Removal of cement residue from implant abutment surfaces

Objective: Residues of cement may contribute to peri-implant inflammation, and the chemical makeup and surface composition of excess cement may influence the composition of the peri-implant biofilm. Given the lack of a consensus on the choice of cement for cement retained implant prostheses, this pilot study investigated how well common cements used clinically could be removed during a simulated procedure involving the clean up of excess cement from an implant prosthesis. Methods: Five common cement types (zinc oxide eugenol, zinc phosphate, an implant-specific methacrylate urethane based cement (Premier), resin modified glass ionomer, and resin cement) were applied onto the surface of 10 mm diameter discs of grade IV commercially pure titanium. These had previously been polished to a mirror finish using a sequence of abrasives (CarbiMet 600 grit and fine flour of pumice). Cements were removed by one designated operator either at tacky set, or when fully set, using a stainless steel scaler. Results: Resin cements and resin-modified GIC cements showed excellent adhesion to the titanium surface, and were difficult to remove. In increasing order of ease of removal were zinc oxide eugenol and zinc phosphate cements, followed by the specifically designed methacrylate urethane implant cement. The latter material was the easiest to remove, in both tacky set and fully set states, with the least accompanying surface alteration. Examination of the cleaned surface using backscatter SEM imaging revealed that cement particles remained lodged within the microscopic grooves of the machined surface, due to cohesive failure of the cement. Conclusion: Because resin cements and resin-modified cements adhere strongly and are difficult to remove, caution should be used if considering these for implant prosthesis cementation retention. The three material types that provide mechanical retention only and do not bind chemically were easier to remove from a smooth titanium surface