calculus

Question 1

supra gingival calculus is defined as being…

Answer 1

coronal to the gingival margin

Question 2

sub gingival calculus is defined as being…

Answer 2

apical to the gingival margin

Question 3

distribution of supra gingival calculus

Answer 3

adjacent to the salivary duct openings: lingual of lower anteriors, buccal of upper molars

Question 4

distribution of sub gingival calculus

Answer 4

random- anywhere in the mouth

Question 5

calcium and phosphate can form many types of crystals.

what are the dominant crystal types in supra gingival calculus and sub gingival calculus respectively

Answer 5

supra gingival= 
1. HAP
2. octa-calcium phosphate
3. brushite
NB. can be small needle shaped or large ribbon shaped

sub-gingival=
1. magnesium whitlock
NB. crystals are smaller

Question 6

theory now accepts that plaque MUST come before calculus formation because ….

Answer 6

plaque provides the organic matter for calcification/mineralisation

Question 7

where do the minerals come from in supra/sub gingival calculus formation respectively.

explain how this relates to the mineral content of each of the calculus types.

Answer 7

supra= saliva
sub= GCF 

the GCF is rich in ca, mg, fl, sr, zn therefore tend to find more here and lesser amounts in the supra gingival calculus

the saliva is rich in carbonate and manganese therefore find more in supra than sub.

Question 8

what is the current theory for the formation of calculus

Answer 8

small crystals form in the microbial matrix between bacteria: matrix will become calcified and the bacteria will become mineralised. (in supra gingival calculus, this can occur even within hours/days of prophylaxis)

the mineralisation occurs in 2 steps:
1. nucleation of crystal seeds- can be homogenous or hetezygous.

2. growth of the crystals: boosted when the local plaque has a HIGHER pH than saliva (which can occur due to co2 loss or ammonia formation).

Question 9

what are the ethnic variations in the formation of calculus

Answer 9

1. indo/pak= low level of na in apical than coronal sub-gingival calculus
2. indo/pak= have lower levels of na and mg in apical samples compared to causations
3. asian populations= have higher amounts of supra gingival calculus AND PD than Caucasians.

Question 10

morphology of supra gingival calculus

Answer 10

amorphous

Question 11

morphological types of sub gingival calculus

Answer 11

1. crusty spiny nodular deposits OR
2. ledge or ring formation
3. thin, smooth veneers
4. finger like formations
5. individual calculus islands/spots
6. on top of subgingival calculus

Question 12

how would you diagnose supra gingival calculus

Answer 12

look at location and distribution

colour of deposit (white/creamy/yellow- may be stained in smokers)

will feel ROUGH when probe with who621 probe

when you air dry the deposit, only supra gingival calculus will get CHALKY

Question 13

how would you diagnose sub gingival calculus

Answer 13

location and distribution

colour of deposit- will be brown

feel it with a who621 probe- will hear a ping as the deposit pushes back

may be clinically visible if there is recession/ attachment loss

the papilla may be darker red in colour

black shadows under the gingival margin

Question 14

why is a pt. having calculus significant ?

Answer 14

1. supra gingival calculus=makes good oral hygiene difficult thus accelerates plaque formation
2. supra gingival calculus= poor aesthetics
3. supra gingival calculus= predisposes to gingival recession
4. supra and sub gingival calculus= act as PRF due to their rough surface
5. Clerehugh and Lennon, in a 2-year longitudinal study found that subgingival calculus have MORE loss of attachment, greater risk of developing PD.