A driver tool for threading a first part into a threaded bore of a second part and unthreading the first part from the threaded bore, comprising:

an elongate member having a handle at a first end and a shaft extending from the handle and having a driving end portion of polygonal cross-sectional shape having an outer end face and an outer surface having multiple flats extending up to the outer end face and configured for engagement in a recess in a first part which is of substantially matching polygonal cross-sectional shape;

one or more flats of the driving end portion each having a grabbing feature extending along at least part of the length of the driving end portion from the outer end face, which is configured to engage a respective opposing flat of the recess when the driver is rotated in opposite clockwise and counter-clockwise directions relative to the recess, wherein the grabbing feature is configured to bite into the respective opposing flat of the recess and apply a greater amount of torque to the first part when the driver is rotated in a counter-clockwise, unthreading direction than when it is rotated in a clockwise, threading direction relative to the recess,

wherein each of the one or more flats is formed as a triangular cut in a flat face of the polygonal cross-sectional shape of the driving end portion of the shaft of the elongate member, each cut defining a pair of flat faces angled with respect to the flat face of the polygonal cross-sectional shape of the driving end portion of the shaft of the elongate member and the pair of flat faces forming an angle.

A dental composition, wherein said composition comprises, on a surface of a dental substrate,

a bonding agent; and

a paste mixture, wherein the paste mixture was formed by mixing together a previously separated first part and a second part, and wherein the first part comprises at least one polymerizable monomer and at least one hydroperoxide, wherein the hydroperoxide is Cumene hydroperoxide (CHP); and the second part comprises at least one thiourea compound, wherein the thiourea is 1-(2-Pyridyl)-2-thiourea (PTU); and

wherein the bonding agent comprises 8% to 16% of 10-Methacryloyloxydecyl dihydrogen phosphate (10-MDP); wherein either the first part or second part of the paste mixture further comprises a copper (II) compound, and wherein bond strength of the dental bonding agent on a dental substrate is more than 15 MPa.