A new look at repairing fractured metal-ceramic restorations: use of a universal bonding system and resin composite, following sandblasting

The fracture of the ceramic from a metal-ceramic restoration may often lead to an emergency attendance, as previously explained.¹ It is the aim of this technique tip to describe a contemporary method of repairing fractured metal-ceramic restorations using only the Cojet sand included in the Cojet system (3M ESPE) but not the other components. Cojet sand contains 30 micron aluminium oxide particles modified with silicic acid: the metal surface is sandblasted with this at a pressure of 0.25 MPa at a distance of 1 cm, causing the surface to become impregnated with silica. This facilitates a bond to resin composite using a silane. In the illustrated case report, the facing debonded from the bridge pontic. The defective bridge was isolated with rubber dam, the patient was provided with a nosepiece and protective eyewear. After sandblasting the exposed metal surface with Cojet Sand (Figure 1), a Universal adhesive (Scotchbond Universal: 3M) containing both a silane and the resin 10-MDP (originally a constituent of the Panavia series of resin-luting agents which have a demonstrable bond to metal^2,3) was applied and light cured. An alternative bonding agent could be Clearfil Universal (Kuraray), as it also contains 10-MDP and a silane. Whereas the full Cojet kit contains a resin-based opaquer, an alternative may be a dentine shade of resin composite. Accordingly, after application and curing of the bonding agent, a dentine shade was applied in order to mask the metal and the repair was then completed using an enamel shade of resin composite (Filtek Supreme XTE: 3M) (Figure 2).