6: Calculus



Table 6.1 Differences between supragingival and subgingival calculus.

  Supragingival calculus Subgingival calculus
Location Coronal to gingival margin Apical to gingival margin within gingival sulcus or periodontal pocket
Distribution Adjacent to openings of salivary ducts:

lingual of mandibular incisors (sublingual duct)
buccal maxillary second molar (parotid duct)
No predilection for particular parts of mouth
Approximal and lingual sites more affected than buccal sites
Appearance Creamy-white colour
May become nicotine-stained in smoker
Brownish-black due to haemorrhagic elements from gingival
crevicular fluid and black pigments from calcified anaerobic rods
Morphology Undifferentiated morphology – amorphous deposit Variable:

• ledges or rings around tooth, especially on the cementenamel junction
• on root surface(s) as crusty, spiny, nodular formations, thin veneers, fern-like arrangements, individual islands.
• supragingival on subgingival deposits
Detection Visible clinically
Detection enhanced by air drying, which gives chalky appearance
By probing – tactile sensation enhanced by using ball end of WHO 621 probe.
If deposit is located at entrance to pocket:

• it may be visible as dark shadow under the gingival margin;
• by directing air jet from three-in-one syringe at entrance
to pocket it may be possible to retract the gingiva and see deposit directly.
Following gingival recession, subgingival deposit may become located supragingivally and be easily visible
Radio-opaque calculus ‘wings’ may be visible on approximal sites on radiographs
Formation Nucleation and crystal growth are heterogeneous Calcification is heterogeneous
Deposit builds up in layers with variable mineral content in the layers
Nucleation and crystal growth are heterogeneous
Calcification is more homogeneous (uniform) than supragingival calculus
Deposit builds up in layers, each with similarly high mineral density
Mineral content and source Mean of 37% by volume (range 16–51% in the different layers)
Derived from saliva
Mean of 58% by volume (range 32–78% in the different layers) Derived from gingival crevicular fluid
Composition 70–80% inorganic salts
Mainly calcium, phosphate (lower ratio than subgingival calculus)
Small amounts of magnesium, sodium, carbonate and fluoride.
Regular distribution of fluoride
Traces of other elements
Organic matrix constitutes 15–20% of dry weight: protein (55%), lipid (10%) and carbohydrate
Greater concentration of calcium, magnesium and fluoride than in supragingival calculus
Higher calcium to phosphorus ratio than in supragingival calculus
Irregular distribution of fluori/>

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Jan 14, 2015 | Posted by in Periodontics | Comments Off on 6: Calculus
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