The aim of this in vitro study was to evaluate the shear bond strengths using six intra-oral repair systems intended for bonding composite resin to alloys. Metal plates were fabricated from Au-Ag, Pd-Ag and Co-Cr alloys. Intra-oral repair systems based on tribochernical silica coating (Cojet), mechanical roughening followed by application of silane (Silistor, Cimara, Ceramic Repair) or functional monomer (Metal Primer 11) were tested for their ability to bond composite resins to the fabricated alloys, whereas functional monomers (Alloy Primer) were used in combination with Cleartil AP-X resin (five specimens each). After thermocycling shear bond strengths according to ISO 10477 and failure modes were assessed. Statistical analysis was carried out with one-way ANOVA and Bonferroni-Dunn's multiple comparisons post hoc analysis (alpha = 0.05). Shear bond strengths exceeding 10 MPa were found for Cojet (Au-Ag 13.0 MPa, Pd-Ag 11.6 MPa and Co-Cr 10.3 MPa with Charisma resin (SD 1.2-2.6 MPa); Au-Ag 19.7 MPa, Pd-Ag 14.6 MPa and Co-Cr 10.3 MPa with Pertac Hybrid resin (SD 5.6-6.3 MPa)) and Alloy Primer (Au-Ag 20.9 MPa, Pd-Ag 15.4 MPa, Co-Cr 25.3 MPa (SD 1.4-3.7 MPa)), regardless of the alloy. Alloy Primer and Cojet exhibited the highest shear bond strengths regardless of the alloy and the repair resin (P < 0.05). Most combinations showed resin-metal interfacial failure modes. (c) Koninklijke Brill NV, Leiden, 2008.