Biomechanical repercussions of bone resorption related to biologic width: a finite element analysis of three implant-abutment configurations.

Most biomechanical studies of implant-supported restorations have not taken into account the biologic changes that occur following exposure of the implants to the oral environment. Therefore, the present finite element analysis study was designed to compare the biomechanical response of three types of implant-abutment configurations both before and after establishment of a new biologic width. The three functional units studied were: a 5-mm implant platform connected with an external hexagon to a 5-mm-diameter abutment (type 1), a 5-mm implant platform connected with an external hexagon to a 4.1-mm-diameter abutment (type 2), and a 4.8-mm implant platform connected with an internal hexagon to a 4.1-mm-diameter abutment (type 3). The type 3 design, which combined platform switching with an internal connection, exhibited the smallest distortions in stress distribution after bone modeling, and the stress was distributed over the entire contact surface most smoothly and uniformly. Bone resorption following creation of the biologic width changes the biomechanical behavior of a restoration. In this study, the two implant-abutment designs featuring a smaller-diameter abutment on a larger-diameter implant platform achieved better results than the implant featuring the same-diameter implant platform and abutment, even though their initial bio?mechanical load potential was lower. (Int J Periodontics Restorative Dent 2009;29:479-487.).