<prompt> Average bond strength of second generation dentin bonding agents:2-5 MPA12-18 MPA20-23 MPA25-30 MPA  <response>: SECOND GEN - Contains halophosphorus esters of unfilled resins.Mechanism of bonding Is by ionic bond to calcium by chlorophosphate groups.Eg: scotchbond, bondlite. Disadvantages: Again poor bond strength 2-5 MPA. Hydrolysis of bond. Bonds to smear layer. Reference-Sturdevant 6th ed Pg: 116 