Mechanical Resistance of Implant-Supported Crowns with Abutments Exhibiting Different Margin Designs

Background: Modern dentistry demands accurate finish line designs for abutments. CAD/CAM systems enable the fabrication of thin prosthetic structures to fulfill this requirement. The aim of this study is to research the mechanical resistance of customized implant abutments with different types of marginal design in laboratory environment. The null hypothesis is there is no difference in fatigue loading and compression strength in custom implant abutments with chamfer or vertical marginal design. Methods: The study model includes 60 specimens of implant suprastructures, organized into four test groups, by the margin design and used material: Group A—suprastructures, made of monolithic zirconia implant crown and titanium custom abutment with vertical marginal design; Group B—suprastructures, monolithic lithium disilicate implant crown and titanium custom abutment with vertical marginal design; Group C—suprastructures, made of monolithic zirconia implant crown and titanium custom abutment with chamfer marginal design; and Group D—suprastructures, made of monolithic lithium disilicate implant crown and titanium custom abutment with chamfer marginal design. All samples were subjected to fatigue loading test in chewing Simulator CS-4 (SD-Mechatronik, Westerham, Germany) for 1250,000 cycles, at a frequency of 2 Hz. The specimens, which survived, was conducted to compressive strength test in universal testing machine Instron M 1185 (Instron, Norwood, MA, USA). Results: The results analysis highlighted Group A as the most resistant to compressive forces (4411 MPa). Group D was with lowest values (1864 MPa)—twice than Group A. Group B (3314 MPa) had lower results than Group A, but higher than Groups C (3130 MPa) and D. Conclusion: Compression strength significantly depends on the choice of marginal design of implant abutments. Vertical margin design has better performance, that chamfer one.