Mechanical stability and technical outcomes of monolithic CAD/CAM fabricated abutment‐crowns supported by titanium bases: An in vitro study

Objectives To evaluate mechanical stability (survival and complication rates) and bending moments of different all‐ceramic monolithic restorations bonded to titanium bases (hybrid abutment‐crowns) or to customized titanium abutments compared to porcelain‐fused‐to‐metal crowns (PFM) after thermo‐mechanical aging. Material and Methods Sixty conical connection implants (4.3 mm‐diameter) were divided in five groups (n = 12): PFM using gold abutment (GAbut‐PFM), lithium disilicate crown bonded to customized titanium abutment (TAbut+LDS), lithium disilicate abutment‐crown bonded to titanium base (TiBase+LDS), zirconia abutment‐crown bonded to titanium base (TiBase+ZR), polymer‐infiltrated ceramic‐network (PICN) abutment‐crown bonded to titanium base (TiBase+PICN). Simultaneous thermocycling (5°–55°C) and chewing simulation (1,200,000‐cycles, 49 N, 1.67 Hz) were applied. Catastrophic and non‐catastrophic events were evaluated under light microscope, and survival and complication rates were calculated. Specimens that survived aging were loaded until failure and bending moments were calculated. Results Survival rates after aging were 100% (TAbut+LDS, TiBase+LDS), 91.7% (GA‐PFM), 66.7% (TiBase+ZR) and 58.3% (TiBase+PICN) and differed among the groups (p = .006). Non‐catastrophic events as screw loosening (GA‐PFM) and loss of retention or micro‐/macro‐movement (TiBase groups) were observed. Complication rates varied among the groups (p