Methods used in dentine bonding tests: an analysis of 102 investigations on bond strength

Bond strength testing of resin-based materials to dentine may provide evidence as to the potential effectiveness of a dentine-bonding agent in producing adhesion and minimising microleakage. The purpose of this analysis was to analyse the methods used in 102 recently-published investigations on bond strength tests of resin composite to dentine. One hundred and two papers, published during the years 1998 to 2002 on the subject of bond strength measurement of resin composite to dentine were identified from a literature search. These papers were assessed for their inclusion of the following variables: type of test, thermal cycling regime, tooth notation, storage medium, preparation of dentine surface, rate of load application, type of dentine, film thickness, dimensions of surface area contact and time of testing. Shear testing was the most common type of test, used in 46% (n=47) of the papers analysed, human dentine was used in 77% (n=79) of the investigations, and 24 h post-placement was the predominant time of specimen testing (67%, n=68). Surface area of contact, or specimen diameter, was stated in 65% (n=66) of the papers analysed. A number of variables were not stated in a majority of papers. There was little standardization of test methods and a number of potentially significant variables may not be reported or recorded in bond strength determinations which limit the overall standardization between different test centres.