Enamel and dentine bonding

Question 1

what are the three approaches to attachment of materials to tooth substance?

Answer 1

micro-mechanical attachments (acid etch)
chemical adhesion to enamel/dentine (coupling agents/cements)
complex ways (dentine bonding agents)

Question 2

what factors effect acid etching?

Answer 2

etching time - too long get smooth surface 10-60s
washing to remove debris
drying to enable hydrophobic resin to penetrate and attach

Question 3

is dentine hydrophobic or hydrophilic?

Answer 3

hydrophilic

Question 4

are dental adhesives hydrophobic or hydrophilic?

Answer 4

hydrophobic

Question 5

what are primers?

Answer 5

dentine conditioners
acids
alter surface appearance and characteristics of dentine

Question 6

what are coupling agents?

Answer 6

primers
act as adhesives
bond hydrophobic composites to hydrophilic dentine

Question 7

what are sealers

Answer 7

resins that flow into dentinal tubules
seals dentine with surface layer rich in methacrylates (base of resin composite also)
ensures bonding to resin in the composite

Question 8

acid opening of tubules risks nano leakage, what is this?

Answer 8

dentine etch greater than resin can penetrate. the dentine microstructure is disrupted leading to failure of the bond.