Shear Bond Strength of a Veneering Resin to a Ni-Cr Alloy Using Two Different Surface Treatment Methods

Statement of problems: a strong and stable bond between veneering materials andmetal framework considerably promotes the aesthetic appearance and clinicallongevity of a resin type restoration. various adhesive metal primers have also beenstudied to enhance the bond strength of the composite resins to different metalsurfaces.purpose: the purpose of the present study was to evaluate the shear bond strength ofone laboratory composite resin bonded to a ni–cr alloy by means of two differentmethods.materials and methods: in this study, 24 wax disks were cast and divided into twoequal groups. in the first group, a metal primer was applied to the casting surface,while an opaque porcelain material was used for the second group. after applicationof the veneering composite resin to the treated surfaces, the specimens were stored ina 37ºc water bath for 15 days. at the end of this period, all the specimens weresubjected to 1200 thermal cycles (5ºc and 55 oc) and then tested for shear strengthin a universal testing machine at a crosshead speed of 0.5 mm/min. fracturedspecimens were examined, using a scanning electron microscope.results: the opaque porcelain group demonstrated higher bond strength (17.55±3.33mpa) in comparison to the metal primed surface (15±4.25 mpa). however, nostatistically significant difference was found between the specimens treated withmetal primer and those treated with opaque porcelain. the two alloy surfacetreatments exhibited mixed failures, however. while the nature of failure for opaqueporcelain was predominately cohesive, the failure for the metal primed group wasadhesive.conclusion: it can be concluded that both techniques have potential to significantlyimprove resin–alloy shear bond strength.