Factors affecting bonding to human enamel with special reference to a plastic adhesive.

A fter prelim inary screening had indi­ cated that a new plastic bonding agent, Eastman 910 adhesive, m ost nearly m et the requirem ents o f an adhesive fo r clini­ cal application in dentistry, in vitro and in vivo tests w ere carried out with this adhesive. T h e follow ing factors w ere fou nd to be im portant: ( 1 ) the enam el surface must be clean, etch ed with acid and dry; ( 2 ) contact betw een enam el and adherend must be the best obtain ­ able, and ( 3 ) the use of a w aterproof adherend is necessary to p rotect the bond from moisture. M oistu re is the greatest deterrent to a solution o f the problem . N o satisfactory solution was fou nd to the clinical ob jective o f bonding to enam el w ithout m echanical retention.