Calculus Flashcards
What is calculus?
Calculus is rock hard accumulations that develop on the surface of teeth and according to
position is classified as either supragingival or subgingival. It is possible that as the gingiva
recedes subgingival calculus could become supragingival. And supragingival calculus
could therefore contains components of both types. Some calculus extends along the
tooth surface into periodontal pockets.
Why might there be more calculus over some teeth?
The heavier accumulations of calculus along the lingual aspect of the mandibular incisors,
might be associated with the close proximity to sublingual openings of mandibular and
sublingual saliva ducts. A similar explanation for the frequent heavier calculus
accumulations at the maxillary fourth premolar and first molar teeth, could be the opening
of parotid and zygomatic’s saliva glands, just dorsal to the maxillary fourth premolar tooth.
Why does calculus accumulate asymmetrically sometimes?
Asymmetric accumulation of calculus could be an indication of the favoured use of the
opposite side. This could indicate pain or sensitivity of the side with heavier calculus. This
is often associated with resorptive lesions or crown fractures.
Where does the organic component of calculus come from?
The organic component of supragingival calculus originate primarily from saliva and for
subgingival calculus, from gingival crevicular fluid. Also included in supragingival calculus
is protein polysaccharide complexes, leucocytes, desquamated epithelial cells, microbes
and protein. Supragingival calculus contains salivary protein whereas subgingival calculus
does not. Subgingival calculus tends to contain more red blood cell breakdown products,
from crevicular fluid and therefore appears darker in colour.
How is calculus formed?
Calculus is the result of mineralisation of plaque and can start between 1-14 days after
plaque formation. Some calculus formation is being reported to occur within four hours .
Mineralisation results from the increased levels of saturation of calcium and phosphate
irons. Seeding agents/initiating foci could also potentially initiate calcification that coalesce
and enlarge. It is generally assumed that plaque bacteria are only passively involved in
calculus formation, but some filamentous bacteria can form calcium hydroxyapatite
crystals intracellularly.
Discuss supra-gingival calculus attachment?
The attachment of supra gingival calculus relies on the attachment of the pellicle to the
crown surface. The attachment to the smooth surface is therefore less effective and could
readily chip away. Calculus does attach more firmly to developmental grooves, other
defects and other plaque stagnation areas. This could be a good argument for polishing
teeth after scaling. This also indicates why it is important that any restorations are flush
with the crown surface and as smooth as possible.
Discuss how sub-gingival calculus attaches?
We have indicated earlier why plaque and therefore calculus, attaches more firmly to the
root surface. It is therefore understandable why removal of sub gingival calculus is more
challenging and requires more time to perform effectively. The irregular surface of the
exposed cementum assists greatly in plaque accumulation. In focal areas, calculus can
extend into the cementum to form firmly interlocked connections. It has been reported that
calculus could extend below the cementum and potentially enter dentinal tubules.
What are the Pathogenic Effects of Calculus?
Physical obstruction caused by calculus can potentially interfere with normal jaw closure,
especially in cats. Calculus accumulation within the periodontal pocket can displace the
gingival sulcus away from the tooth, further compromising the situation. The main role of
calculus is to facilitate plaque attachment.
What is Materia Alba?
This whitish or greyish material forms sticky accumulations on teeth, lacks the organised
structure of plaque. It consists of desquamated epithelial cells, microbes leucocytes,
proteins and lipids. These accumulations can usually be washed away with a water
stream. This should be considered as intra oral, superficial puss that accumulates on the
oral and gingival surface.
