Bonding Characteristics of Luting Cements to Several Dental Metals by a Newly Developed Tensile Bond Test

Abstract

The bonding characteristics of eight dental luting cements (polycarboxylic acid cement and resin cement : four kinds of each) to dental metals (nonprecious or precious : two kinds respectively) were evaluated by using a newly developed tensile bond test. Tensile bond strength (TBS) to the surfaces of polished dental metals and residual cement areas (%) on the fractured surfaces were measured to evaluate bonding characteristics. TBS to dental metals produced quite different, results, depending on the kind of cement, and the TBS of resin cements were 1.0-26.3 MPa; especially SB cement showed the highest bonding strength to all metals. The TBSs of polycarboxylic acid cements were 0.5-7.1 MPa and were lower than apparently that of resin cements, with the exception of VM. Moreover, the TBSs of glass polyalkenoate cements to two precious metals were unmeasurable by bonding fractured. The TBS of nonprecious metals revealed significantly higher results than that of precious metals. That of cpTi was the highest TBS because of its stable passive oxide layer. The TBS measuring technique used in this study was capable of measuring not only TBS, but also the residual cement area on the fractured surface by means of image analysis. The secondary regression line between TBS and the residual cement area on resin cement was clearly indicated with a high coefficient of relationship (r²=0.78). These results suggest that bonding characteristics should be evaluated both by TBS and by quantitative analysis of the fractured surface as residual cement.