Purpose This in-vitro study compared the effect of implant abutment modification on cement extrusion at the crown-abutment margin using CAD/CAM replicas. Materials and Methods Seventy-five standardized 3D-printed abutments (4° TOC, 7 mm height) and copings were designed using TinkerCAD™ and printed with Elegoo ABS™ resin on an Elegoo Saturn™ Printer (Elegoo™, Shenzhen, China). Abutments were divided into five groups (n=15 each): (1) Closed Abutment (CLA)—screw access channel filled with Filtek™ Universal Restorative (3M ESPE™, St. Paul, MN, USA); (2) Open Abutment (OA)— open screw access channel with PTFE tape over the screw head; (3) Internal Vented Abutment (IVA)—similar to OA but with two 1.5-mm vent holes; (4) Cone Abutment (COA)—internal cone design; and (5) Internal Vented Cone Abutment (IVCA)— combining IVA and COA features. Vertical reference marks (5 mm) were placed to ensure proper orientation. Cementation was performed using TempBond™ NE cement (Kerr™, Orange, CA, USA), mixed per manufacturer instructions and loaded into a 1.2-ml fine-tip syringe (Ultradent™, South Jordan, UT, USA). Copings were fully filled with cement and seated onto the abutments under 5 kg of force using a calibrated spring compression device for 10 minutes. Each abutment-coping assembly (CAA) was weighed before cementation (CAA weight) using a Sartorius™ analytical balance (Model GD 503, Sartorius AG™, Göttingen, Germany). Post-setting, assemblies were weighed before (pre-cement removal weight) and after excess cement removal (post-cement removal weight) using a graphite scaler and Orange Solvent™ (EP Industries™, West Yorkshire, UK). Cement retention was calculated as pre-cement removal weight minus postcement removal weight, while total cement loaded was determined as pre-cement removal weight minus CAA weight. The percentage of extruded cement was derived from these values. Results Cement extrusion was highest for CLA and lowest for IVCA (IVCA < OA < IVA < COA < CLA), with statistically significant differences (P < 0.05). Conclusions Within the parameters of our study, the following conclusions are made: • Modifying the abutment design significantly affects the retained cement within the abutment. • Incorporating a vent, cone or both into the abutment design significantly reduces the amount of extruded cement when using TempBond NE cement.
Nouf S. AlShaalan (Sat,) studied this question.