ACID ETCHING

● 37% phosphoric / orthophosphoric acid
● 10-15 second
● Also known as conditioning of dentin.
● While GIC by 10% polyacrylic Acid for 10 seconds.
● White frosted appearance
● Objective ー to increase the surface area and remove smear layer*
● Alterations in time
1. Primary tooth(inorganic content is less)ー 30 Secs
2. Fluorosed tooth ー30 seconds
3. Contaminated tooth, when doing re-etching ー etch for lesser time only ー 10 seconds
● What happens during improper / inadequate acid-etching -- bond of composite weakness ー in turn results in microleakage
● If over dried with air after etch ー causes nano leakage
● The time duration for complete remineralization of accidentally etched tooth- 24hrs
● Read generations for DHA, recent gen etc

Dentine bonding

● 10-15second
● 5th generation – 25 Megapascal
● The strength of bonding enamel 25 MP
● While bonding dentin 35 MP.