Pharmaceuticals/Chemical Properties of Dental Tissues W1

Question 1

What is the difference in mineralisation (inorganic material) between Enamel and Dentine

Answer 1

Enamel: 95-98% (Hydroxyapatite crystals and trace minerals (Sr, Mg, F)
Dentine: 70% (Hydroxyapatite crystals - calcium and phosphate)

Question 2

List and describe the composition of Mature Enamel

Answer 2

Inorganic material: 95-98% (Hydroxyapatite crystals + Trace minerals ie. Sr, Mg, F)
Organic material: 1-2% (High affinity to bond hydroxyapatite crystals)
Water: 4%

Question 3

List and describe the composition of Dentine

Answer 3

Inorganic: 70% (calcium and phosphate ie. Hydroxyapatite crystals)
Organic 30% (20% Type I Collagen, ground substance + 10% Water)

Question 4

How are Hydroxyapatite crystals arranged in enamel

Answer 4

Arranged in rods…
Rod sheath - matrix of enamelins surrounding rods
Interrod enamel/cement

Question 5

List and describe the composition of Cementum and its function

Answer 5

Inorganic 45-50% (Hydroxyapatite)
Organic 50-55% (Mainly Type I and Type III Collagen)

Anchors teeth to socket by periodontal ligament

Question 6

List and describe the composition of Pulp

Answer 6

Soft tissue, unmineralized
70-80% water, 20-30% organic material

Question 7

What are the main important functions of Saliva

Answer 7

Stabilize tooth surface
Form acquired enamel pellicle

Question 8

List the formula for a Hydroxyapatite Unit Cell

Answer 8

Ca10 (PO4)6 (OH)2

Question 9

Hydroxyapatite vs Fluorapatite formula/description

Answer 9

F- replace OH- in Hydroxyapatite
Creates a more dense, stable crystal structure

Question 10

What form of phosphate is present in the precursor for Hydroxyapatite crystals (ie. present in the amporus solid form)

Answer 10

Monohydrogen phosphate (H PO4 2-)

Question 11

List the steps in the transformation of Hydroxyapatite to Fluorapatite

Answer 11

Hydroxyapatite -> Monofluroapatite + 1 F ion -> Fluorapatite + 2 F ions

Question 12

Regarding Demineralization and Remineralization, what happens to the phosphate in hydroxyapatite as the pH decreases

Answer 12

At pH 7: CaHPO4(2-) = Ca + HPO4(2-)
pH 6.2: HPO4(2-) = H2PO4-
pH below 6.2: HPO4(2-) < H2PO4-

Question 13

What is Critical pH and how does the critical pH change with Fluorapatite?

Answer 13

Highest pH with net loss of minerals from enamel
Critical pH can be lower with Fluorapatite as its more protective and prevents loss of minerals

Question 14

What is Fluorosis?

Answer 14

Chronic Fluoride induced condition
Occurs when excess fluoride incorporated into tooth enamel, it disrupts enamel formation

Question 15

What is Calcium Phosphate Ca3(PO4)2 and its clinical applications

Answer 15

Similar to bones and teeth, promote osteogenesis/new bone formation
Used in bone substitutes/grafts, tooth replacement, scaffolds

Question 16

1ppm in weight/volume

Answer 16

1g in 1,000,000mL

Question 17

What is the major inorganic component of dentine?

Answer 17

HAP crystals - Ca and PO4

Question 18

What leads to the decreased solubility of hydroxyapatite?

Answer 18

Adding FAP

Question 19

Define Isomorphic Replacement.
Provide an example of an isomorphic replacement reaction that occurs in the enamel and draw the corresponding chemical equation.

Answer 19

Ion replacement. For example going from HAP OH2 (19Da) to FAP F2 (17Da). Produces denser more stable structure to be more resistant to acid attack and increases the rate of remineralisation.

Question 20

What is the calcified tissue that covers the anatomical crown of the tooth?

Answer 20

Enamel

Question 21

What structure is permeable to caries and acid?

Answer 21

Enamel pores created by configuration of enamel rods.

Question 22

What is the caries incidence with patient who has dry mouth?

Answer 22

Role of saliva is to remineralise by promoting Ca and PO4 in the mouth.
1. No availability of the ions needed for remineralisation.

2. Low saliva can’t penetrate through the plaque therefore more anaerobic bacteria.
3. Reduced buffering capacity.

Question 23

Patient who has undergone a prevention of caries clean and has been using the GC Tooth Mousse Plus comes into the clinic and complains of severe nausea and discharge from the nose. What is the most likely cause and what would you do to treat these symptoms?

Answer 23

Dental Fluorosis- above 1.0ppm of fluoride patient can develop symptoms. Treat with calcium gluconate, milk or 1% CaCl2 before sending to hospital.

Question 24

What does a high concentration of CO3 replace?
A) Replaces OH
B) Replaces Ca
C) Replaces PO4

Answer 24

A - high conc of CO3 will replace OH, whereas low CO3 will replace phosphate

Question 25

What is the role of ions Na and Mg and what do they replace?

Answer 25

Make HAP more soluble, and replace Calcium

Question 26

Which type of metabolites are...Natural products, do NOT participate directly in growth and deveopment, hormonal, toxicolical, behavioural effects

Answer 26

Secondary metabolites

Question 27

What is the origin of secondary metabolites

Answer 27

Derived from primary metabolites, they are modified (example: methylation, glycosylation ect) After Krebs cycle through different pathways

Question 28

What are Terpenes comprised of

Answer 28

Isoprene Units (5 carbon long units)

Question 29

Describe the three isprene unit links

Answer 29

Head-Head: \ / - not common Head-Tail: \ \ Tail-Tail: / \

Question 30

What pathway do Terpenes originate from

Answer 30

Mevalonate pathway ie. Mevalonic acid pathway (after Krebbs cycle)

Question 31

What is the basic molecular formula of a Terpene

Answer 31

C5H8

Question 32

How many isoprene units are monoterpenoids, sesquiterpenoids and diterpenoids made of?

Answer 32

Mono: 2 Sesqui: 3 Di: 4

Question 33

How many isoprene units are steroids made of?

Answer 33

6 (Triterpenoids)

Question 34

Which class of secondary metabolites ends with -ene or -ol

Answer 34

Terpenes (Terpenoids)

Question 35

What is the difference between a Terpene and Terpenoid

Answer 35

Terpene: hydrocarbon Terpenoid: contains oxygen (Terpene + function group attached)

Question 36

What is the secondary metabolite class which contains Nitrogen?

Answer 36

Alkaloids (Amine group!)

Question 37

What are the main uses of Alkaloids and some examples?

Answer 37

Drugs, medicines, poisons Morphine, Cocaine, nicotine, atropine, codiene, curare, Quinidine, LSD

Question 38

What class of secondary metabolites ends in -ine

Answer 38

Alkaloids due to the Amine group (N)

Question 39

What is the molecular structure of Steroids?

Answer 39

30 carbons 3 x 6 membered rings 1 x 5 membered ring

Question 40

When substituents are added to steroids on the saturated carbon below the plane of the ring they are refered to as...

Answer 40

a (alpha) configuration - below the plane of the ring b (beta) configuration - above the plane of the ring

Question 41

What is the structure of Phenols (Phenolics)

Answer 41

Benzene ring (aromatic ring) + >1 OH substituent

Question 42

What molecule and pathway do Phenols originate from?

Answer 42

Derived from Pentose phosphate ie. Shikimatte and phenylpropanoid pathway

Question 43

What are some examples and uses of Phenols

Answer 43

Disinfectant in cleaners and mouthwash Tyrosine (aa) in protein NT: Epinephrine, Serotonin Flavouring/essential oils: Vanillin, Methyl Salicylate (from wintergreen), Eugenol (fom cloves)

Question 44

Demineralisation is the result of loss of Ca and PO4 and HAP dissolves. What happens when there is a prolonged acid attack?

Answer 44

1. Crystalline structure shrinks 2. Pores enlarge 3. Carious sessions develop

Question 45

What structure does acid penetrate in enamel vs dentine?

Answer 45

Dentine: penetrates peritubular collagen matrix Enamel: penetrates inter rod of enamel- enamel rods

Question 46

What is the role of ions Na and Mg and what do they replace?

Answer 46

Make HAP more soluble, and replace Calcium

Question 47

What does CPP-ACP stand for*

Answer 47

Casein phosphopeptide-amorphous calcium phosphate nanocomplexes (CPP-ACP)