Effect of Different Torque Values on Marginal Fit of Titanium and Zirconia Abutments with Three Different Connection Designs - A Finite Element Analysis Study

A BSTRACT Context: Limitations during the manufacturing process of two-piece dental implants include microgaps at the implant-abutment interface (IAI) which causes bacterial accumulation. Aim: The aim of this study was to evaluate the effect of abutment material and three different abutment connections on the marginal gap at the IAI. Materials and Methods: 3D finite element analysis (FEA) with DICOM images that are derived from a computerized tomography (CT) of the maxilla and Pro/Engineer Wildfire 2.0 software was used to model three different implant designs, solid tapered implant (Straumann Roxolid SLA), solid tapered (Straumann BLX), solid tapered (Noble replace), and abutments (Titanium and zirconia). A prosthesis made of zirconia was also designed for all three implant designs. The marginal gap in the IAI was analyzed, by applying torque values of 30, 35, and 40 NCm to the prosthetic screw of the abutment. The values were tabulated and subjected to statistical analysis. Results: Results indicated that increasing torque values led to reduced marginal gaps, with mean gaps of 4.10 ± 0.93 μm at 30 Ncm, 3.48 ± 0.84 μm at 35 Ncm, and 3.05 ± 0.87 μm at 40 Ncm, although this reduction was not statistically significant ( P = 0.153). Among the connection types, the Crossfit connection had the smallest marginal gap (2.67 ± 0.57 μm), significantly lower than both the Torcfit (3.41 ± 0.46 μm) and internal hex conical (4.55 ± 0.56 μm) connections ( P < 0.05). The mean marginal gap was 3.37 ± 1.04 μm for titanium and 3.72 ± 0.85 μm for zirconia abutments, a difference that was not statistically significant ( P = 0.439). Conclusion: As the torque is increased, the marginal gap decreases subsequently irrespective of the connection type and abutment material used. The Crossfit implant-abutment connection model with titanium abutment placed had the least marginal gap compared to the other groups.