The bond strength of SB ( 5 s : 15.5 MPa + / - 4.4 ; 15 s : 16.5 MPa + / - 3.1 ; 30 s : 16.8 MPa + / - 3.2 ) and OS ( 5 s : 13.7 MPa + / - 1.8 ; 15 s : 12.4 MPa + / - 3.8 ; 30 s : 10.6 MPa + / - 3.8 ) showed no significant differences ( p < 0.05 ) for the different etching times .
