Senay Canay1, Kvanç Akça. 1. Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, Ankara, Turkey.
Abstract
PURPOSE: To evaluate the effect of diameter shifting at implant-abutment interface on load distribution at periimplant bone and within implant-abutment complex. MATERIALS: Eight different implant-abutment connections were designed and simulated numerically. Implant-abutment microgap at bone level was hypothetically set-off inward toward the central axis of implant to create "diameter shifting" or "platform switching" concept. The conceptual design was further characterized with horizontal set-off distance, emergence angle, and restorative height. A control model of conventional implant-abutment connection with restorative relation was also involved for comparison of developed stresses in periimplant bone and within implant-abutment complex. A 14 mm x 16 mm acrylic cylinder with vertically placed implant-abutment complex was considered for all designs. Principal and Von Mises stresses under vertical and oblique static loading conditions were evaluated numerically and presented descriptively. RESULTS: Stress distribution at periimplant bone was almost identical with similar magnitudes for all designs. Increase in the horizontal set-off distance generated higher stress magnitudes and increased stress intensity within the implant-abutment complex. DISCUSSION: : Platform switching based designs of implant-abutment connections need more mechanical studies to identify the optimum design for long-term mechanical stability. CONCLUSIONS: Relocation of microgap and redefinition implant-abutment connection at bone level does not influence the stress characterization at periimplant marginal bone but may noticeably affect the mechanical properties of the implant-abutment connection.
PURPOSE: To evaluate the effect of diameter shifting at implant-abutment interface on load distribution at periimplant bone and within implant-abutment complex. MATERIALS: Eight different implant-abutment connections were designed and simulated numerically. Implant-abutment microgap at bone level was hypothetically set-off inward toward the central axis of implant to create "diameter shifting" or "platform switching" concept. The conceptual design was further characterized with horizontal set-off distance, emergence angle, and restorative height. A control model of conventional implant-abutment connection with restorative relation was also involved for comparison of developed stresses in periimplant bone and within implant-abutment complex. A 14 mm x 16 mm acrylic cylinder with vertically placed implant-abutment complex was considered for all designs. Principal and Von Mises stresses under vertical and oblique static loading conditions were evaluated numerically and presented descriptively. RESULTS: Stress distribution at periimplant bone was almost identical with similar magnitudes for all designs. Increase in the horizontal set-off distance generated higher stress magnitudes and increased stress intensity within the implant-abutment complex. DISCUSSION: : Platform switching based designs of implant-abutment connections need more mechanical studies to identify the optimum design for long-term mechanical stability. CONCLUSIONS: Relocation of microgap and redefinition implant-abutment connection at bone level does not influence the stress characterization at periimplant marginal bone but may noticeably affect the mechanical properties of the implant-abutment connection.