proteins, epithelial cells, leukocytes, and microorganisms, constituting 1.9-9.1% carbohydrates.

Attachment Mechanisms

Four modes of calculus attachment:
- Organic pellicle on cementum/enamel
- Mechanical locking into surface irregularities
- Close adaptation to tooth surface
- Penetration into cementum.

Formation and Mineralization

Dental plaque mineralizes within 4-8 hours, with salts precipitating between the 1st and 14th day.
Calculus can become 50% mineralized in 2 days and 60-90% in 12 days.
Saliva contributes to supragingival mineralization; gingival crevicular fluid is a source for subgingival calculus.
Calcium content in plaque can exceed that in saliva by 2 to 20 times.

Microbial Influence and Periodontal Disease

Mineralization starts extracellularly around organisms; both gram-positive and gram-negative species play a role.
Calculus is consistently covered with nonmineralized plaque, complicating the assessment of its impact on gingiva.
Positive correlation exists between calculus presence and gingivitis, but plaque is a stronger etiologic factor for periodontal disease.
Key periodontal pathogens found within calculus, including Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis.

Additional Deposits

Materia alba is a soft, sticky deposit containing bacteria, desquamated cells, and proteins, less adherent than plaque.
Dental stains are pigmented deposits that can accumulate on tooth surfaces.

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Description

This quiz covers the types and characteristics of dental calculus, including supragingival and subgingival calculus. It details their locations, visibility, and composition. Test your knowledge on the formation and significance of calculus in oral health.