comparison of shear bond strength of composite to stainless steel crowns using two mechanical surface treatments and two bonding systems

objectives: this study aimed to compare the shear bond strength (sbs) of composite to stainless steel crowns (ssc) using two mechanical surface treatments (msts) and two bonding systems. materials and methods: eighty-four sscs were divided into six groups of 14; group1: no mst+scotchbond universal adhesive (n+u), group 2: surface roughening by a diamond bur+scotchbond universal adhesive (r+u), group 3: sandblasting+scotchbond universal adhesive (s+u), group 4: no mst+alloy primer+clearfil se primer and bond (n+a), group 5: surface roughening by a diamond bur+alloy primer+clearfil se primer and bond (r+a), group 6: sandblasting+alloy primer+clearfil se primer and bond (s+a). after mst and bonding procedure, composite cylinders were bonded to the lingual surface of sscs, then the sbs of composite to sscs was measured using a universal testing machine following thermocycling. results: the sbs of groups r+u and s+u was significantly higher than that of group n+u. no significant difference was noted in sbs of groups r+u and s+u. the sbs of group s+a was significantly higher than that of groups n+a and r+a. no significant difference was noted in the sbs of groups n+a and r+a (p>0.05). conclusions: in scotchbond universal adhesive groups, sandblasting and surface roughening by diamond bur significantly increased the sbs of composite to sscs compared to no mst. in alloy primer groups, sandblasting significantly increased the sbs of composite to ssc compared to surface roughening with diamond bur and no mst.