L5 : Bonding agents

Question 1

what does acid etching technique do?

Answer 1

produces clean and roughened enamel surface . it produces a durable micromechanical retentive interference of restorative material with tooth structure

Question 2

describe the mechanism of adhesion :

Answer 2

occurs either through chemical attraction or micromechanical interlocking

it works by removing hydroxyapatite particles , forming micropores that are infiltrated by resin forming what is known as resin tags

Question 3

how does acid etching affect the smear layer on enamel when compared with how it affects it on dentine ?

Answer 3

acid etching removed smear layer from dentine completely but removes it from dentine only partially

Question 4

what concentration of phosphoric acid is used in acid etching technique ?

Answer 4

37%(gel)
10-15% solution

Question 5

etched enamel must be____ to form strong bond

Answer 5

completely dry

Question 6

etched dentine must be _____ to form hybrid layer

Answer 6

moist ,

if insufficient water is present then the collagen network will collapse, no hybrid layer

if too much water is present , resin infiltration cannot occur in collagen network

Question 7

what is the purpose of a priming step before etching of dentine ?

Answer 7

make sure the correct amount of water is present

Question 8

how long should etching time be ?

Answer 8

15 seconds

Question 9

moist dentine =hybrid ?

Question 10

what is an example of a primer?

Answer 10

HEMA ( ALSO AN ADHESIVE )

Question 11

Bis-GMA , UDMA , TEGMA are all examples of ?

Answer 11

adhesives

Question 12

what does total etch mean ?

Answer 12

enamel and dentine are etched simultaneously

Question 12

what does total etch mean ?

Answer 12

enamel and dentine are etched simultaneously