Pharmaceuticals/Chemical Properties of Dental Tissues W1 Flashcards
What is the difference in mineralisation (inorganic material) between Enamel and Dentine
Enamel: 95-98% (Hydroxyapatite crystals and trace minerals (Sr, Mg, F)
Dentine: 70% (Hydroxyapatite crystals - calcium and phosphate)
List and describe the composition of Mature Enamel
Inorganic material: 95-98% (Hydroxyapatite crystals + Trace minerals ie. Sr, Mg, F)
Organic material: 1-2% (High affinity to bond hydroxyapatite crystals)
Water: 4%
List and describe the composition of Dentine
Inorganic: 70% (calcium and phosphate ie. Hydroxyapatite crystals)
Organic 30% (20% Type I Collagen, ground substance + 10% Water)
How are Hydroxyapatite crystals arranged in enamel
Arranged in rods…
Rod sheath - matrix of enamelins surrounding rods
Interrod enamel/cement
List and describe the composition of Cementum and its function
Inorganic 45-50% (Hydroxyapatite)
Organic 50-55% (Mainly Type I and Type III Collagen)
Anchors teeth to socket by periodontal ligament
List and describe the composition of Pulp
Soft tissue, unmineralized
70-80% water, 20-30% organic material
What are the main important functions of Saliva
Stabilize tooth surface
Form acquired enamel pellicle
List the formula for a Hydroxyapatite Unit Cell
Ca10 (PO4)6 (OH)2
Hydroxyapatite vs Fluorapatite formula/description
F- replace OH- in Hydroxyapatite
Creates a more dense, stable crystal structure
What form of phosphate is present in the precursor for Hydroxyapatite crystals (ie. present in the amporus solid form)
Monohydrogen phosphate (H PO4 2-)
List the steps in the transformation of Hydroxyapatite to Fluorapatite
Hydroxyapatite -> Monofluroapatite + 1 F ion -> Fluorapatite + 2 F ions
Regarding Demineralization and Remineralization, what happens to the phosphate in hydroxyapatite as the pH decreases
At pH 7: CaHPO4(2-) = Ca + HPO4(2-)
pH 6.2: HPO4(2-) = H2PO4-
pH below 6.2: HPO4(2-) < H2PO4-
What is Critical pH and how does the critical pH change with Fluorapatite?
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
What is Fluorosis?
Chronic Fluoride induced condition
Occurs when excess fluoride incorporated into tooth enamel, it disrupts enamel formation
What is Calcium Phosphate Ca3(PO4)2 and its clinical applications
Similar to bones and teeth, promote osteogenesis/new bone formation
Used in bone substitutes/grafts, tooth replacement, scaffolds
1ppm in weight/volume
1g in 1,000,000mL
What is the major inorganic component of dentine?
HAP crystals - Ca and PO4
What leads to the decreased solubility of hydroxyapatite?
Adding FAP
Define Isomorphic Replacement.
Provide an example of an isomorphic replacement reaction that occurs in the enamel and draw the corresponding chemical equation.
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.
What is the calcified tissue that covers the anatomical crown of the tooth?
Enamel
What structure is permeable to caries and acid?
Enamel pores created by configuration of enamel rods.
What is the caries incidence with patient who has dry mouth?
Role of saliva is to remineralise by promoting Ca and PO4 in the mouth.
1. No availability of the ions needed for remineralisation.
- Low saliva can’t penetrate through the plaque therefore more anaerobic bacteria.
- Reduced buffering capacity.
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?
Dental Fluorosis- above 1.0ppm of fluoride patient can develop symptoms. Treat with calcium gluconate, milk or 1% CaCl2 before sending to hospital.
What does a high concentration of CO3 replace?
A) Replaces OH
B) Replaces Ca
C) Replaces PO4
A - high conc of CO3 will replace OH, whereas low CO3 will replace phosphate
What is the role of ions Na and Mg and what do they replace?
Make HAP more soluble, and replace Calcium
Which type of metabolites are…Natural products, do NOT participate directly in growth and deveopment, hormonal, toxicolical, behavioural effects
Secondary metabolites
What is the origin of secondary metabolites
Derived from primary metabolites, they are modified (example: methylation, glycosylation ect)
After Krebs cycle through different pathways
What are Terpenes comprised of
Isoprene Units (5 carbon long units)
Describe the three isprene unit links
Head-Head: \ / - not common
Head-Tail: \ \
Tail-Tail: / \
What pathway do Terpenes originate from
Mevalonate pathway ie. Mevalonic acid pathway (after Krebbs cycle)
What is the basic molecular formula of a Terpene
C5H8
How many isoprene units are monoterpenoids, sesquiterpenoids and diterpenoids made of?
Mono: 2
Sesqui: 3
Di: 4
How many isoprene units are steroids made of?
6 (Triterpenoids)
Which class of secondary metabolites ends with -ene or -ol
Terpenes (Terpenoids)
What is the difference between a Terpene and Terpenoid
Terpene: hydrocarbon
Terpenoid: contains oxygen (Terpene + function group attached)
What is the secondary metabolite class which contains Nitrogen?
Alkaloids (Amine group!)
What are the main uses of Alkaloids and some examples?
Drugs, medicines, poisons
Morphine, Cocaine, nicotine, atropine, codiene, curare, Quinidine, LSD
What class of secondary metabolites ends in -ine
Alkaloids due to the Amine group (N)
What is the molecular structure of Steroids?
30 carbons
3 x 6 membered rings
1 x 5 membered ring
When substituents are added to steroids on the saturated carbon below the plane of the ring they are refered to as…
a (alpha) configuration - below the plane of the ring
b (beta) configuration - above the plane of the ring
What is the structure of Phenols (Phenolics)
Benzene ring (aromatic ring) + >1 OH substituent
What molecule and pathway do Phenols originate from?
Derived from Pentose phosphate ie. Shikimatte and phenylpropanoid pathway
What are some examples and uses of Phenols
Disinfectant in cleaners and mouthwash
Tyrosine (aa) in protein
NT: Epinephrine, Serotonin
Flavouring/essential oils: Vanillin, Methyl Salicylate (from wintergreen), Eugenol (fom cloves)
Demineralisation is the result of loss of Ca and PO4 and HAP dissolves. What happens when there is a prolonged acid attack?
- Crystalline structure shrinks
- Pores enlarge
- Carious sessions develop
What structure does acid penetrate in enamel vs dentine?
Dentine: penetrates peritubular collagen matrix
Enamel: penetrates inter rod of enamel- enamel rods
What is the role of ions Na and Mg and what do they replace?
Make HAP more soluble, and replace Calcium
What does CPP-ACP stand for*
Casein phosphopeptide-amorphous calcium phosphate nanocomplexes (CPP-ACP)
