Debonding Forces for Two-Piece Zirconia Abutments with Implant Platforms of Different Diameter and Use of Different Luting Strategies

Purpose: The forces needed to detach zirconia copings from titanium inserts of two-piece abutments were evaluated for implant platforms of different diameters (4.8 and 6.5 mm) and different luting strategies. Materials and Methods: Eight specimens (four for each platform diameter) were prepared to simulate two-piece zirconia implant abutments with prefabricated titanium inserts and computer-aided design/ computer-aided manufactured (CAD/CAM) zirconia copings. Half of the copings were luted to their titanium inserts by use of composite cement; the others were luted after additional bonding treatment of the titanium and zirconia surfaces. All specimens were subjected to tensile forces up to failure. Samples were used with or without artificial aging. Each specimen was luted and subsequently debonded 12 times; thus, a total of 96 tests were conducted. Results: All debonding forces exceeded approximately 600 N. Larger platform diameters (P .001) and additional bonding treatment (P = .021) resulted in significantly better retention; artificial aging had no effect (P = .165). Conclusion: Forces for debonding of titanium bases from zirconia abutments were favorable. The use of these abutments might be a viable prosthetic treatment option in specific clinical cases. Keywords: debonding forces, implant, titanium, zirconia abutment