6 - Plaque and Calculus

Question 1

3 things in plaque

Answer 1

Microbial clusters
Polysaccharides
Glycoproteins

Question 2

Amorphous material composed of plaque, food debris, desquamative epithelium, and NP

Answer 2

Material alba

Question 3

Matrix produced in a biofilm by microbes

Answer 3

Glycocalyx

Question 4

3 sugars + bacteria in glycocalyx

Answer 4

Glucose –> dextrose (Strep)
Fructose –> levans (Strep)
Uronic acid + Ca2+ –> alginate (Gram negative)

Question 5

Examples of autoinducers

Answer 5

Acylated homoserine lactones (gram negative)

Oligopeptides (gram positive)

Question 6

4 phases of biofilm growth

Answer 6

Adherence
Lag
Rapid growth
Steady state

Question 7

Molecule cleaved by neuraminidase to expose terminal galactose sugar

Answer 7

Mucin

Question 8

Molecule that binds Ca2+ and HA

Answer 8

Proline rich proteins (PRP)

Question 9

Molecule that binds Ca2+ and phosphate

Answer 9

Statherins

Question 10

Histidine rich molecule

Answer 10

Histatin

Question 11

Molecule that inhibits cysteine rich proteinases (Cathepsin BHL)

Answer 11

Cystatin

Question 12

HA surface of teeth have a ____ charge which attracts the _____ charge on glycoproteins

Answer 12

Negative

Positive

Question 13

Thickness of pellicle before acquiring bacteria?

Time frame?

Answer 13

1-2um

1 hour

Question 14

What 3 things forms the glycocalyx

Answer 14

Alginates
Dextrans
Levans

Question 15

Bacteria clumping together within a suspension

Answer 15

Coaggregation

Question 16

Bacteria within the saliva bind to bacteria that are bound to the substrate surface

Answer 16

Coadhesion

Question 17

How far does oxygen penetrate a biofilm?

Answer 17

25-30um

Question 18

How are bacteria able to invade gingival epithelial cells?

Answer 18

• Widened intercellular spaces due to inflammation
• NP migration leaves channels that bacteria follow
• Sulcular epithelium is ulcerated

Question 19

What bacteria invade gingival epithelial cells?

Answer 19

AA

PG

Question 20

Who showed that spirochetes invade tissue? How far?

Answer 20

Listgarten

250um

Question 21

Zones of spirochete invasion

Answer 21

Bacterial
NP
Necrotic
Spirochete

Question 22

Evidence for why calculus contributes to periodontitis (3)

Answer 22

Tan - viable bacteria within calculus samples under LM
Allen - non-autoclaved calculus caused abscess/suppuration
Loe - Sri Lankan study

Question 23

Do bacteria need to be present for calculus to form? (2 sources)

Answer 23

NO

Glas & Gustafsson

Calculus formation in germ free mice within the pellicle

Question 24

Is saliva necessary for calculus formation? (Source)

Answer 24

Yes, it’s the source of calcium + phosphate

Kakehashi - animals w/ major salivary glands removed don’t form calculus

Question 25

Calculus formation occurs by nucleation or crystal seeding within the dental plaque matrix

Answer 25

Epitactic Mechanism

Question 26

Proteolytic activity of bacteria increases the pH by urea and ammonium products that causes precipitation of the mineral calcium phosphate

Answer 26

Booster mechanism

Question 27

4 types of calculus and percentages

Answer 27

Brushite 9%
Octacalcium phosphate 12%
Magnesium whitlockite 21%
HA 58%

Question 28

Most prevalent subgingival calculus

Answer 28

HA

Question 29

Found predominantly in posterior teeth

Answer 29

Magnesium whitlockite

Question 30

97-100% of supragingival calculus

Answer 30

Octacalcium phosphate

Question 31

Dominant in newly formed supragingival calculus

Answer 31

Brushite

Question 32

Increases as calculus ages

Answer 32

HA
Octacalcium phosphate
Magnesium whitlockite

Question 33

Decreases as calculus ages

Answer 33

Brushite

Question 34

Brushite formula

Answer 34

CaHPO4 2H20

Question 35

Octacalcium phosphate formula

Answer 35

CaH(PO4)3 2H20

Question 36

HA formula

Answer 36

Ca10(PO4)6(OH)2

Question 37

Magnesium Whitlockite formula

Answer 37

Ca9(PO4)6 MgF PO7