Remineralisation of enamel lesions

Question 1

Talk about the remineralisation of enamel crystals

Answer 1

• Here, new apatite unit cells are to be create on existing partially dissolved structures
• Central perforation: crystals begin to grow in void
• Periphery: crystals formation occurs on defected crystal surfaces. This is more challenging

2. Growth of current crystals:
   With this mechanism, the remin occurs on the surface of the surviving crystals, leading to the fusion of adjacent crystals
3. Formation of new crystals:
   Involves formation of new crystals in an enlarged inter-crystalline space

Question 2

Talk about the remineralisation at the rod and inter-rod level

Answer 2

Rod and inter-rod: remin process happens within the remaining framework of the rod and inter-rod structure

Question 3

Talk about the remineralisation at tissue level

Answer 3

• Enamel remin occurs in only 2 zones out of the 4. It occurs in the surface layer and dark zone
• The translucent and body of lesion are zones of demin

Question 4

What are current challenges for remin of enamel caries

Answer 4

1. Presence of high density surface layer: the surface layer of enamel carries acts like a dense barrier, preventing the access of external minerals and bioactive molecules to the porous demineralised areas beneath the surface
2. Surface precipitation: Putting in more minerals on top reduces permeability of the surface layer and causes rapid reduction in mineral ion gradient
3. Lack of concentration gradient:
   the concentration gradient of the remineralising minerals between inside and outside of the lesion is usually not enough to transport the necessary minerals deep into the lesion
4. Remineralising within the hierarchy of enamel: Remineralisation can only happen if the framework of the rod and interrod units/ crystals are preserved

Question 5

What are current remineralisation products?

Answer 5

1. Fluoride:
   · Decreases adherence of bacteria to enamel crystals
   · Limits actions of strept mutans and lactobacilli by increasing plaque pH
   · Is bactericidal as it causes hydrogen fluoride to diffuse into bacteria
   · Decreases the susceptibility of newly erupted teeth through the acceleration of enamel maturation
   · Makes enamel stronger and less acid resistant via the formation of fluorapatite crystals. It replaces the central hydroxyl ion and sits in there.
   · Enhances remineralisation through catalysing the accelerating of bring the calcium and phosphate ions together
2. Calcium/ phosphate based systems:
   • Have 3 systems of delivering calcium and phosphate ions:

1• Unstabilised amorphous calcium phosphate systems: not crystallised salts. Thus, they react together to form a crystal structure quickly, but prematurely. So it crystallises before it can get into the actual body of the lesion

2• Crystalline calcium phosphate systems: pre crystallised

3• Stabilised amorphous calcium phosphate systems: not crystallised salts. Thus, they react together to form a crystal structure quickly however, they do not crystallise prematurely. Rather, they only begin to crystallise when in the lesion