Theories and Formation of Dental Calculus

These flashcards review key definitions, historical milestones, classifications, composition, formation timelines, attachment modes, and major theories related to dental calculus based on the lecture notes.

What is dental calculus (tartar)?

A hard deposit formed by mineralization of dental plaque on the surfaces of natural teeth or dental prostheses, usually covered by a layer of unmineralized plaque.

From which Greek word is the term "calculus" derived, and what does it mean?

From the Greek word "Calcis," meaning limestone.

List four common synonyms for dental calculus.

Tartar, Calcis, Odontolithiasis, Fossilized plaque.

Who first described the relationship between calculus and dental disease and recommended its removal?

Albucasis (936–1013 AD).

Which scientist (1493–1541) proposed the "doctrine of calculus" linking systemic metabolic refuse (“tartarus”) to pathologic calcifications?

Paracelsus.

Who observed "animalcules" (micro-organisms) in tartar in 1683?

Antonie van Leeuwenhoek.

Define supragingival calculus.

Tightly adhering calculus that forms on the crowns of teeth coronal to the gingival margin.

Define subgingival calculus.

Calcified deposit that forms on tooth surfaces apical to the free gingival margin (within periodontal pockets).

What is the primary source of minerals for supragingival calculus?

Saliva.

What is the primary source of minerals for subgingival calculus?

Gingival crevicular fluid (serum).

Which teeth and surfaces most commonly accumulate supragingival calculus?

Facial surfaces of maxillary molars and lingual surfaces of mandibular anterior teeth.

Typical color of supragingival calculus vs. subgingival calculus?

Supragingival: white/yellow; Subgingival: brown or greenish-black.

Visibility difference between supra- and subgingival calculus in routine clinical exam?

Supragingival is clinically visible; subgingival is usually not visible without instruments or radiographs.

State the general inorganic and organic percentage composition of supragingival calculus.

Inorganic 70–90 %; organic 10–30 %.

Name the four principal calcium-phosphate crystals found in calculus.

Hydroxyapatite, Octacalcium phosphate, Magnesium whitlockite, Brushite.

What percentage of the inorganic portion of calculus is calcium phosphate?

Approximately 75.9 %.

How soon can plaque begin to mineralize and what percentage may be mineralized by day 2?

Mineralization can start within 1–14 days; about 50 % of plaque may be mineralized by day 2.

By approximately how many days can 60–90 % of plaque be mineralized?

About 12 days.

List the four main modes by which calculus attaches to tooth surfaces.

(1) Organic pellicle, (2) Mechanical interlocking into surface irregularities, (3) Penetration into cementum, (4) Close adaptation to unaltered cementum depressions.

According to rate of accumulation, name the four categories of calculus formers.

Non-formers, slight formers, moderate formers, heavy formers.

Give three common morphologic forms of subgingival calculus deposits.

Crusty/spiny/nodular; ring-like or ledge-like; veneer type (also finger-like, island, or combinations).

What is the core idea of the Booster Concept of calculus formation?

Local rise in saturation of calcium and phosphate ions (often due to increased pH) precipitates mineral salts.

How does the Salivary pH Theory (Hodge & Leung) explain mineral precipitation?

Loss of CO₂ and ammonia production raise salivary pH, lowering the solubility of calcium phosphate and causing precipitation.

Summarize the Epitactic (Seeding) Mechanism.

Crystal formation begins on seeding agents (e.g., carbohydrate-protein complexes) that attract calcium, forming nuclei that enlarge and fuse into calculus.

What does the Inhibition Theory propose about calcification sites?

Calcification occurs only where local inhibitors (e.g., pyrophosphates, polyphosphates) are absent or overwhelmed.

Describe the Transformation Theory of calculus formation.

Non-crystalline deposits (amorphous or brushite) sequentially transform into octacalcium phosphate and then hydroxyapatite.

Which microorganisms are most implicated in the Bacterial Theory of calculus formation?

Leptotrichia and Actinomyces species.

According to the Enzymatic Theory, which enzyme drives calculus formation and on what substrate?

Phosphatases act on salivary phosphate-containing complexes to precipitate mineral.

What is the "Reversal Phenomenon" in calculus accumulation?

A decline in calculus buildup after a peak reached between 10 weeks and 6 months, often due to mechanical wear from oral tissues and food.

What experimental observation shows saliva’s necessity for calculus formation?

Animals whose major salivary glands were surgically removed did not form calculus.

How far back in human history has calculus been identified on teeth?

In remains of Neanderthals over 400,000 years old.