Enamel Structure and Biomechanical Properties Flashcards
What is the enamel thickness of incisors?
0 to 2mm
What is the enamel thickness of molars?
0 to 2.6mm
What is the refractive index of enamel?
1.655
Comment on the solubility of enamel
Soluble in acids
What is Mucopolysaccharidosis?
- Genetic abnormality
- Doesn’t allow enamel and dentine to bond at EDJ
- So could potentially cause cracks in enamel
Describe the crystallite orientation throughout the enamel
- All the crystals are in different directions
- Perpendicular from the EDJ
On the Moh scale what is the hardness of enamel?
5 to 8
What is the compressive strength of enamel?
350 MPa
What is the shear strength of enamel?
90 MPa
What is the tensile strength of enamel?
10 MPa
What is the maximum biting force administered to the teeth?
640 N
What is the maximum stress administered to the teeth?
20 MPa
What is the elastic modulus of enamel?
50GPa to 100GPa
Compare the elastic modulus of cross sectional enamel to surface enamel
Cross-sectional enamel has a lower elastic modulus than surface enamel
What does high fracture toughness show?
High fracture toughness shows improved clinical performance and reliability.
Comment on the structural integrity of enamel when there is crack propagation and subsequent fracture
Crack propagation and subsequent fracture leads to ultimate structural failure.
What is the enamel microstructure made of?
How does this help its function
Nano-scale HAP crystallites
High strength
Why is the thickness of crystallites 30nm?
This thickness is optimum for stress resistance
