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