METHODS	After removal of residual sealer with an alcoholmoistened foam pellet , different pretreatments were performed : groups 1 and 5 : no further pretreatment ; groups 2 and 6 : use of a water cooled high-speed diamond bur ; groups 3 and 7 : etch-and-rinse with 37 % H3PO4 for 10 s ; groups 4 and 8 : diamond bur and etching .\